125 research outputs found

    STUDY ON THE LITFSI-BASED ELECTROLYTES FOR Li/MnO_2 BATTERIES

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    为改善lI/MnO2电池的低温放电性能,制备了一系列新型lITfSI系电解液,并且溶剂中加入适量乙酸甲酯.研究结果表明,电解液lITfSI(1 MOl/l)/PC∶dME∶EC∶MA是一种较好的体系.To improve the discharge performance of Li/MnO2 batteries at low temperatures,a series of new LiTFSI-based electrolytes were prepared.The methyl acetate was added into the mixed solvent.The experiments indicate that the LiTFSI(1 mol/L)PC∶DME∶EC∶MA(1∶1∶1∶3) is a good electrolyte

    An Optical High Temperature Thermometer for Plume Measurement of Solid Propellant Rocket Motor

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    利用辐射光谱测量温度的原理,设计并制造了一种新型的非接触式光学辐射高温计.详细介绍该温度计的基本原理和标定方法,并将该温度计应用于火箭发动机喷管出口羽流的温度测量中,初步的实验结果和数值模拟结果相一致

    代谢组学数据分析方法及在糖尿病研究中的应用

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    对NMR波谱数据的统计分析是基于NMR代谢组学研究的关键问题之一.鉴于NMR波谱信号可以近似为样品中各种成分谱信号的线性叠加,本文将非负矩阵分解(NMF)方法引入基于NMR代谢组学的数据处理中,并与代谢组学中常用的统计方法——主成分分析(PCA)进行比较.通过NMF和PCA两种方法对健康志愿者与2型糖尿患者血液和尿液的NMR谱图的统计分析,对所获取的特征代谢物进行比较和验证,并探讨了PCA方法可能存在的不足之处及其原因;阐明了NMF方法是基于NMR的代谢组学研究中较理想的数据分析方法.最后,讨论了基于NMR代谢组学在糖尿病研究中的前景

    Identification of Bohai Sea crude oil based on characteristic fingerprinting by MSPD-RP-HPLC

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    建立渤海原油的高效液相色谱(HPlC)特征指纹图谱,为渤海原油的鉴别提供一种新方法。以氧化铝作为基质固相分散剂进行样品处理,采用HPlC法进行分析,双反相C18色谱柱串联,以乙腈-水为流动相,二元线性梯度洗脱,流速为1.0 Ml/MIn,柱温为20℃,双波长检测226 nM、254 nM,进样量10μl;采用所发展的方法对10批渤海原油样品进行分析,建立渤海原油的HPlC特征指纹图谱,结合相似度分析用于渤海原油的鉴别。该方法具有很好的精密度、重复性和稳定性,10批渤海原油特征指纹图谱有13个共有峰,结合相似度分析可以用于渤海原油样品的鉴别,说明HPlC特征指纹图谱是渤海原油鉴别的有力工具。Based on the high performance liquid chromatography(HPLC) characteristic fingerprinting,a new method for crude oil identification of Bohai Sea was developed.The sample pretreatment was done using matrix solid-phase dispersion,and Al2O3 was used as the dispersant.The chromatographic fingerprints were determined by injecting 10 L sample solution each time on two reverse phase C18 columns in series with the gradient elution solvent system composed of water and acetonitrile.The flow rate was 1.0 mL/min,the column temperature was maintained at 20℃ and the signals were acquired at 226 nm and 254 nm.The characteristic fingerprints of crude oil were established by analysis of ten representative samples derived from Bohai Sea,and identification was carried out by the similarity analysis of the characteristic fingerprints.The method was ideally suited for the fingerprinting of Bohai Sea crude oil with good precision,repeatability and stability.13 peaks were selected as the common peaks of the characteristic fingerprint and used for the similarity analysis,which could be applied to distinguish crude oil of Bohai Sea from that of other sources.The characteristic HPLC fingerprinting technique thus was a powerful tool for the identification of crude oil originated from Bohai Sea.海洋公益性行业科研专项(200705011;201005034-3);中国海监技术支撑体系项目;2008年海洋环境保护及节能减排专

    Simultaneous determination of 7 nucleosides in Asterias rollestoni using reversed-phase high performance liquid chromatography

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    建立了罗氏海盘车中7种核苷化合物的反相高效液相色谱分析测定方法。采用超声波辅助提取,选用两根不同的C18色谱柱串联,以甲醇和0.2%(体积分数)乙酸/水溶液为流动相梯度洗脱分离。优化的色谱条件为:柱温为室温,检测波长为260nM,流速为0.8Ml/MIn,进样量为20μl。结果表明,7种核苷化合物在一定的浓度范围内线性关系良好,次黄嘌呤和胸苷的线性范围为0.65~40Mg/l,尿苷、黄嘌呤和肌苷的线性范围为0.80~40Mg/l,胸腺嘧啶的线性范围为1.15~40Mg/l,鸟苷的线性范围为0.50~40Mg/l。样品中7种核苷化合物的加标回收率为90.00%~105.00%,相对标准偏差为0.72%~3.23%。该方法操作简便、灵敏度高、重复性好,回收率高,适用于罗氏海盘车中7种核苷类成分的同时分析,也可用于罗氏海盘车的质量控制和综合评价。A method for the simultaneous determination of 7 nucleosides in Asterias rollestoni was devel-oped using reversed-phase high performance liquid chromatography ( RP-HPLC) .Analytes were extracted by ultrasonic-assisted extraction and separated on two different C18 columns,which were connected in se-ries,under the gradient elution with the mobile phases of methanol and 0.2% ( v/v) acetic acid/water at room temperature.The chromatographic conditions were as follows: flow rate,0.8 mL/min; detection wavelength,260 nm; injection volume,20 μL.Under the optimized conditions,good linear relationships between the values of mass concentrations and the peak areas of hypoxanthine,uridine,xanthine,thy-mine,inosine,guanosine and thymidine were observed in the ranges of 0.65-40,0.80-40,0.80-40,1.15-40,0.80-40,0.50-40,and 0.65-40 mg/L,respectively.The relative standard devia-tions were around 0.72%-3.23% and the recoveries were around 90.00%-105.00%.The results showed that the developed method is sensitive,accurate and reproducible.It is suitable for the analysis of nucleosides in Asterias rollestoni with high recoveries and it is expected to be used for the quality control and evaluation of Asterias rollestoni.国家自然科学基金项目(20905017);海洋公益性行业科研专项(200705011;200805039);海洋局青年基金项目(2010140);海洋一所基本科研业务专项(GY-022008T32;2010G25);中国科学院实验海洋生物学重点实验室开放基金课

    Electrocatalytic Oxidation of Formic Acid on Pd/Ni Heterostructured Catalyst

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    通过两步还原法制备了Pd/Ni双金属催化剂.由于金属Pd原子在先行还原的Ni纳米粒子表面的外延生长以及其在Ni表面及Pd表面生长表现出的吉布斯自由能差异,最终导致了异结构Pd/Ni纳米粒子的形成.高分辨电子透射显微镜结果证实了异结构的存在,然而X射线衍射测量表明Pd/Ni纳米粒子具有类似于Pd的面心立方结构.制备的Pd/Ni纳米粒子与同等条件下合成的Pd纳米粒子相比对甲酸氧化呈现了更高的电催化活性,而且电催化稳定性也要明显优于纯Pd纳米粒子,证明Pd/Ni双金属催化剂是可选的直接甲酸燃料电池阳极催化剂.双金属催化剂对甲酸氧化电催化活性和稳定性增强可能是Ni原子的修饰改变了Pd粒子表面配位不饱和原子的电子结构所致.A Pd/Ni bimetallic nanostructured electrocatalyst was fabricated via a two-step reduction route. Owing to an epitaxial growth of Pd atoms on the surface of Ni nanoparticles, heterostructured Pd/Ni nanocomposites were formed and verified by high resolution transmission electron microscopy combined with energy-dispersion X-ray spectroscopy. X-ray diffraction confirmed that the as-prepared Pd/Ni nanocomposites possessed a single face-centered-cubic (fcc) Pd structure, probably due to a weaker diffraction intensity of metallic Ni and/or overlapping by that of Pd. The intrinsic catalytic activity on the Pd/Ni is higher than that on the Pd. Moreover, the durability of formic acid oxidation on the Pd/Ni was much enhanced over the Pd nanoparticles. The change in electronic structure of the surface coordination unsaturated Pd atoms and the possible dissolution of Ni species from the Pd/Ni heterostructure may account for such an improved durability for formic acid oxidation.This work was supported by the National Basic Research Program of China (973 Program) (No. 2012CB932800), the Natural Science Foundation of China (No. 21073219), Shanghai Science and Technology Committee (No. 11DZ1200400) and the Knowledge Innovation Engineering of the CAS (No. 12406, 124091231).This work was supported by the National Basic Research Program of China (973 Program) (No. 2012CB932800), the Natural Science Foundation of China (No. 21073219), Shanghai Science and Technology Committee (No. 11DZ1200400) and the Knowledge Innovation Engineering of the CAS (No. 12406, 124091231).作者联系地址:1. 中国科学院上海高等研究院,上海 201210;2. 中国科学院研究生院,北京 100039Author's Address: 1. Shanghai Advanced Research Institute, Chinese Academy of Sciences CAS, Shanghai 201210, China; 2. Graduate School of the CAS, Beijing 100039, China通讯作者E-mail:[email protected] & [email protected]

    Preparations and Electrochemical Properties of BC/CoNi2S4@PPy Flexible Composites for Supercapacitors

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    本文采用溶剂热、原位聚合和真空抽滤相结合的方法制备了用于超级电容器的细菌纤维素/镍钴硫化物/聚吡咯(BC/CoNi2S4@PPy)柔性电极材料,通过X射线衍射、场发射扫描电镜、红外光谱、氮气吸脱附、拉伸强度和接触角表征了材料的形貌结构、组成、机械性能和亲水性,并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能。结果表明,表面含氧官能团丰富的BC纤维网络结构对氧化还原活性物质CoNi2S4的生长和导电聚合物PPy的分布具有引导作用,CoNi2S4均匀分布在BC网络中,且PPy均匀包覆在BC纤维和CoNi2S4纳米球表面构成具有丰富孔隙结构的三维导电网络,使得该复合材料具有较好的机械性(抗拉强度达28.0±0.1 MPa)、亲水性(对6 mol·L-1 KOH的瞬间接触角为43.6°)及良好的导电性。该电极材料在1 A·g-1下比电容高达2670 F·g-1,充放电循环10000次后比电容的保持率为82.73%,且经1000次反复弯曲后电化学性能保持不变。此外,将其与活性炭组成的非对称超级电容器,在1 A·g-1下比电容为1428 F·g-1,最高能量密度和功率密度分别达49.8 Wh·kg-1和741.8 W·kg-1。Flexible supercapacitor is one of the most promising energy storage devices for portable and wearable electronic products due to its advantages of high power density, fast charging and long cycle life. Therefore, self-supporting flexible electrode materials with high performance have attained more and more attention both in academia and in industry recently. In this work, using bacterial cellulose (BC) as a flexible substrate, the bacterial cellulose/nickel-cobalt sulfide@polypyrrole (BC/CoNi2S4@PPy) flexible composites with three-dimensional porous network and good conductivity were prepared by a combined solvothermal-in-situ polymerization-vacuum filtration method. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectrometry, N2 physisorption, tensile strength and contact angle measurements. Their electrochemical performances were tested by cyclic voltammetry, galvanostatic charge/discharge testing and electrochemical impedance spectroscopy. The results show that the three-dimensional porous network of BC fibers with rich oxygen-containing surface groups play a guiding role in the growth of the redox active material CoNi2S4 and the distribution of conductive polymer PPy, resulting in uniformly distributed CoNi2S4 nanospheres in the network of BC fibers, both coated evenly with a layer of conductive PPy. The resulting BC/CoNi2S4@PPy composites, a three-dimensional conductive network with high porosity, displayed good mechanical property (tensile strength up to 28.0±0.1 MPa), hydrophilicity (the instantaneous contact angle in 6 mol·L-1 KOH is 43.6°), as well as excellent electrochemical performance. The specific capacitance of the flexible BC/CoNi2S4@PPy was 2670 F·g-1 at 1 A·g-1 in a three-electrode system, and retained 82.7% after 10000 charge and discharge cycles. In addition, the electrochemical performance remained unchanged after 1000 times of repeated bending. In an asymmetric supercapacitor composed of BC/CoNi2S4@PPy and activated carbon, the area specific capacitance was 1428 F·g-1 at 1 A·g-1. The asymmetric supercapacitor achieved the maximum energy density of 49.8 Wh·kg-1 and power density of 741.8 W·kg-1.国家重点基础研究发展计划项目(2014CB239702);国家自然科学基金项目(21676082)通讯作者:周静红E-mail:[email protected]:Jing-HongZhouE-mail:[email protected]华东理工大学化工学院,上海 200237School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, Chin

    1978~2008年中国湿地类型变化

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    分别基于美国陆地卫星(Landsat MSS/TM/ETM+)和中巴资源卫星(CBERS-02B)影像数据,以人工目视解译为主,完成了中国1978~2008年4期(基准年分别为1978,1990,2000和2008年)湿地遥感制图,并进行了大量的室内外验证.在此基础上,对我国湿地现状及近30年来湿地变化进行了初步分析,得到以下主要结论:(ⅰ)截止2008年,中国湿地面积约为324097km2,其中以内陆沼泽(35%)和湖泊湿地(26%)为主.(ⅱ)1978~2008年,中国湿地面积减少了约33%,而人工湿地增加了约122%.过去30年里湿地减少的速度大幅降低,由最初5523km2/a(1978~1990年)降为831km2/a(2000~2008年).(ⅲ)减少的自然湿地(包括滨海湿地和内陆湿地),其类型变化由湿地向非湿地转化的比例逐渐降低.初期(1978~1990年)几乎全部(98%)转换为非湿地;在1990~2000年间减少的自然湿地约有86%转化为非湿地,而在2000~2008年,这一比例下降为77%.(ⅳ)气候变化和农业活动是中国湿地变化的主要驱动因素,湿地变化在中国分为三大不同特征区域,即西部三省/自治区(西藏、新疆和青海)、北部两省/自治区(黑龙江和内蒙古)和其他省市区.其中西部区域尤其是青藏高原,湿地变化的驱动因子以气候增温为主;新疆湿地由于气候增温和农业活动共同作用造成变化不大.北部省/自治区的湿地变化则主要由农业活动引起;而其他省市区的湿地变化几乎完全受控于人类的农业经济活动

    Y型聚乙二醇干扰素琢-2b注射液治疗HCV基因2/3型慢性丙型肝炎患者疗效和安全性的多中心随机对照试验研究

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    目的以标准剂量的聚乙二醇干扰素(Peg IFN)α-2a联合利巴韦林作为阳性对照,评价新型试验药物Y型Peg IFNα-2b注射液联合利巴韦林治疗2型/3型慢性丙型肝炎(CHC)患者的疗效和安全性。方法采用多中心、随机开放、阳性药对照的Ⅲ期临床试验,筛选符合要求的2型/3型CHC患者,按照2:1的比例随机分配到Y型Peg IFNα-2b组和Peg IFNα-2a组,同时口服利巴韦林,疗程24 w,停药随访24 w。采用Abbott Real Time HCV Genotype II检测HCV基因型,采用Cobas Taq Man实时定量PCR法检测血清HCV RNA水平。详细记录不良事件。主要疗效指标为持续病毒学应答(SVR),并进行非劣效检验。结果本试验实际入组2型/3型CHC患者255例,实际治疗241例。全分析集(FAS)数据显示,158例试验组和83例对照组患者SVR分别为85.4%(95%CI 79.94%~90.94%)和79.5%(95%CI 70.84%~88.20%,P=0.2402);对符合方案分析集(PPS)人群分析显示,试验组和对照组患者SVR分别为87.9%(95%CI 82.45%~93.27%)和85.9%(95%CI 77.82%~94.01%,P=0.7060),率差的95%可置信区间均符合非劣效标准;对PPS人群分析显示,85.8%受试者获得了早期病毒学应答(RVR),RVR的阳性预测值为90.1%;试验组和对照组不良事件发生率相似,分别为95.6%和95.2%,严重不良事件发生率分别为3.8%和3.6%。结论应用Peg IFNα联合利巴韦林治疗2型/3型CHC患者,新型试验药物Y型Peg IFNα-2b具有与对照药物Peg IFNα-2a相似的疗效和安全性。国家科技部“十二五”重大专项(编号:2012ZX10002-003);“重大新药创制”十二五科技重大专项(编号:2012ZX09303019)

    关于“经济发展方式转变进程中的财税政策”的探讨(笔谈)

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    转变经济发展方式是当前中国的热门话题,而上海在城市发展中又肩负着率先转变的重要任务,在这一意义和背景下,2010年4月24日由上海金融学院学院主办、上海金融学院公共经济管理学院承办的“《中国城市财政发展报告2009/2010:促进‘两个中心’建设的上海城市财政》首发式暨‘经济发展方式转变进程中的财税政策’论坛“在我校举行。与会专家围绕经济发展方式转变进程中的财税政策的“趋势与目标“、“机遇和挑战“、“实施方略“和“地方实践“等四个专题进行研讨,各抒己见,智慧交锋。现将其真知灼见整理摘要与读者分享,以期待更多学者共同关注当前经济发展方式转变进程中的财税政策
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