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Rare earth elements distribution in marine sediments of Malaysia coasts 被引量:11
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作者 Rezaee Ebrahim Saraee Khadijeh Saion B.Elias +1 位作者 Abdul Khalik Wood Abdi Mohammad Reza 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第6期1066-1071,共6页
In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collecte... In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24–26 cm in EC4 increased to 114.1 μg/gr at 20–22 cm in EC5.The measured concentration of ... 展开更多
关键词 enrichment factor rare earth elements marine sediments South China Sea shale average
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Automatic analytical approach for the determination of 12 illicit drugs and nicotine metabolites in wastewater using on-line SPE-UHPLC-MS/MS 被引量:6
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作者 Jingyuan Wang Likai Qia +8 位作者 Chenzhi Hou Tingting Zhang Mengyi Chen Haitao Meng Mengxiang Su Hui Xu Zhendong Hua Youmei Wang Bin Di 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2021年第6期739-745,共7页
In this study,we developed a novel on-line solid phase extraction(SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illic... In this study,we developed a novel on-line solid phase extraction(SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illicit drugs and metabolites(methamphetamine,amphetamine,morphine,codeine,6-monoacetylmorphine,benzoylecgonine,3,4-methylenedioxymethamphetamine,3,4-methylenedioxyamphetamine,cocaine,ketamine,norketamine,and methcathinone)and cotinine(COT)in wastewater samples.The analysis was performed by loading 2 m L of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step(5%methanol)to eliminate interference with a total run time of 13 min.The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process.Typical analytical characteristics used for method validation were sensitivity,linearity,precision,repeatability,recovery,and matrix effects.The limit of detection(LOD)and limit of quantification(LOQ)of each target were set at 0.20 ng/L and 0.50 ng/L,respectively.The linearity was between 0.5 ng/L and250 ng/L,except for that of COT.The intra-and inter-day precisions were<10.45%and 25.64%,respectively,and the relative recovery ranged from 83.74%to 162.26%.The method was used to analyze various wastewater samples from 33 cities in China,and the results were compared with the experimental results of identical samples analyzed using off-line SPE.The difference rate was between 19.91%and-20.44%,and the error range could be considered acceptable.These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples. 展开更多
关键词 Illicit drugs and metabolites Wastewater analysis On-line solid phase extraction Ultra-high-performance liquid CHROMATOGRAPHY Mass spectrometry
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Genotoxicity of Pesticide Waste Contaminated Soil and Its Leachate 被引量:2
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作者 S.D.SIVANESAN K.KRISHNAMURTHI +1 位作者 S.D.WACHASUNDER T.CHAKRABARTI 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2004年第3期257-265,共9页
Objective Improper land disposal of hazardous waste can result in leaching of hazardous constituents which may contaminate ground and surface water leading to adverse impact on human health and environment consequenc... Objective Improper land disposal of hazardous waste can result in leaching of hazardous constituents which may contaminate ground and surface water leading to adverse impact on human health and environment consequences. The present study utilized mammalian cell culture for the genotoxicity assessment of waste and its leachate. Methods Genotoxic potential and chemical analysis of pesticide derived tarry waste contaminated soil extract and its leachate was assessed using in vitro human lymphocyte cultures and GC-MS. Results The investigation revealed that the soil extract could cause significant to highly significant genotoxicity in the form of DNA strand break at 25 mL (P<0.01), 50 mL, 100 mL and 200 mL (P<0.001) and chromosomal aberration at 25 mL (P<0.01) and 50 mL and 100 mL (P<0.001). The leachate could cause significant DNA strand break and chromosomal aberration only at 100 mL and 200 mL (P<0.01) dose levels. Conclusion The genotoxicity observed is attributed to carbaril and tetra methyl naphthyl carbamate, the major ingredients of the extracts, as revealed by GC-MS. 展开更多
关键词 GENOTOXICITY Soil extract LEACHATE DNA strand break Chromosomal aberration Gas chromatography mass spectrometery (GC-MS) Fluorimetric analysis of DNA unwinding assay (FADU)
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Analyzing Effect of Demand Rate on Safety of Systems with Periodic Proof-tests 被引量:1
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作者 Manoj Kumar A.K.Verma A.Srividya 《International Journal of Automation and computing》 EI 2007年第4期335-341,共7页
Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only syste... Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only system parameters, such as configuration, hazard rate, coverage, repair rate, etc. along with periodic proof-tests (or inspection). Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants, chemical plants, etc. In this paper, a basic model of IEC 61508 is used. The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test. A new safety index, probability of failure on actual demand (PFAD) based on extended model and demand rate is proposed. Periodic proof-test makes the model semi-Markovian, so a piece-wise continuous time Markov chain (CTMC) based method is used to derive mean state probabilities of elementary or aggregated state. Method to determine probability of failure on demand (PFD) (IEC 61508) and PFAD based on these state probabilities are described. In example, safety indices of PFD and PFAD are compared. 展开更多
关键词 Probability of failure on demand fail safe Markov model continuous time Markov chain IEC 61508 diagnosis REPAIR proof-test DEMAND safety system.
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Analysis of isoquinoline alkaloids from Mahonia leschenaultia and Mahonia napaulensis roots using UHPLC-Orbitrap-MSn and UHPLC-QqQ LIT-MS/MS 被引量:9
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作者 Awantika Singh Vikas Bajpai +2 位作者 Sunil Kumar Ajay Kumar Singh Rawat Brijesh Kumar 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2017年第2期77-86,共10页
Mahonia leschenaultia(ML) and Mahonia napaulensis(MN) are less known and unexplored medicinal plants of the family Berberidaceae. They are used by the Todas of Nilgiris in their religious and medical practices but... Mahonia leschenaultia(ML) and Mahonia napaulensis(MN) are less known and unexplored medicinal plants of the family Berberidaceae. They are used by the Todas of Nilgiris in their religious and medical practices but chemically less identified. Hence, we decided to do extensive phytochemical analysis to explore the potential of these plant extracts. An ultrahigh performance electrospray tandem mass spectrometry(UHPLC-ESI-MS/MS)method was successfully developed for qualitative analysis of the bioactive components in Mahonia species using Orbitrap Velos Pro mass spectrometer. Sixteen compounds were identified by comparison of their retention times and mass spectra(MS) with authentic standards and reported literature. Multi-stage mass spectra(MS(2-8)) for the identification of protoberberine and aporphine alkaloids showed the sequential expulsion of all the substituents attached with their basic skeleton followed by CO loss. Eight of the identified compounds(berberine, jatrorrhizine, palmatine, magnoflorine, isocorydine, glaucine, tetrahydropalmatine and tetrahydroberberine) were simultaneously determined by another UHPLC-ESI-MS/MS method under the multiple reactions monitoring(MRM) mode quantitatively using triple quadrupole linear ion trap mass spectrometer. The analytical method was validated for 8 bioactive compounds with overall recovery in the range98.5%-103.6%(RSD≤2.2%), precise(RSD≤2.07%) and linear(r≥0.9995) over the concentration range of 0.5-1000 ng/mL and successfully applied in ML and MN roots, which suggests the suitability of the proposed approach for the routine analysis of Mahonia species and their quality control. 展开更多
关键词 Orbitrap-MS QqQLIT-MS Mahonia leschenaultia Mahonia napaulensis Isoquinoline alkaloids
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Exploring Greenhouse Gases Water and Climate Changes:Scientific Opportunities for the Climate and Atmospheric Composition Exploring Satellites Mission 被引量:2
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作者 LIU Congliang KIRCHENGAST Gottfried +8 位作者 SUN Yueqiang WANG Xin LU Daren BAI Weihua DU Qifei LOSCHER Armin SYNDERGAARD Stig TIAN Longfei ZHANG Zhihua 《空间科学学报》 CAS CSCD 北大核心 2020年第2期151-168,共18页
The Essential Climate Variables(ECVs),such as the atmospheric thermodynamic state variables and greenhouse gases,play an important role in the atmosphere physical processes and global climate change.Given the need of ... The Essential Climate Variables(ECVs),such as the atmospheric thermodynamic state variables and greenhouse gases,play an important role in the atmosphere physical processes and global climate change.Given the need of improvements in existing ground-based and satellite observations to successfully deliver atmosphere and climate benchmark data and reduce data ambiguity,the Climate and Atmospheric Composition Exploring Satellites mission(CACES)was proposed and selected as a candidate mission of the Strategic Priority Research Program of Chinese Academy Science(SPRPCAS).This paper presents an overview of the key scientific questions and responses of EC Vs in relation to global change;the principles,algorithms,and payloads of microwave occultation using centimeter and millimeter wave signals between low Earth orbit satellites(LEO-LEO microwave occultation,LMO)as well as of the LEO-LEO infrared-laser occultation(LIO);the CACES mission with its scientific objectives,mission concept,spacecraft and instrumentation. 展开更多
关键词 CLIMATE Greenhouse gases WATER Microwave OCCULTATION INFRARED-LASER OCCULTATION
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Gamma-ray luminosity function of gamma-ray bright AGNs 被引量:1
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作者 Debbijoy Bhattacharya P.Sreekumar R.Mukherjee 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第1期85-94,共10页
Detection of γ-ray emissions from a class of active galactic nuclei (viz blazars), has been one of the important findings from the Compton Gamma-Ray Observatory (CGRO). However, their γ-ray luminosity function h... Detection of γ-ray emissions from a class of active galactic nuclei (viz blazars), has been one of the important findings from the Compton Gamma-Ray Observatory (CGRO). However, their γ-ray luminosity function has not been well determined. Few attempts have been made in earlier works, where BL Lacs and Flat Spectrum Radio Quasars (FSRQs) have been considered as a single source class. In this paper, we investigated the evolution and γ-ray luminosity function of FSRQs and BL Lacs separately. Our investigation indicates no evolution for BL Lacs, however FSRQs show significant evolution. Pure luminosity evolution is assumed for FSRQs and exponential and power law evolution models are examined. Due to the small number of sources, the low luminosity end index of the luminosity function for FSRQs is constrained with an upper limit. BL Lac luminosity function shows no signature of break. As a consistency check, the model source distributions derived from these luminosity functions show no significant departure from the observed source distributions. 展开更多
关键词 GALAXIES active -- galaxies evolution -- galaxies luminosity function -- gamma-rays OBSERVATIONS
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Chemo-Divergence in Essential Oil Composition among Thirty One Core Collections of <i>Ocimum sanctum</i>L. Grown under Sub-Tropical Region of Jammu, India 被引量:1
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作者 S. Kitchlu Rekha Bhadauria +3 位作者 Gandhi Ram Kushal Bindu Ravi K. Khajuria Ashok Ahuja 《American Journal of Plant Sciences》 2013年第2期302-308,共7页
Evaluation of thirty one core collections of Ocimum sanctum L. synonyms O. tenuiflorum L. collected from different ecological regions representing contrasting environment of India was carried out. All the collections ... Evaluation of thirty one core collections of Ocimum sanctum L. synonyms O. tenuiflorum L. collected from different ecological regions representing contrasting environment of India was carried out. All the collections were grown under sub-tropical region of Jammu, India. Study revealed wide range of variability in quantitive and qualitative attributes of oil. Essential oil content ranged between 0.16% ± 0.01% - 0.55% ± 0.08% showing the presence of fifteen constituents. Methyl eugenol (1.54% - 93.16%) and Eugenol (0.06% - 70.41%), were the major constituent. The other major constituent of the oil was β-Caryophyllene (4.60% - 33.77%) which was detected in almost all the collections. Borneol, Copane, α Caryophyllene were other constituents detected in almost all the accessions. α selinene was detected in traces in only three accessions (OS-01, OS-03, OS-50) and β-selinene was detected in four accessions (OS-01, OS-03, OS-50, OS-72. Accession OS-70 collected from Patna, showed distinct chemical profile having β-Elemene (32.81%), β-Cary- ophyllene (16.37%), Germacrene-D (18.05%), β-Ocimene (17.69%) and Copane (5.738%). Being distinct in oil profiling, Patna collection was designated as distinct chemotype. Collections OS-50 from Gwalior from Central India and OS-59 from Rajkot Western India have been identified as methyl eugenol (93.16%) and eugenol (70.41%) rich geno- types. The data collected provided useful information with respect to composition of essential oil among core collection evaluated representing various agro-climatic zones. 展开更多
关键词 β-Caryophyllene CHEMOTYPE EUGENOL Germacrene-D Methyl EUGENOL β-Ocimene Variability
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Contribution from unresolved discrete sources to the extragalactic gamma-ray background(EGRB)
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作者 Debbijoy Bhattacharya Parameswaran Sreekumar Reshmi Mukherjee 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2009年第11期1205-1214,共10页
The origin of the extragalactic gamma-ray background (EGRB) is still an open question, even nearly forty years after its discovery. The emission could originate either from truly diffuse processes or from unresolved... The origin of the extragalactic gamma-ray background (EGRB) is still an open question, even nearly forty years after its discovery. The emission could originate either from truly diffuse processes or from unresolved point sources. Although the majority of the 271 point sources detected by EGRET (Energetic Gamma Ray Experiment Telescope) are unidentified, of the identified sources, blazars are the dominant candidates. Therefore, unresolved blazars may be considered the main contributor to the EGRB, and many studies have been carried out to understand their distribution, evolution and contribution to the EGRB. Considering that γ-ray emission comes mostly from jets of blazars and that the jet emission decreases rapidly with increasing jet to line-of-sight angle, it is not surprising that EGRET was not able to detect many large inclination angle active galactic nuclei (AGNs). Though Fermi could only detect a few large inclination angle AGNs during the first three months of its survey, it is expected to detect many such sources in the near future. Since non-blazar AGNs are expected to have higher density as compared to blazars, these could also contribute significantly to the EGRB. In this paper, we discuss contributions from unresolved discrete sources including normal galaxies, starburst galaxies, blazars and off-axis AGNs to the EGRB. 展开更多
关键词 GALAXIES active -- galaxies jets -- gamma-rays observations
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Contribution from normal and starburst galaxies to the extragalactic gamma-ray background (EGRB)
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作者 Debbijoy Bhattacharya Parameswaran Sreekumar 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第5期509-519,共11页
The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could ... The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar matter and radiation (-90%) along with a small contribution from discrete point sources (-10%). Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous atγ-ray energies to be detected by the current γ-ray mission (Fermi Gamma-ray Space Telescope). 展开更多
关键词 GALAXY general -- galaxies luminosity function -- galaxies starburst -- gamma-rays observations
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BINARY TISSUE CLASSIFICATION STUDIES ON RESECTED HUMAN BREAST TISSUES USING OPTICAL COHERENCE TOMOGRAPHY IMAGES
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作者 M.BHATTACHARJEE P.C.ASHOK +3 位作者 K.DIVAKAR RAO S.K.MAJUMDER Y.VERMA P.K.GUPTA 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2011年第1期59-66,共8页
We report the results of a comparative study of Fourier domain analysis(FDA)and texture analysis(TA)of optical coherence tomography(OCT)images of resected human breast tissues for binary classification between normal... We report the results of a comparative study of Fourier domain analysis(FDA)and texture analysis(TA)of optical coherence tomography(OCT)images of resected human breast tissues for binary classification between normalabnormal classes and benignmalignant classes.With the incorporation of Fisher linear discriminant analysis(FLDA)in TA for feature extraction,the TA-based algorithm provided improved diagnostic performance as compared to the FDAbased algorithm in discriminating OCT images corresponding to breast tissues with three different pathologies.The specificity and sensitivity values obtained for normalabnormal classification were both 100%,whereas they were 90% and 85%,respectively for benignmalignant classification. 展开更多
关键词 Optical coherence tomography breast tissue texture analysis Fourier domain analysis CLASSIFICATION
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First large scale application of novel Si stripixel detector in real large experiment: Si VTX in PHENIX upgrade at RHIC
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作者 LI Zheng H. ENYO +6 位作者 Y. GOTO J. TOJO Y. AKIBA R. NOUICER A. L. DESHPANDE K. BOYLE V. CIANCIOLO 《中国有色金属学会会刊:英文版》 CSCD 2006年第B01期141-145,共5页
2D position sensitive, single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) ... 2D position sensitive, single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) in Brookhaven National Laboratory (BNL). This is the first large scale application of the novel Si stripixel detector in a real large experiment after many years of research and development at BNL. The first and second prototype fabrication runs of the SVX stripixel detectors were carried out successfully in BNL’s Si detector development and processing Lab. The processing of these stripixel detectors is similar to that for the standard single-sided strip detectors: one-sided processing, single implant for the pixel (strip) electrodes, etc. The only additional processing step is the double metal process, a technology that is simple and well matured by many Si detector processing industries and labs, including BNL. The laser and beam tests on those prototype detectors show the 2D position sensitivity and good position resolution in both X and U coordinates (about 25 μm for 80 μm pitch). For the mass production of 400 sensors needed for the Si SVX, the processing technology has been successfully transferred to the industrial: Hamamatsu Photonics (HPK). HPK has produced a pre-production run of stripixel sensors with the full PHENIX SVX specification on 150 mm diameter wafers. The laser tests on these pre-production wafers show good signal to noise ratio (about 20∶1). 展开更多
关键词 相对论性重离子碰撞 PHENIX探测器 天顶跟踪器 硅顶点探测器 硅条探测器 应用
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Regioselective Direct Carboxylation of 2-Naphthol with Supercritical CO<sub>2</sub>in the Presence of K<sub>2</sub>CO<sub>3</sub>
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作者 Shigeki Furukawa Kensuke Otokawa +2 位作者 Osamu Sasaki Ken Nakayasu Tatsuaki Yamaguchi 《International Journal of Organic Chemistry》 2013年第3期210-213,共4页
A direct regioselective preparation of 2-hydroxynaphthalene-6-carboxylic acid, a useful industrial intermediate of aro-matic polyester from 2-naphthol was conducted by use of excess amount of K2CO3 (10-fold molar to 2... A direct regioselective preparation of 2-hydroxynaphthalene-6-carboxylic acid, a useful industrial intermediate of aro-matic polyester from 2-naphthol was conducted by use of excess amount of K2CO3 (10-fold molar to 2-naphthol) under supercritical CO2 at 10 MPa and 473 K. The obtained yield under this condition was ca. 20 mol% to 2-naphthol. The further investigations may provide an alternative process to the conventional Kolbe-Schmitt reaction, because of no use of strong alkali and recoverability of K2CO3. Theoretical explanation about the regioselectivity was achieved by means of DFT calculations. 展开更多
关键词 Supercritical CO2 CO2 Utilization Kolbe-Schmitt Reaction CARBOXYLATION 2-NAPHTHOL Potassium Carbonate 2-Hydroxynaphthalene-6-carboxylic Acid DFT Calculation
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Pulsed Magnetic Field Measurement Outside Finite Length Solenoid: Experimental Results &Mathematical Verification
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作者 Shibaji Basu Siddhartha Shankar Pany +1 位作者 Partha Bannerjee Sabyasachi Mitra 《Journal of Electromagnetic Analysis and Applications》 2013年第10期371-378,共8页
The paper deals with magnetic field mapping outside a finite length solenoid electromagnet, by an in-house designed and calibrated inductive pick-up or search coil. The search coil is calibrated in a unique methodolog... The paper deals with magnetic field mapping outside a finite length solenoid electromagnet, by an in-house designed and calibrated inductive pick-up or search coil. The search coil is calibrated in a unique methodology based on the azimuthal magnetic field component generated by a straight wire. This unique calibration technique helps us to avoid additional circuitry to integrate the signal obtained from search coil. The methodology proves advantageous in diffusion, implosion studies where the signal frequency changes with dimension and material of experimental job-piece (hollow metal tube). Remedial measures have been taken to avoid electrostatic capacitive pick-up (which eventually exacerbates with integration) keeping measurement simple and accurate. The experimentally measured field values have also been compared with electromagnetic field results obtained from mathematical calculations and finite element based simulations. Two different mathematical approaches have been demonstrated for field computation based on Biot-Savart Law. Both the methods have taken into account the exact geometry of the solenoid, including the inter-turn gaps. The methods use appropriate combination of closed-form mathematical expression and numerical integration techniques and are capable of determining all the vector components of magnetic field anywhere around the finite length solenoid. The mathematical computations are equally significant contributions in the paper especially because exact determination of magnetic fields outside finite length solenoids has not been discussed in sufficient specific details in already existing literature. The mathematical computations, finite element simulations and experimental verification together provide a holistic solution to magnetic field determination problems in pulse power applications that have not been discussed in available literature or books in specific details. 展开更多
关键词 PULSED Magnetic Field Biot-Savart LAW Search COIL
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用塞曼双频激光器作光源的一种新颖长扫描表面的仪器设计(英文)
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作者 林跃 PETERZ.TAKACS +1 位作者 王润文 陈祥祯 《光学学报》 EI CAS CSCD 北大核心 1991年第4期294-300,共7页
本文报道一套光学结构用于同步辐射反射镜表面轮廓高精度大面积的测量。采用了光学外差测量与接收技术,以伺服聚焦双折射透镜组分离“o”光与“e”光的聚焦区域,并再共轴组合比较其相位差,从而获得表面起伏的误差值。线性运动的测量工... 本文报道一套光学结构用于同步辐射反射镜表面轮廓高精度大面积的测量。采用了光学外差测量与接收技术,以伺服聚焦双折射透镜组分离“o”光与“e”光的聚焦区域,并再共轴组合比较其相位差,从而获得表面起伏的误差值。线性运动的测量工作台使镜面可测量范围从数微米到一米,而最小起伏量及曲率可达很高的测量精度。 展开更多
关键词 轮廓仪 激光器 光外差 反射镜
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Induction of apoptosis in leukemic cells by the alkaloid extract of garden cress(Lepidium sativum L.)
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作者 Shriniwas S.Basaiyye Sanjay Kashyap +1 位作者 Kannan Krishnamurthi Saravanadevi Sivanesan 《Journal of Integrative Medicine》 SCIE CAS CSCD 2019年第3期221-228,共8页
Objective: Garden cress(Lepidium sativum L.) is an important herb in traditional medicine used to improve production of breast milk in women and semen in men. In the present research the authors evaluated its ability ... Objective: Garden cress(Lepidium sativum L.) is an important herb in traditional medicine used to improve production of breast milk in women and semen in men. In the present research the authors evaluated its ability to destroy leukemic cancer(Jurkat E6-1) cells, using the alkaloid extract of this plant.Methods: Constituents of the alkaloid extract were analyzed by gas chromatography–mass spectrometry(GC–MS) and their cytotoxicity in leukemic cancer cells and healthy peripheral blood mononuclear cells(PBMCs) was assessed. Cell death via apoptosis was confirmed by DNA laddering, caspase-3 activity,annexin V-fluorescein isothiocyanate and mitochondrial toxicity assays. The specific course of gene activation in treated cells was determined through quantitative polymerase chain reaction(qPCR).Results: GC–MS analysis identified six alkaloids and proto-alkaloids, namely, benzyl isothiocyanate(1),2-ethoxy-4 H-3,1-benzoxazin-4-one(2),(4 R)-2-(2-aminophenyl)-4-phenyloxazoline(3), 5-acetyl-1,2-di hydro-6-methyl-2-oxo-4-phenyl-3-pyridinecarbonitrile(4), benzo[b][1,8]-naphthyridin-5(10 H)-on e,2,4,7-trimethyl(5) and 1,4-diaminoanthraquinone(6), in the alkaloid extract of L. sativum. Of these,compound 1 was previously identified in the seeds of L. sativum. Exposure to the alkaloid extract caused death of Jurkat E6-1 cells, with median lethal concentration(LC50) of 75.25 mg/mL. However, the alkaloid extract also showed a nontoxic and proliferative(1.6-fold) effect in healthy PBMCs. Further experiments performed with Jurkat cells at LC50 and sub-LC50 doses demonstrated DNA fragmentation, activation of caspase-3 and time-dependant phosphatidylserine translocation(apoptosis) from inner to outer cell membranes. Cell toxicity and assessment of adenosine triphosphate level, together with using qPCR to evaluate expression profile of major apoptosis genes, revealed that apoptosis may be induced by disruption in the mitochondrial outer membrane potential, through activation of extrinsic and intrinsic apoptosis pathways in Jurkat cells.Conclusion: The ability of the alkaloid extract of L. sativum seeds to induce apoptosis indicates a potential pharmacological use in cancer chemotherapy. The separation of individual active compounds and further in-depth exploration of the molecular mechanism of apoptosis may lead to novel chemotherapeutic compounds in our future antineoplastic research. 展开更多
关键词 LEPIDIUM sativum BENZYL ISOTHIOCYANATE APOPTOSIS Peripheral blood MONONUCLEAR cell Mitochondrial toxicity
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Front-end readout electronics system of ProtoDUNE-SP LAr TPC
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作者 Hans-Gerd Berns Hucheng Chen +15 位作者 Alessio D’Andragora Jack Fried Daniel Gastler S.Gao Eric Hazen Wenbin Hou Shaorui Li Feng Liu Veljko Radeka Maura Spanu Emerson Vernon Elizabeth Worcester Matthew Worcester Krithika Yethiraj Bo Yu Junbin Zhang 《Radiation Detection Technology and Methods》 CSCD 2019年第3期192-201,共10页
Purpose As a prototype of Deep Underground Neutrino Experiment far detector,ProtoDUNE single-phase Liquid Argon(LAr)Time Projection Chamber(TPC)sits in H4 beam line at CERN to characterize detector response.It consist... Purpose As a prototype of Deep Underground Neutrino Experiment far detector,ProtoDUNE single-phase Liquid Argon(LAr)Time Projection Chamber(TPC)sits in H4 beam line at CERN to characterize detector response.It consists of 6 full-size Anode Plane Assemblies(APAs)plus 18 Cathode Plane Assembly(CPA)modules to form two 3.6-m drift regions with a total of 15,360 readout channels.To achieve a good signal-to-noise ratio with this noble liquid detector(770ton LAr),cold electronics developed at BNL for extremely low temperature(77K–89K)operation is an optimal solution,which decouples the electrode and cryostat design from the readout design.Methods With CMOS front end ASICs integrated with the TPC electrodes,the electronic noise is independent of the fiducial volume and much lower than with readout electronics at room temperature.In addition,signal digitization and multiplexing to high-speed links inside the cryostat result in large reduction in the quantity of cables and the number of cryostat penetrations,giving the designers of both the TPC and the cryostat the freedom to choose the optimum configurations.Results and conclusions By April 2018,we have successfully instrumented 6 APAs with cold electronics,and the results of the integration test before the final installation in the cryostat look very promising. 展开更多
关键词 ProtoDUNE-SP TPC APA Cold electronics Integration test Introduction
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Cytochrome P450 BM3 of Bacillus megaterium-A possible endosulfan biotransforming gene
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作者 Muhil Vannan Seralathan Saravanadevi Sivanesan +4 位作者 Amit Bafana Sanjay Madanchand Kashyap Arrigo Patrizio Kannan Krishnamurthi Tapan Chakrabarti 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第11期2307-2314,共8页
Computing chemistry was applied to understand biotransforrnation mechanism of an organochlorine pesticide, endosulfan. The stereo specific metabolic activity of human CYP-2B6 (cytochrome P450) on endosulfan has been... Computing chemistry was applied to understand biotransforrnation mechanism of an organochlorine pesticide, endosulfan. The stereo specific metabolic activity of human CYP-2B6 (cytochrome P450) on endosulfan has been well demonstrated. Sequence and structural similarity search revealed that the bacterium Bacillus megaterium encodes CYP-BM3, which is similar to CYP-2B6. The functional similarity was studied at organism level by batch-scale studies and it was proved that B. megaterium could metabolize endosulfan to endosulfan sulfate, as CYP-2B6 does in human system. The gene expression analyses also confirmed the possible role of CYP-BM3 in endosulfan metabolism. Thus, our results show that the protein structure based in-silico approach can help us to understand and identify microbes for remediation strategy development. To the best of our knowledge this is the first report which has extrapolated the bacterial gene for endosulfan biotransformation through in silico prediction approach for metabolic gene identification. 展开更多
关键词 Protein structure similarity CYP-2B6 CYP-BM3 Endosulfan
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