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Now showing items 65 - 80 of 96

  • Knowledge Management Sytem Based on Knowledge Flow in Web2.0 Environment

    Wang Xianbin   Liu Rui   Wang Weijun  

    This article argues the objective of knowledge management and indicates its core as reinforcing knowledge flow and application. Based on the documented Knowledge Management System weaknesses and feature of Web2.0,we have developed the infrastructure of Knowledge Flow Based KMS in Web2.0 Environment and an innovative approach to design, realize and strengthen it. The new system infrastructure offers a paradigm shift by putting emphasis on integration of Web2.0 and KMS by knowledge flow. Open source tools are used as development tools and four key modules known as system integration module, knowledge processing module, flow integration module and knowledge service module are illustrated. Ultimately, the Knowledge Flow Based KMS in Web2.0 Environment, in spite of its challenges and limits, proposes a new agenda for promoting tacit knowledge sharing and knowledge transfer among members of different levels within an organizationt.
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  • Analysis of Bistatic SAR Frequencey Synchronization

    Liu Rui   Xiong Jintao   Huang Yulin  

    In this paper, a bistatic SAR echo's mathematical expression with frequency errors is given, and the frequency error was analysed. Two types of frequency synchronization errors were considered. We analysed the different effects about imaging of bistatic SAR in the condition that the echo with different frequency errors. The analytical result is proved by simulation, it can be the reference for bistatic SAR system design.
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  • Formation and Movement of Groundwater in the Thick Loess-Palaeosol Sequences of the Chinese Loess Plateau

    Ma Yandong   Zhao Jingbo   Liu Rui   Zhou Qi   Yin Leipeng  

    Permeability and water-bearing space are important hydrological characteristics of the loess strata. In this study a systematic experiment was conducted to measure the magnetic susceptibility, grain size, porosity, and infiltration rate of the loess and palaeosol layers on a loess tableland of the central Chinese Loess Plateau, in order to investigate the differences in hydrological conditions between the loess and palaeosol layers. The magnetic susceptibility of the loess layer was lower than that of the palaeosol layer, but the average quasi-steady infiltration rate was about 0.31 mm min(-1) higher, the coarse silt and very fine sand contents were about 7.1% greater, and the porosity was about 5.7% higher. These differences were mainly due to pedogenesis, which was affected by the Quaternary climate. The pedogenesis differences between the loess and palaeosol layers resulted in hydrological property differences in terms of permeability and water-bearing space. The loess layer had a higher permeability and more water-bearing space than the palaeosol layer, which meant that the loess layer is more likely to form aquifers and the palaeosol layer is more prone to form aquitards. The groundwater in the loess strata had a multilayered characteristic, which depended on the relative impermeability of palaeosol layer and the alternate deposition of loess-palaeosol layers. The hydrological characteristics of the loess strata demonstrated that the Quaternary climate had an important control function on the formation and movement of groundwater. This knowledge provides a reliable theoretical basis for water resource development and utilization on the Chinese Loess Plateau, and this study extends the application of Quaternary climate change theory to hydrological systems in loess deposits.
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  • Effects of Panax notoginseng saponins on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats in vivo.

    Liu Rui   Qin MengNan   Hang PengZhou   Liu Yan   Zhang ZhiRen   Liu GaoFeng  

    The aim of this study was to assess the influence of the Panax notoginseng saponins (PNS) on the activities of the drug-metabolizing enzymes cytochrome P450 (CYP450) 1A2, 2C9, 2D6 and 3A4 in rats. The activities of CYP1A2, 2C9, 2D6 and 3A4 were measured using specific probe drugs. After pretreatment for 1week with PNS or physiological saline (control group), probe drugs caffeine (10 mg/kg; CYP1A2 activity), tolbutamide (15 mg/kg; CYP2C9 activity), metoprolol (20 mg/kg; CYP2D6 activity) and dapsone (10 mg/kg; CYP3A4 activity) were administered to rats by intraperitoneal injection. The blood was then collected at different times for ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis. The data showed that PNS exhibited an induction effect on CYP1A2 by decreasing caffeine Cmax (36.3%, p<0.01) and AUC0- (22.77%, p<0.05) and increasing CL/F (27.03%, p<0.05) compared with those of the control group. Western blot analysis was used to detect the effect of PNS on the protein level of CYP1A2, and the results showed that PNS could upregulate the protein expression of CYP1A2. However, no significant changes in CYP2C9, 2D6 or 3A4 activities were observed. In conclusion, the results indicate that PNS could induce CYP1A2, which may affect the disposition of medicines primarily dependent on the CYP1A2 pathway. Our work may be the basis of related herb-drug interactions in the clinic.
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  • Characterisation of nucleosides and nucleobases in Mactra veneriformis by high performance liquid chromatography coupled with diode array detector-mass spectrometry (HPLC-DAD-MS).

    Liu Rui   Ji Jing   Wang LingChong   Chen ShiYong   Guo Sheng   Wu Hao  

    Mactra veneriformis has been used as sea food and traditional Chinese medicine (TCM) for thousands of years in China. In the present study, a high performance liquid chromatograph coupled with photodiode array detector and electrospray ionisation-mass spectrometer (HPLC-DAD-ESI-MS) method was established for detection of the nucleosides and nucleobases in M. veneriformis from four aquaticultural area of Jiangsu during different harvest time of one year. The validated method was successfully applied to identifying 10 nucleosides and nucleobases in 48 M. veneriformis samples. Quantitative analysis showed that nucleosides and nucleobases are rich in all M. veneriformis samples. However, their contents vary in different areas and harvest times. Principal component analysis (PCA) was used to classify the 48 samples based on the contents of the nucleosides and nucleobases. As a result, the samples could be mainly clustered into four groups, which was similar as aquaticultural areas classification. Based on the results, present method might be applicable for the quality control of M. veneriformis, or even other marine shellfish aquiculture and their products, and the quality of M. veneriformis might be more related with aquaticultural areas.
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  • Discovery and study of silver sulfate mineral in S-5 from the eastern suburb of Xi'an

    Zhao JingBo   Cao JunJi   Shao TianJie   Liu Rui   Yue YingLi   Du Juan  

    The paleosol samples from the fifth layer of the loess profile at Renjiapo in the eastern suburb of Xi'an are observed and analyzed using electron microscope and energy spectrum. Minerals such as AgSO4 and molybdenum, which are rare to find and can indicate typical dry climate environment, are found in this layer of paleosol. Secondary mineral is usually granular form of ellipsoidal and crystallization, and has the characteristics of chemical precipitating crystallization of apertures and fracture. Molybdenum minerals have the characteristics of colloidal substances. There are two kinds of secondary minerals. One is silver sulfate mineral and the other is silver oxide mineral. The movement of secondary silver, molybdenum and cobalt minerals, new clay mineral, Fe2O3 and Al2O3 indicates that S-5 has experienced strong chemical weathering and mineral dissolution during its development. Silver, molybdenum, and cobalt can be released from primary minerals. During that period, the precipitation was abundant in Xi'an where soil reached an acidity stage of chemical weathering. At the later development stage of paleosol in the lowest part of S-5, warm and wet monsoon climate had changed to dry and non-monsoon climate. In the period of the formation of AgSO4, which is easier to dissolve than CaSO4, a dry and non-monsoon climate was present in the Guanzhong Plain. Strong evaporation resulted in the accumulation of SO42- in the soil water solution and the formation of AgSO4. At that time, summer monsoon of East Asia was weak and did not cross Qinling Mountains to reach Guanzhong Plain. And at that time, the precipitation in Xi'an was less than 300 mm, and it was drier then in Xi'an than at present in Lanzhou.
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  • Viral proteomics: The emerging cutting-edge of virus research

    Zhou ShengTao   Liu Rui   Wei YuQuan  

    Viruses replicate and proliferate in host cells while continuously adjusting to and modulating the host environment. They encode a wide spectrum of multifunctional proteins, which interplay with and modify proteins in host cells. Viral genomes were chronologically the first to be sequenced. However, the corresponding viral proteomes, the alterations of host proteomes upon viral infection, and the dynamic nature of proteins, such as post-translational modifications, enzymatic cleavage, and activation or destruction by proteolysis, remain largely unknown. Emerging high-throughput techniques, in particular quantitative or semi-quantitative mass spectrometry-based proteomics analysis of viral and cellular proteomes, have been applied to define viruses and their interactions with their hosts. Here, we review the major areas of viral proteomics, including virion proteomics, structural proteomics, viral protein interactomics, and changes to the host cell proteome upon viral infection.
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  • Improving root growth and cichoric acid derivatives production in hairy root culture of Echinacea purpurea by ultrasound treatment.

    Liu Rui   Li Wei   Sun LiYang   Liu ChunZhao  

    An efficient ultrasound-stimulation strategy was developed for improving the hairy root growth and caffeic acid derivatives (CADs) biosynthesis in the hairy root cultures of Echinacea purpurea L. The 15-day-old hairy roots stimulated every 5 days by ultrasound for 6 min produced the highest amount of CADs after 30 days of culture among all ultrasound treatment experiments. The obvious increase of CADs production in E. purpurea hairy roots stimulated by ultrasound was related to the increase of both rolB-regulated endogenous indole-3-acetic acid biosynthesis and phenylalanine ammonium lyase (PAL) activity. These results provided a basis for understanding of improving growth and secondary metabolism in the process of hairy root culture stimulated by ultrasound.
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  • Study on dynamic fracture behavior of TA15ELI alloy under mode-II loading by caustics method

    Liu Rui   Hui Songxiao   Ye Wenjun   Mi Xujun   Xiong Baiqing   You Zhenping  

    The dynamic fracture behavior of TAI5ELI alloy with lath-like microstructure was studied by caustics method. Specimens with double-side pre-notch were tested under the plane-stress condition at mode-II loading with a drop hammer system. Caustics information recorded in films illustrated the histories of both crack length and stress intensity factor. The dynamic fracture toughness and crack growth velocity of TAI5ELI with lath-like microstructure were determined to be 279 MPa.m(1/2) and 32.6 m/s, respectively. SEM fractograph analysis showed a mixed feature of mainly plastic mode for TA15ELI alloy in dynamic mode-II fracture. Shear localization was observed in the vicinity of the crack initiation area.
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  • Removal of AOX,Chroma and TOC in Chemical Dyestuff Wastewater with Iron Scraps-Fenton-Coagulation Combined Process

    Xu Can-can   Zhu Jing-na   Zhao Yuan   Liu Rui  

    Iron scraps-Fenton-coagulation process was applied to chemical dyestuff wastewater. The removal performance of absorbable organic halogens(AOX), chroma and total organic carbon (TOC) was investigated at different molar ratios of Fe2+ to H2O2 (1:3-1: 15), iron scraps reaction time (2-5 h) and Fenton reaction time (20-80 min). The results showed that the removal ratios of AOX, chroma and TOC firstly increased and then decreased with the decrease of the molar ratio of Fe2+ to 11202, while continuously increased with the increase of iron scraps and Fenton reaction time. The optimal condition was determined as Fe2+:H2O2 ratio of 1:8, iron scraps reaction time of 4 h and Fenton reaction time of 60 min, under which 94. 2% of AOX, 93.7% of chroma and 27. 2% of TOC were removed. A comparison study revealed that the iron scraps-Fenton-coagulation combined process could achieve much better removal of AOX, chroma and TOC than any other single or combined processes of iron treatment, Fenton oxidation and coagulation. GC-MS analysis revealed that halogenated compounds and anilines were efficiently removed, as well as nitrobenzenes, phenols, benzaldehydes, ethers, nitriles and heterocyclic compounds. center dot OH was found to devote much in the Fenton reaction according to the tert-butyl alcohol trapping hydroxyl radicals test.
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  • A novel hydrolytic product from flesh of Mactra veneriformis and its bioactivities in calcium supplement

    Wang Lingchong   Chen Shiyong   Liu Rui  

    To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the most suitable enzyme for hydrolyzing the flesh residue to release calcium-binding peptides among the seven tested proteases. The pepsin hydrolyzate (PHM) was divided into three fractions according to the molecule weight of its composition, which ranged from 0.5 to 15 kDa. The low-molecule-weight fraction named PHM-3 had the highest capability in combining calcium. The peptides existing in the PHM-3 fraction consisted of higher contents of Glu, Ala and Leu, and could produce one type of calcium-peptide complex by powerfully chelating calcium ions. PHM-3 products could effectively increase calcium absorption and retention while they decreased the calcium excretion in animal tests. Additionally, symptoms caused by low calcium bioavailability in ovariectomized rats, such as bone mineral density reduction and mechanical strength loss could be significantly ameliorated by the hydrolytic products addition in diet.
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  • Using Elitist Particle Swarm Optimization to Facilitate Real Estate Portfolio Based on Information Entropy

    Liu Rui   Wang Xiaoya  

    The real estate industry has been the pillar industry Of national economic. And the high returns and high risks would coexist in this industry. First, this paper established the real estate portfolio model based on information entropy, with the smallest risk as the greatest benefits. In addition, this paper developed a new algorithm to find the optimal real estate portfolio to achieve the smallest risk as the greatest benefits. And the proposed algorithm modified a population based search procedure, particle swarm optimization, by adopting an elite archiving scheme to store nondominated solutions and by aptly using members of the archive to direct further search. Moreover, the termination of the proposed algorithm was set to that no new members have entered into the elite archive. In addition, through a practical case, the proposed algorithm is shown effective and efficient in real estate portfolio.
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  • Simultaneous determination of seven major triterpenoids in Pyrola decorata H. Andres by LC-MS method.

    Zhang YuanYuan   Zhang Chao   Ren Rui   Liu Rui  

    A liquid chromatography-mass spectrometry method was developed and validated for the quantitative determination of seven triterpenoids, 3-beta-O-alpha-L-arabinopyranosylsiaresinolic acid-28-O-beta-D-glucopyranosyl ester, ziyuglycoside I, pomolic acid, maslinic acid, colosic acid, oleanolic acid and ursolic acid in Pyrola decorata H. Andres. Chromatographic separation was achieved on a Hypersil C 18 column using isocratic elution followed by a linear gradient elution of methanol and water as mobile phase. The analytes were ionized by atmospheric pressure chemical ionization source and determined on selected ion monitoring mode. All analytes showed good linearity ( r2≥0.9984) within the test ranges and the recovery rates were 94.5%-103.3%. Satisfactory precision and reproducibility were obtained with relative standard deviation less than 5%. The method was simple, accurate and performed well in application to the determination of twenty commercial samples of P. decorata collected from different regions of China. It could be used for the quality control of both plant materials and preparations of P. decorata.
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  • Concept of the solar ring mission: Overview

    Wang YuMing   Ji HaiSheng   Wang YaMin   Xia LiDong   Shen ChengLong   Guo JingNan   Zhang QuanHao   Huang ZhengHua   Liu Kai   Li XiaoLei   Liu Rui   Wang JingXiu   Wang Shui  

    The concept of the Solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phase study was funded by the National Natural Science Foundation of China in November 2018 and then by the Strategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. Solar Ring mission will be the first attempt to routinely monitor and study the Sun and inner heliosphere from a full 360-degree perspective in the ecliptic plane. The current preliminary design of the Solar Ring mission is to deploy six spacecraft, grouped in three pairs, on a sub-AU orbit around the Sun. The two spacecraft in each group are separated by about 30 degrees and every two groups by about 120 degrees. This configuration with necessary science payloads will allow us to establish three unprecedented capabilities: (1) determine the photospheric vector magnetic field with unambiguity, (2) provide 360-degree maps of the Sun and the inner heliosphere routinely, and (3) resolve the solar wind structures at multiple scales and multiple longitudes. With these capabilities, the Solar Ring mission aims to address the origin of solar cycle, the origin of solar eruptions, the origin of solar wind structures and the origin of severe space weather events. The successful accomplishment of the mission will advance our understanding of the star and the space environment that hold our life and enhance our capability of expanding the next new territory of human.
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  • Effect of silica particles on electrical treeing initiation in silicone rubber

    Zhou Yuan-xiang   Liu Rui   Hou Fei   Xue Wen-bin   Zhang Xu  

    Silicone rubber (SIR) widely used in the insulation of the prefabricated power cable accessories is actually a kind of polymer composite which is usually composited by neat SIR and several weight percentages of silica (SiO 2) particles. The aim of dispersing SiO 2 powders into the SIR is mainly to enhance the mechanic properties of the polymer. Some research indicates that the particles may also affect the electrical treeing progress of the polymer composite. Electrical treeing is one of the main causes of degradation and breakdown of solid insulating material such as SIR. In this article, a serial of SIR samples with different weight percentages of SiO 2 particles were made, a classic needle-plate electrode system was used to test their electrical treeing initiation performance and an optical microscope system was founded to observe the electrical treeing progress. In the experiment, the AC voltage applied on the electrodes was raised at a certain rate and when the electrical trees initiated in the SIR samples, the voltages and the photos of the trees were recorded. By comparing the results of experiment, it was found that when the weight percentages were under a threshold value, the SiO 2 particles hindered the electrical tree growth in the polymer composites. This work afforded experimental evidence to the research on the electrical treeing in polymers.
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  • Microstructure and Mechanical Properties of Nano-Size Zirconium Carbide Dispersion Strengthened Tungsten Alloys Fabricated by Spark Plasma Sintering Method

    Xie Zhuoming   Liu Rui   Fang Qianfeng   Zhang Tao   Jiang Yan   Wang Xianping   Liu Changsong  

    W-(0.2, 0.5, 1.0)wt% ZrC alloys with a relative density above 97.5% were fabricated through the spark plasma sintering (SPS) method. The grain size of W-1.0wt% ZrC is about 2.7 mu m, smaller than that of pure W and W-(0.2, 0.5)wt% ZrC. The results indicated that the W-ZrC alloys exhibit higher hardness at room temperature, higher tensile strength at high temperature, and a lower ductile to brittle transition temperature (DBTT) than pure W. The tensile strength and total elongation of W-0.5wt% ZrC alloy at 700 degrees C is 535 MPa and 24.8%, which are respectively 59% and 114% higher than those of pure W (337 MPa, 11.6%). The DBTT of W-(0.2, 0.5, 1.0)wt% ZrC materials is in the range of 500 degrees C-600 degrees C, which is about 100 degrees C lower than that of pure W. Based on microstructure analysis, the improved mechanical properties of the W-ZrC alloys were suggested to originate from the enhanced grain boundary cohesion by ZrC capturing the impurity oxygen in tungsten and nano-size ZrC dispersion strengthening.
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