小肽BCEOC衍生物的非水毛细管电泳分离研究

以1,2-苯并-3,4二氢咔唑-9-乙基氯甲酸酯(BCEOC)作为柱前衍生试剂,采用非水毛细管电泳对衍生小肽进行分离。在甲醇乙腈混合液为溶剂,乙酸-乙酸铵为缓冲体系,20℃,28kV,235nm二极管阵列检测(DAD)条件下,采用非水毛细管电泳模式,考察并优化小肽衍生物的分离条件,实现四种小肽衍生物的基线分离。     

单宁微球固载α-淀粉酶及其催化性能

以单宁微球为载体,采用戊二醛交联法固定α-淀粉酶。探讨了最佳固定化条件,并考察了温度、pH值和淀粉初始浓度等对固定α-淀粉酶催化淀粉水解的影响。结果表明,单宁微球对α-淀粉酶的吸附率达到了96.99%。最佳固定条件为:戊二醛质量分数0.10%,pH5.5,温度25℃,时间2h。固定α-淀粉酶的重复5次后仍具有较好的催化效果。     

R-1-苯基乙基氨基甲酸酯-β-环糊精键合手性固定相的制备与应用研究

利用R-1-苯基乙基异氰酸酯对β-环糊精键合固定相进行衍生,合成了R-1-苯基乙基氨基甲酸酯-β-环糊精手性固定相,填充后在反相条件下考察其对氢化安息香、安息香和α-苯乙醇的手性拆分,探讨了流动相中乙腈含量、缓冲盐类型等对手性拆分的影响。氢化安息香获得了基线分离,分离因子可达1.214,安息香得到了部分分离,α-苯乙醇未能拆开。结合线性溶剂强度(LSS)模型和计量置换理论(SDM-R)对色谱保留机理进行了探讨,认为水分子和乙腈分子一起参与了溶质的置换。     

聚(4-甲基-1-戊烯)对PET/TiO2体系的协同阻光效应

目的在不降低包装阻光性能的前提下,降低阻光聚酯（PET）瓶包装中二氧化钛（TiO2）的添加量,使包装材料更有利于后续的回收再利用。方法利用聚（4-甲基-1-戊烯）(PMP)与PET之间的不相容特性以及折射率上的显著差异,在PET吹瓶过程中的拉伸过程形成界面和孔穴,同时,通过引入相容剂,减小PMP在PET中的分散粒径,形成更多的两相界面,在两相界面处对外界入射光线进行多次的折射、反射,从而削弱光线的穿透能力,起到协同阻光的效果。结果母粒中PMP的质量分数为32%,相容剂与PMP的质量比为1∶11时,阻光效果最佳。在PMP的协同下,TiO2质量分数为3.9%的PET瓶可见光阻光率与传统的TiO₂质量分数为6%的PET瓶相当,650 nm以下的光线的阻隔比例大于99%。结论在阻光PET瓶应用中,通过PMP与相容剂的配合使用,能够起到有效的协同阻光效果,显著减少TiO₂的添加量。     

毛细管电泳电化学检测水果中的抗坏血酸

利用毛细管电泳电化学检测法检测了抗坏血酸,考察了缓冲液的pH值、缓冲液浓度、分离电压、检测电势等实验参数对检测的影响。在最佳实验条件下,检测抗坏血酸的浓度范围是(1.0×10-5-5.0×10-3)mol.L-1,线性回归系数为0.9995,浓度检测限(S/N=3)为3.7×10-6mol.L-1,并以此方法检测了新鲜水果中的抗坏血酸的含量。     

柱前衍生气相色谱法分离手性二醇类化合物

本文建立了柱前衍生气相色谱法分离1,3-丁二醇、2,3-丁二醇、2,5-己二醇和3,6-辛二醇4种二醇类化合物的手性分离方法。分别使用N-甲基-N-(三甲基硅烷)三氟乙酰胺和三氟乙酸酐为衍生剂与二醇化合物反应,生成相应的衍生物,用CP-Chirasil-Dex CB色谱柱分离二醇对映体,采用分流进样方式,检测器为氢火焰离子化检测器(FID)。在选定的色谱条件下,四种手性化合物分别在2.50～8×10³μg/mL、1.30～8×10³μg/mL、3.5～1×10⁴μg/mL、5～1×10⁴μg/mL范围内呈线性关系,相关系数分别为0.9994、0.9997、0.9990和0.9971,手性分离度均达到2以上,检测限分别为0.8μg/mL、0.4μg/mL、1.8μg/mL、2.5μg/mL。该方法适用于生物酶催化反应所生成的(2R,3R)-2,3-丁二醇、(R)-1,3-丁二醇、(2S,5S)-2,5-丁二醇和(3S,6S)-3,6-辛二醇的检测以及酶促反应过程的监控。     

1-3型压电复合材料的机械品质因素

采用切割-填充法制作1-3型压电复合材料,PZT-5A作为压电相,改性618环氧树脂作为聚合物相。研究了1-3型压电复合材料的机械品质因素Qm值与压电相的体积分数及形状参数的关系。压电相的体积分数及形状参数优选后的1-3型压电复合材料可获得较低的机械品质因素Qm值,其值可达10,谐振频率可达850kHz,频带宽度可达86kHz。     

柱前衍生HPLC-UV法测定氯氮平片中乳糖的含量

采用1-苯基-3-甲基-5-吡唑啉酮(PMP)为衍生试剂,建立柱前衍生高效液相色谱法准确测定氯氮平片中乳糖的含量.实验结果显示,在0.0604～0.3997 mg/mL范围内,衍生目标物的峰面积与乳糖质量浓度呈现良好的线性关系,线性相关系数R2为0.9994,加标回收率在96.7％～99.2％之间,定量限为0.32μg/mL.随机抽选3个批次氯氮平片仿制样品进行检测,乳糖含量分别是42.09,43.36,43.45 mg/片,实测含量与处方含量的偏差不超过2.0 mg/片,结果完全满足氯氮平参比制剂中乳糖含量的检测需要.与现有的检测方法相比较,所提方法具有专属性强、灵敏度高、结果准确可靠等优点,可为氯氮平一致性评价处方的开发提供数据支持,有利于加快仿制药的开发速率和成功率.     

乙腈对环己烷单体溶液中沉降聚合聚3,4-乙撑二氧噻吩涂层结构与光电性能的影响EI北大核心CSCD

为利用溶剂化效应来优化液相沉降聚合聚3,4-乙撑二氧噻吩(PEDOT)的结构和光电性能,将吸附Fe(OTs)3的聚对苯二甲酸乙二醇酯(PET)膜悬于含乙腈的EDOT环己烷溶液中,于60℃原位合成PEDOT涂层。以紫外-可见吸收光谱、X射线光电子能谱分析所合成PEDOT的共轭链结构和掺杂度,以四探针测量表面电阻,研究乙腈含量对合成PEDOT结构与性能的影响。当乙腈体积分数为0.05%时,添加的乙腈能抑制短共轭链的生成,提高掺杂度,在降低表面电阻的同时,改善透光率。乙腈体积分数在0.24%以内时,PEDOT的导电性随乙腈体积分数的上升而增加。当乙腈体积分数超过0.7%时,PEDOT中短共轭链数目增加,光电性能下降。当乙腈体积分数为8%时,由于吸附的Fe(OTs)_3溶解太快,无法在PET表面合成导电PEDOT膜。乙腈体积分数为0.24%时,获得的PEDOT膜的表面电阻可达174Ω,透光率80%,粘附力为5B级。     

大孔树脂-聚酰胺联用纯化桑葚花色苷

目的 为了得到纯度更高的桑葚花色苷.方法 以桑葚为研究对象,比较AB-8,D4020,D101,NKA-9,HPD100等5种大孔树脂对桑葚花色苷吸附和解吸性能的影响,确定最佳工艺条件.结果 HPD100大孔树脂是最合适的桑葚花色苷纯化物质,测得吸附率和解吸率分别为93.6％和37.9％;纯化工艺最佳条件为上样流速1.5 mg/mL、上样pH值2.4、乙醇体积100 mL、洗脱流速1.5 mg/mL、乙醇体积分数70％,在此条件下测得纯度为35.15％.运用聚酰胺树脂进行2次纯化得到的最佳纯化条件为上样pH值3.4、乙醇体积分数70％,在此条件下测得纯度为50.76％.结论 此最佳纯化工艺条件能够有效提高桑葚花色苷的纯度,为后续桑葚花色苷研究提供重要参考.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.