There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA...There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA) estimation system based on self-organizing map (SOM) and designed for arbitrarily distributed sensor array is proposed. The essential principle of this method is that the map from distance difference of arrival (DDOA) to DOA is Lipschitz continuity, it indicates the similar topology between them, and thus Kohonen SOM is a suitable network to classify DOA through DDOA. The simulation results show that the DOA estimation errors are less than 1° for most signals between 0° to 180°. Compared to MUSIC, Root-MUSIC, ESPRIT, and RBF, the errors of signals under signal-to-noise ratios (SNR) declines from 20 dB to 2 dB are robust, SOM is better than RBF and almost close to MUSIC. Further, the network can be trained in advance, which makes it possible to be implemented in real-time.展开更多
Objective This study aimed to evaluate the clinical efficacy and safety of foldable capsular vitreous body(FCVB)implant surgery in silicone oil-dependent eyes.Methods A total of 22 participants with silicone oil-depen...Objective This study aimed to evaluate the clinical efficacy and safety of foldable capsular vitreous body(FCVB)implant surgery in silicone oil-dependent eyes.Methods A total of 22 participants with silicone oil-dependent eyes who received treatment with FCVB implant surgery between January 2019 and June 2020 were included in this retrospective study.The intraocular pressure(IOP),best-corrected visual acuity(BCVA),demographic data,and any recorded complications were evaluated.Results The postoperative IOP(12.73±4.20 mmHg)was significantly improved(P=0.03)compared to the preoperative IOP(10.23±3.69 mmHg)(the main endpoint).There was no significant difference(P=0.33)in the final BCVA preoperation and 3rd month postoperation(the secondary endpoint).The most common postoperative complication was hyphema.Other common postoperative complications included corneal opacity,a shallow anterior chamber,and a low IOP.Conclusion FCVB implant surgery is a safe and effective method for treating silicone oil-dependent eyes;however,attention should be paid to the prevention and timely treatment of complications.展开更多
Focusing on the design problem of high-performance radiators for planar motors in the wafer stage of the lithography machine,a thermal-fluid coupling optimization scheme based on parametric solid components was propos...Focusing on the design problem of high-performance radiators for planar motors in the wafer stage of the lithography machine,a thermal-fluid coupling optimization scheme based on parametric solid components was proposed.The mapping method between component parameters and pseudo-density values was established.An analytical solution for the sensitivity of pseudo-density to component parameters was given.The conjugate heat transfer function with the shallow channel approximation term was solved through the pseudo-density information.In the optimization example,circular components were selected,and the position and the size of solid components were chosen as design variables.In order to eliminate calculation errors caused by pseudo-density,an optimized pseudo-density field was converted into the result based on parametric components.Compared to the reference motor radiator,the average surface temperature rise of the optimized water-cooling motor radiator is reduced by 22.4%,which verifies the feasibility and effectiveness of the proposed method.展开更多
Objective To investigate reductive dechlorination of 4-chlorophenol （4-CP） by nanoscale Fe^0 under different conditions. Methods Nanoscale Fe^0 was synthesized by using reductive method. 4-CP and its intermediate pr...Objective To investigate reductive dechlorination of 4-chlorophenol （4-CP） by nanoscale Fe^0 under different conditions. Methods Nanoscale Fe^0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope （ESEM）. Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate, whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover, the stability and durability of nanoscale Fe^0 was evaluated through batch studies over extended periods of time. Conclusion The nanoscale Fe^0 can be used for sustainable treatment of contaminants in groundwater.展开更多
A new four-coordinated manganese compound Mn2（BPTC） （BPTC =- biphenyl- 2,4,4＇,6-tetracarboxylate） with flu topology net was synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis con...A new four-coordinated manganese compound Mn2（BPTC） （BPTC =- biphenyl- 2,4,4＇,6-tetracarboxylate） with flu topology net was synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis confirms its crystal belongs to the monoclinic system, space group C2/c with a = 12.2092（11）, b = 14.6932（9）, c = 8.9998（10） A, t= 108.256（12）°, Z= 4, V= 1533.2（2） A3, Dc = 1.889 mg/m3,μ = 1.69, F（O00） = 864, the final R = 0.063 and wR = 0.201 for 1407 observed reflections （I 〉 20（/））. UV-Vis absorption spectrum shows the title compound has a strong absorption at 326 and 238 nm and the optical diffuse reflectance determination shows the band gap of the title compound is 3.15 eV. The theory calculation elucidated that the UV absorptions of the title compound mainly arise from the electron transition from bonding orbitals of BPTC4- ligand to the empty orbitals of BPTC4- and Mn（II） ions.展开更多
The anomaly of the summer sea temperature is analyzed by a spatial-temporal synthetically rotated Empirical Orthogonal Function(REOF)at three different depths(0 m,40 m,and 120 m)over the area 110°E^100°W and...The anomaly of the summer sea temperature is analyzed by a spatial-temporal synthetically rotated Empirical Orthogonal Function(REOF)at three different depths(0 m,40 m,and 120 m)over the area 110°E^100°W and 30°S^60°N.The spatial-temporal distribution shows that the“signal”of annual anomaly is stronger in the sub-surface layer than the surface layer,and it is stronger in the eastern equatorial Pacific than in the western area.The spatial structure of the sea temperature anomaly at different layers is related to both the ocean current and the interaction of ocean and atmosphere.The temporal changing trend of the sub-surface sea temperature in different areas shows that the annual mean sea temperature increases and the annual variability evidently increases since the 1980s,and these keep the same trend with the increasing El Nino phenomenon very well.展开更多
The COVID-19 pandemic remains ever prevalent and afflicting—partially because one of its transmission pathways is aerosol.With the widely used central air conditioning systems worldwide,indoor virus aerosols can rapi...The COVID-19 pandemic remains ever prevalent and afflicting—partially because one of its transmission pathways is aerosol.With the widely used central air conditioning systems worldwide,indoor virus aerosols can rapidly migrate,thus resulting in rapid infection transmission.It is therefore important to install microbial aerosol treatment units in the air conditioning systems,and we herein investigated the possibility of combining such filtration with UV irradiation to address virus aerosols.Results showed that the removal efficiency of filtration towards f2 and MS2 phages depended on the type of commercial filter material and the filtration speed,with an optimal velocity of 5 cm/s for virus removal.Additionally,it was found that UV irradiation had a significant effect on inactivating viruses enriched on the surfaces of filter materials;MS2 phages had greater resistance to UV-C irradiation than f2 phages.The optimal inactivation time for UV-C irradiation was 30 min,with higher irradiation times presenting no substantial increase in inactivation rate.Moreover,excessive virus enrichment on the filters decreased the inactivation effect.Timely inactivation is therefore recommended.In general,the combined system involving filtration with UV-C irradiation demonstrated a significant removal effect on virus aerosols.Moreover,the system is simple and economical,making it convenient for widespread implementation in air-conditioning systems.展开更多
文摘There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA) estimation system based on self-organizing map (SOM) and designed for arbitrarily distributed sensor array is proposed. The essential principle of this method is that the map from distance difference of arrival (DDOA) to DOA is Lipschitz continuity, it indicates the similar topology between them, and thus Kohonen SOM is a suitable network to classify DOA through DDOA. The simulation results show that the DOA estimation errors are less than 1° for most signals between 0° to 180°. Compared to MUSIC, Root-MUSIC, ESPRIT, and RBF, the errors of signals under signal-to-noise ratios (SNR) declines from 20 dB to 2 dB are robust, SOM is better than RBF and almost close to MUSIC. Further, the network can be trained in advance, which makes it possible to be implemented in real-time.
文摘Objective This study aimed to evaluate the clinical efficacy and safety of foldable capsular vitreous body(FCVB)implant surgery in silicone oil-dependent eyes.Methods A total of 22 participants with silicone oil-dependent eyes who received treatment with FCVB implant surgery between January 2019 and June 2020 were included in this retrospective study.The intraocular pressure(IOP),best-corrected visual acuity(BCVA),demographic data,and any recorded complications were evaluated.Results The postoperative IOP(12.73±4.20 mmHg)was significantly improved(P=0.03)compared to the preoperative IOP(10.23±3.69 mmHg)(the main endpoint).There was no significant difference(P=0.33)in the final BCVA preoperation and 3rd month postoperation(the secondary endpoint).The most common postoperative complication was hyphema.Other common postoperative complications included corneal opacity,a shallow anterior chamber,and a low IOP.Conclusion FCVB implant surgery is a safe and effective method for treating silicone oil-dependent eyes;however,attention should be paid to the prevention and timely treatment of complications.
基金Supported by the National Natural Science Foundation of China(51677104)。
文摘Focusing on the design problem of high-performance radiators for planar motors in the wafer stage of the lithography machine,a thermal-fluid coupling optimization scheme based on parametric solid components was proposed.The mapping method between component parameters and pseudo-density values was established.An analytical solution for the sensitivity of pseudo-density to component parameters was given.The conjugate heat transfer function with the shallow channel approximation term was solved through the pseudo-density information.In the optimization example,circular components were selected,and the position and the size of solid components were chosen as design variables.In order to eliminate calculation errors caused by pseudo-density,an optimized pseudo-density field was converted into the result based on parametric components.Compared to the reference motor radiator,the average surface temperature rise of the optimized water-cooling motor radiator is reduced by 22.4%,which verifies the feasibility and effectiveness of the proposed method.
基金The work was supported by the National Natural Science Foundation of China (Grant No. 50325824 50678089).
文摘Objective To investigate reductive dechlorination of 4-chlorophenol （4-CP） by nanoscale Fe^0 under different conditions. Methods Nanoscale Fe^0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope （ESEM）. Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate, whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover, the stability and durability of nanoscale Fe^0 was evaluated through batch studies over extended periods of time. Conclusion The nanoscale Fe^0 can be used for sustainable treatment of contaminants in groundwater.
基金supported by the Natural Science Foundation of Fujian Province(No.2014J01029)the National Natural Science Foundation of China(No.91122028)
文摘A new four-coordinated manganese compound Mn2（BPTC） （BPTC =- biphenyl- 2,4,4＇,6-tetracarboxylate） with flu topology net was synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis confirms its crystal belongs to the monoclinic system, space group C2/c with a = 12.2092（11）, b = 14.6932（9）, c = 8.9998（10） A, t= 108.256（12）°, Z= 4, V= 1533.2（2） A3, Dc = 1.889 mg/m3,μ = 1.69, F（O00） = 864, the final R = 0.063 and wR = 0.201 for 1407 observed reflections （I 〉 20（/））. UV-Vis absorption spectrum shows the title compound has a strong absorption at 326 and 238 nm and the optical diffuse reflectance determination shows the band gap of the title compound is 3.15 eV. The theory calculation elucidated that the UV absorptions of the title compound mainly arise from the electron transition from bonding orbitals of BPTC4- ligand to the empty orbitals of BPTC4- and Mn（II） ions.
基金This study is supported by the National Science Foundation of China(91837205,41805032,41975111).
文摘The anomaly of the summer sea temperature is analyzed by a spatial-temporal synthetically rotated Empirical Orthogonal Function(REOF)at three different depths(0 m,40 m,and 120 m)over the area 110°E^100°W and 30°S^60°N.The spatial-temporal distribution shows that the“signal”of annual anomaly is stronger in the sub-surface layer than the surface layer,and it is stronger in the eastern equatorial Pacific than in the western area.The spatial structure of the sea temperature anomaly at different layers is related to both the ocean current and the interaction of ocean and atmosphere.The temporal changing trend of the sub-surface sea temperature in different areas shows that the annual mean sea temperature increases and the annual variability evidently increases since the 1980s,and these keep the same trend with the increasing El Nino phenomenon very well.
基金the National Natural Science Foundation of China(No.52070192),which was greatly acknowledged.
文摘The COVID-19 pandemic remains ever prevalent and afflicting—partially because one of its transmission pathways is aerosol.With the widely used central air conditioning systems worldwide,indoor virus aerosols can rapidly migrate,thus resulting in rapid infection transmission.It is therefore important to install microbial aerosol treatment units in the air conditioning systems,and we herein investigated the possibility of combining such filtration with UV irradiation to address virus aerosols.Results showed that the removal efficiency of filtration towards f2 and MS2 phages depended on the type of commercial filter material and the filtration speed,with an optimal velocity of 5 cm/s for virus removal.Additionally,it was found that UV irradiation had a significant effect on inactivating viruses enriched on the surfaces of filter materials;MS2 phages had greater resistance to UV-C irradiation than f2 phages.The optimal inactivation time for UV-C irradiation was 30 min,with higher irradiation times presenting no substantial increase in inactivation rate.Moreover,excessive virus enrichment on the filters decreased the inactivation effect.Timely inactivation is therefore recommended.In general,the combined system involving filtration with UV-C irradiation demonstrated a significant removal effect on virus aerosols.Moreover,the system is simple and economical,making it convenient for widespread implementation in air-conditioning systems.
