高氯酸铵质量分数测量不确定度的评定

对高氯酸铵质量分数测定的不确定度进行了评定,不确定度主要来源为重复测量引入的不确定度,滴定试样消耗氢氧化钠标准溶液体积引入的不确定度,氢氧化钠标准滴定溶液浓度引入的不确定度,称量试样质量引入的不确定度。实验结果表明,滴定试样消耗氢氧化钠标准溶液体积和氢氧化钠标准滴定溶液浓度引入的不确定度贡献最大。高氯酸铵质量分数测量结果为(99.78±0.26)%。     

气相色谱法测定二硫化碳中甲苯的测量结果不确定度评定

采用气相色谱法对二硫化碳中甲苯含量进行测试,找出影响测量不确定度的因素,通过建立数学模型对影响测量的各不确定度分量进行计算,求出合成不确定度和扩展不确定度,给出了气相色谱法测定二硫化碳中甲苯含量测量的相对扩展不确定度.     

白乳胶pH值测量结果不确定度的评定

依据JJF1059.1-2012《测量不确定度评定与表示》对GB/T8325-1987《聚合物和共聚物水分散体pH 值测定方法》中酸度计测量哥俩好1#白乳胶 pH 值的不确定度进行评定,对影响测量不确定度的因素进行探究。结果表明,影响测量结果的主要不确定度分量是仪器基本误差引入的不确定度,其次是重复性测量和缓冲溶液配制过程中引入的不确定度。     

氢化物原子荧光法测定尿汞及其不确定度评定

研究了用氢化物发生-原子荧光光谱法测定尿汞含量并对测量不确定度进行评定。样品经湿法消解,用原子荧光仪检测,应用检测不确定度评定方法对测量结果进行不确定度分析与评定。该检测方法线性良好,相关系数r=0.9991,相对标准偏差为2.42%~2.63%,加标回收率为92.27%~97.33%,不确定度报告为(12.84±0.80)μg/L,取k=2。     

乙酰丙酮法测定水中甲醛含量的测量结果不确定度分析

对乙酰丙酮法测定环境水样中甲醛含量的测量结果的不确定度进行了全面评估;系统分析了影响分析方法测定结果不确定度的各种因素,并计算出各因素所对应的相对不确定度分量;对比构成总的合成相对不确定度的各个分量,可知方法测量结果的不确定度主要来源是标准曲线的绘制过程;最后通过计算得出了分析方法的合成不确定度和扩展不确定度.     

水中化学需氧量测定结果的不确定度评定

对化学需氧量测定的不确定度进行合理评定,充分考虑测定过程中的不确定度来源;分析取样、测量重复性、试剂纯度、测量条件、摩尔质量等因素对化学需氧量测量不确度的影响;建立了重铬酸钾法测定水样中化学需氧量不确定度的数学模型,通过具体实验进行详尽的分析和计算,得出了本次样品CODCr的测定结果为73.8 mg/L,测得其合成标准不确定度2.66 mg/L,扩展不确定度为5.32 mg/L。     

化妆品菌落总数测定结果的不确定度评定

采用直观的因果图,对化妆品菌落总数测量的不确定度的来源及其对测量的不确定度的影响进行分析.建立有效的数学模型,利用相对标准不确定度分量进行测量不确定度的评定,并在样品的测定中获得其合成标准不确定度.     

水杨酸分光光度法测定水中氨氮的测量不确定度评定

应用测量不确定度评定理论,结合水杨酸分光光度法对水中氨氮测量不确定度进行全面分析,找出其影响不确定因素并对不确定度进行评估,实验分析表明水杨酸分光光度法测定水中氨氮含量为1.44 mg/L的样品,其扩展不确定度为0.054 mg/L,影响不确定度最大的主要分量是样品重复性测量引入的不确定度,同时,提高量器精密度也是降低不确定度的有效方法。     

火焰原子吸收分光光度法测定土壤中铜元素的不确定度分析

对原子吸收分光光度法测定土壤中铜元素含量的不确定度进行评定,分析其不确定度的主要影响因素。结果表明影响其测量不确定度的主要原因是由标准溶液引入的不确定度、标准曲线引入的不确定度和重复测量引入的不确定度。     

亚甲蓝分光光度法测定水中阴离子表面活性剂的测量不确定度评定

应用测量不确定度评定理论,结合亚甲蓝分光光度法对水中LAS测量不确定度进行全面分析,找出其影响不确定因素并对不确定度进行评估,实验分析表明亚甲蓝分光光度法测定水中LAS含量为20.3 mg/L的样品,其扩展不确定度为0.70 mg/L,影响不确定度最大的主要分量是样品重复性测量引入的不确定度,同时,提高量器精密度也是降低不确定度的有效方法。     

Physico-Chemical Studies of the CaO-Ethylene Glycol System. Determination of free lime in industrial products

Optimum conditions for a conductometric determination of free lime in industrial products, using alternating current conductometry are elaborated. The analysis of the variation of the conductivity in dependence on concentration in the temperature (°C) range [25–100] allowed the determination of dissociation parameters of calcium glycolate viz. dissociation constant and equivalent conductivity at infinite dilution, which in turn led to the determination of the calcium glycolate concentration from the measured conductivity. The conductometric determination of free lime is only influenced by the presence of SrO. The water content of the solvent (ETG) must not exceed 0.5%.     

Accurate determination of calcium stearate by atomic absorption spectrophotometric method in polymer

In this study, an atomic absorption spectrophotometric method is presented for the determination of calcium stearate in polymer samples after their pyrolysis. Samples of polymers were burned in an electrical furnace at 500°C. After thermal degradation of polymeric matrix, 1M HCl solution was added to dissolve the residue. Then the absorbance of solution was measured by an atomic absorption spectrophotometer at calcium atomic line. This method has an extent linear dynamic range (0.4–50 mg/L) with a limit of detection (LOD) 0.1 mg/L in solution. LOD of the proposed method in polymer sample using 0.5 g sample size is 15 ppm as calcium stearate. Some effective parameters such as time and temperature of pyrolysis and concentration of hydrochloric acid were studied. Finally, this method was successfully applied for the determination of calcium stearate content of standard and real polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

王水水浴消解—冷原子荧光光谱法测定人发中汞的含量

测定头发中汞的含量对疾病诊断和环境管理有着重要的意义,文章采用(1+1)王水水浴消解头发样品,利用原子荧光光谱法测定。结果显示:汞的相对标准偏差为0.94%;加标回收率为97%~110%;不完全溶解的沉淀物对测定结果无影响。结论:此方法结果准确,能够满足要求。     

New anionic surface‐active agent derived from wool proteins for hair treatment

An anionic surface‐active agent derived from wool proteins was developed as an alternative to the anionic surfactants extensively used in shampoo formulations. The physicochemical properties of this new surface‐active agent prepared form wool proteins and its application for human hair treatments were studied. This new product could be considered a new mild anionic surface‐active agent, as evidenced by the results found by the evaluation of its physicochemical properties. The new wool anionic surface‐active agent was shown to be very substantive to hair, coating the fiber surface, giving rise to a significant improvement in the mechanical properties of the hair fibers, and providing a certain damage‐prevention effect on the hair. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Hydrophobization of hair to improve the interfacial adhesion between hair and high-density polyethylene

Concerned about environmental pollution, and aware of the comfort that polyethylene provides for daily human life, this work sought to replace a percentage of high-density polyethylene (HDPE) with human or bovine hair. Hair is natural, abundant, light weight, non-toxic, and disposed of as garbage. The main disadvantage of natural composites is the interfacial adhesion. To increase the interfacial adhesion between hair and HDPE, stearic acid or oleic acid was chemically anchored on the hair surface, which leads to an improved contact angle hysteresis and hydrophobicity. Dynamic-mechanical properties of the composites were investigated focusing on the type of carboxylic acid used (stearic or oleic acid), hair length, hair type (human or bovine) and amount of hair used in the composite. Taking 40°C as a reference, using 15% of hair with a length of 1 ± 0.15 mm, the highest storage modulus value was obtained with HDPE with human hair modified with oleic acid, exceeding the value of the storage modulus of HDPE by 67.64%. Increasing storage modulus on composites indicates of interfacial interaction and chemical affinity improvement between hair and polyethylene.     

微波在测定磷矿浮选水体中总磷的应用

GB11893-89钼酸胺分光光度法测定水中总磷[1],方法精密度高,准确度好,具有广泛的工业用途,但水样的预处理操作繁琐、耗时、耗电、分析成本高、操作繁琐、易产生误差。现先用微波消解代替传统消解,免除了用布和绳子等扎紧;高压蒸气加热方法的繁琐工序,后加钼酸盐室温发色用微波作用发色代替,提高了分析效率、安全性;具有快速、成本低、结果准确、便于推广的特点,结果与GB11893-89方法测定磷矿浮选水体中总磷相比较,无显著性差异。     

Hydrocarbons of Scalp Hair Lipids from Teenage Males

Lipids extracted with ethyl ether from 2 pools of hair each from Caucasian (ages: 13–14 and 15–18 yr) and Black teenagers (17 and 18 yr) were saponified and the unsaponifiable portions chromatographed over alumina toward concentration of the hydrocarbons. Of these, the paraffins were further enriched by use of silica gel columns, the petroleum ether eluate containing the saturated members; elution with solvents of increasing polarity gave rise to cuts high in squalene together with small amounts of other olefins. Temperature-programmed gas chromatography was applied to the determination of the saturated hydrocarbon peaks, the branched and cyclic components which occurred at far lower levels, being ascertained by a heated pre-column containing Linde Molecular sieves (5 Å). Then-paraffins displayed peaks of C₁₅-C₃₄, with several of up C₄₅ being more conspicuous with the Black pools. The present preliminary data point possibly to a higher total hydrocarbon content in the Blacks especially, as reflected in the elevated saturated hydrocarbon contents. In terms of μg/g hair, the recoveries of squalene were 1642 and 1746 of a total of 1870 and 1987 for the respective white pools while the corresponding values were 2273 and 1640 of overall yields of 6935 and 3656 for the Black hair. The ratios of squalene to nonsqualene hydrocarbons were 7.2 for the Caucasian pools and 0.5 and 0.8 for the Black teenagers.     

Raman spectroscopic analysis of L‐phenylalanine and hydrolyzed eggwhite protein penetration into keratin fibers

To investigate the penetration of amino acids and hydrolyzed protein derived from eggwhites (HEWP) into keratin fibers, the structure of cross‐sectional samples at various depths of virgin white human hair treated with L ‐phenylalanine (Phe) and bleached black human hair treated with HEWP was directly analyzed without isolating the cuticle and cortex using Raman spectroscopy. The hydrophobic amino acids clearly penetrated into the virgin white human hair, while hydrophilic amino acids did not penetrate at all. The Phe hydrophobic amino acid content at various depths of the virgin white hair increased by performing the Phe treatment (at 50°C for 16 h), indicating that Phe deeply penetrated into the virgin human hair. Also, the disulfide (? SS? ) and random coil contents at various depths of the bleached human hair increased by performing the HEWP treatment, indicating that HEWP also deeply penetrated into the bleached human hair. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

火焰原子吸收光谱法测定人发中的微量元素

首先用H2 SO4 将头发炭化 ,再用H2 SO4 、HClO4 及H2 O2 溶解碳化物 ,利用火焰原子吸收光谱法 ,可以安全、准确、迅速地测定出人发中钙、铁、锌、铜的含量     

Effect of relatively nontoxic thermal stabilizers on photodegradation of poly(vinyl chloride)

The influence of relatively nontoxic thermal stabilizers including different types of organic calcium complex (Ca/Zn system of liquid stabilizers) and organotin on photodegradation of poly(vinyl chloride) (PVC) was investigated by color difference measurement, viscosity‐average molecular weight determination, UV–vis spectroscopy, Fourier transform infrared (FTIR), and thermogravimetric (TG) analysis. PVC films containing relatively nontoxic thermal stabilizers were prepared by solution casting and then exposed to xenon‐arc light source with the irradiance of 0.51 W/(m²·nm) at 65°C. Two major chain processes, photodehydrochlorination and photo‐oxidation, occur simultaneously during photodegradation of PVC. It has been confirmed by both color difference and UV–vis spectra that during the former 300 h of irradiation, organic calcium complex stabilizers retard photodehydrochlorination as well as initial color development of PVC films while organotin stabilizers remarkably accelerate photodehydrochlorination after 100 h. Relative carbonyl index (RCI) is first introduced to the analysis of FTIR results, which implies that organotin has a better ability to inhibit photo‐oxidation than organic calcium complex and ensures longer stabilization time. The antioxidation of mercaptan organotin has been observed because it is an effective decomposer of peroxides and hydroperoxides. TG analysis reveals that some unstable structures generated due to the irradiation of ultraviolet can easily split away off from PVC macromolecular backbones under relatively low temperature. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers