高压消解-电感耦合等离子体原子发射光谱法测定电子电气产品塑料中的铅、镉、铬和汞

采用密闭高温压力罐技术，将电子电气产品中塑料样品用硝酸-氟硼酸-过氧化氢在180℃的温度下加热4h溶解后，用全谱直读的电感耦合等离子体原子发射光谱（ICP-AEs）同时测定塑料中的铅、镉、铬和汞，方法的检测限为0．0015～0．014μg／mL，方法的回收率和精密度分别为87．7％～100．8％和0．12％～4．60％，实际样品的检测结果较为满意。该方法快速简便，可应用于电子电气产品塑料中的铅、镉、铬和汞的日常检验。     

电子电气产品中铅、汞、镉、铬、溴不确定度评定

给出了用X射线荧光光谱检测电子电气产品中铅、汞、镉、铬、溴的不确定度来源和测量不确定度评定方法。依据SN/T2003.1-2005《电子电气产品中铅、汞、镉、铬、溴的测定第1部:X射线荧光光谱定性筛选法》,选取含量接近法规限值的代表性样品,对检测过程中引入的不确定度进行了分类和量化。系统全面地评定了各个不确定度分量,得到该方法的相对标准不确定度。     

电感耦合等离子体发射光谱法检测电子电气产品中的金属四项

本文以电子电气产品为研究和实验的对象,强调电子电气产品拆分后的均质材料样品的制备方法,并利用电感耦合等离子体发射光谱法测试电子电气产品中铅、镉、铬、汞四元素。详细的介绍了各拆分件的具体消解方法;电感耦合等离子体发射光谱仪(ICP-OES)的实验用具、实验过程和实验效果,总结了电感耦合等离子体发射光谱法的分析特点,同时与GBW 08409 RoHS检测用ABS中铅(Pb)、镉(Cd)、铬(Cr)、汞(Hg)成分分析标准物质作比对。此次实验的结果表明,国家标准物质和电子电气产品中铅(Pb)、镉(Cd)、铬(Cr)、汞(Hg)的测定均获得满意结果。     

高压消解-电感耦合等离子体原子发射光谱法测定电子电气产品陶瓷和玻璃中的铅、镉、铬和汞

采用高温压力罐,将陶瓷和玻璃样品用硝酸-氟硼酸-过氧化氢溶解后,用ICP-AES同时测定电子产品中陶瓷和玻璃里的铅、镉、铬和汞,方法的检测限为0.0015￣0.012μg/mL,方法的回收率和精密度分别为90.4%￣94.4%和0.12%￣4.60%,结果较为满意。该方法快速简便,可应用于陶瓷中的铅、镉、铬和汞日常检验。     

ICP-MS法测定大米中铬、砷、镉、汞、铅的含量

采用微波消解法处理大米样品,应用ICP-MS测定了大米中铬、砷、镉、汞、铅等5种重金属元素的含量,结果表明:5种元素的检出限范围为0.05~5.43μg·kg-1;线性关系良好(r0.9993);回收率为94.9%~106.1%,RSD小于5.0%。该方法准确、灵敏、简便,适用于大米中铬、砷、镉、汞、铅等元素含量的检测。     

能量色散X射线荧光光谱法同时测定涂料中的铅、铬、镉、汞

建立了用能量色散X射线荧光光谱法同时测定涂料中的铅、铬、镉、汞的一种新的测试方法。实验结果表明,各待测元素在25-200mg/kg范围内,线性关系良好;铅、铬、镉、汞的检出限分别为13、7、4、9mg/kg;回收率在91.8%-101.6%之间;相对标准偏差在1.2%-4.3%之间。同国家标准规定的测试方法相比,本方法缩短了测试时间,更简单,但其准确度、检出限完全可以满足涂料中铅、铬、镉、汞含量的半定量分析,可广泛应用于涂料重金属检测当中。     

电感耦合等离子体原子发射光谱法同时测定金属饰品中铅、镉、铬、汞、锑、砷、硒、钡、镍含量

采用电感耦合等离子体原子发射光谱法同时测定金属饰品中铅、镉、铬、汞、锑、砷、硒、钡、镍的含量.用体积比为3∶1的浓硝酸和浓盐酸微波溶解样品,研究了样品的消解方法、消解介质、分析谱线及工作参数等对检测结果的影响.方法的检测限(mg/L):铅0.06、镉0.009、铬0.002、汞0.04、砷0.02、硒0.01、钡0.0...     

ICP-MS法测定美白祛斑类化妆品中的汞、砷、铅、镉和铬

为建立电感耦合等离子体质谱法(ICP-MS法)测定美白祛斑类化妆品中汞、砷、铅、镉、铬5种元素含量的方法,将样品经硝酸和过氧化氢微波消解后,用电感耦合等离子体质谱仪测定美白祛斑类化妆品中重金属汞、砷、铅、镉、铬的含量。结果发现:汞、砷、铅、镉、铬混合标准溶液在0～100 ng/mL范围内线性关系良好,相关系数为0.9998～1.0000,各元素最低检出浓度均小于0.1 mg/kg,各元素加标回收率在97. 5%～108. 6%之间。该方法简便、灵敏,有较低的检出限,符合方法学验证要求,可用于美白祛斑类化妆品中汞、砷、铅、镉、铬的同时测定。     

微波等离子体炬原子发射光谱法测定地下水中的铅、铬、镉

采用微波消解微波等离子体炬原子发射光谱法(MPT-AES)检测地下水中的铅、铬、镉含量,对分析谱线、酸效应、共存离子干扰等对发射强度的影响进行了详细研究,确定了最佳检测条件。在最佳检测条件下,测得铅、铬、镉的工作曲线相关系数均大于0.999 5,方法检出限分别为4.18、4.37、3.28μg·L-1,相对标准偏差(RSD)均小于2.54%,结果表明所测地下水中铅、铬、镉含量均符合国家标准,铅、铬、镉的加标回收率分别为95.6%~102.3%、95.4%~103.5%、94.7%~104.1%。     

电感耦合等离子体质谱法同时测定化妆品中的铅、汞、砷和镉

建立了电感耦合等离子体质谱法(ICP-MS)同时测定化妆品中铅、汞、砷和镉含量的方法。样品经密闭微波消解后,以铟作为内标物质,用ICP-MS同时测定铅、汞、砷和镉的含量,并将该方法和国家法定方法的检测结果进行比较。结果表明,4种元素标准曲线的线性关系良好,r值均为0.999 7,检出限为0.006~0.1μg·L-1,重复性实验(n=6)的RSD为0.65%~4.82%,回收率为94.1%~108.6%。方法学比较表明该方法和国家法定方法的测定结果基本一致。     

Male-specific conversion of the host plant compound,myrcene, to the pheromone, (+)-ipsdienol,in the bark beetle,Dendroctonus brevicomis

When both sexes of the bark beetle,Dendroctonus brevicomis LeConte, were exposed to vapors of myrcene from ponderosa pine, only the male produced (+)-ipsdienol. In the field, racemic ipsdienol significantly reduced the attraction of both sexes in flight to a mixture of myrcene and the aggregation pheromones,exo-brevicomin and frontalin. This suggests that ipsdienol may be involved in regulating colonization density ofD. brevicomis. The implications of the biosynthesis of various enantiomers of ipsdienol byD. brevicomis and the cohabitating bark beetles,Ips paraconfusus andI. pini, in relation to their behavioral responses are discussed in regard to reducing interspecific competition.Coleoptera: Scolytidae.     

电镀污泥中铜、镍、铬、锌的回收利用研究

研究电镀污泥中铜、镍、铬、锌的回收工艺流程,确定最佳的工艺条件。结果表明,电镀污泥中铜、镍、铬、锌的浸出率分别达到97.8%、98.6%、94.8%和99.0%,并可循环回收;废渣无害化,可按一般工业固废处置;生产过程闭路循环,无任何排放,实现清洁生产.     

Identification, Synthesis, and Field Testing of the Sex Pheromone of the Citrus Leafminer, Phyllocnistis citrella

The citrus leafminer is an important vector of citrus canker in many of the major citrus production areas of the world. (7Z,11Z)-Hexadecadienal was reported as a sex attractant for this insect in the 1980s, based on trap catches during pheromone screening trials in Japan. However, attempts to reproduce this work in other areas of the world have not been successful. We report here that (7Z,11Z)-hexadecadienal is only one component of the pheromone, with the other critical component being the analogous trienal, (7Z,11Z,13E)-hexadecatrienal. Both compounds were identified in the effluvia from live female moths by coupled gas chromatography (GC)-electroantennography using nonpolar and polar GC columns, and the identifications were confirmed by comparisons of mass spectra with those of authentic standards. Stereoisomers of the two compounds, and a number of analogs, were synthesized to confirm the identifications. In field trials, neither compound alone was attractive to male moths, but blends of the two were highly attractive, with thousands of insects being caught per trial. Addition of the isomeric (7Z,11Z,13Z)-hexadecatrienal inhibited attraction to the two-component blend. Electronic Supplementary Material Supplementary material is available for this article at and accessible for authorized users. This paper and the preceding paper (Leal et al.) were submitted within a few days of each other. The editors and the authors agreed that they should be published in tandem.     

Isolation,identification, synthesis,and bioassay of the pheromone of the comstock mealybug and some analogs

The sex pheromone of the Comstock mealybug,Pseudococcus comstocki (Kuwana) was isolated from volatiles trapped from air passing over virgin female insects. Combined gas chromatography, mass and infrared spectroscopy, and microreactions indicated that the structure was 2,6-dimethyl-1,5-heptadien-3-ol acetate. This was confirmed by synthesis; several analogs were also prepared. The natural and synthetic pheromone caused similar trap capture of male insects. Synthetic analogs were significantly less attractive in field tests and the addition of minor amounts of the corresponding alcohol to the pheromone appeared to enhance trap capture, but the results were not statistically conclusive.     

Fate of the Dietary Terpene, P-Cymene, in the Male Koala

The fate of the dietary terpene, p-cymene, is reported in a specialist Eucalyptus leaf folivore, the koala (Phascolarctos cinereus). Six male koalas were given two single oral doses of p-cymene (0.37 mmol/kg and 1.49 mmol/kg). Urine and feces were collected for two 24-hr periods after each dose and analyzed for metabolites by extraction, gas chromatography, and mass spectrometry. A total of six metabolites were detected in the urine. A novel, extensively oxidized metabolite, 4-(1,2-dihydroxy-1-methylethyl)-benzoic acid, was identified and its structure elucidated by high resolution and chemical ionization mass spectrometry. Minor amounts of two glycine conjugated metabolites were also detected. Five metabolites were present in sufficient amounts to quantify, using isolated urinary metabolites as reference standards. The mean fractional recovery of administered p-cymene was 0.77 ± 0.09 and 0.84 ± 0.12 for the low and high dose, respectively. The major metabolite excreted was the novel carboxy diol compound. No fecal metabolites were found. Thus, the koala employs a strategy in the metabolism of p-cymene that promotes the production of extensively oxidized metabolites that consequently have increased polarity and enhanced renal excretion. This strategy is compared with that employed by other Eucalyptus leaf folivores.     

热成型工艺的解决方案

成功的塑料热成型工艺解决方案,要求对加工工艺、模具设计、材料性能等因素进行全面综合分析。众多的热成型加工厂商往往只着眼于调整和改进工艺,以此来解决生产过程中所遇到的各种制品缺陷问题。其中采取的措施包括:试图延长加工循环周期、二次加工工序、或者通过改良设备装置     

隔壁塔用于苯、甲苯、二甲苯分离的控制

在稳态模拟的基础上,研究了用于苯、甲苯、二甲苯分离的隔壁塔的控制策略和动态特性。动态模拟中采用继电反馈法和Tyreus-Luyben准则进行PID参数整定,在Aspen Dynamic平台上,对比分析了DB/LSV、DV/LSB、LB/DSV和LV/DSB 4种典型组成控制策略的动态特性,并重点考察了LV/DSB基础上的温度控制、温度组成联合控制和温度组成串级控制策略。结果表明,当出现进料组成或流率干扰时,隔壁塔具有很好的可控性,调节时间TS最短至2.97 h,产品质量要求与设定值之间的摩尔最大偏差A最低至0.0015。     

Effect of concentration, temperature, moisture, liming and organic matter on the efficacy of the nitrification inhibitors benzotriazole, o-nitrophenol, m-nitroaniline and dicyandiamide

Laboratory experiments were carried out to study the effect of various factors that affect the efficacy of the nitrification inhibitors, benzotriazole, o-nitrophenol, m-nitroaniline and dicyandiamide. In a Paleustalf, increasing concentrations of the inhibitors from 0 to 15 mg/kg soil prolonged the nitrification up to 60 days. Increase in temperature from 10 to 30°C decreased the efficacy of all four nitrification inhibitors (by 6–62% at 30 days). Benzotriazole was equally effective in soil moisture conditions ranging from 40 to 80% of the maximum water holding capacity of the soil (WHC). o-Nitrophenol and m-nitroaniline were more effective at 60% WHC, while the efficacy of DCD was more at 40% WHC. Addition of 1000 mg/kg soil of fresh organic matter reduced the efficacies of o-nitrophenol, m-nitroaniline and benzotriazole by 55, 65 and 22%, respectively while the reduction in the efficacy of dicyandiamide was non-significant. Liming an acidic soil (Kandiustalf) to change the pH from 5.4 to 8.3 decreased the efficacies of the nitrification inhibitors and decreased the ammonium content in the soil at 30 days from 55 to 9 mg/kg in case of o-nitrophenol and m-nitroaniline and from 53 to 35 mg/kg in case of benzotriazole and dicyandiamide.     

Raman spectroscopic determination of the length, strength, compressibility, Debye temperature, elasticity, and force constant of the C-C bond in graphene

From the perspective of bond relaxation and bond vibration, we have formulated the Raman phonon relaxation of graphene, under the stimuli of the number-of-layers, the uni-axial strain, the pressure, and the temperature, in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of the Raman shifts, which are due to the number-of-layers reduction, of the G-peak shift and arises from the vibration of a pair of atoms, while the D- and the 2D-peak shifts involve the z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C(3v) bond geometry to the C(2v) uni-axial bond elongation; (iii) the thermal softening of the phonons originates from bond expansion and weakening; and (iv) the pressure stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift as well as the length, energy, force constant, Debye temperature, compressibility and elastic modulus of the C-C bond in graphene, which is of instrumental importance in the understanding of the unusual behavior of graphene.