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Search Results: 1 - 10 of 104208 matches for " ZHANG ZhengXi "
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Lithium secondary batteries using an asymmetric sulfonium-based room temperature ionic liquid as a potential electrolyte
ShiChun Luo,ZhengXi Zhang,Li Yang
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-007-0526-0
Abstract: A new asymmetric sulfonium-based ionic liquid, 1-butyldimethylsulfonium bis(trifluoromethylsulfonyl) imide (S114TFSI), was developed as electrolyte material for lithium secondary battery. Its cathodic potential was a little more positive against the Li/Li+, so vinylene carbonate (VC) was added into the LiTFSI/S114TFSI ionic liquid electrolyte to ensure the formation of a solid electrolyte interface (SEI), which effectively prevented the decomposition of the electrolyte. The properties of the Li/LiMn2O4 cell containing S114TFSI-based electrolyte were studied and the cycle performances were compared to those with a conventional organic electrolyte (1 mol/L LiPF6/DMC:EC=1:1(w/w)) at room temperature. Electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) were conducted to analyze the mechanisms affecting the cell performances at different temperatures. The lithium secondary battery system, using the above ionic liquid electrolyte material, shows good cycle performances and good safety at room temperature, and is worthwhile to further investigate so as to find out the potential application.
Lithium secondary batteries using an asymmetric sulfonium-based room temperature ionic liquid as a potential electrolyte
LUO ShiChun,ZHANG ZhengXi,YANG Li,

科学通报(英文版) , 2008,
Abstract: A new asymmetric sulfonium-based ionic liquid, 1-butyldimethylsulfonium bis(trifluoromethylsulfonyl) imide (S114TFSI), was developed as electrolyte material for lithium secondary battery. Its cathodic po- tential was a little more positive against the Li/Li , so vinylene carbonate (VC) was added into the LiTFSI/S114TFSI ionic liquid electrolyte to ensure the formation of a solid electrolyte interface (SEI), which effectively prevented the decomposition of the electrolyte. The properties of the Li/LiMn2O4 cell containing S114TFSI-based electrolyte were studied and the cycle performances were compared to those with a conventional organic electrolyte (1 mol/L LiPF6/DMC:EC=1:1(w/w)) at room temperature. Electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) were conducted to analyze the mechanisms affecting the cell performances at different temperatures. The lithium secondary bat- tery system, using the above ionic liquid electrolyte material, shows good cycle performances and good safety at room temperature, and is worthwhile to further investigate so as to find out the potential application.
Li/LiFePO4 battery performance with a guanidinium-based ionic liquid as the electrolyte
XinYue Zhang,ShaoHua Fang,ZhengXi Zhang,Li Yang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4655-0
Abstract: A new guanidinium-based ionic liquid (IL) was investigated as a novel electrolyte for a lithium rechargeable battery. The viscosity, conductivity, lithium redox behavior, and charge-discharge characteristics of the lithium rechargeable batteries were investigated for the IL electrolyte with 0.3 mol kg 1 lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. Li/LiFePO4 cells incorporating the IL electrolyte without additives showed good cycle properties at a charge-discharge current rate of 0.1 C, and exhibited good rate capabilities in the presence of a mass fraction of 10% vinylene carbonate or gamma-butyrolactone.
Electrochemical behavior of aluminum foil in 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids electrolytes
Chengxin Peng,Li Yang,Baofeng Wang,Zhengxi Zhang,Nan Li
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2179-9
Abstract: Aluminum (AI) foil is widely used as a current collector in lithium ion batteries, EDLCs and other electrochemical devices, and its electrochemical behavior in electrolytes has great effect on the cycle performances and safety of the electrochemical devices. In this work, corrosion behavior of AI foil in 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids and its electrolytes containing LiTFSI as salt were studied using cyclic voltammogram method. It was found that a passive film was firmly formed on the surface of AI foil after the anodic polarization in BMI-BF4 compared to those in EMI-BF4 and PMI-BF4. In addition, anodic polarization research showed that the passive film on AI surface in BMI-TFSI did not well exist. A good passive film formed on the surface of AI foil in BMI-BF4 was not broken down until the potential was up to 94.58 V. Moreover, EDX and XPS analysis showed that F and O exist on the AI surface after the anodic polarization in BMI-BF4, which indicated that a passive film like AIF3 and Al2O3 may be formed on its surface.
A New Sesquilignan Glucoside from Uraria sinensis
Yingda Yang,Zhengxi Hu,Zengwei Luo,Yongbo Xue,Guangmin Yao,Yanyan Wang,Yonghui Zhang
Molecules , 2014, DOI: 10.3390/molecules19011178
Abstract: A new sesquilignan glucoside, urariasinoside A ( 1), together with eight known compounds, including two lignans, a sesquilignan, a dilignan, and four flavonoid derivatives were isolated from the aerial parts of Uraria sinensis. Their structures were determined on the basis of extensive spectroscopic analyses and comparison with literature data. Compound 1 was evaluated for in vitro cytotoxicity activity against HL-60, SMMC-7721, A549, MCF-7, SW480, and BEAS-2B cell lines.
Baseline-Dependent Responses of Soil Organic Carbon Dynamics to Climate and Land Disturbances
Zhengxi Tan,Shuguang Liu
Applied and Environmental Soil Science , 2013, DOI: 10.1155/2013/206758
Abstract:
Baseline-Dependent Responses of Soil Organic Carbon Dynamics to Climate and Land Disturbances
Zhengxi Tan,Shuguang Liu
Applied and Environmental Soil Science , 2013, DOI: 10.1155/2013/206758
Abstract: Terrestrial carbon (C) sequestration through optimizing land use and management is widely considered a realistic option to mitigate the global greenhouse effect. But how the responses of individual ecosystems to changes in land use and management are related to baseline soil organic C (SOC) levels still needs to be evaluated at various scales. In this study, we modeled SOC dynamics within both natural and managed ecosystems in North Dakota of the United States and found that the average SOC stock in the top 20 cm depth of soil lost at a rate of 450?kg?C?ha?1?yr?1 in cropland and 110?kg?C?ha?1?yr?1 in grassland between 1971 and 1998. Since 1998, the study area had become a SOC sink at a rate of 44?kg?C?ha?1?yr?1. The annual rate of SOC change in all types of lands substantially depends on the magnitude of initial SOC contents, but such dependency varies more with climatic variables within natural ecosystems and with management practices within managed ecosystems. Additionally, soils with high baseline SOC stocks tend to be C sources following any land surface disturbances, whereas soils having low baseline C contents likely become C sinks following conservation management. 1. Introduction Soil carbon (C) dynamics and change rate caused by land surface disturbances and climate change are generally related to the magnitude of initial soil organic C (SOC) [1–10]. These investigators observed a strong negative relationship between the rate of change in SOC and the baseline SOC content, and this relationship has been thought to have no effect on any other soil properties [4]. However, the effect of the baseline SOC content has been neither evaluated under considerations of individual land use and land cover (LULC) types and their temporal change nor counted in the assessment on the potential of terrestrial ecosystem C sequestration through adaptation strategies. To further assess ecosystem-climate system feedback and define a strategy to reduce the buildup of atmospheric greenhouse gases using terrestrial C sequestration as an option, it is necessary to improve our understanding of not only the C biogeochemical cycles associated with LULC dynamics, but also the sensitivity of SOC stock to transient land disturbances and its relation to the baseline SOC level at multiple temporal and spatial scales. And the data obtained from specific sites have to be upscaled to a regional scope through modeling algorithms that can constrain uncertainties derived from local scales. The General Ensemble biogeochemical Modeling System (GEMS) is a new type of multilevel
Analysis of the effects of 17β-oestradiol and serum deprivation on the contents of proteins in breast cancer cells by isobaric tags for relative and absolute quantification and two-dimensional liquid chromatography-tandem mass spectrometry
用于相对和绝对定量的等量异位标签-二维液相色谱-串联质谱法分析雌二醇和血清剥夺对乳腺癌细胞内蛋白质含量的影响

ZHU Lei,NI Guoxin,ZHANG Zhengxi,XU Xuemin,HU Xiaofang,LI Wei,
朱镭
,倪国新,张政希,徐学敏,胡晓芳,李伟

色谱 , 2009,
Abstract: 雌激素和血清中的激素及各种生长因子在乳腺癌的发生、发展过程中发挥着重要的作用.研究雌激素和血清对乳腺癌细胞中蛋白质组成和含量的影响对于阐明雌激素和血清对乳腺癌细胞影响的分子机理具有重要的意义.利用四重用于相对和绝对定量的等量异位标签(isobaric tags for relative and absolute quantification, iTRAQ)标记结合二维液相色谱-串联质谱(two-dimensional liquid chromatography-tandem mass spectrometry, 2D-LC-MS/MS)对雌二醇(17β-oestradiol, E2)和血清各自以及共同作用对MCF7乳腺癌细胞内蛋白质表达的影响进行了比较,共鉴定到置信度在95%以上的蛋白质576种,其中各组相对于正常培养组的细胞共找到26种差异在1倍以上的蛋白质,其中10种上调,16种下调.研究发现E2和血清可显著影响细胞内与蛋白质合成相关的蛋白质的水平.实验结果表明:iTRAQ-LC-MS/MS是进行多个样品差异蛋白组比较的一种有效方法.
Simulated responses of soil organic carbon stock to tillage management scenarios in the Northwest Great Plains
Zhengxi Tan, Shuguang Liu, Zhengpeng Li, Thomas R Loveland
Carbon Balance and Management , 2007, DOI: 10.1186/1750-0680-2-7
Abstract: Model simulations show that the average amount of C (kg C ha-1yr-1) released from croplands between 1972 and 2000 was 246 with ATM, 261 with CT, and 210 with NT. The reduction in the rate of C emissions with conversion of CT to NT at the ecoregion scale is much smaller than those reported at plot scale and simulated for other regions. Results indicate that the response of SOC to tillage practices depends significantly on baseline SOC levels: the conversion of CT to NT had less influence on SOC stocks in soils having lower baseline SOC levels but would lead to higher potentials to mitigate C release from soils having higher baseline SOC levels.For assessing the potential of agricultural soils to mitigate C emissions with conservation tillage practices, it is critical to consider both the crop rotations being used at a local scale and the composition of all cropping systems at a regional scale.Many studies have identified the potential of soils cultivated with conservation practices (e.g., no-till) to sequester large amounts of carbon (C) [1,2]. It is estimated that conservation tillage practices across the United States may drive large-scale sequestration on the order of 24–40 Tg C yr-1 (Tg: teragram; 1 Tg = 1012 g), and that additional C sequestration of 25–63 Tg C yr-1 can be achieved through other modifications to traditional agricultural practices [3]. In regard to the C credit scenario established by the Kyoto Protocol, it is widely suggested that conversion of conventional tillage (CT) to no-till (NT) can help to support the profitability of C credits for farmers. The uncertainties of these sequestration scenarios, however, depend on soil organic carbon (SOC) monitoring and/or models [2].Recently, eddy-covariance measurements have been used to evaluate the contribution of NT practice to C dynamics in corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation ecosystems at regional and national scales [1,2]. However, the relationships between net ecosystem
Identification and expression profiling of putative odorant-binding proteins in the malaria mosquitoes, Anopheles gambiae and A. arabiensis
Zhengxi Li,Jing-Jiang Zhou,Zuorui Shen,Field Lin
Science China Life Sciences , 2004, DOI: 10.1360/03yc0232
Abstract: Olfaction plays a major role in host-seeking behaviour of mosquitoes. An informatics-based genome-wide analysis of odorant-binding protein (OBP) homologues is undertaken, and 32 putative OBP genes in total in the whole genome sequences of Anopheles gambiae are identified. Tissue-specific expression patterns of all A. gambiae OBP candidates are determined by semi-quantitative Reverse Transcription (RT)-PCR using mosquito actin gene as internal expression control standard. The results showed that 20 OBP candidates had strong expression in mosquito olfactory tissues (female antennae), which indicate that OBPs may play an important role in regulating mosquito olfactory behaviours. Species-specific expression patterns of all putative anopheline OBPs are also studied in two of the most important malaria vectors in A. gambiae complex, i.e. A. gambiae and A. arabiensis, which found 12 of the putative OBP genes examined displayed species-differential expression patterns. The cumulative relative expression intensity of the OBPs in A. arabiensis antennae was higher than that in A. gambiae (the ratio is 1441.45:1314.12), which might be due to their different host preference behaviour. While A. gambiae is a highly anthropophilic mosquito, A. arabiensis is more opportunistic (varying from anthropophilic to zoophilic). So the latter should need more OBPs to support its host selection preference. Identification of mosquito OBPs and verification of their tissue- and species-specific expression patterns represent the first step towards further molecular analysis of mosquito olfactory mechanism, such as recombinant expression and ligand identification.
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