异相共混螯合滤膜的制备及其性能研究

通过探讨共混比例、螯合树脂粒径、PSF（聚砜）浓度及制膜液温度对膜性能的影响,用相转换法制备出对Cu^2＋具有大螯合容量的D418树脂／聚砜异相共混螯合滤膜。研究了膜对Cu^2 的吸附及盐溶液pH值和盐浓度对螯合容量的影响。对膜进行动态螯合吸附测试表明该膜对Cu^2 可实现萃取与反萃取同级进行。     

醋酸纤维素/聚乙烯基亚胺共混微孔滤膜对Cu2+的吸附

以二醋酸纤维素N(CA)／聚乙烯基亚胺(PEI)共混制备微孔滤膜,利用PEI对重金属离子的螯合作用吸附水溶液中的Cu^2 ,实验考察了吸附时间、pH对Cu^2 静态吸附性能的影响．膜对Cu^2 的等温吸附符合Langmuir型吸附,其饱和吸附量取决于膜中PEI的含量．     

使用支撑液膜从Fe^3＋／Cu^2＋溶液中选择分离Fe^3＋的研究（I）液液萃取实验

支撑液膜在水溶液金属离子的分离中有着独特的优势。报道了从Fe^3 ／Cu^2 溶液中选择分离Fe^3 液／液萃取研究结果。水相为Fe^3 ／Cu^2 硫酸溶液,萃取相为正癸醇（n-de-canol）,载体为二（2－乙基己基）磷酸（D2EHPA）。实验研究了溶液相中硫酸浓度以及有机相中载体D2EHPA浓度金属离子萃取速率的影响。研究发现水溶液的酸浓度对Fe^3 的萃取影响较明显,而对Cu^2 的萃取影响很小。在两相界面处Fe^3 与D2EHPA的反应速度比Cu^2 快很多。Fe^3 、Cu^2 与D2EHPA的络合物在有机相中的扩散速度都较慢,但是Fe^3 与D2EHPA的络合物的界面反应速度比络合物的扩散速度快。有机相中载体浓度对金属离子萃取速率的影响也很明显。液液萃取研究结果显示,在使用支撑液膜进行铁离子选择分离时,可以通过改变溶液相酸的浓度,有机相中载体浓度,或者通过缩短分离时间来提高选择率。     

纤维素/二氧化钛复合纳米纤维膜的制备及对Cu^(2+)吸附性能EI北大核心CSCD

采用静电纺丝技术与水解后处理的方法相结合,制备了纤维素/TiO_2复合纳米纤维膜。通过扫描电镜、红外光谱、X射线衍射、接触角及力学性能测试对复合纳米纤维膜进行了表征。结果表明,复合纳米纤维膜表面光滑,纤维呈三维杂乱排列;加入TiO_2后,纳米纤维的平均直径略有下降,纤维素的结晶度减小,断裂强度降低;但亲水性大幅提升。Cu^(2+)吸附试验结果表明,溶液pH、Cu^(2+)初始浓度和吸附时间是影响吸附效果的重要因素,Cu^(2+)的最大平衡吸附量可达66.54mg/g。Cu^(2+)在纤维素/TiO_2复合纳米纤维膜上的等温吸附规律可以用Langmuir和Freundlich吸附等温模型进行描述,从相关系数来看,纤维素/TiO_2复合纳米纤维对Cu^(2+)的吸附行为用Freundlich模型描述更为合理。     

AOPAN/RC纳米纤维膜的制备及对金属离子吸附性能

采用静电纺丝技术制备聚丙烯腈/醋酸纤维素(PAN/CA)纳米纤维膜,通过化学改性制备偕胺肟化聚丙烯腈/再生纤维素(AOPAN/RC)纳米纤维膜,研究了纳米纤维膜对单一金属离子(Fe~(3+))和混合金属离子(Cu~(2+)、Cd~(2+)、Fe~(3+))的吸附性能。通过扫描电镜、红外光谱、X射线能谱仪等测试对纳米纤维膜进行了表征,并通过静态接触角测定纳米纤维膜亲水性能。研究表明,改性后制备的AOPAN/RC纳米纤维膜的亲水性能得到较大改善,同时纳米纤维膜能够高效吸附溶液中的金属离子,纳米纤维膜对单一组分Fe~(3+)的饱和吸附可达411.21mg/g,对于混合金属离子溶液,纳米纤维膜对其吸附能力顺序为Fe~(3+)Cu~(2+)Cd~(2+),而且纳米纤维膜具备优良的重复使用能力。     

硫代乙酰胺键合硅胶吸附剂的制备及对铜铅的吸附性能

制备了硫代乙酰胺键合硅胶(TAA-SG),并以它作为固相萃取吸附剂,通过火焰原子吸收光谱法(FAAS)研究了对Cu2+、Pb2+的萃取性能。系统考察了pH、振荡时间和吸附容量等静态吸附性能实验以及流速、洗脱液条件、最大试样体积和干扰离子等动态吸附性能实验对Cu2+、Pb2+定量回收的影响,确定了最佳吸附条件。实验结果表明,当介质的pH为5时,振荡25 min时吸附达到平衡,对Cu2+、Pb2+的最大吸附容量分别为15.05 mg/g和21.10 mg/g。TAA-SG用于饮用水中痕量Cu2+、Pb2+的吸附富集测定,加标回收率在98.4%~102.0%之间。     

大豆蛋白在聚砜膜上的吸附行为

结合扫描电镜（SEM）观察,系统研究了溶液化学特性（包括pH、离子强度和给液浓度）对大豆蛋白在疏水聚砜膜上吸附行为的影响．大豆蛋白一膜间的相互作用符合静电作用机理,吸附量在其等电点附近取得最大值．低pH时随pH升高吸附量增加;高pH时随pH升高吸附量降低,离子强度降低,同性电荷物质之间的静电排斥增加吸附,也降低异性电荷物质之间的静电吸引,降低吸附．溶液化学条件同样影响大豆蛋白在聚砜膜上的吸附速率（膜污染速率）．大豆蛋白吸附等温线遵循兰格缪尔方程,通过实验给出了有关的方程参数,由此可预计不同溶液化学条件的膜污染程度和速率．为了确定对流力和静电作用对大豆蛋白吸附行为的影响,进行了静态和动态吸附实验的比较,结果表明,静电作用在大豆蛋白吸附到膜表面的过程中起着关键作用,控制静电作用可以有效减轻大豆蛋白在膜表面的吸附,进而降低膜的长期通量降低．     

两性离子聚合物功能化改性PVDF膜及其性能研究

通过活性自由基聚合用羧酸甜菜碱丙烯酸甲酯(CBMA)和苯乙烯(St)制备了一种含有两性离子的聚合物P(St_x-co-CBMA_y),并将其作为添加剂,采用非溶液致相分离(NIPS)法制备了改性聚偏氟乙烯(PVDF)膜,并对膜性能进行测试研究.通过ATR-FTIR及XPS分析可知,改性膜表面出现两性离子聚合物的富集.两性离子的加入对膜的微观结构有明显影响,改性膜的孔隙率及膜厚明显增加.两性离子聚合物的加入改变了膜表面电荷分布,膜的等电点升高,对膜的抗污染性能具有一定的影响.改性膜在静态吸附条件下(pH=5.3)对1.0 g/L牛血清蛋白(BSA)和溶菌酶(LYZ)的吸附量明显降低,具有优异的抗污染性能.用改性膜对BSA和海藻酸钠(SA)进行动态过滤,结果表明,改性膜M-P1对BSA及SA的污染大部分为可逆污染,膜具有较高的通量恢复率.     

茶碱分子印迹膜色谱的性能

采用自由基热聚合法在PVDF中空纤维膜表面制备茶碱分子印迹膜,采用SEM测试手段对膜聚合前后的表面形貌进行表征,证明分子印迹膜表面聚合层的存在,并将所得分子印迹膜及空白膜组装成膜组件,以膜色谱形式应用于茶碱和可可碱混合物的萃取分离,比较了相同条件下空白膜和印迹膜对荼碱和可可碱选择性吸附性能,同时考察了不同浓度混合液和不同乙酸酸度的甲醇萃取液对过滤结果的影响.结果表明,印迹膜的选择性因子随混合液浓度和萃取液中乙酸含量的增加而降低.     

荷电膜表面电性能对截留性能的影响

研究了流动电位和Zeta电位与无机盐溶液的浓度及测试压力的关系,以及随操作压力、无机盐溶液种类和浓度等因素的变化荷电膜对无机盐溶液截留性能的影响.结果表明,荷电膜由于离子吸附而带有负电荷,在低浓度溶液中荷电膜的表面电学性能对膜的截留性能有重要影响,而在高浓度溶液中荷电膜电性能的影响不大.     

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.