期刊文献+
共找到4,512篇文章
< 1 2 226 >
每页显示 20 50 100
Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft 被引量:1
1
作者 Liu Liu Kangli Bao +4 位作者 Jianchao Feng Xiaofei Zhu Haoyu Wang Xiaofeng Zhang Jun Lin 《Astronomical Techniques and Instruments》 CSCD 2024年第1期52-61,共10页
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat... In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs. 展开更多
关键词 Solar Close observations and Proximity Experiments Adaptive thermal control method thermal field planning method Pumped liquid cooling system Advanced thermal management system
下载PDF
The Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays
2
作者 Tao Wen Songzhan Chen Benzhong Dai 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期245-252,共8页
With great advance of ground-based extensive air shower arrays,such as LHAASO and HAWC,many very high energy(VHE)gamma-ray sources have been discovered and are being monitored regardless of the day and the night.Hence... With great advance of ground-based extensive air shower arrays,such as LHAASO and HAWC,many very high energy(VHE)gamma-ray sources have been discovered and are being monitored regardless of the day and the night.Hence,the Sun and Moon would have some impacts on the observation of gamma-ray sources,which have not been taken into account in previous analysis.In this paper,the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is estimated.The tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some period.The absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are achieved.The main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray background.The influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission. 展开更多
关键词 astroparticle physics Sun:general methods:observational Sun:UV radiation
下载PDF
The Clinical Observation of 80 Patients with Diseases of Lumbar Vertebrae Treated by Reinforcing and Reducing Methods of Mani
3
作者 Wang Junzao(Pingding COunty Suyu Coal Mine in Shanxi Province,Shanxi 045209, China) 《中国针灸》 CAS CSCD 北大核心 1995年第S2期281-282,共2页
TheClinicalObservationof80PatientswithDiseasesofLumbarVertebraeTreatedbyReinforcingandReducingMethodsofManip... TheClinicalObservationof80PatientswithDiseasesofLumbarVertebraeTreatedbyReinforcingandReducingMethodsofManipulationSelectedCo... 展开更多
关键词 observation DISEASES LUMBAR Mani methods CLINICAL PATIENTS REDUCING Reinforcing the
下载PDF
The First Ground-based White Light Lunar Polarization Imaging:A New Kind of FeO Observation on the Near Side of the Moon
4
作者 Wei-Nan Wang Jin-Song Ping +4 位作者 Ming-Yuan Wang Wen-Zhao Zhang Han-Lin Ye Xing-Wei Han Song-Feng Kou 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期1-6,共6页
Lunar optical polarization is a fascinating phenomenon that occurs when sunlight reflects off the surface of the Moon and becomes polarized.This study employs a novel split-focus plane polarimetric camera to conduct t... Lunar optical polarization is a fascinating phenomenon that occurs when sunlight reflects off the surface of the Moon and becomes polarized.This study employs a novel split-focus plane polarimetric camera to conduct the initial white light polarimetric observations on the near side of the Moon.We obtained the linear degree of polarization(DOP)parameters of white light by observation from the eastern and western hemispheres of the Moon.The findings indicate that the white light polarization is lower in the lunar highland than in the lunar maria overall.Combining the analysis of lunar soil samples,we noticed and determined that the DOP parameters of white light demonstrate high consistency with iron oxide on the Moon.This study may serve as a new diagnostic tool for the Moon. 展开更多
关键词 techniques:photometric POLARIZATION methods:observational MOON
下载PDF
The In-Flight Realtime Trigger and Localization Software of GECAM
5
作者 Xiao-Yun Zhao Shao-Lin Xiong +86 位作者 Xiang-Yang Wen Xin-Qiao Li Ce Cai Shuo Xiao Qi Luo Wen-Xi Peng Dong-Ya Guo Zheng-Hua An Ke Gong Jin-Yuan Liao Yan-Qiu Zhang Yue Huang Lu Li Xing Wen Fei Zhang Jing Duan Chen-Wei Wang Dong-Li Shi Peng Zhang Qi-Bin Yi Chao-Yang Li Yan-Bing Xu Xiao-Hua Liang Ya-Qing Liu Da-Li Zhang Xi-Lei Sun Fan Zhang Gang Chen Huan-Yu Wang Sheng Yang Xiao-Jing Liu Min Gao Mao-Shun Li Jin-Zhou Wang Xing Zhou Yi Zhao Wang-Chen Xue Chao Zheng Jia-Cong Liu Xing-Bo Han Jin-Ling Qi Jia Huang Ke-Ke Zhang Can Chen Xiong-Tao Yang Dong-Jie Hou Yu-Sa Wang Rui Qiao Xiang Ma Xiao-Bo Li Ping Wang Xin-Ying Song Li-Ming Song Shi-Jie Zheng Bing Li Hong-Mei Zhang Yue Zhu Wei Chen Jian-Jian He Zhen Zhang Jin Hou Hong-Jun Wang Yan-Chao Hao Xiang-Yu Wang Zong-Yuan Yang Zhi-Long Wen Zhi Chang Yuan-Yuan Du Rui Gao Xiao-Fei Lan Yan-Guo Li Gang Li Xu-Fang Li Fang-Jun Lu Hong Lu Bin Meng Feng Shi Hui Wang Hui-Zhen Wang Yu-Peng Xu Jia-Wei Yang Xue-Juan Yang Shuang-Nan Zhang Chao-Yue Zhang Cheng-Mo Zhang Zhi-Cheng Tang Cheng Cheng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第10期11-24,共14页
Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CP... Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic Box.This onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation system.This paper provides a detailed description of the design and development of the trigger and localization software system for GECAM.It covers the general design,workflow,the main functions,and the algorithms used in the system.The paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation. 展开更多
关键词 telescopes instrumentation:detectors methods:observational
下载PDF
Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods
6
作者 F.Momo TEMGOUA L.Akana NGUIMDO DNJOMO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第2期278-292,共15页
Mathematical modeling of the interaction between solar radiation and the Earth's atmosphere is formalized by the radiative transfer equation(RTE), whose resolution calls for two-stream approximations among other m... Mathematical modeling of the interaction between solar radiation and the Earth's atmosphere is formalized by the radiative transfer equation(RTE), whose resolution calls for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the development of the phase function and the intensity into a third-order series of Legendre polynomials. This new approach, which adds one more term in the expression of the intensity and the phase function, allows in the conditions of a plane parallel atmosphere a new mathematical formulation of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Delta Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work also determines the conversion function of the proposed New Method using the fundamental definition of two-stream approximation(F-TSA) developed in a previous work. Notably,New Method has generally better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angle μ 0, but tends to deviate from the Disort method with the zenith angle, especially for high values of optical thickness. In spite of this divergence in reflectance for high values of optical thickness, very strong correlation with the Disort method(R ≈ 1) was obtained for most cases of optical thickness in this study. An analysis of the Legendre polynomial series for simple functions shows that the high precision is due to the fact that the approximated functions ameliorate the accuracy when the order of approximation increases, although it has been proven that there is a limit order depending on the function from which the precision is lost. This observation indicates that increasing the order of approximation of the phase function of the RTE leads to a better precision in flux calculations. However, this approach may be limited to a certain order that has not been studied in this paper. 展开更多
关键词 Radiative Transfer Equation two-stream method Legendre polynomial optical thickness moments of specific intensity conversion function TRANSMITTANCE reflectance
下载PDF
Possible Habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in the Initial Conditions of High-mass Star Formation
7
作者 Quan-Ling Cui Chuan-Peng Zhang Jun-Jie Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第4期237-252,共16页
The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)<18 K)involved.Under such conditions,many molecules be... The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)<18 K)involved.Under such conditions,many molecules become depleted from the gas phase by freezing out onto dust grains.However,the N-bearing and deuterated species could remain gaseous under these extreme conditions,suggesting that they may serve as ideal tracers.In this paper,using the Plateau de Bure Interferometer and Very Large Array observations at 1.3 mm,3.5 mm,and 1.3 cm,we investigate the possible habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in eight massive precluster and protocluster clumps G18.17,G18.21,G23.97N,G23.98,G23.44,G23.97S,G25.38,and G25.71.We found that the NH3cores are in good agreement with the 3.5 mm peak emission,but the NH_(3)is much more extended than the 3.5 mm emission structure.The SO distributions agree well with the 3.5 mm peaks for the evolved star formation stage,but we did not detect any SO emission in the four earliest star formation sources.C^(18)O is a poor tracer in conditions of the cold(■18 K)and dense(■10^(4)cm^(-3))cores,e.g.,the prestellar cores.We also found that the NH_(2)D cores are mainly located in the temperature range of 13.0-20.0 K,and the NH_(2)D lines may be strongly depleted above 20 K. 展开更多
关键词 galaxies:star formation techniques:interferometric methods:observational
下载PDF
Criteria for assessing the diagnostic significance of modern methods of imaging gastrointestinal diseases in practical gastroenterology
8
作者 Sergey M Kotelevets 《Artificial Intelligence in Medical Imaging》 2024年第1期13-17,共5页
Imaging methods are frequently used to diagnose gastrointestinal diseases and play a crucial role in verifying clinical diagnoses among all diagnostic algorithms.However,these methods have limitations,challenges,benef... Imaging methods are frequently used to diagnose gastrointestinal diseases and play a crucial role in verifying clinical diagnoses among all diagnostic algorithms.However,these methods have limitations,challenges,benefits,and advantages.Addressing these limitations requires the application of objective criteria to assess the effectiveness of each diagnostic method.The diagnostic process is dynamic and requires a consistent algorithm,progressing from clinical subjective data,such as patient history(anamnesis),and objective findings to diagnostics ex juvantibus.Caution must be exercised when interpreting diagnostic results,and there is an urgent need for better diagnostic tests.In the absence of such tests,preliminary criteria and a diagnosis ex juvantibus must be relied upon.Diagnostic imaging methods are critical stages in the diagnostic workflow,with sensitivity,specificity,and accuracy serving as the primary criteria for evaluating clinical,laboratory,and instrumental symptoms.A comprehensive evaluation of all available diagnostic data guarantees an accurate diagnosis.The“gold standard”for diagnosis is typically established through either the results of a pathological autopsy or a lifetime diagnosis resulting from a thorough examination using all diagnostic methods. 展开更多
关键词 Imaging methods Gastrointestinal diseases Sensitivity SPECIFICITY Accuracy of the method
下载PDF
Observation of the Effect of Video Assessment Method on the Operation Skills of Individual Nurses
9
作者 Jianhua Qin Xiaolu Wan Nannan Ma 《Journal of Clinical and Nursing Research》 2024年第8期122-128,共7页
Objective:To explore the application effect of video assessment method in clinical nurses’nursing operation skills.Method:To select 58 nurses who participated in the individual soldier standard in the children’s hos... Objective:To explore the application effect of video assessment method in clinical nurses’nursing operation skills.Method:To select 58 nurses who participated in the individual soldier standard in the children’s hospital in 2019 and 2020 as the research objects,among which the nurses who participated in the individual soldier standard in 2019 were the nurses who participated in the individual soldier standard in 2019 and 2020.A total of 29 people in the first batch were set as the control group,using traditional assessment methods.In 2020,the second batch of 29 nurses who participated in the individual soldier standard reached the experimental group.Using the video assessment method,there was no significant difference in general information between the two groups(P>0.05).After the assessment,the scores,coping with work pressure,and proactiveness of the two groups of research subjects were compared.Results:The experimental group’s nursing operation assessment scores,coping with work pressure,and proactiveness were significantly better than those of the control group,the difference was statistically significant(P<0.05).Conclusion:The application of the video assessment method improves the passing rate of nurses’operational skills examination,enhances nurses’initiative in learning,reduces examination pressure,and can be accurately,timely,and safely applied to clinical nursing work,which is worthy of study and promotion. 展开更多
关键词 Video assessment method NURSE Operation skills Effect observation
下载PDF
Clinical Study on the Treatment of Low Anal Fistula in Infants and Young Children by Anal Gland Excision and Virtual Hanging Procedure
10
作者 Hongbo Su Linmei Sun +5 位作者 Yimiao Liang Jiansheng Hu Yongli Zhang Ni Wei Chaoyang Li Lin Tang 《Journal of Clinical and Nursing Research》 2024年第3期18-25,共8页
Objective:To compare the efficacy of anal adenectomy with virtual hanging wire and anal fistulotomy in the treatment of low anal fistula in infants and children.Methods:60 children with low anal fistula who were admit... Objective:To compare the efficacy of anal adenectomy with virtual hanging wire and anal fistulotomy in the treatment of low anal fistula in infants and children.Methods:60 children with low anal fistula who were admitted to our hospital from October 2021 to March 2022 and met the inclusion criteria were randomly divided into two groups of 30 cases each;the treatment group was treated with anal adenectomy and virtual hanging wire surgery,and the control group was treated with anal fistula resection.The clinical efficacy after treatment was compared.Results:The total effective rate of both groups was 96.67%and the difference between the two groups was not statistically significant(P>0.05).The postoperative pain score of the treatment group was lower than that of the control group(P<0.05).The length of hospitalization and healing time of the treatment group was lower than that of the control group(P<0.05).The anal function of the patients in both groups was normal,and there was no adverse reaction.Conclusion:Anal gland excision and virtual hanging surgery for the treatment of low anal fistula in infants and children have the advantages of mild pain,reduced length of hospitalization,short healing time,and better patient experience as compared to anal fistula excision. 展开更多
关键词 Anal fistula Anal gland excision Virtual hanging procedure Surgical method observation index Clinical efficacy
下载PDF
Solar observation with the Fourier transform spectrometer Ⅰ:Preliminary results of the visible and near-infrared solar spectrum 被引量:2
11
作者 Xian-Yong Bai Zhi-Yong Zhang +6 位作者 Zhi-Wei Feng Yuan-Yong Deng Xing-Ming Bao Xiao Yang Yong-Liang Song Li-Yue Tong Shuai Jing 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第10期257-267,共11页
The Fourier transform spectrometer(FTS)is a core instrument for solar observation with high spectral resolution,especially in the infrared.The Infrared System for the Accurate Measurement of Solar Magnetic Field(AIMS)... The Fourier transform spectrometer(FTS)is a core instrument for solar observation with high spectral resolution,especially in the infrared.The Infrared System for the Accurate Measurement of Solar Magnetic Field(AIMS),working at 10-13μm,will use an FTS to observe the solar spectrum.The Bruker IFS-125 HR,which meets the spectral resolution requirement of AIMS but simply equips with a point source detector,is employed to carry out preliminary experiment for AIMS.A sun-light feeding experimental system is further developed.Several experiments are taken with them during 2018 and 2019 to observe the solar spectrum in the visible and near infrared wavelength,respectively.We also proposed an inversion method to retrieve the solar spectrum from the observed interferogram and compared it with the standard solar spectrum atlas.Although there is a wavelength limitation due to the present sun-light feeding system,the results in the wavelength band from 0.45-1.0μm and 1.0-2.2μm show a good consistency with the solar spectrum atlas,indicating the validity of our observing configuration,the data analysis method and the potential to work in longer wavelength.The work provided valuable experience for the AIMS not only for the operation of an FTS but also for the development of its scientific data processing software. 展开更多
关键词 Sun:general methods:observational instruments:Fourier transform spectrometer
下载PDF
Discussion on the Nature of English for Specific Purpose and ESP Teaching Methods
12
作者 宋健 《疯狂英语(教师版)》 2012年第2期134-140,共7页
This paper clears up the scientific justification for the existence of ESP through the analysis of ESP's nature.The specific features of ESP teaching goals and focuses require us to adopt suitable ESP teaching met... This paper clears up the scientific justification for the existence of ESP through the analysis of ESP's nature.The specific features of ESP teaching goals and focuses require us to adopt suitable ESP teaching methods for the completion of ESP teaching tasks.The ESP teaching method introduced here as "Contrastive Approach" is from our ESP teaching practice and will play a positive role in the ESP education to Chinese students. 展开更多
关键词 English for Specific Purpose NATURE ESP teaching method teaching method
下载PDF
The Quality Specifications of Mischmetal Wire and Rod and the Method of Adding Rare Earth in Steel
13
作者 鞠远峰 左生华 +3 位作者 林勤 刘爱生 王群 林东晖 《Journal of Rare Earths》 SCIE EI CAS CSCD 1994年第3期231-233,共3页
The quality of mischmetal wire and rod and the method of adding rare earth into steel are quite important for making high quality steel. This paper proposes a quality specification of wire and rod as well as related a... The quality of mischmetal wire and rod and the method of adding rare earth into steel are quite important for making high quality steel. This paper proposes a quality specification of wire and rod as well as related adding method. The paper also provides principles for selecting raw material and adding method. 展开更多
关键词 mischmetal wire and rod Quality specification Adding method
下载PDF
Spectroscopic and photometric observations of unidentified ultraviolet variable objects in the GUVV-2 Catalog
14
作者 You Li Jing Wang +1 位作者 Jian-Yan Wei Xiang-Tao He 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2011年第7期833-842,共10页
An NUV-optical diagram composed from sources from the second Galaxy Evolution Explorer(GALEX) Ultraviolet Variability(GUVV-2) Catalog provides us with a method to tentatively classify the unknown GUVV-2 sources by... An NUV-optical diagram composed from sources from the second Galaxy Evolution Explorer(GALEX) Ultraviolet Variability(GUVV-2) Catalog provides us with a method to tentatively classify the unknown GUVV-2 sources by their NUV-optical magnitudes.For the purpose of testing the correctness and generality of the method,we carry out a program on the spectroscopic observations of the unidentified GUVV-2 sources.The spectroscopic identification of these 37 sources are 19 type-A to-F stars,10 type-G to-K stars and 7 M dwarf stars together with an AGN.We also present the light curves in the R-band for two RR Lyrae star candidates selected from the NUV-optical diagram,both of which undergo cyclic variations.Combining their light curves and colors,we classify them as RR Lyrae stars.To confirm the re-sults,we show a color-color diagram for the 37 newly identified spectroscopic objects compared with previously identified ones,which are consistent with our previous re-sults,indicating that the ultraviolet variable sources can initially be classified by their NUV/optical color-color diagram. 展开更多
关键词 stars:variables:general—galaxies:active—methodsobservational—ultraviolet emission
下载PDF
Calculation of Electromagnetic Field and SAR Dis- tributions of Two Antenna Structures for Bone Tu- mors Microwave Hyperthermia 被引量:1
15
作者 席晓莉 汪文秉 王丽黎 《Journal of Nanjing Medical University》 2003年第3期143-148,共6页
Objective: To investigate the electromagnetic field and specific absorptionrate (SAR) distribution of different structure applicators with different depths for treating bonetumors using microwave hyperthermia. Methods... Objective: To investigate the electromagnetic field and specific absorptionrate (SAR) distribution of different structure applicators with different depths for treating bonetumors using microwave hyperthermia. Methods: The finite element method (FEM) was used to calculate,electromagnetic field and SAR distribution. Two different structure applicators were simulated. Theone is simple coaxial antenna, which has been successfully used in clinic treating bone tumors inTangdu hospital of the Forth Military Medical University several years. It was formed by a coaxialcable peeled off the out copper at end. The other applicator was coaxial- slot antenna, which waswidely used in microwave hyperthermia. The applicator inserted into the cylindrical bone withdifferent depths, and worked at the frequency of 2 450 MHz. Results: The electric field and SARgenerated by the simple coaxial applicator were mainly concentrated out the tissues, and were notuniform in the tissues, while the coaxial- slot applicator well transmits the electric field and SARinto the tissues, and can easily treat different position by adjusting the slat position.Conclusion: The results calculated by EFM, were well accordant with the experimental and clinicalresulls, and will be important for improving the clinical effects of microwave hyperthermia. 展开更多
关键词 bone tumors microwave hyperthermia finite element method electromagnetic field specific absorption rate
下载PDF
On Application of Mathematic Idea and Method in English Grammar Teaching and Learning
16
作者 李海 《海外英语》 2011年第1X期35-37,共3页
English grammar is at any time the important part of English learning,even if under the implementation of the New Course Standard.However,English grammar is considered to be difficult due to its complexity.My paper he... English grammar is at any time the important part of English learning,even if under the implementation of the New Course Standard.However,English grammar is considered to be difficult due to its complexity.My paper here is to explore and study the application of mathematic ideas and methods in English grammar teaching and learning,helping to facilitate the students to master the regularities,accuracy and systematization of English grammar,to improve learning efficiency,to enhance the learners' logic thinking,and at the same time,pointing out the specific strategies in practical use,which can be of great significance to the students' innovation and creativity and the students' development of the ability of cross-subject study advocated by both the Quality-Education and New Curriculum Standard. 展开更多
关键词 mathematic ideas and methods English GRAMMAR APPLICATION specific strategies FEASIBILITY and significance
下载PDF
Study on the applicability of frequency spectrum of micro-tremor and dynamic characteristics of surface ground in Asia area 被引量:5
17
作者 CHE Ai-lan IWATATE Takahiro +1 位作者 ODA Yoshiya GE Xiu-run 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第11期1856-1863,共8页
The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan), Xi’an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were ... The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan), Xi’an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were observed and analyzed by fast Fourier transform method (FFT). The response of ground soil to frequency of ground micro-tremor is revealed, and func- tions with frequency-dependence and frequency-selection of micro-tremor for different foundation soil strata are also researched. The horizontal to vertical spectral ratio (H/V, Nakamura technique) of micro-tremor observed at the surface ground was used to evaluate the site’s predominant period. This paper also discusses the application of micro-tremor on site safety evaluation, and gives the observed calculation results obtained at multiple points. The experimental foundation and the deduction process of the method are described in detail. Some problems of the method are pointed out. Potential use of the technique’s good expandable nature makes it a useable means for preventing and reducing disaster’s harmful effects. 展开更多
关键词 Micro-tremor observation Nakamura method Predominant period Earthquake observation Spectral analysis
下载PDF
Identification of highly conserved domains in hemagglutinin associated with the receptor binding specificity of influenza viruses: 2009 H1N1, avian H5N1, and swine H1N2 被引量:10
18
作者 Wei Hu 《Journal of Biomedical Science and Engineering》 2010年第2期114-123,共10页
The hemagglutinin (HA) of influenza viruses facilitates receptor binding and membrane fusion, which is the initial step of virus infection. Human influenza viruses preferentially bind to receptors with α2-6 lin- kage... The hemagglutinin (HA) of influenza viruses facilitates receptor binding and membrane fusion, which is the initial step of virus infection. Human influenza viruses preferentially bind to receptors with α2-6 lin- kages to galactose (SAα2,6Gal), whereas avian influenza viruses prefer receptors with α2-3 linkages to galactose (SAα2,3Gal). The current 2009 H1N1 pandemic is caused by a novel influenza A virus that has its genetic materials from birds, humans, and pigs. Its pandemic nature is characterized clearly by its dual binding to the α2-3 as well as α2-6 receptors, because the seasonal human H1N1 virus only binds to the α2-6 receptor. In a previous study, the informational spectrum method (ISM), a bioinformatics technique, was applied to uncover one highly conserved region in the HA protein associated with receptor binding preference in each of various influenza subtypes. In the present study, we extended the previous work by discovering multiple such domains in HA of 2009 H1N1 and avian H5N1 to expand our repertoire of known key regions in HA responsible for receptor binding affinity. Three such domains in HA of 2009 H1N1 were found at residue positions 106 to 130, 150 to 174, and 191 to 221, and another three domains in HA of avian H5N1 were located at residue positions 46 to 65, 136 to 153, and 269 to 286. These identified domains could be utilized as therapeutic and diagnostic targets for the prevention and treatment of influenza infection. 展开更多
关键词 Binding SPECIFICITY Discrete Fourier Transform Electron-Ion Interaction Potential Entropy HEMAGGLUTININ INFLUENZA Informational Spectrum Method
下载PDF
The radio environment of the 21 Centimeter Array:RFI detection and mitigation 被引量:3
19
作者 Yah Huang Xiang-Ping Wu +2 位作者 Qian Zheng Jun-Hua Gu Haiguang Xu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第2期135-144,共10页
Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detecti... Detection and mitigation of radio frequency interference (RFI) is the first and also the key step for data processing in radio observations, especially for ongoing low frequency radio experiments towards the detection of the cosmic dawn and epoch of reionization (EoR). In this paper we demonstrate the tech- nique and efficiency of RFI identification and mitigation for the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of EoR. For terrestrial, man-made RFI, we concen- trate mainly on a statistical approach by identifying and then excising non-Gaussian signatures, in the sense that the extremely weak cosmic signal is actually buried under thermal and therefore Gaussian noise. We also introduce the so-called visibility correlation coefficient instead of conventional visibility, which allows a further suppression of rapidly time-varying RFI. Finally, we briefly discuss removals of the sky RFI, the leakage of sidelobes from off-field strong radio sources with time-invariant power and a featureless spec- trum. It turns out that state of the art technique should allow us to detect and mitigate RFI to a satisfactory level in present low frequency interferometer observations such as those acquired with the 21CMA, and the accuracy and efficiency can be greatly improved with the employment of low-cost, high-speed computing facilities for data acquisition and processing. 展开更多
关键词 dark ages reionization first stars -- instrumentation interferometers -- methods data anal-ysis observational -- techniques: interferometric
下载PDF
Gas Chromatographic Method for Identification and Quantification of Commonly Used Residual Solvents in Pharmaceuticals Products
20
作者 Sreekanta Nath Dalal Pranab Kumar Das 《American Journal of Analytical Chemistry》 CAS 2024年第8期241-252,共12页
Background: Impurities are not expected in the final pharmaceutical products. All impurities should be regulated in both drug substances and drug products in accordance with pharmacopeias and ICH guidelines. Three dif... Background: Impurities are not expected in the final pharmaceutical products. All impurities should be regulated in both drug substances and drug products in accordance with pharmacopeias and ICH guidelines. Three different types of impurities are generally available in the pharmaceutical’s product specification: organic impurities, inorganic impurities, and residual solvents. Residual solvents are organic volatile chemicals used or generated during the manufacturing of drug substances or drug products. Purpose: The aim of this study is to develop a cost-effective gas chromatographic method for the identification and quantification of some commonly used solvents—methanol, acetone, isopropyl alcohol (IPA), methylene chloride, ethyl acetate, tetrahydrofuran (THF), benzene, toluene, and pyridine—in pharmaceutical product manufacturing. This method will be able to identify and quantify the multiple solvents within a single gas chromatographic procedure. Method: A gas chromatography (GC) equipped with a headspace sampler and a flame ionization detector, and a column DB 624, 30-meter-long × 0.32-millimeter internal diameter, 1,8 μm-thick, Brand-Agilent was used to develop this method. The initial GC oven temperature was 40°C and held for 5 minutes. It was then increase to 80˚C at a rate of 2˚C per minute, followed by a further increase to 225˚C at a rate of 30˚C per minute, with a final hold at 225˚C for 10 minutes. Nitrogen was used as a carrier gas at a flow rate of 1.20 mL per minute. Dimethyl sulfoxide (DMSO) was selected as sample solvent. Results: The developed method is precise and specific. The percent RSD for the areas of six replicate injections of this gas chromatographic method was within 10.0 and the recovery result found within 80.0% to 120.0%. 展开更多
关键词 Method Development Gas Chromatography Compendial Method GDP SPECIFICITY RECOVERY
下载PDF
上一页 1 2 226 下一页 到第
使用帮助 返回顶部