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Search Results: 1 - 10 of 127011 matches for " Zhengxi Li "
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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.
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.
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.
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.
Wolbachia extensively harbored by Bemisia tabaci in China
我国烟粉虱自然种群中存在广泛的Wolbachia感染现象

Xiaopeng Guo,Zhengxi Li,
郭晓鹏
,李正西

微生物学报 , 2008,
Abstract: Wolbachia are a group of maternally inherited bacteria harbored by a variety of arthropods and can ma- nipulate the reproductivity of their hosts. Eighteen populations of whiteflies were collected from Hebei, Xinjiang, Beijing, Shandong, Zhejiang, Guangxi, Hainan, Guangzhou and Fujian provinces, China. These whiteflies were molecularly identified using internal transcribed spacer 1 ITS1 rDNA sequences. They were then detected for Wolbachia infection using Wolbachia-specific primers designed based on 16S rDNA and wsp gene sequences. The results showed that almost all populations were detected positive for Wolbachia infection. Whiteflies of B / Q group mainly carried Wolbachia belonging to supergroup A, while non-B / Q whiteflies were commonly detected for Wolbachia superinfection. This study indicated that the infection rate of Wolbachia in natural populations of B. tabaci might be much higher than expected, and the threshold of detection methods may be one of the key factors influencing detection of Wolbachia infection.
Effect of pollen of conventional cotton and transgenic Cry1Ac+CpTI cotton on reproduction and survival of the parasitoid wasp Trichogramma confusum Viggiani(Hymenoptera: Trichogrammatidae)
常规棉花粉和转Cry1Ac+CpTI棉花粉对拟澳洲赤眼蜂繁殖和存活的影响

GENG Jinhu,SHEN Zuorui,LI Zhengxi,ZHENG Li,
耿金虎
,沈佐锐,李正西,郑礼

生态学报 , 2005,
Abstract: The cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is the most important pest of cotton in China, causing both quantitative and qualitative losses. Trichogramma confusum Viggiani (Hymenoptera: Trichogrammatidae) is an endemic egg parasitoid of cotton bollworm H. armigera in China and is a potential biological control agent. The availability and quality of food played an important role in determing the effectiveness of parasitoids as control agents. Adult Trichogramma spp. are known...
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
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