Studies on Amidothiosemicarbazides and Related Hcterocyclic Derivatives ( XIII) --Synthetic Studies on 2-(3-Pyridyl)-5-Arylamino- 1,3, 4-Thiadiazoles and Oxadiazoles

By ring-closure of 1-nicotinyl-4-arylthiosemicarbazides under the catalysis of concentrated sulfuric acid or mercuric acetate, a series of 2-(3-pyridyl)-5-arylarnino-1,3,4-thiadiazoles and 2-(3-pyridyl)-5-ary-lamino-1,3,4-oxadiazoles were synthesized, respectively. All the products were subjected to testing of biological activity. Furthermore, the IR, 1H NMR and MS spectral properties of these new compounds were studied in details and some significant conclusions were drawn.     

Structure and properties of gel-spun ultra-high molecular weight polyethylene fibers with high gel solution concentration

The gel-spun ultra-high molecular weight polyethylene(UHMWPE) fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry(DSC), wide angle X-ray diffraction(WAXD) and small angle X-ray scattering(SAXS). With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length(〈L _(shish)〉) and shish misorientation(B_φ) of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.     

Nanomechanical properties of polyaniline and azo polyelectrolyte multilayer films

<正>Nanomechanical properties of multilayer films constructed of polyaniline(PANI) and azobeneze-containing polyelectrolytes(PNACN and PPAPE) were studied by using nanoindentation method.The multilayer films were prepared by the electrostatic layer-by-layer self-assembly through alternately dipping in the polymer solutions.The multilayer films deposited onto the glass slides after proper dry were used for the nanomechanical property testing.The nanomechanical measurement indicated that the PANI/PNACN and PANI/PPAPE multilayers possessed the mean elastic modulus of 5.42 GPa and 4.35 GPa,and hardness of 0.26 GPa and 0.18 GPa,respectively.The nanoscratch properties of the PANI/PNACN and PANI/PPAPE multilayer films were also measured.The critical loads of PANI/PNACN and PANI/PPAPE films were 103.52 mN and 100.59 mN.The degree of electrostatic cross-linking in the multilayers could be altered by exposing the films to aqueous solutions with different pH values.As a result,the modulus and hardness of the multilayer films were changed through the solvent treatment.Both modulus and hardness of the PANI/PNACN films obviously increased after dipping the multilayer films in solutions with pH in a range from 9 to 11.     

STUDY ON THE PREPARATION AND PERFORMANCES OF P(VAc-MMA) POLYMER ELECTROLYTES FOR LITHIUM ION BATTERY

A random copolymer P(VAc-MMA)was synthesized via seeded emulsion copolymerization with vinyl acetate (VAc)and methyl methacrylate(MMA)as monomers,and the polymer electrolytes comprising blend of corresponding copolymer P(VAc-MMA)as a host polymer and LiClO_4 as a dopant were prepared by solution casting technique. Performances of the synthesized copolymer and prepared polymer membrane and electrolyte were studied by FTIR,XRD, TG,DSC,mechanical testing and AC impedance.According to the study of FTIR and D...     

EFFECT OF DISPERSION OF MICA IN MATRIX ON YOUNG''''S MODULUS OF MICA FILLED POLYETHYLENE

The correlation between Young's modulus of mica-filled high density polyethylene (HDPE), low density polyethylene(LDPE) and the state of dispersion of plasma-treated mica in the polymer matrices was studied. The modulus and the number average diameter of mica aggregates in matrix were determined with tensile testing and image analysis respectively. The interface structure of the filler/matrix and the bulk structure of matrix were examined through the dielectric spectrometry, differential scanning calorimetry (DSC) and dynamic viscoelastic spectrometry. The results show that the Young's modulus of the filial polyethylene depends to a great extent upon the state of dispersion of filler in matrix, but it is independent of the interface structure and bulk structure. The better the dispersion, the higher the Young's modulus.     

Electrodeposited Ni and Ni-Co alloys using cysteine and conventional ultrasound waves

Ni-Co alloys were electroplated from sulphate electrolyte using addition agents including sodium gluconate,boric acid and cysteine on copper foil by the galvanostatic technique and ultrasound waves.The chemical composition,surface morphologies,crystalline structure and hardness of the Ni-Co alloys were studied using energy dispersive spectroscopy,scanning electron microscope,X-ray diffraction and Vickers testing method,respectively.The effect of current density and addition agents on the microstructure and morphology of Ni-Co alloys were examined.The appropriate concentration of additives and ultrasound waves were found to produce fine and smooth crystals leading to higher hardness of Ni-Co alloys.The microhardness of the Ni-Co alloys was varied between 4860–7530 HV.The surface morphology of coatings was changed from granular to fine due to using of gluconate,boric acid,cysteine and ultrasound waves.The mechanical properties of nanocrystalline Ni-Co alloys showed an increase of the hardness with the growing of Ni content in the alloy.The X-ray diffraction studies indicated that nanocrystalline structure was face-centred cubic for pure Ni and Ni-Co alloys with Co content in the range of 1–75 wt.%.A hexagonal closed-package structure was obtained for pure Co and Ni-Co alloys with the cobalt content with range of 75–99wt.%.     

ENHANCEMENT OF COMPATIBILITY OF POLYPROPYLENE AND NYLON-66 BY MALEATED POLYPROPYLENE

The compatibility of PP/N-66 blending system modified with maleated polypropylene was studied by means of SEM, DMA and other mechanical testing. It was found that when proper amount of modifier was applied, the compatibility was greatly enhanced and the impact toughness was significantly improved. An important direct evidence of the formation of the interfacial copolymer was also found. However, when excessive amount of modifier was used, the modification effect was not conspicuous. The phenomena were interpreted from a view of molecular motion that the interfacial block copolymer forced the two components to 'compatibilize' and many flexible PP molecules were set free from the restraint of the crystallites of plain PP so as to absorb much more impact energy.     

Ni-Co/Mg-Al catalyst derived from hydrotalcite-like compound prepared by plasma for dry reforming of methane

Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.     

EPOXY RESINS TOUGHENED WITH CARBOXYL TERMINATED POLYETHERS

Carboxyl terminated polyethers, the adducts of hydroxyl terminated polytetrahydrofuran and maleic anhydride, were used as toughener for epoxy resins. The morphology of the toughened resins was investigated by means of turbidity measurement, dynamic mechanical testing and scanning electron microscope observation. It turned out that the molecular weight and the carboxyl content of the polyether and the cure conditions are important factors, which affect the particle size of the polyether-rich domains and, in turn, the mechanical properties of the cured resin. Carboxyl terminated polytetrahydrofurans have a low glass transition temperature, and in appropriate amount they do not affect the thermal resistance of the resin. These advantages make them preferable as toughener for epoxy resins.     

非爆炸且不可还原农用硝酸铵的改性研究与测试技术

Based on a study of the relationship of ammonium nitrate （AN） explosion and its thermal stability, inert agents were added to AN for eliminating the explosive characteristic of AN and in order to be irrestorable. The results of using a large quantity of experiments and various testing technologies show that the improvement on thermal stability of modified AN is the basic reason for eliminating explosive characteristic of AN. The modification scheme was considered to have the following features： reliable and stable technology, market-demanded product, low investment and good economic returns. And during the revamping period, the normal production of AN will not be af- fected, and the economic, social and environmental benefits are good.     

Harmonization and transferability of performance assessment: experience from four serum aluminum proficiency testing schemes

Proficiency testing schemes monitor laboratory performance and provide a stimulus for improvement in accuracy. Where several schemes operate in the same analytical sector, there are risks that assessments of performance may be in conflict. Performance assessment for the determination of trace elements such as aluminum in serum is particularly important due to the high risk of contamination and therefore erroneous results. The objectives of this work were (1) to compare several mathematical models to establish a predefined standard deviation for proficiency assessment and (2) to evaluate the influence of instrumental methods and proficiency testing scheme on the assessment of performance for serum aluminum measurements. For this purpose, three samples were sent to the participants of four proficiency testing schemes. Assigned values were calculated according to algorithm A according to ISO 13528 and standard deviation for proficiency assessment according to three methods based on individual variability, state of the art or previous proficiency testing results. The method based on individual variability produced a more stringent standard deviation compared to analytical imprecision based on the state of the art. The instrumental methods gave similar results, whereas significant differences were observed between the four proficiency testing schemes indicating that harmonization of the standard deviation for proficiency assessment fails to allow transferability from one proficiency testing scheme to another and that additional factor(s) contribute to variability in performance assessment.     

氧指数检测能力验证结果分析

为了解氧指数检测实验室的能力水平,中国合格评定国家认可委员会(CNAS)开展了"塑料燃烧性能试验(氧指数法)"能力验证计划。通过对氧指数能力验证计划的结果进行统计分析,评价了氧指数检测实验室的整体水平,指出了氧指数检测实验室普遍存在的几类问题并提出了相应的建议。     

实验室能力验证的发展

实验室能力验证对于判定实验室的检测能力非常重要。回顾了国际实验室能力验证的起源和发展,重点分析了我国能力验证的发展历程和成就,探讨了我国实验室能力验证中存在的问题和有争议的技术要点。     

土壤中重金属元素检测的质量认证

探讨了土壤中重金属检测能力验证的质量控制措施,为确保能力验证结果的准确性及不断提高实验室的检测技术水平提供参考.     

能力验证计划中防止数据串通的措施

为保证能力验证结果评价有效、可信、公平,对能力验证计划防止数据串通的措施进行了探讨。从样品设计、样品量发放、检测周期3个方面介绍了防止数据串通的措施,以CNAS PT0017–T029"离子色谱法测定水中Cl~–,SO_4^(2–)及NO_3~–三种阴离子的含量"能力验证计划为例,讨论能力验证计划防止数据串通措施的具体实施方法。结果显示,设计分割水平样品、减少样品发放量、缩短能力验证结果上报周期等几种措施可以有效地防止能力验证数据的串通,为能力验证活动的健康发展提供了参考。     

Regular participation in proficiency testing provides long term improvements in laboratory performance: an assessment of data over time

Data from various proficiency testing schemes, operated by LGC Standards, was collated and reviewed to determine whether regular involvement within third party, proficiency testing, either over a prolonged period of time or via multiple participation, had improved the performance of those laboratories taking part. Three statistical evaluations were applied to historical PT results, a review of improvements over time, demonstrated by the evaluation of satisfactory performance scores achieved, a review of the relative robust standard deviations obtained from multiple methods and a focused review of one analyst participating in proficiency testing over a prolonged period of time. In each case the data indicated that long term participation and evaluation via proficiency testing had resulted in consistent and sustained improvements in laboratory performance.     

Proficiency testing in analytical laboratories: how to make it work

 This paper covers the role of proficiency testing schemes in providing an occasional but objective means of assessing and documenting the reliability of the data produced by a laboratory, and in encouraging the production of data that are "fit-for-purpose". A number of aspects of proficiency testing are examined in order to highlight features critical for their successful implementation. Aspects that are considered are: accreditation, the economics and scope of proficiency testing schemes, methods of scoring, assigned values, the target value of standard deviation σ_p, the homogeneity of the distributed material, proficiency testing in relation to other quality assurance measures and whether proficiency testing is effective. Stress is placed on the importance of any proficiency testing scheme adhering to a protocol that is recognised, preferably internationally. It is also important that the results from the scheme are transparent to both participating laboratory and its "customer". Received: 03 November 1995 Accepted: 20 November 1995     

水中易释放氰化物能力验证样品的研制及应用

根据国家地表水环境质量监测网监测任务要求和环境监测的实际需要,制备了水中易释放氰化物能力验证样品。通过均匀性、稳定性检验以及量值一致性评价,研制的样品均匀性良好,在3℃~6℃冷藏避光保存条件下1年内稳定,样品配制值与多家实验室协作测定结果一致。探讨了样品在能力验证活动中的应用,共有来自全国11个省的32家实验室参加了水中易释放氰化物的能力验证计划,实验室满意率在80%以上,实验室结果出现有问题或不满意主要是由于样品前处理以及检测过程质量控制不当导致的。经检测及实验室反馈的数据验证,该能力验证样品能够应用于能力验证活动。     

Review of the new edition of ISO 13528

The international standard ISO 13528 is an important reference document for proficiency testing providers and testing laboratories alike, which provides guidance on the use of statistical methods in proficiency testing. With a view to bringing the document in harmony with the ISO/IEC 17043:2010, the first edition of ISO 13528 was revised and the new edition was published in September 2015. This paper attempted to review and discuss the major changes introduced in the new edition of ISO 13528, particularly the part on statistical design with respect to the objective of proficiency testing scheme and the considerations on assigned value determination and performance scoring. Moreover, procedures provided in the new edition of ISO 13528 for qualitative proficiency testing schemes and various robust statistical methods would also be briefly discussed in the paper.     

实验室熟练水平测试方案简介

介绍了实验室熟练水平测试方案(LPTS)的目的,类型,以及实验室熟练水平测试的组织、基本运行程序和实施的具体步骤。