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1.
Clin Neurol Neurosurg ; 246: 108548, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39278008

RESUMEN

BACKGROUND: Percutaneous balloon compression (PBC) is widely used to treat trigeminal neuralgia due to its significant efficacy and low treatment cost. However, there is considerable variation in postoperative pain recurrence among patients. Currently, the factors influencing pain recurrence after PBC are under discussion. This study aims to explore the impact of individual patient parameters and surgical parameters on postoperative pain recurrence following PBC. The goal is to provide clinicians with a reference for preoperative assessment of pain recurrence risk and to offer insights for effectively intervening in controllable influencing parameters. METHODS: A analysis was conducted on 114 patients who underwent PBC in the Department of Neurosurgery at Hebei General Hospital. Univariate Kaplan-Meier analysis and multivariate Cox regression analysis were performed on the general and surgical data of the patients to identify factors potentially associated with postoperative pain recurrence. RESULTS: The results of the multivariate Cox regression analysis showed that a history of hypertension, MRI indicating trigeminal nerve compression and a non-ideal pear-shaped balloon were statistically significant factors for pain recurrence after PBC. Additionally, the guidewire path during the procedure had a statistically significant impact on the rate of achieving a pear-shaped balloon (P<0.05). CONCLUSION: A history of hypertension, MRI indicating trigeminal nerve compression and a non-ideal pear-shaped balloon shape are independent risk factors for pain recurrence after PBC. Additionally, to avoid pain recurrence due to an unfavorable balloon shape, it is recommended to use 3D-slicer for preoperative guidewire path simulation and 3D reconstruction of Meckel's cavity.

2.
Environ Pollut ; 361: 124886, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39245203

RESUMEN

Thermal power plants serve as significant CO2 sources, and accurate monitoring of their emissions is crucial for improving the precision of global carbon emission estimates. In this study, a measurement method based on measuring point source plumes was employed in ground-based remote sensing experiments at the thermal power plant. By simulating CO2 plumes, we analyzed the impact of surrounding urban structures, the geometric relationship between measurement points and plumes, and the influence on measurement points selection. We also assessed the capability and uncertainties in quantifying CO2 emissions. For the Hefei power plant, CO2 emission estimates were on average 7.98 ± 10.01 kg/s higher with surface buildings compared to scenarios without buildings (approximately 4.09% error). By selectively filtering discrete data, the emission estimation errors were significantly reduced by 7.31 ± 7.13 kg/s compared to pre-filtered data. Regarding the relationship between observation paths and plume geometry, simulation studies indicated that the ability to estimate CO2 emissions varied for near and middle segment observations. The lowest emission rate error was found in the mid-segment near 1.5-2.0 km, reaching 7.13 ± 5.39 kg/s. CO2 distribution at the mid-segment position becomes more uniform relative to the near segment, making it more suitable for meeting emission estimation requirements. Optimizing measurement schemes by considering environmental factors and precisely selecting measurement points significantly enhances emission estimation accuracy, providing crucial technical support for top-down estimates of anthropogenic CO2 emissions.

3.
Neurosurg Rev ; 47(1): 605, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39269622

RESUMEN

BACKGROUND: The neurovascular conflict (NVC) at the brainstem exit zone of the facial nerve is considered the primary etiology of primary hemifacial spasm (HFS). Therefore, microvascular decompression (MVD) has become the preferred treatment for HFS. Successful neurovascular decompression can achieve significant therapeutic effects, and accurately identifying the site of compression is crucial for the success of this surgery. Detailed diagnostic neuroimaging plays an important role in accurately identifying the site of compression.The purpose of this study is to explore the feasibility and predictive value of preoperative visualization assessment of the neurovascular relationship in HFS using 3D Slicer software based on multimodal imaging fusion. This aims to reduce the omission of responsible vessels and lower the incidence of postoperative complications, thereby potentially improving the efficacy and safety of the surgery. METHODS: This study retrospectively analyzed 80 patients with HFS who underwent MVD surgery. All patients underwent preoperative cranial MRI scans, including the 3D-FIESTA and the 3D-TOF MRA sequences. Three-dimensional models were reconstructed from the multimodal MRI images using 3D Slicer software. Independent observers, who were blinded to the surgical outcomes, evaluated the neurovascular relationships using both the three-dimensional models and multimodal MRI images. The assessment results were compared with intraoperative findings, and statistical analysis was conducted using SPSS 22.0 software. RESULTS: The agreement between preoperative assessment using the 3D-TOF MRA sequence combined with the 3D-FIESTA sequence and intraoperative findings was represented by a Kappa value of 0.343, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.637. There was a statistically significant difference between the two methods ( X2 = 18.852, P = 0.001 ). The sensitivity and specificity of the 3D-TOF MRA sequence combined with the 3D-FIESTA sequence for evaluating neurovascular relationships were 92.4% and 100%, respectively, while for three-dimensional reconstruction, both were 100%. The Kappa value for agreement between preoperative the 3D-TOF MRA sequence combined with the 3D-FIESTA sequence prediction of offending vessels and intraoperative findings was 0.625, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.938, showing a statistically significant difference ( X2 = 317.798, P = 0.000 ). The Kappa value for agreement between preoperative the 3D-TOF MRA sequence combined with the 3D-FIESTA sequence assessment of the anatomical location of facial nerve involvement in neurovascular compression and intraoperative findings was 0.608, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.918, also showing a statistically significant difference ( X2 = 504.647, P = 0.000 ). CONCLUSIONS: The preoperative visualization assessment of neurovascular relationships in HFS using 3D Slicer software based on multimodal imaging fusion has been demonstrated to be reliable. It is more accurate than combining the 3D-TOF MRA sequence with the 3D-FIESTA sequence and shows higher consistency with intraoperative findings. This method provides guidance for surgical procedures and thereby potentially enhances the efficacy and safety of surgeries to a certain extent.


Asunto(s)
Espasmo Hemifacial , Imagen por Resonancia Magnética , Cirugía para Descompresión Microvascular , Imagen Multimodal , Humanos , Espasmo Hemifacial/cirugía , Femenino , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Cirugía para Descompresión Microvascular/métodos , Adulto , Imagen Multimodal/métodos , Anciano , Imagen por Resonancia Magnética/métodos , Nervio Facial/cirugía , Nervio Facial/diagnóstico por imagen , Cuidados Preoperatorios/métodos , Resultado del Tratamiento , Imagenología Tridimensional/métodos
4.
Clin Neurol Neurosurg ; 243: 108387, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38924844

RESUMEN

BACKGROUND: 3D-Slicer is an open-source medical image processing and visualization software. In the surgical treatment of trigeminal neuralgia, it is commonly used to predict the responsible vessels. However, there are few reports on the use of 3D-Slicer software to quantitatively measure the bilateral trigeminal nerve volume in patients with primary trigeminal neuralgia (PTN) based on the three-dimensional images. Therefore, this study aims to explore the role of three-dimensional fused images processed by 3D-Slicer in the evaluation of trigeminal nerve atrophy, providing an objective basis for the diagnosis of PTN. METHODS: 57 PTN patients who underwent microvascular decompression (MVD) or percutaneous balloon compression (PBC) surgery in Hebei general hospital between January 2020 and April 2023 were included. Additionally, 30 patients with facial spasms(HFS) were included as a control group. All patients underwent 3D-TOF-MRA and 3D-FIESTA sequence examinations. Comparisons of bilateral trigeminal nerve volumes within and between groups were conducted by performing image fusion using 3D-slicer. RESULTS: The volume of the affected trigeminal nerve in the MVD group (33.96 mm³±12.61 mm³) and PBC group (23.05 mm³±7.71 mm³) was smaller than that of the unaffected trigeminal nerve in the MVD group (39.61 mm³±12.83 mm³) and PBC group (26.14 mm³±6.42 mm³), as well as the average volume of the trigeminal nerve in the control group (40.27 mm³±10.25 mm³) (P<0.05). The differences in bilateral trigeminal ganglion volume (∆V) was significant between the MVD group (∆V=23.59 %±14.32 %) and the control group (∆V=14.64 %±10.00 %) (P<0.05). There was no statistical difference in the trigeminal nerve volume difference between the MVD group (∆V=23.59 %±14.32 %) and the PBC group (∆V=26.52 %±15.00 %) (P>0.05). CONCLUSION: Trigeminal nerve atrophy is correlated with primary trigeminal neuralgia. 3D-slicer software can quantitatively measure trigeminal nerve volume and assist in the diagnosis of primary trigeminal neuralgia based on the difference in bilateral trigeminal nerve volumes. However, trigeminal nerve atrophy is not associated with postoperative pain recurrence in patients.


Asunto(s)
Atrofia , Cirugía para Descompresión Microvascular , Imagen Multimodal , Nervio Trigémino , Neuralgia del Trigémino , Humanos , Neuralgia del Trigémino/cirugía , Neuralgia del Trigémino/diagnóstico por imagen , Femenino , Masculino , Persona de Mediana Edad , Nervio Trigémino/diagnóstico por imagen , Nervio Trigémino/patología , Nervio Trigémino/cirugía , Estudios Retrospectivos , Anciano , Atrofia/patología , Cirugía para Descompresión Microvascular/métodos , Imagen Multimodal/métodos , Adulto , Imagenología Tridimensional/métodos
5.
Appl Opt ; 62(22): 5839-5849, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37706932

RESUMEN

The greenhouse gas monitoring instruments were carried on the Gaofen-5-II satellite, which was launched into orbit from the Taiyuan Satellite Launch Center on September 7, 2021. In order to improve the on-orbit data quantification level, a calibration device based on diffuse reflector system was designed, which can realize on-orbit spectral and radiation calibration. In this paper, the principle of standard spectral line selection is given, and the characteristic spectral lines that can be used for on-orbit spectral calibration are extracted. The wavelength deviation evaluation function is established by using the method of matching the high-resolution reference spectrum after the linear function of the convolution instrument with the on-orbit calibration measurement spectrum, and finally using the Levenberg-Marquardt algorithm to evaluate the function. The optimization solution is the on-orbit wavelength calibration result. According to the above method, the on-orbit calibration data are processed. After calibration, the maximum deviation of the on-orbit spectral offset is changed from 0.133 to 0.009c m -1, and variations in magnitude less than 10% of the spectral resolution for C O 2 (1.57 µm) band have been detected.

6.
Altern Ther Health Med ; 29(8): 352-355, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37632961

RESUMEN

Objective: To explore the diagnostic value of blink reflex combined with trigeminal somatosensory evoked potential (TSEP) in trigeminal neuralgia. Methods: A total of 147 patients with trigeminal neuralgia were enrolled as the research objects between February 2022 and February 2023. After admission, all underwent blink reflex on affected/healthy sides and TSEP examinations. The diagnostic value of the blink reflex combined with TSEP was analyzed. Results: The latency of R1, R2, and R2' waves (refers to the different nerve signal waveforms that are recorded when a facial nerve conduction speed test is performed) on the affected side was significantly longer than that on the healthy side (t = 26.324, 18.391, 20.801,Ps < .001), and latency of W1, W2 and W3 waves was also significantly longer than that on the healthy side (t = 16.045, 10.814, 10.349, P < .001). The results of Pearson correlation analysis showed that the latency of R1, W1, W2, and W3 waves was positively correlated with the VAS score (r = 0.539, 0.611, 0.577, 0.586, P < .001). The results of receiver operating characteristic (ROC) curves analysis showed that area under the curve (AUC) values of R1, R2, R2', W1, W2, and W3 waves latency on the affected side in the diagnosis of trigeminal neuralgia were 0.753, 0.634, 0.651, 0.748, 0.756 and 0.736, respectively. The AUC of combined detection was 0.926, significantly greater than that of the single index (P < .001). Conclusion: Blink reflex combined with TSEP monitoring can improve the diagnostic value of trigeminal neuralgia, and the latency is related to pain.


Asunto(s)
Neuralgia del Trigémino , Humanos , Neuralgia del Trigémino/diagnóstico , Nervio Trigémino/fisiología , Parpadeo , Potenciales Evocados Somatosensoriales , Dolor
7.
J Plast Reconstr Aesthet Surg ; 85: 210-216, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37524033

RESUMEN

OBJECTIVE: To investigate the application value of calcium phosphate cement (CPC) in repairing cranial defects during microvascular decompression (MVD) surgery via the retrosigmoid approach. METHODS: A retrospective study was carried out on patients who underwent MVD. According to the two different cranial reconstruction methods, patients were divided into a titanium mesh (TM) group and a CPC group. We compared in the two groups the length of postoperative hospital stay, the incidence of postoperative cerebrospinal fluid (CSF) leakage, the number of patients with suspected postoperative intracranial infection who underwent lumbar puncture, the number of patients with a definitive etiologic diagnosis of intracranial infection, and the imaging evaluation of plastic shape satisfaction. RESULTS: Patients in the CPC group had an average hospital stay of 9.15 ± 2.00 days, shorter than that in the TM group (10.69 ± 2.86 days), P < 0.001. In the TM group, the rate of plasticity satisfaction was 70/89 (78.65%), which was significantly lower than that in the CPC group (60/66, 90.91%), P = 0.040. Among the patients with a definitive etiologic diagnosis of intracranial infection, there were eight cases in the TM group and one case in the CPC group, and the difference was statistically significant, P = 0.049. CONCLUSIONS: CPC is another viable alternative for complete cranial reconstructions of microvascular decompression craniectomies. The use of CPC does not increase the incidence of postoperative complications, such as CSF leakage and intracranial infection, and can reduce the average length of hospital stay and the incidence of etiologic diagnosis of intracranial infection. Furthermore, the evaluation of the plastic shape is satisfactory.


Asunto(s)
Cirugía para Descompresión Microvascular , Humanos , Estudios Retrospectivos , Craneotomía/métodos , Cráneo/cirugía , Complicaciones Posoperatorias/epidemiología , Cementos para Huesos/uso terapéutico , Pérdida de Líquido Cefalorraquídeo/epidemiología , Pérdida de Líquido Cefalorraquídeo/cirugía , Fosfatos de Calcio/uso terapéutico
8.
Hereditas ; 160(1): 29, 2023 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-37349788

RESUMEN

BACKGROUND: Glioma stem cells (GSCs) are responsible for glioma recurrence and drug resistance, yet the mechanisms underlying their maintenance remains unclear. This study aimed to identify enhancer-controlled genes involved in GSCs maintenance and elucidate the mechanisms underlying their regulation. METHODS: We analyzed RNA-seq data and H3K27ac ChIP-seq data from GSE119776 to identify differentially expressed genes and enhancers, respectively. Gene Ontology analysis was performed for functional enrichment. Transcription factors were predicted using the Toolkit for Cistrome Data Browser. Prognostic analysis and gene expression correlation was conducted using the Chinese Glioma Genome Atlas (CGGA) data. Two GSC cell lines, GSC-A172 and GSC-U138MG, were isolated from A172 and U138MG cell lines. qRT-PCR was used to detect gene transcription levels. ChIP-qPCR was used to detect H3K27ac of enhancers, and binding of E2F4 to target gene enhancers. Western blot was used to analyze protein levels of p-ATR and γH2AX. Sphere formation, limiting dilution and cell growth assays were used to analyze GSCs growth and self-renewal. RESULTS: We found that upregulated genes in GSCs were associated with ataxia-telangiectasia-mutated-and-Rad3-related kinase (ATR) pathway activation, and that seven enhancer-controlled genes related to ATR pathway activation (LIN9, MCM8, CEP72, POLA1, DBF4, NDE1, and CDKN2C) were identified. Expression of these genes corresponded to poor prognosis in glioma patients. E2F4 was identified as a transcription factor that regulates enhancer-controlled genes related to the ATR pathway activation, with MCM8 having the highest hazard ratio among genes positively correlated with E2F4 expression. E2F4 bound to MCM8 enhancers to promote its transcription. Overexpression of MCM8 partially restored the inhibition of GSCs self-renewal, cell growth, and the ATR pathway activation caused by E2F4 knockdown. CONCLUSION: Our study demonstrated that E2F4-mediated enhancer activation of MCM8 promotes the ATR pathway activation and GSCs characteristics. These findings offer promising targets for the development of new therapies for gliomas.


Asunto(s)
Glioma , Humanos , Glioma/genética , Glioma/metabolismo , Factores de Transcripción/metabolismo , Proliferación Celular/genética , Células Madre Neoplásicas/metabolismo , Proteínas de Mantenimiento de Minicromosoma/metabolismo , Factor de Transcripción E2F4/metabolismo , Proteínas Asociadas a Microtúbulos , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo
9.
Altern Ther Health Med ; 29(3): 43-47, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36881536

RESUMEN

Objective: This study aimed to compare the clinical outcomes of a modified microvascular decompression (MVD) with a traditional MVD in hemifacial spasm. Methods: A tota1 of 120 patients with hemifacial spasm who received a modified MVD (modified MVD group) and 115 patients who received a traditional MVD (traditional MVD group) from January 2013 to March 2021 were retrospectively reviewed. The surgery efficiency rate, surgery time and postoperative complications in both groups were recorded and analyzed. Results: There was no significant difference between the 2 groups regarding surgery: efficiency rate (modified MVD group VS traditional MVD group: 92.50% vs 92.17%, respectively; P = .925). The intracranial surgery time and postoperative complications rate in the modified MVD group were significantly lower than in the traditional MVD group (31.00 ± 1.78 min vs 48.00 ± 1.74 min, respectively; P < .05; 8.33% vs 20.87%; P = .006, respectively). There was no statistical difference between open skull time and close skull time between the 2 groups (modified MVD group vs traditional MVD group: 38.50 ± 1.76 min vs 40.00 ± 1.78 min, respectively; P = .055; 38.50 ± 1.76 min vs 36.00 ± 1.78 min, respectively; P = .086). Conclusion: The modified MVD for hemifacial spasm can achieve satisfactory clinical outcomes and reduce intracranial surgery time and postoperative complications.


Asunto(s)
Espasmo Hemifacial , Cirugía para Descompresión Microvascular , Humanos , Espasmo Hemifacial/cirugía , Espasmo Hemifacial/complicaciones , Resultado del Tratamiento , Estudios Retrospectivos , Cirugía para Descompresión Microvascular/efectos adversos , Complicaciones Posoperatorias/prevención & control , Complicaciones Posoperatorias/cirugía , Pérdida de Líquido Cefalorraquídeo/complicaciones , Pérdida de Líquido Cefalorraquídeo/cirugía
10.
Opt Express ; 31(2): 3028-3045, 2023 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-36785303

RESUMEN

Interference data obtained by a spatial heterodyne spectrometer (SHS) is subject to various error factors and suffers from complex phase distortion. Traditional phase correction methods, such as the Amplitude, Merzt, and Forman methods, extract phase distortion in the spectral domain and correct it, which cannot effectively correct spatial phase distortion. Through theoretical derivation and numerical simulation, the spatial phase distortion is firstly determined and corrected in the interference domain. The frequency-dependent phase distortion is then extracted in the spectral domain and corrected. This novel phase distortion correction method named the phase decomposition method was applied to the in-orbit interference data of Greenhouse gases Monitoring Instrument-II (GMI-II). Compared with traditional phase correction methods, the root-mean-square error of the spectrum corrected using the phase decomposition method is reduced by 81.37%.

11.
Clin Neurol Neurosurg ; 217: 107241, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35429853

RESUMEN

BACKGROUND: To compare the diagnostic accuracy of 3D fast imaging employing steady-state acquisition (FIESTA) combined with 3D-time-of-flight (TOF) MR angiography (MRA) sequences (FTMS) and 3D-reconstuction synthesized by 3D-slicer program in evaluation the neurovascular relationships and offending vessels preoperatively in patients with hemifacial spasm (HFS). METHODS: Clinical data of HFS patients who underwent microsurgical vascular decompression (MVD) were analyzed. All patients underwent MRA scans with FTMS and 3D-reconstruction before surgery. The neurovascular relationship and offending vessels were evaluated and compared with intraoperative findings. RESULTS: Forty patients were included in this study, 18 (45%) of them were male. The mean age was 49.6 years. The Kappa identity tests identified the agreement between the FTMS and intraoperative findings in evaluating the neurovascular relationship and offending vessel was 0.263 and 0.643, respectively. The agreement between the 3D-reconstruction and intraoperative findings was 0.633 and 0.921 respectively. There was borderline significant difference between the two methods in predicting neurovascular relationship (χ2 = 9.363, P = 0.053), and there were significant differences between the two methods in predicting offending vessels (χ2 = 188.408, P < 0.001). The sensitivity and specificity of FTMS in evaluating the neurovascular relationship were 89.7% and 100%, respectively, while those with 3D-reconstruction were both 100%. Moreover, the correct 3D- reconstruction examinations in predicting vessel and nerve relationships (r = 0.634, P = 0.034) and offending vessels (r = 0.652, P = 0.028) were significantly correlated with completely symptoms remission. CONCLUSIONS: The 3D-reconstuction synthesized by 3D-slicer program was more accurate than FTMS in preoperative evaluation of neurovascular relationship and offending vessel. The technique is expected to be helpful in preoperative evaluation. AVAILABILITY OF DATA AND MATERIAL: The dataset used and/or analyzed during the current study are available from the corresponding author on reasonable request.


Asunto(s)
Espasmo Hemifacial , Cirugía para Descompresión Microvascular , Descompresión , Femenino , Espasmo Hemifacial/diagnóstico por imagen , Espasmo Hemifacial/cirugía , Humanos , Imagenología Tridimensional/métodos , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/métodos , Sensibilidad y Especificidad , Resultado del Tratamiento
12.
Appl Opt ; 60(22): 6614-6622, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-34612904

RESUMEN

Considering the distribution characteristics of interference data of a temporally and spatially modulated spatial heterodyne interference imaging spectrometer, an algorithm based on spatial dimension baseline of interference data for the detection and correction of invalid data is proposed. The intensity ratio of the target interference data far away from the zero optical path difference has been extracted and calculated, and the intensity of the interference data is compensated; the baseline of the compensated interference data is carried out along the spatial dimension direction, and the deviation matrix is calculated, and combined with the 3σ method for the detection and correction of invalid data. A simulation experiment is carried out in the laboratory to obtain the target push-sweep imaging interference data, and the spectrum is the output spectrum of the integrating sphere halogen tungsten lamp. The experimental results show that the invalid data in the interference data (including invalid data near zero optical path difference) can be effectively identified and corrected using the invalid data detection and correction algorithm described in this paper, which has a good effect on the correction of fixed invalid data and flash pixel.

13.
Appl Opt ; 58(21): 5602-5611, 2019 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-31503860

RESUMEN

OH radicals in the upper and middle atmosphere are important oxidants and play an important role in atmospheric photochemistry. A hyper-resolution spectrometer based on 308 nm glow was developed for obtaining OH radical concentration data in the upper and middle atmosphere. In order to verify the performance of the OH radical hyper-resolution spectrometer, several comprehensive ground experiments were carried out in this paper. The spectrometer observes OH radicals produced by a photochemistry reactor chamber to verify the detection ability of the instrument for characteristic signals. A solar observation experiment is used to evaluate the hyper-resolution spectroscopic ability of the spectrometer and the on-orbit field-of-slice-view function. In order to evaluate the detection ability of weak atmospheric background radiation, the experimental study of solar scattering light observation was carried out. The experimental results show that the spectrometer has the characteristics of ultrahigh spectral resolution (0.0086 nm), high sensitivity, and high signal-to-noise ratio. The ground observation results are consistent with the theoretical simulation values.

14.
Appl Opt ; 57(34): 10009-10016, 2018 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-30645253

RESUMEN

Greenhouse gas monitoring instruments (GMI) are spatial heterodyne spectroscopy (SHS) sensors that monitor greenhouse gases (GHG) from space. Due to several kinds of polarization-sensitive optical elements in GMIs, to some extent, the instrument becomes a polarization-sensitive sensor. Its polarization sensitivity will reduce the radiometric accuracy and spectral inversion accuracy of GHG column concentration. Theoretical radiation response models for analyzing the polarization sensitivity of a GMI, which is mainly affected by a scanning mirror beam splitter and diffraction gratings, are presented in this paper. Based on these models and the polarization performance testing, the theoretical and experimental results of the main spectral band of a GMI, covering the wavelength range of 1.568-1.583 µm for carbon dioxide (CO2) detection, have been given. The result shows that the linear polarization sensitivity is less than 0.65% and 1.32% in the nadir (45°, 0°) and in the oblique view direction (45±20°, ±31°), respectively, and that it meets the qualification requirement for an absolute radiometric calibration accuracy better than 5%. The absolute radiometric calibration accuracy directly affects the accuracy of GHG concentration retrieval.

15.
Appl Spectrosc ; 72(1): 151-158, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28627233

RESUMEN

Raman spectroscopic detection is one of the suitable methods for the detection of chemical warfare agents (CWAs) and simulants. Since the 1980s, many researchers have been dedicated to the research of chemical characteristic of CWAs and simulants and instrumental improvement for their analysis and detection. The spatial heterodyne Raman spectrometer (SHRS) is a new developing instrument for Raman detection that appeared in 2011. It is already well-known that SHRS has the characteristics of high spectral resolution, a large field-of-view, and high throughput. Thus, it is inherently suitable for the analysis and detection of these toxic chemicals and simulants. The in situ and standoff detection of some typical simulants of CWAs, such as dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), triethylphosphate (TEP), diethyl malonate (DEM), methyl salicylate (MES), 2-chloroethyl ethyl sulfide (CEES), and malathion, were tried. The achieved results show that SHRS does have the ability of in situ analysis or standoff detection for simulants of CWAs. When the laser power was set to as low as 26 mW, the SHRS still has a signal-to-noise ratio higher than 5 in in situ detection. The standoff Raman spectra detection of CWAs simulants was realized at a distance of 11 m. The potential feasibility of standoff detection of SHRS for CWAs simulants has been proved.

16.
Appl Opt ; 56(12): 3531-3537, 2017 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-28430223

RESUMEN

The Doppler asymmetric spatial heterodyne (DASH) interferometer provides the capability to retrieve wind speed in the upper atmosphere. The data processing leads to a significant retrieving error with the development of wind precision. The influence of window parameters on the isolated interferogram is analyzed theoretically. Based on the derivation, the system is established, and the interferogram with a small shift is sampled. The phase and wind speed are calculated under various window types and window width values. We conclude that, by choosing the Nuttall window with a small width, the wind retrieving error can be minimized.

17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 37(3): 933-8, 2017 Mar.
Artículo en Chino, Inglés | MEDLINE | ID: mdl-30160442

RESUMEN

It can't satisfy the requirement of correction for response non-uniformity at systematic levelif only if the array detector for spatial heterodyne spectrometer is corrected. Traditional methods, such as irradiation with uniform source and column-flat-fielding, are not suitable for spatial heterodyne spectrometer. The article expounds convection arm-blocking method for spatial heterodyne spectrometer briefly at first. This method leads to kinds of mismatches including pixel and sub-pixel level shift and rotation in a single arm data after gluing gratings. The effect of registration accuracy of flatfielding coefficients has been analyzed for the experimental breadboard. The result shows that the registration accuracy of flatfielding coefficients needs to be better than 0.1 pixel for the breadboard. The shift at pixel level is calculated by solving the rotational degree by using logarithm-polar coordinate and phase correlation method for the requirement of registration. The shift at sub-pixel level is estimated with DFT based on matrix multiplication. The flow path of flatfielding method at systematic level is concluded. The integral condition of interferometer after actual gluing is modulated by adjusting the positions of gratings slightly. The flatfielding flow path is applied to the data acquired from the modulated interferometer after gluing. Then, the result is compared with the spectrum after the correction with totally matched signal arm data. The final result shows that the spectral deviation is 0.6% between the two spectra compared with the spectral deviation of 4.1% without correction. The accuracy of recovered spectrum after correction has been improved markedly. This can be the foundation for the follow data processing.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(12): 3951-7, 2016 Dec.
Artículo en Chino | MEDLINE | ID: mdl-30235500

RESUMEN

Spatial heterodyne Raman spectroscopy (SHRS) is a new type of Raman spectroscopic detection technique with characteristics of high optical throughout, high spectral resolution, and no moving parts. SHRS is very suitable for the planetary exploration missions, which can be used to the analysis of minerals and find the biomarkers maybe exist on the surface of planetary. The authors have applied the technique to the standoff Raman spectroscopic detection, analyzed the main characteristics, including spectral resolution, bandpass and signal to noise (SNR), of standoff SHRS and proved it through experiments. The basic theory of standoff SHRS has been described briefly while a breadboard has been designed, built and calibrated. On the basis, the Raman spectra of some inorganic solids, organic liquids and some natural minerals have been achieved at a distance of 10 m, the SNR of the breadboard has been estimated. Due to the poor adjustment and the defects of the optical elements, the breadboard is far away from an ideal system. But the results show that the SNR is better than 5 for most of the main Raman peaks of the samples, which can meet the basic requirement of clear positive detection of typical Raman peaks and the feasibility of standoff SHRS has been proved. SHRS can overcome the main defects of dispersive grating Raman spectrometers and Fourier transform Raman spectrometers and it has a great application prospect on the detection and analysis of the planetary surface. The work of the authors can prove the potentiality of SHRS on standoff detection and can provide reference for the engineering realization of standoff SHRS.

19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(7): 2296-9, 2016 Jul.
Artículo en Chino | MEDLINE | ID: mdl-30036016

RESUMEN

The detection of hyper-spectral atmosphere CO2 needs remote sensor to be characterized and calibrated precisely while spectral calibration is the most basic work. The high uncertainty of wavelength calibration coefficient is a big problem as to the traditional laboratory calibration methods. In order to solve this problem, the research of error correction of spectral calibration based on gas absorption principle is carried out. The method is in accordance with the using conditions of instrument and it improves the practicability of the calibration coefficient. First, theoretical spectrum and error components are simulated by using radiative transfer. Then, the experiment of atmosphere CO2 absorption spectrum measurement is performed based on the atmosphere environmental simulation calibration house. Last, spectral error is corrected and optimized with LM algorithm. The result of spectral calibration of error correction shows that the mean value of spectral error deviation decreases from 0.03 cm-1 before correction to 0.008 cm-1 after correction, and systematic and mutable errors are removed. The spectral calibration precision on the ground is improved significantly, which lays the foundation for the subsequent greenhouse gas retrieval.

20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(9): 3014-9, 2016 Sep.
Artículo en Chino | MEDLINE | ID: mdl-30085496

RESUMEN

By using doppler asymmetric spatial heterodyne spectroscopy and doppler effect, the wind speed can be achieved through detecting the interferogram of airglow in the upper atmosphere. This paper mainly analyses the data processing method of the interferogram and then derive the interferometer phase in order to get the wind speed. Comparing with the traditional spatial heterodyne spectroscopy, not only the noise and error of the system should be taken into consideration, but the window function that used to isolate the spectrum has a great influence during the data processing. Then the effect of window type and window width on phase difference of interferogram and the wind error curve are simulated through software. On basis of this the wind error curve under the noise of system and flat field factor are simulated by choosing appropriate window function. The window function simulation indicates that although the joining of window leads to a distortion of the interferogam and phase, the wind speed error can be less than 0.5% with Hanning window in the appropriate optical path difference. The noise of the system simulation indicates that the wind speed error increases with the noise, so it is necessary to control the system noise and preprocess the sampling data. The research on data processing method has great theoretical significance and practical value for designing the system parameter and improving the precision of spatial heterodyne wind detection.

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