检索结果-南通市图书馆

Fluorescence fluctuation spectroscopy and its artifacts:simulations and tests

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 336-344页

作者： MENG Fanbo 1 , CHEN Bo 1 , LIU Guang 1 , DING Jianying 1 & MA Hui 2.1 1. Department of Physics and Key Laboratory of Atomic and Molecular Nano Sciences, Ministry of Educa- tion, Tsinghua University, beijing 100084, china 2. {2. school at Shenzhen, Tsinghua University, Shenzhen 518055, china Department of Physics and Key Laboratory of Atomic and Molecular Nano Sciences Ministry of Education Tsinghua University Beijing China graduate school at Shenzhen Tsinghua University Shenzhen China

Fluorescence fluctuation spectroscopy (FFS) technique is capable of monitoring changes in concentration, mass, size and structure of fluorescent-labeled bio-molecules in microscopic volume and is suitable for measuring biological interactions in living cells. FFS data may be affected by many experimental factors in complicated biological systems. Using a Monte Carlo approach, we generate fluorescence fluctuation data for different experimental systems. This approach helps to separate the contributions by different experimental factors in a complicated fluorescence fluctuation spectrum. It also helps to validate new theoretical models and new fitting formulations. We describe the algorithm of the simulation program and tests on its statistical performance. The program is then used successfully to study the effects of several experimental factors on FFS detection.

关键词： fluorescence fluctuation spectroscopy, fluorescence correlation spectroscopy, Monte Carlo simulation.

Preparation of Pt/K_2.a_2.i_3O_(10) and its photo-catalytic activity for hydrogen evolution from methanol water solution

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2006年第2期49卷 162-168页

作者： CUI Wenquan1,3, LIU Li2. FENG Liangrong1, XU Chenghua1, LI Zijian1, Lü Shaojie1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, china 2. Chemistry Department, Sichuan University of Science & Engineering, Zigong 643033, china 3. {2. school of the Chinese Academy of Sciences, beijing 100039, china Correspondence should be addressed to Qiu Fali Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu China graduate school of the Chinese Academy of Sciences Beijing China Chemistry Department Sichuan University of Science & Engineering Zigong China

A layered perovskite-type oxide K2.a2.i3O10 was prepared with high-temperature solid-state reaction, and characterized with X-ray diffraction (XRD) and ultraviolet-visible diffuse re-flectance spectroscopy (UV-Vis DRS). Platinum was loaded onto K2.a2.i3O10 as a co-catalyst with different methods. The dispersion of platinum on K2.a2.i3O10 was determined with HOT method. The photocatalytic activity of Pt/K2.a2.i3O10 was studied. This catalyst showed much higher activity in hydrogen evolution reaction than Ni/K2.a2.i3O10. The effects of different amounts of loaded platinum and several preparation methods were evaluated. The best achieved hydrogen evolution rate was 2.3.88 μmol·h?1 by Pt(2.)/K2.a2.i3O10. A possible band structure and mechanism were discussed based on the results.

关键词： photocatalysis hydrogen platinum K_2.a_2.i_3O_(10) support

Mass Spectrometric Evidence of Heparin Disaccharides for the Catalytic Characterization of A Novel Endolytic Heparinase

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第12期36卷 840-844页

作者： Yapeng CHAO1,3, Shaoxiang XIONG2. Xiulan CHENG1, and Shijun QIAN1* 1Institute of Microbiology, Chinese Academy of Sciences, beijing 100080, china 2.enter of Mass Spectrometry, Institute of Chemistry, Chinese Academy of Sciences, beijing 100080, china 3graduate school of the Chinese Academy of Sciences, beijing 100039, china Institute of Microbiology Chinese Academy of SciencesBeijing 100080 China graduate school of the Chinese Academy of Sciences{2. 100039 China Center of Mass Spectrometry Institute of Chemistry Chinese Academy of SciencesBeijing 100080 China

Heparinase from different sources can eliminate heparin or/and heparan sulfate into various low-molecular weight heparins with different characteristics. Porcine intestinal mucosa heparin was de- graded into a series of oligosaccharides by a novel heparinase from the species Sphingobacterium. Disaccha- ride components from the digests were separated and purified by ultrafiltration and HPLC. Five major peaks appeared as three types according to their retention time. The mass spectrometry of peak I mainly gave the non-sulfated disaccharide with the mass of 379 Da. Peak II and III were indicated as two major monosulfated disaccharides with molecular mass of 417 and 459 Da respectively. Moreover, the peak III represented an N- acetyl disaccharide. Both peak IV and V showed the same mass of 496 Da, hinting that they were disulfate- substituted disaccharides. No trisulfate-substituted disaccharides were detected in the mixture of the heparin digest though they were abundant in the heparin structure. The results revealed that the heparinase might specifically cut the sites with low sulfated domain in heparin.

关键词： electrospray ionization-mass spectrometry heparin disaccharides heparinase high perfor- mance liquid chromatography Sphingobacterium sp.

De-interlacing technique based on total variation with spatial-temporal smoothness constraint

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science in china(Series F) 2007年第4期50卷 561-575页

作者： YIN XueMin1,2.3, YUAN JianHua1,2. LU XiaoPeng1,2.& ZOU MouYan1,2.1 Institute of Electronics, Chinese Academy of Sciences, beijing 100080, china 2.{2. school, Chinese Academy of Sciences, beijing 100039, china 3 Jiuquan Satellite Launch Center, Lanzhou 732.50, china Institute of Electronics Chinese Academy of Sciences Beijing China graduate school Chinese Academy of Sciences Beijing China Jiuquan Satellite Launch Center Lanzhou China

This paper introduces a new method of converting interlaced video to a progressively scanned video and image, The new method is derived from Bayesian framework with the spatial-temporal smoothness constraint and the MAP is done by minimizing the energy functional, The half-quadratic regularization method is used to solve the corresponding partial differential equations （PDEs）, This approach gives the improved results over the conventional de-interlacing methods, Two criteria are proposed in the paper, and they can be used to evaluate the performance of the de-interlacing algorithms,

关键词： video processing de-interlacing total variation spatio-temporai smoothness constraint PDEs half-quadratic regularization

Integrated precise orbit determination of Shenzhou IV unmanned spacecraft

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2004年第5期47卷 518-525页

作者： L Congmin1,2. GU Yidong3, LIN Baojun3 & GUO Jiong3 1. Center for Space Science and Applied Research, Chinese Academy of Sciences, beijing 100080, china 2. {2. school of the Chinese Academy of Sciences, beijing 100039, china 3. General Establishment of Space Science and Application, Chinese Academy of Sciences, beijing 100080, china Correspondence should be addressed to L Congmin Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China graduate school of the Chinese Academy of Sciences Beijing China General Establishment of Space Science and Application Chinese Academy of Sciences Beijing China

Considering the characteristic orbit of Shenzhou IV spacecraft and the advantages and disadvantages of several types of domestic orbit measurements, a scheme of IPOD is determined, which uses GPS, SLR and USB observation data jointly plus precise ionosphere corrections to GPS observation data. IPOD system and mathematic models of OD are introduced. The results of different joint OD are analyzed using true observation data, and show that radial accuracy is better than 2.m.

关键词： Shenzhou IV unmanned spacecraft integrated precise orbit determination GPS SLR USB.

Prediction method for October 2.03 solar storm

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2006年第5期49卷 629-640页

作者： XIE Yanqiong1, 2. 3, WEI Fengsi1, FENG Xueshang1 & ZHONG Dingkun1, 2.1. State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, beijing 100080, china 2. {2. school, Chinese Academy of Sciences, beijing 100039, china 3. Institute of Meteorology, PLA University of Science and Technology, Nanjing 2.1101, china State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China graduate school Chinese Academy of Sciences Beijing China Institute of Meteorology PLA University of Science and Technology Nanjing China

Aiming at two intense shock events on October 2. and 2., 2.03, this paper presents a two-step method, which combines synoptic analysis of space weather ——“observing” and quantitative prediction ——“palpating”, and then uses it to test predictions. In the first step of “observing”, on the basis of observations of the solar source surface magnetic field, interplanetary scintillation (IPS) and ACE spacecraft, we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources, and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks. As the two fast ejection shock events, the fast explosion of coronal mass of the extremely high temperature, the strong magnetic field, and the high speed background solar wind are also helpful to their rapid propagation. In the second step of “palpating”, we adopt a new membership function of the fast shock events for the ISF method. The predicted results show that for the onset time of the geomagnetic disturbance, the relative errors between the observational and the predicted results are 1.8% and 6.7%; and for the magnetic disturbance magnitude, the relative errors are 4.1% and 3.1%, re- spectively. Furthermore, the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous. The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.

关键词： solar storm, interplanetary shock, interplanetary scintillation, two-step method, ISF method.

A Novel and Convenient Assay for the Determination of OH Produced by Fenton Reaction

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1998年第6期9卷 569-571页

作者： Zhuo Bin YUAN Zhi Ru MA(Department of Chendstry, graduate school, USTC, Academia Sinica,{2.) Department of Chemistry Graduate School Academia Sinica Beijing 100039 Taiwan

A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52. vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.

关键词： hydroxyl radicals Fenton reaction spin trap reagent PBN electrochemical method

Effects of diatoms on reproduction and growth of marine copepods

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第10期14卷 1-7页

作者： ZHANG Guangtao 1,2. and SUN Song 1 (1.Key Laboratory of Marine Ecology&Environment Sciences,Institute of Oceanology,Chinese Academy of Sciences,Qingdao2.6071,china 2.graduate {2.,Chinese Academy of Sciences,beijing100039,china) Lab. of Marine Ecology Inst. of Oceanology Chinese Acad. of Sci. Qingdao 266071 China graduate Sch. Chinese Acad. of Sci. Beijing 100039 China

Two hot spots in marine ecology,deleterious effects of diatoms and feeding selectivity of copepods,as well as new progress on these two issues achieved in the recent ten years,are *** two issues are considered correlated *** and their metabolites can induce deleterious effects on growth,reproduction and development of copepods,including increase of mortality and decrease of egg production,hatching and growth *** negative effects,resulting from either chemical toxin or nutritional defi-ciency,can be conquered in natural environments by diverse *** is therefore concluded that deleterious effects of diatoms observed in laboratory or during blooming period are only a special case that accommodation of feeding strategy of copepods is *** under-stand their feeding strategy in natural environments is a prerequisite to explaining the mechanisms of deleterious effects caused by diatoms,and makes it possible to re-evaluate the energy flow in marine ecosystems.

关键词： diatoms copepod feeding strategy reproduction deleterious effects

Urban Water Supply Industry Marketization of china in View of Public Water Service and Water Resource Management

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2010年第2期8卷 55-60页

作者： Wang Yining 1,2.1.Institute of Geographic Science and Natural Resources Research,cas,beijing 100101,{2. 2.graduate school of the Chinese Academy of Sciences,beijing 100049,{2. Institute of Geographic Science and Natural Resources Research CAS Beijing 100101 China graduate school of the Chinese Academy of Sciences Beijing 100049 China

Started with the discussions on the value orientation of urban water supply industry marketization,the article points out that the current urban water supply industry marketization reform is inconsistent with the goal of public water service equalization to some *** article also analyzes the problems emerged in urban water supply industry marketization reform and various rea-sons in view of efficiency and *** efficiency and fairness oriented management model is built in this article to illustrate how the government should conciliate interests of various communities involved in the process of marketization reform of the urban water supply industry so as to actualize the coordination of efficiency and *** the end,an assumption on urban water price is put forward to help achieve the public water service equalization.

关键词： urban water supply industry marketization public water service water resource management