空气中偏二甲肼气体标准物质的研制

采用称量法制备空气中偏二甲肼气体标准物质,分别用F检验和回归曲线法对研制的标准物质进行均匀性和稳定性检验。结果表明,研制的空气中偏二甲肼气体标准物质具有良好的均匀性和稳定性,定值结果分别为10,500μmol/mol,定值结果的相对扩展不确定度为2%(k=2)。该标准物质可用于偏二甲肼报警器的检定或校准。     

氢化可的松纯度标准物质的研制

介绍纯度标准物质氢化可的松的研制方法.采用高效液相色谱法对该标准物质进行了定值及均匀性、稳定性检验.该标准物质定值结果为99.5%,扩展不确定度为0.2%,其均匀性和稳定性检验结果表明,该标准物质符合国家一级标准物质的技术要求.     

耐辐照玻璃成分分析标准物质的研制

采用高温熔融方法制备了玻璃成分分析标准物质.对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析.研制的耐辐照成分分析标准物质具有良好的均匀性和稳定性,各组分不确定度均小于5％.     

氦离子化气相色谱仪校准用混合物中甲烷气体标准物质研制

介绍氦中甲烷气体标准物质的制备方法.以超纯氦气和高纯甲烷为原料,采用称量法制备特性值为10μmol/mol的氦中甲烷气体标准物质.采用气相色谱法(DID检测器)对制备的标准物质进行均匀性、稳定性检验,并对定值结果的不确定度进行评定.研制的气体标准物质均匀性和稳定性良好,有效期为12个月,相对扩展不确定度为2％(k=2)...     

硝基胍标准物质的制备及其均匀性和稳定性研究

以工业品硝基胍为基体,经热过滤、重结晶、低沸点溶剂煮洗、真空干燥、平衡水分等步骤,制备了硝基胍标准物质。采用高效液相色谱法测试了主体成分含量,对制备的标准物质进行了均匀性初检,并采用方差分析法进行均匀性、稳定性评价。实验结果表明,硝基胍标准物质纯度为99.89%,均匀性良好,稳定性在1年以上,已达到标准物质的技术指标要求。     

20nm银粉末粒度标准物质的研制

研制了用于X射线小角散射仪校准的20 nm粉末粒度标准物质,并对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析。研制的银粉末粒度标准物质具有良好的均匀性和稳定性,标准值为17.2 nm,相对扩展不确定度为6%。     

聚甲基丙烯酸甲酯氧指数标准物质的研制

介绍聚甲基丙烯酸甲酯氧指数标准物质的研制过程：对标准物质的制备技术、均匀性检验、稳定性考察及定值和不确定度进行了逐项分析。采用本体聚合的聚甲基丙烯酸甲酯板材直接加工制备标准物质，标准物质具有良好的均匀性和稳定性，定值准确可靠，标准值为17．9％，扩展不确定度为0．28％。     

大米成分分析标准物质的研制

从辽宁盘锦、四川简阳和湖南岳阳采集3个大米标准物质为候选物,粉碎至粒径小于0.18 mm的颗粒,并充分混匀.采用X-射线荧光光谱法进行均匀性检验,采用等离子体质谱法进行稳定性检验,结果显示制备的大米标准物质均匀性、稳定性良好.由14家实验室联合定值,采用高灵敏度、高精度的方法测试了58种元素,其中43种元素给出标准值.     

硬质聚氯乙烯氧指数标准物质的研制

研制硬质聚氯乙烯(硬质PVC)氧指数标准物质。对制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析。研制的硬质PVC标准物质具有良好的均匀性和稳定性,定值数据呈正态分布,各实验室数据等精度。硬质PVC标准物质氧指数标准值为43．6％,扩展不确定度为0．7％。     

二级粘度液标准物质的研制

以基础油为原料研制了二级粘度液标准物质,对其均匀性和稳定性进行了考察,用方差分析法进行了评价,用标准毛细管粘度计对其进行了定值。实验结果表明,该粘度液标准物质的均匀性良好,稳定性在1年以上,量值准确可靠,达到二级标准物质的技术指标要求。     

偏二甲肼纯度分析方法的改进

采用毛细管气相色谱内标法代替标准工作曲线法测定偏二甲肼纯度(UDMH),内标法的使用避免了微量进样不准确的缺陷.结果显示,该方法线性范围宽,偏二甲肼的标准曲线相关系数为0.9959,样品加标回收率98.39%,样品的测定标准偏差为0.0015,方法的准确度高、重现性好.     

废水中偏二甲肼在Ni/Fe催化剂上的催化分解研究

研究了Ni/Fe催化剂对废水中偏二甲肼臭氧化分解的催化作用,考察了组分含量、体系的pH值和偏二甲肼初始浓度对催化反应的影响.结果表明,Ni/Fe催化剂对水中偏二甲肼的臭氧化具有良好的催化活性.催化剂组分含量、体系的pH值和初始浓度对反应的影响程度不大.对催化剂的XRD表征结果表明,催化剂主要由尖晶石结构的铁酸盐和FeNi3合金相组成,催化剂的良好催化性能与催化剂中尖晶石结构的铁酸盐和FeNi3合金相的形成有关.     

STUDY ON PREPARATION OF INORGANIC COMPOSITE MEMBRANE AND ITS PROPERTIES FOR HYDROGEN PERMEATION

IntroductionDevclopmcntoftcchniqucsforthcscparationofgascousmixturesisofgrcatimportancetochemicalindustries.Rccentadvanccsinceramicmaterialprocessinghavcstimulatedtheeffortstodcvclopccramicormctallicmcmbrancsforgasseparation.Suchmembraneswouldbesuitableforthescparationsathightemperatureatx`hichthcx`ellcstablishedorganicpol}mermcmbranescannotfunctionButmostcommercialceramicmembranesxvhichcanbcobtainedinmarkctaremicroporous(porediamcterfromO.ItoloPm)whereseparationmcchanismisgovcrncdbyKnudscnd…     

Ion chromatography as a tool for the investigation of unsymmetrical hydrazine degradation in soils

A new procedure for the determination of 1,1-dimethylhydrazine (UDMH) in soil samples was developed. This involves the distillation of UDMH from an alkaline suspension of soil and ion chromatographic analysis of the distillate. The separation was performed on a silica cation-exchanger column with ammonium acetate buffer solution as mobile phase and amperometric detection at +1.2?V. Hydrazine (Hy) and methylhydrazine (MH), which are decomposition products of UDMH, can be determined simultaneously. The limits of detection in aqueous solutions were 0.2, 0.5 and 1?µg?L^?1 for Hy, MH and UDMH, respectively. The developed technique was used for investigating the behaviour of UDMH in spills of rocket fuels on soils. It was found that the addition of 4?kg?m^?2 UDMH resulted in a 0.02% residue one year after the soil treatment. The vertical migration of UDMH in soil was less than 50?cm.     

溴代聚-4-甲基戊烯-1的溶解性能及其膜的形态结构和结晶状态

<正> 迄今为止,用于气体分离的高分子膜,其气体透过速率和选择分离系数仍不够高。究其原因,一是膜材料的气体透过系数较低;二是某些气体透过系数较高的高分子材料又难以形成超薄膜层。     

Oxygen permeation study in a tubular Ba0.5Sr0.5Co0.8Fe0.2O3-δ oxygen permeable membrane

Dense tubular Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCFO) membranes were successfully prepared by the plastic extrusion method. The oxygen permeation flux was determined at different oxygen partial pressures in the shell side and different temperatures between 700 and 900 °C. The oxygen vacancy diffusion coefficients (D_v) at different temperatures were calculated from the dependence of oxygen permeation flux on the oxygen partial pressure term based on the surface current exchange model. No unsteady-state of oxygen permeation flux was observed at the initial stage in our experiments. The reason is the equilibrium time is too short (less than 10 min) to observe the unsteady-state in time. The increase of the helium flow rate can increase the oxygen permeation flux, which is due to the decrease of the oxygen partial pressure in the tube side with increasing of the helium flow rate. The oxygen permeation flux can also be affected by the air flow rate in the shell side when the air flow rate is lower than 150 ml/min. But the oxygen permeation flux is insensitive to the air flow rate when the air flow is higher than 150 ml/min. The membrane tube was operated steadily for 150 h with oxygen permeation flux of 1.12 ml/(cm² min) at 875 °C. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analysis showed that both the surface exposed to air and the surface exposed to helium of the BSCFO membrane tube after permeation for 150 h are similar to the fresh membrane tube in composition and structure. These results indicated that the membrane tube exhibits high structure stability.     

水溶性甲壳素及其膜的制备与表征

通过对高脱乙酰度壳聚糖进行均相乙酰化反应，制得脱乙酰度为51．7％的水溶性甲壳素，产物有很好的水溶性．通过红外光谱、X-射线衍射、差热分析等测试表征了水溶性甲壳素结构．结果表明，水溶性甲壳素的结构发生了较大变化，结晶性显著下降是导致水溶性增加的主要原因．     

澄清溶液中NaA型分子筛膜的合成及气体渗透性能

The use of zeolite membranes in separation or combined reaction and separation processes is very attractive. Advantages of using such a type of membranes include their ability to discriminate molecules based on the molecular size and their stability[1]. In the past ten years, most efforts were involved in the synthesis and permeation studies of MFI zeolite membrane[2, 3]. Recently, NaA zeolite membrane has attracted much attention because of its high potential in the dehydration of organic liquids[4]. However, few gas permeation results were reported[5]. Furthermore, most of the NaA zeolite membrane was synthesized from gel[4]. In this letter, the synthesis of NaA zeolite membrane from clear solution and its gas permeation properties are reported.     

Electrophysical properties of In2O3-and WO3-based gas-sensitive semiconducting films as sensors for unsymmetrical dimethylhydrazine in air

Some n-type semiconductor metal oxide sensors based on WO₃ and In₂O₃ were studied in detecting unsymmetrical dimethylhydrazine (UDMH) vapors. The sensors are highly sensitive to the presence of UDMH vapors in air at concentrations equal to or lower than the MPC. They have short response and relaxation times in detecting UDMH vapors in air. It was found that, when ammonia was present in air in concentrations comparable to those of UDMH, it did not affect the electrophysical properties of the semiconductor sensors.     

Screening of transformation products in soils contaminated with unsymmetrical dimethylhydrazine using headspace SPME and GC-MS

The paper describes a novel SPME-based approach for sampling and analysis of transformation products of highly reactive and toxic unsymmetrical dimethylhydrazine (UDMH) which is used as a fuel in many Russian, European, Indian, and Chinese heavy cargo carrier rockets. The effects of several parameters were studied to optimize analyte recovery. It was found that the 85 μm Carboxen/polydimethylsiloxane fiber coating provides the highest selectivity for selected UDMH transformation products. Optimal sampling/sample preparation parameters were determined to be 1-h soil headspace sampling time at 40 °C. The GC inlet temperature was optimized to 170 °C held for 0.1 min, then 1 °C s⁻¹ ramp to 250 °C where it was held for 40 min. Temperature programing resulted in a fast desorption along with minimal chemical transformation in the GC inlet. SPME was very effective extracting UDMH transformation products from soil samples contaminated with rocket fuel. The use of SPME resulted in high sensitivity, speed, small labor consumption due to an automation and simplicity of use. It was shown that water addition to soil leads to a significant decrease of recovery of almost all target transformation products of UDMH. The use of SPME for sampling and sample preparation resulted in detection of the total of 21 new compounds that are relevant to the UDMH transformation in soils. In addition, the number of confirmed transformation products of UDMH increased from 15 to 27. This sampling/sample preparation approach can be recommended for environmental assessment of soil samples from areas affected by space rocket activity.