检索结果-南通市图书馆

Synthesis, catalytic and biological activity of novel dinuclear copper complex with Schiff base

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2006年第3期49卷 225-229页

作者： WEI Danyi1,2, li ning1, LU Gui1 & YAO Kemin1 1. Department of Chemistry, Zhejiang University, Hangzhou 310027, China 2. Institute of Inorganic Chemistry, ningbo University, ningbo 315211, China Department of Chemistry Zhejiang University Hangzhou China Institute of Inorganic Chemistry Ningbo University Ningbo China

A novel dinuclear copper complex with tetraglycol aldehyde-phenylalanineSchiff base has been synthesized. It was characterized and formulated as [Cu_2L(NO_3)]NO_3 byelemental analysis, magnetic susceptibility, TG-DTA, IR, EPR and ~1H NMR spectra. The obtainedcomplex can be used as a good catalyst for the polymerization of methyl methacrylate (MMA). Theoptimum polymerization conditions are: MMA/catalyst = 500 (molar ratio); [catalyst] =7.5x10^(-3)mol·L^(-1); dioxane as solvent; 80℃; 6 h. Polymethyl methacrylate (PMMA) with 80%conversion, 7.2x10^5 viscosity-average molecular weight and 60.5% syndiotacticity was obtained. Thiscomplex has also been shown to play an important role in scavenging O_2^-.

关键词： novel copper complex, Schiff base, catalytic activity, scavenging effect of O-·2.

Forms and functions of inorganic carbon in the Jiaozhou Bay sediments

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2009年第6期28卷 30-41页

作者： li Xuegang SONG Jinming YUAN Huamao lining Institute of Oceanology Chinese Academy of Science Qingdao 266071 China

Inorganic carbon forms and their influencing factors, mutual transformation and contribution to carbon cycling in the Jiaozhou Bay sediments were discussed. The results show that inorganic carbon in sediments could be divided into five forms： NaCl form, NH3-H20 form, NaOH form, NH20H-HCl form and HCI form. Thereinto, *** form and HCl form account for more than 70% of total inorganic carbon. There was close relationship among every form of inorganic carbon and their correlativity was clearly different with different sedimentary environment except the similar strong positive correlation among NH-OH-HCl form, HCl form and total inorganic carbon in all regions of the Jiaozhou Bay. All forms of inorganic carbon were influenced by organic carbon, pH, Eh, Es, nitrogen and phosphorus in sediments, but their influence had different characteristics in different regions. Every form of inorganic carbon transformed into each other continuously during early diagenesis of sediments and the common phenomenon was that NaCl form, NH3-H2O form, NaOH form and NH2OH-HCl form might transform into steady HCl form. NaCl form, NH3-H2O form, NaOH form and NH2OH-HCl form could participate in carbon recycle and they are potential carbon source; HCl form may be buried for a long time in sediments, and it may be one of the final resting places of atmospheric C02. Inorganic carbon which entered into sediments was about 4.98× 1010 g in the Jiaozhou Bay every year, in which about 1.47×1010 g of inorganic carbon might be buried for a long time and about 3.51 × 1010 g of inorganic carbon might return into seawater and take part in carbon recycling.

关键词： different forms of inorganic carbon marine carbon cycling the Jiaozhou Bay sediments

A 6.2–9.5 GHz receiver for Wimedia MB-OFDM and China UWB standard

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第2期54卷 407-418页

作者： GAO Ting1, ZHOU Feng1, li Wei1, LAN Fei1, li ning1 & REN JunYan1,2 1State Key Laboratory of ASIC & System, Fudan University, Shanghai 201203, China 2Micro-/Nano-Electronics Science and Technology Innovation Platform, Shanghai 201203, China State Key Laboratory of ASIC & System Fudan University

An integrated 6.2–9.5 GHz UWB receiver for both WiMedia MB-OFDM and China UWB standard is proposed. The receiver can cover Group#3, Group#4 for WiMedia and Group#2–5 for China UWB standard respectively. The fully differential receiver consists of a wideband LNA and a down conversion mixer with high gain and low gain mode. A low-pass filter with controllable gain and cut-o? frequency along with a programmable gain amplifier are also included. The chip was fabricated in TSMC 0.13-μm RF CMOS process. Measurement results show that the receiver achieves voltage gain from 21 to 69 dB with 2 dB/step and an NF of 3.2–4.6 dB over 6.2–9.5 GHz and 1-dB compression point of ?21 dBm. The intermediate frequency of the receiver can be switched between 264 and 132 MHz, which enables the receiver applicable for both WiMedia and China UWB standard. Power consumption is only 47 mA with 1.2–V supply voltage.

关键词： CMOS ultra-wideband (UWB) MB-OFDM China UWB standard radio frequency (RF) low noise amplifier (LNA) quadrature mixer low-pass filter (LPF) Gm-C noise figure

A current-mode RF transmitter for 6–9 GHz MB-OFDM UWB application

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(Information Sciences) 2011年第2期54卷 419-428页

作者： CHEN YunFeng1, FAN JinHan1, li Wei1, li ning1 & REN JunYan1,2 1State Key Laboratory of ASIC & System, Fudan University, Shanghai 201203, China 2Micro-/Nano-Electronics Science and Technology Innovation Platform, Fudan University, Shanghai 201203, China State Key Laboratory of ASIC & System Fudan University

This paper presents a current-mode 6–9 GHz RF transmitter for MB-OFDM UWB systems. The proposed current-mode transmitter consists of current-mode IQ LPF, current mirror amplifier, IQ up-conversion mixer (up-mixer), differential power driver amplifier (PA) and high-speed divider with LO buffers for generating IQ LO signals. All circuits are designed to possess high linearity and wide bandwidth. The transmitter is fabricated in TSMC 0.13 μm 1P8M RF CMOS technology with a die area of 1.56 mm2. Measurement results show that a maximum output power of -0.7 dBm with an LO leakage/sideband rejection ratio (LOL/SB RR) around -33/ - 35 dBc is achieved, and that this transmitter excels the traditional voltage-mode counterpart in terms of high linearity (about +1 dBm output 1-dB compression point, +10 dBm output IP3 in average) with comparable power consumption (drawing 48 mA current from 1.2 V supply).

关键词： current-mode RF transmitter high linearity MB-OFDM UWB high speed divider CMOS

Spatial distributions and seasonal variations of particulate phosphorus in the Jiaozhou Bay in North China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2009年第1期28卷 99-108页

作者： YUAN Huamao SONG Jinming li ning li Xuegang ZHANG Ying XU Sisi Key Laboratory of Marine Ecology. and Environmental Sciences Institute of Oceanography Chinese Academy of Sciences Qingdao 266071 China Graduate School Chinese Academy of Science Beijing 100039 China

Based on the measurements of particulate phosphorus（PP） in the Jiaozhou Bay from May 2003 to April 2004,the spatial distribution,seasonal variation and biogeochemical characteristics of PP were investigated to understand the fates and roles of phosphorus in the Jiaozhou Bay *** concentration of the total PP ranged from 0.07 to 2.09 μmol/*** concentration of POP was from 0.01 to 1.83 μmol/dm3,with an average of 0.32 μmol/dm3,which accounted for 49.6% in total *** concentration of PIP was from 0.01 to 1.49 μmol/dm3,with an average of 0.33 μmol/dm3,which accounted for 50.4% in total *** general,the concentrations of PP in surface water show obvious seasonal variations in the Jiaozhou *** was the highest in spring,which derived from the accumulation of phyto-detritus and was the lowest in autumn,which was decomposed into seawaters to participate the recycle of *** was the highest in spring and summer and was the lowest in autumn and *** was mainly influenced by river input in the inner bay but POP derived from autochthonous source in the outer ***,the concentrations of PP in the inner bay were higher than those in mouth and the outer *** the inner bay,the concentrations of PP with the area near the shore were higher than those in the center of the *** PP showed the decreasing trend with depth especially in spring and *** high value of PP emerged in 20 and 10 m corresponding to summer and autumn,*** changes of POP showed hysteretic effect compared with the changes of Chl a in the investigated ***,according to the change of Chl a,the second high value of POP which should be emerged in October was missing due to the remineralization of POP and participation in the recycle of phosphorus,which lead to the high concentration of orthophosphate in seawaters.

关键词： particulate phosphorus Jiaozhou Bay seawaters

Studies on the regional feature of organic carbon in sediments off the Huanghe River Estuary waters

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2004年第1期23卷 129-134页

作者： YUAN Huamao1, 2, liU Zhigang3, SONG Jinming1, L Xiaoxia1, 2 li Xuegang1, 2, li ning1, 2, ZHAN Tianrong1, 21. MEES, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China3. Zhoushan Marine Eco-environmental Monitoring Station of Zhejiang Province, Zhoushan 316004, China MEES Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Organic carbon (OC) in definitely small area sediments(according to marine dimension)off the Huanghe River Estuary is investigated in order to evaluate the feature of regional difference of physical and chemical properties in marginal sea *** distributions of OC in sediments with natural grain size and the relationship with the pH,Eh ,Es and Fe3+/Fe2+ are *** addition,OC decomposition rates in surfacial/subsurfacial sediments are *** concentrations range from 0.26% to 1.8%(wt)in the study area. Significant differences in OC content and in horizontal distribution as well as various trends in surfacial /subsurfacial sediments exhibit the feature of regional difference remarkably in marginal sea sediments. The complicated distribution of OC in surface sediments is due to the influence of bacterial activity and abundance, bioturbation of benthos and physical disturbance. The OC decomposition rate constant in surfacial /subsurfacial sediments ranges from 0.009 7 to 0.076 a-1 and the relatively high values may be mainly related to bacteria that are mainly responsible for OC mineralization;meio-and macrofauna affect OC degradation both directly, through feeding on it, and indirectly through bioturbation and at the same time coarse sediments are also disadvantageous to OC *** almost all the middle and bottom sediments the contents of OC decrease with the increase of deposition depth, which indicates that mineralization of OC in the middle and bottom sediments has occurred via processes like SO reduction and Fe-oxide reduction.

关键词： regional feature organic carbon sediments Huanghe River Estuary

Production of porcine cloned transgenic embryos expressing green fluorescent protein by somatic cell nuclear transfer

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(life Sciences) 2006年第2期49卷 164-171页

作者： ZHANG Yunhai1, PAN Dengke1,2, SUN Xiuzhu1, SUN Guojie1, WANG Xiaobo1, liU Xiaohui1, li Yan1, DAI Yunping1 & li ning1 1. State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100094, China 2. College of Animal Science and Technology, China Agricultural University, Beijing 100094, China State Key Laboratory for Agrobiotechnology China Agricultural University Beijing China College of Animal Science and Technology China Agricultural University Beijing China

In the present study, nuclear transferred embryos (NTEs) were reconstructed by using pig fetal fibroblasts as donors; in vitro matured oocytes as recipients. The effects of G418 selection on donor cells, duration of IVM of prepubertal gilt oocytes; oxygen tension in IVM of oocytes were investigated. The results were as follows: (i) When G418 selected cells expressing GFP were used as donors, the cleavage rate of NTEs decreased drastically in comparison to NTEs derived from donors without antibiotic selection (47.5% vs. 71.6%, p>0.05). For the blastocyst rate, no significant difference was observed between two groups (10% vs. 10.4%, p0.05). However, no statistical difference was observed between NTEs derived from oocytes of 36 h IVM group; NTEs from oocytes of 42 h IVM group in the rates of cleavage (59.3% vs. 73.6%, p13.2%, p1%, p11.8% vs. 12.3%, p18 selection does not have a significant effect on cleavage rate of NTEs expressing GFP. (ii) Nuclear maturation is greatly improved by prolonging IVM duration from 36 to 42 h, while no significant differences were observed for developmental potential of transgenic embryos. Thus IVM 42 h is the better choice in order to obtain maximum number of MII oocytes as recipients. (iii) Lower oxygen tension; higher oxygen tension in IVM have no significant effect on development of cloned embryos.

关键词： transgenic cloning, GFP, Pig, early development.

具有乳腺导管再生能力的小鼠乳腺原基细胞群黏附因子的表达特点

在线全文

学校读者我要写书评

暂无评论

生物化学与生物物理进展 2010年第5期37卷 490-495页

作者：宋嘉哲薛恺李松李宁中国农业大学生物学院农业生物技术国家重点实验室北京100193 北京济普霖生物技术有限公司北京100193

乳腺干细胞是研究器官形成、细胞增殖、分化、生存和凋亡等信号通路的理想模型,而近来的研究发现许多成体干细胞的特异性表面标记都与细胞黏附分子(celladhesion molecule,CAM)家族相关.因此,研究胚胎期乳腺干/祖细胞群的黏附分子基因... 详细信息

乳腺干细胞是研究器官形成、细胞增殖、分化、生存和凋亡等信号通路的理想模型,而近来的研究发现许多成体干细胞的特异性表面标记都与细胞黏附分子(celladhesion molecule,CAM)家族相关.因此,研究胚胎期乳腺干/祖细胞群的黏附分子基因表达特点,对于纯化和鉴定胚胎期乳腺干/祖细胞具有重要指导意义.用成年小鼠乳腺上皮干细胞的标记CD24和CD49f来分选小鼠胚胎期14天乳腺原基细胞群,发现CD24+和CD49f+双阳性的乳腺原基细胞包含两个细胞群:CD24hiCD49f+细胞群和CD24medCD49f+细胞群.它们占乳腺原基总细胞的比例分别为16%和47%.在随后的细胞培养实验和体内移植再生实验中发现,CD24medCD49f+细胞群可以贴壁,而且具有再生乳腺导管的能力,相反,CD24hiCD49f+细胞群既不能贴壁也不具有移植再生能力.这些结果表明,这两个细胞群分别代表不同的细胞类型,而CD24medCD49f+细胞群有可能包含具有自我更新能力的乳腺原基干/祖细胞.挑选了可能与乳腺相关的19个黏附分子,并对这两群细胞进行了定量PCR检测.结果表明,具有乳腺导管重建能力的CD24medCD49f+细胞群的黏附分子基因表达明显区别于CD24hiCD49f+细胞群,而且其中几个与成体干细胞相关的标记基因在CD24medCD49f+细胞群中的表达显著高于CD24hiCD49f+细胞群.

关键词：乳腺原基乳腺干细胞细胞黏附分子再生

在线全文

学校读者我要写书评

暂无评论

一种无线局域网节能协议研究

系统仿真学报 2004年第12期16卷 2831-2836页

作者：黎宁徐艳谢胜利广州通信研究所广东广州510310 华南理工大学电子与信息学院广东广州510640

提出了一种基于802.11DCF的分布式报文驱动节能协议802.11PS协议,通过使结点在既不能发送又无需接收时进入睡眠状态来节省其能量消耗。采用近似方法分析了协议在全互连网络中的节能性能,并通过仿真验证了近似分析的合理性。结果表明,在... 详细信息

提出了一种基于802.11DCF的分布式报文驱动节能协议802.11PS协议,通过使结点在既不能发送又无需接收时进入睡眠状态来节省其能量消耗。采用近似方法分析了协议在全互连网络中的节能性能,并通过仿真验证了近似分析的合理性。结果表明,在没有接入点的无线局域网环境中,当网络负荷较高时,802.11PS协议能够有效降低网络结点无线网卡总功耗(最多可节能70%以上),并且其时延和吞吐率性能仍与802.11DCF协议大体相当。协议无需全网同步,也可用于多跳ad hoc网络。

关键词： 802.11DCF 802.11PS 无线网卡(NIC) 无线局域网节能