氧弹燃烧-离子色谱法测定螺旋藻中碘

建立氧弹燃烧-离子色谱法测定螺旋藻中碘含量方法。方法选用Metrosep A Supp 4色谱柱,1.8mmol/L Na2CO3+1.7mmol/L NaHCO3淋洗液,流速1mL/min,电导检测器。样品氧弹燃烧法处理,然后用(0.714g NaHCO3+0.954g Na2CO3)/L吸收液吸收,定容后过滤待测。用于螺旋藻样品分析,回收率为102%。本法快速、简便、灵敏。样品测定结果令人满意。     

离子色谱法测定面粉中的溴酸盐

采用离子色谱法测定面粉中的溴酸盐,选用M etrohm 861型离子色谱仪,Metrosep Asupp5-250阴离子分析柱,以3.2mmol/LNaCO3+1.0mmol/LNaHCO3溶液为淋洗液(流动相)。标准曲线的线性范围为0.2~1.2mg/L(r=0.999807),BrO3-的检出限为0.02mg/L(进样体积20μL),相对标准偏差为1.173%,用本方法测定面粉样品,加标回收率在91.9%以上。实验表明,本方法快速、准确,灵敏,重复性较好,结果令人满意。     

浓硝酸中痕量阴离子的测定

目的：提出了一种用离子色谱测定浓硝酸组分及含量的方法。方法：采用MIC-7型离子色谱仪,METROSEP A Supp 16高容量阴离子分离柱;25mmol NaOH＋3mmol Na2CO3的淋洗液;进样体积10μL;流速0.8mL/min,F^-和Cl^-的保留时间分别为4.8min和7.0min。结果：三点标准曲线线性相关性良好,相关系数为0.99968和0.99979,3次重复进样结果表明此法测定F^-,Cl^-的相对标准偏差分别为1.1%和0.1%。讨论：可以实现F^-和Cl^-在大量硝酸基体下的完全分离。     

高温燃烧吸收-离子色谱法测定氟醚橡胶中氟溴

采用高温燃烧吸收仪与离子色谱仪联用技术,建立同时测量氟醚橡胶中氟溴含量的方法。优化的实验条件为:燃烧炉燃烧管进口温度为850℃,出口温度为1 000℃,称样量为10 mg,以0.05 mol/L氢氧化钠为吸收液,0.02 mol/L氢氧化钾为淋洗液,采用抑制型电导检测器。氟离子在1～100 mg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r~2=0.999 3,检出限为0.04%,回收率为93.0%～104.1%。溴离子在0.1～10 mg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r~2=0.999 6,检出限为0.005%,回收率为94.0%～104.0%。与传统氧瓶燃烧、氧弹燃烧-离子色谱法相比,该方法方便、快捷,可连续处理样品,在30 min之内即可完成样品的检测。     

采用离子色谱法测定饮用水及环境水样中的溴酸盐

采用离子色谱方法测定了饮用水及环境水样中溴酸盐的含量,水样经Ion Pac AS11-HC阴离子分析柱和IonPac AG11-HC(4×250 mm)保护柱分离,以不同浓度的Na OH溶液为淋洗液;Br O3-在0.0157-1.57μg/L的范围内线性关系良好,检出限为0.005mg/L,空白水样的加标回收率在87.1%~110.2%之间,相对标准偏差(n=6)均小于5.0%。     

教科书中荧光增白剂VBL的分析方法研究

利用高效液相色谱-荧光检测器法对教科书中VBL荧光增白剂进行了测定。具体方法为用岛津LC-20AD高效液相色谱系统,Eclipse-C18柱(250 mm×4.6mm,5.0μm)色谱柱,流动相A为甲醇,B为8mmol/L乙酸铵水溶液,流速0.5mL/min,激发波长350nm,发射波长430nm,进样量1μL。外标法测定教科书中VBL荧光增白剂的含量,检测线性关系R~2=0.9985,回收率为92.5%～94.5%之间,相对标准偏差为0.81%(n=6)。研究结果表明,高效液相色谱-荧光检测器法操作简便,结果准确,不受木质素和其他荧光物质的干扰,具有较好的重现性与稳定性,可用于教科书中VBL荧光增白剂含量的测定。     

毛细管电泳测定大黄素主成分的含量

以熔融石英毛细管柱(60.2 cm×50μm,有效长度50 cm)为分离柱,70 mmol/L Na2B4O7、70 mmol/LNa2CO3和80 mmol/L羟丙基-β-环糊精(pH 9.7)为分离缓冲溶液,测定了纯化后的大黄素的主成分含量为98.50%,方法精密度为0.1%(n=9),并与高效液相色谱法的测定结果进行了比较,二者无显著性差异.     

系统组织工程技术优化的正丁胺含量离子色谱检测

该文采用系统组织工程技术(ZTSO)快速优化并建立正丁胺含量测定的离子色谱法。选用AcelaimTMTrinityTM P1(3.0 mm×100 mm,3μm)为色谱柱,18 mmol/L乙酸铵(用乙酸调p H 3.4)∶乙腈(56∶44,ν∶ν)为淋洗液,在柱温37℃,流量0.15 m L/min的条件下等度洗脱,电导检测器检测,20 min内完成正丁胺的含量测定。结果表明:正丁胺质量浓度在10.01~500.5μg/m L范围内线性关系良好(r2=0.999 8),检测限为5.05μg/m L(S/N≥3),定量限为10.01μg/m L(S/N≥10),日内和日间精密度分为0.33%和0.90%,正丁胺供试品溶液在24 h内稳定(RSD=0.54%),3批正丁胺原料的平均含量为99.79%(RSD=0.125%),3批肿瘤血管抑制剂XY03中正丁胺的平均含量为20.32%(RSD=4.09%),热干燥时,XY03中铵盐的下降率与其溶解度呈正相关。ZTSO技术具有较好的条件优化功能,所建立的方法快速、简便和准确,是正丁胺或含正丁铵盐化合物含量测定的较好方法。     

在线基体消除离子色谱电导法测定碳酸锂中氯、硫酸根

建立了在线基体消除离子色谱电导法测定碳酸锂中氯、硫酸根的方法。利用在线的样品中和制备模块(SPM)除去锂,将Li2CO3转化为H2CO3;然后利用CO2抑制模块(MCS),将H2CO3转化为CO2,消除CO32-对氯离子的干扰及对氯、硫酸根保留时间的影响。选用Supp 5-150阴离子色谱柱,3.2 mmol/L碳酸钠/1.0 mmol/L碳酸氢钠作为洗脱液进行分离测定。该方法应用于实际碳酸锂样品中氯和硫酸根的测定,氯和硫酸根含量的RSD(n=6)分别为为0.51%~0.83%和1.2%~1.3%。该法简便、快速、准确、灵敏。     

色谱法测定注射用头孢西丁钠的含量研究

目的采用离子对色谱法测定注射用头孢西丁钠的含量，为完善注射用头孢西丁钠质量标准提供依据。方法采用离子对色谱法，色谱柱为AgⅡentZORBAX80AExtendC18柱（150mm×4．6mm，5μm）；流动相为5mmol·L—1氢氧化四丁基铵溶液乙腈（体积比750：250）；检测波长254nm；流速为1mL·min-1。结果头孢西丁的质量在0．3101～3．1010μg范围内与峰面积线性关系良好，r=0．99998；平均回收率为100．2％，RSD为1．05％。结论本文方法简单、准确、重复性好，为完善注射用头孢西丁钠含量测定方法提供了依据。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

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.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.