空气中的水含量表及其在色谱分析中的应用

在一定温度下,空气中含有一定量的水分。如果能够利用简单的式子计算出或者在表上查出某一温度下1ml空气中的水含量(mg/ml),就可以将该温度下的空气送入色谱柱,经分离后得到水的峰高(或面积)。从而计算出单位峰高(或面积)所代表的水含量(mg)。以此为基准可以方便地计算出液体或气体样品中的水含量,可以省去配制标准水样的繁琐工作。为此我们推导出了空气中的水含量计算式。并利用此计算式和空气的相对湿度表进而计算、编制出了空气中的水含量表(mg/ml)。这样     

聚甲醛电纺纤维表面孔结构的控制

研究了环境相对湿度、 温度、 溶液浓度、 纺丝电压和接收距离对聚甲醛(POM)电纺纤维表面孔形貌的影响. 结果表明, 空气中一定含量的水对孔的形成至关重要; 纺丝液浓度对孔的大小有影响. 并对POM 纤维表面成孔的可能机理进行了分析.     

气体中微量油分析方法研究

对GJB 3403—98气体中微量油分析方法存在的不足进行了分析,对技术指标、标准物质、冷源、流速、取样量、油含量单位进行了探讨,并以实验证明了用冷凝富集-紫外分光光度法测定氦气、氮气、空气中微量油含量的可行性。方法改进后可以提高氮气、氦气、空气等气体中油含量分析的可靠性。     

离子色谱-伏安极谱法联用同时测量空气中阴阳离子及重金属含量

通过空气样品液化器中真空泵的作用,空气转化为液体,从而能持续提供样品流,以供离子色谱仪和伏安极谱仪检测。阐述了将空气样品液化器(PILS)与伏安极谱仪(VA)、离子色谱仪(IC)联机分析空气中气溶胶的方法,其中伏安极谱仪可以分析空气中的Zn、Cd、Pb、Cu等重金属含量,离子色谱仪可以分析空气中的Cl-、NO2-、NO3-、SO42-、Li+、Na+、NH4+、K+、Ca2+、Mg2+等阴、阳离子的含量。方法取得了很好的精密度与准确度。     

对“空气中氧气含量测定实验”的改进

通过文献研究和实验研究，得出用吸氧腐蚀原理测量空气中氧气含量，比传统用红磷燃烧测量空气中氧气含量的方法更加科学、准确，并提出改进方案。     

BaxCe0.8Y0.2O3-α固体氧化物燃料电池性能

用高温固相反应法合成了BaxCe0.8Y0.2O3-α（x=1.03,1,0.98)系列固体电解 质，用粉末X射线衍射法研究了样品的晶体结构，用氢及氧浓差电池方法研究了样 品的质子及氧离子导电特性，测定了它们的氢－空气燃料电池的放电性能。结果表 明，各样品均为钙钛矿斜方晶单相结构；质子导电和燃料电池输出电流密度均随样 品中钡离子含量的增加而增大，Ba1.03Ce0.8Y0.2O3-α具有最大的质子导电性和燃 料电池输出电流密度；各样品的氧离子导电性几乎不受钡离子含量影响。     

初中化学实验的改进与创新

对初中化学的4个实验——空气中氧气含量的测定、氢气在空气中的燃烧、金属与盐酸或稀硫酸的反应、水排气与气排水进行了改进与创新。     

气态污染物氯化氰的分光光度法测定

探索了氯化氰（CNCI）气体在不同介质中的稳定性和可吸收性,及光度测定条件,方法用于三聚氯氰工厂烟道气、车间空气及厂区空气中CNCI含量的测定。 结果满意。     

硫氰酸汞分光光度法测定空气颗粒物中的氯化氢

用硫氰酸汞分光光度法分别测定空气及空气颗粒物和空气中氯化氢的含量,利用相减法得出空气颗粒物中氯化氢的含量。线性范围为0～1．00μg/mL,线性回归方程为A=0．0799c 0．00124,相关系数为0.9995。该方法灵敏、简便,测定结果的相对标准偏差为6．8％(n=7),加标回收率为98．1％～103．9％。     

镁条表面“灰黑色外衣”的探究

金属表面锈蚀物的成分比较复杂。镁是一种活泼金属,在空气中也容易生锈。但在空气中久置的镁条表面的"灰黑色物质"到底含有哪些物质?着重研究镁条表面的锈蚀物的形成过程及镁锈的主要成分。     

Monolayers of some liquid-crystal forming compounds

Summary A study of monolayer characteristics of some thermotropic liquid-crystal forming molecules on water surfaces has been carried out. Monolayers of horizontal rigid molecules with two polar heads collapse on compression by a roll over mechanism. Variation of temperature within an appropriate range gradually changes from liquid-like to a crystal-like collapse. Between these two extremes a combination of both states could be obtained. The state of the corresponding film is attributed to mesogenic properties of the compounds investigated. This investigation proves that some mesogenic compounds are able to form liquid-crystals on the water surface.With 6 figures and 1 table     

Polyphenol content in white table grape (Vitis Vinifera) berries of cultivar Italia: interactive effect of irrigation, delayed harvest and storage

Polyphenol concentrations were quantified by rapid resolution liquid chromatography/mass spectrometry in white table grape. The experimental vineyard was subjected to different kinds of water supply and supply rates. Samples from the same vineyards were also analysed after 6 weeks of storage in a refrigerator and after 6 weeks of delayed harvesting. Berry skins and seeds were analysed separately. A statistical treatment of the screening kind, namely the 2(k) full factorial design, was used for the interpretation of results. Storage, delayed harvesting and the different kinds of water supply appeared to be the variables most affecting grape polyphenol content. In some cases, results showed that polyphenol content diminished by more than 50% after 6 weeks if the grapes were stored in a refrigerator, or if a sprinkler was used for irrigation.     

Characteristics of the Permafrost Structure on the Fildes Peninsula, King George Island, Antarctica

Based on the data from the pitting, geoelectrical prospectings, temperature measuring, and the divided layers frost-heaving instruments, this paper, first, discusses the structure features of active layers in this region, and proves the presence of the bowlshaped frost table in the stone circles area. Second, it analyses the temperature distributive rule in the active layer, meantime, according to the vertical-profile parameters of granularity, clay mineral, salt content and resistivities, it also discusses the different features of permafrost structure and their control actions on the periglacial landform development between high and low places. It suggests that the four-layer structure should exist in the permafrost region (including under-bedrock), that is, active layer, frost sand and gravels layer, frost volcanic rock permeated by sea water, and frost volcanic rock unpermeated by sea water. Finally, the permafrost table and its vertical gradient are deduced.     

Uranium, radium and tritium groundwater monitoring at INFN-Gran Sasso National Laboratory, Italy

Uranium groundwater anomalies, which were observed in cataclastic rocks crossing the underground Gran Sasso National Laboratory before the L’Aquila earthquake (April 6th, 2009), have been studied versus radium and tritium contents. The radionuclide analysis supports the role of endogenic fluid dynamics for uranium content in groundwater rather than percolation processes, due to meteoric events occurring above the water table of the Gran Sasso aquifer. The uranium anomalies represent a key geochemical signal of a progressive increase of deep fluids fluxes at middle-lower crustal levels associated with the geodynamics of the earthquake. Moreover, the uranium represents a more precise strain-meter than radon as its presence can be modulated during the preparation phase of the earthquake, and only successively released by microfracturing during the main shock and aftershocks.     

Spectrophotometric Determination of Water Content in Alcohol Organic Solvents

In this work, the absorption spectral characteristics and color‐change reaction mechanism of cobalt(II) chloride(CoCl₂) in alcohol organic solvents has been investigated in the presence of water, and then the optimum conditions for determining the water content in the solvents were selected. Results indicated that the absorption spectra of CoCl₂ in alcohols decreased with the increment of water content. At the maximum absorption wavelength of 656 nm, there were good linear relationships between the logarithm of the absorbance and the water content in organic solvents such as ethanol, n‐propanol, iso‐propanol and n‐butanol with related coefficients in the range of 0.9996?0.9998. For determining water content in organic solvents, this method is simple, rapid, sensitive, reproducible and environmentally friendly. Furthermore, the linear range cannot restrict determination of the water content in organic solvents. This method had been applied to determine the water content in ethanol and n‐butanol with satisfactory recovery of water in n‐butanol between 98.41%?101.29%.     

Simple and rapid determination of iodide in table salt by stripping potentiometry at a carbon-paste electrode

A simple and rapid procedure, utilising constant-current stripping analysis (CCSA) at a carbon-paste electrode containing tricresyl phosphate as a pasting liquid (TCP-CPE), has been developed for the determination of iodide in table salt. Because of a synergistic accumulation mechanism based on ion-pairing and extraction of iodide in combination with electrolytic pretreatment of the TCP-CPE, the method is selective for iodide and enables direct determination of iodide in samples of table salt containing anti-caking agents such as K(4)[Fe(CN)(6)] (food additive "E 536") or MgO. The iodide content (calculated as KI) can be determined in a concentration range of 2 to 100 mg kg(-1) salt, with a detection limit (S/N=3) of 1 mg kg(-1), and a recovery from 90 to 115%. The proposed method has been used to determine iodide in several types of artificially iodised table salt and in one sample of natural sea salt. The results obtained agreed well with those obtained by use of three independent reference methods (titration, spectrophotometry, and ICP-MS) used to validate the CCSA method, indicating that the developed method is applicable as a routine procedure for rapid testing in salt production process control and in the analysis of marketed table salts.     

Assessment of ground water quality in a fractured aquifer under continue wastewater injection

Experimental studies have been carried out in a fractured coastal aquifer of the Salento Region (Nardò (Le), Italy), subject since 1991 to injection of 12,000 m3/d of treated municipal wastewater in a natural sink. The analytical parameters of ground water sampled in monitoring wells, have been compared before and after the injection started. The mound of water table (1.5 m), the reduction of seawater extent of 2 km and the spreading of pollutants injected were evaluated by means of mathematical model results. After ten years operation, the volume of the available resource for agricultural and drinking use has been increased, without notable decrease of the preexistent ground water quality. Moreover for preserving such resource from pollution, the mathematical model allowed the standards of wastewater quality for recharge to be identified. Around the sink, a restricted area was also defined with prohibition of withdrawals, to avoid infection and other risks on human health.     

The heat of immersion of zinc oxide in water

Summary The immersional heats of zinc oxide in water have been measured in connection with the variation of the outgassing temperature of the sample. The heats show a maximum on the sample treated at 400° to 500°C. This phenomenon can be explained in terms of chemisorption which occurs on the dehydrated site on the surface, followed by physical adsorption on the surface hydroxyl groups due to hydrogen bonding.The heats of adsorption and chemisorption of water molecules on the surface of zinc oxide were calculated separately from the data of the immersional heat and the water content.

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Zusammenfassung Es wurde die Benetzungswärme von Zinkoxid in Wasser in Abhängigkeit von der Vorbehandlungstemperatur bestimmt. Bei den Proben, die zwischen 400° und 500°C entgast wurden, trat ein Maximum in der Benetzungswärme auf, das durch eine besonders starke Chemisorption erklärt wird. An den bei anderen Temperaturen entgasten Präparaten findet nur eine physikalische Adsorption statt. Aus den gemesenen Benetzungswärmen und dem H₂O-Gehalt der Oberfläche wurden die Adsorptionswärmen von Wasser an Zinkoxid bei physikalischer und bei chemischer Adsorption berechnet.

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With 4 figures and 1 table