一种抗干扰的H_2S传感器

在ＺｎＯ基体材料中添加稀土金属氧化物ＣｅＯ２制成了抗干扰的Ｈ２Ｓ气体传感器，研究了其对Ｈ２Ｓ气的响应特性，发现在１０ｐｐｍ的Ｈ２Ｓ气中，灵敏度可高达２０倍、且响应迅速，而对几种干扰气ＣＯ（１００ｐｐｍ），ＣＨ４（３０００ｐｐｍ），ｉ－Ｃ４Ｈ１０（１００ｐｐｍ）响应很小．     

烟草中总氮的测定

研究了克达尔法测定烟草中总氮含量时ＨｇＯ和ＣｕＳＯ＿４两种催化剂的催化效果。结果表明，ＨｇＯ催化回收率为１００．００％，ＣｕＳＯ＿４催化回收率为９５．８５％；同时研究了Ｈ＿３ＢＯ＿３和Ｈ＿２ＳＯ＿４两种氨吸收液对测定结果的影响，表明Ｈ＿３ＢＯ＿３吸收液可行，操作简便。     

由工业氯化钡制备高纯度碳酸钡的研究

本文以工业ＢａＣｌ２．２ＨＯ为原料,采用混合溶剂法除去了Ｃａ＾２＋,Ｓｒ＾２＋等主要杂质,获取了高纯度ＢａＣｌ２．２ＨＯ。将所得高纯度ＢａＣｌ２．２Ｈ２Ｏ与ＮＨ４ＨＣＯ３反应,并经６０℃二次蒸馏水行销条,１２０℃干燥,制备了纯度为９９．９１％高纯度ＢａＣＯ３,其中的Ｃａ＾２＋,Ｓｒ＾２＋含量低于２０ｐｐｍ。     

印染助剂实用指南 十

印染助剂实用指南（十）吴庆源（常州化工研究所常州２１３００１）２２超柔软型柔软剂Ｓ２Ｓ２２．１结构或组成［（Ｃ＿（１８）Ｈ＿（３７））＿２Ｎ（ＣＨ＿３）＿２］￣＋Ｃｌ￣－２２．２规格及标准外观为米黄色稠液，含固量８％～１０％，阳离子型，ｐＨ值６．５～...     

气敏元件的表面修饰技术的研究与应用

表面修饰技术是一种利用物理和化学的方法对气敏元件的表面进行改性的方法，具体地说，它又可分为以下３种方法：１）表面掺杂法，即把贵金属及金属氧化物掺在氧化物气敏半导体表面上的方法（共混，共沉淀，浸渍，喷涂分解和物理吸附等）；２）表面处理法，即将已完成的气敏元件，放入各种气氛中进行处理的方法；３）表面催化层法，即在元件表面上，涂上一种催化层，以除去干扰气体并把非活性气体进行分解的方法，近几年我们通过表面掺杂法，对ＳｎＯ２，ＺｎＯ，ＮｉＯ，ＷＯ３等敏感材料进行掺杂，获得了Ｈ２，Ｈ２Ｓ，Ｏ２，ＮＯ２，Ｃ２Ｈ５ＯＨ和ＣＨ４等高灵敏度、高选择性气体传感器．通过制作掺Ｐｄ，Ｇａ２Ｏ３等催化活性层、防止了Ｃ２Ｈ５ＯＨ等气体的干扰，研制出高选择性ＣＨ４元件并使其实用化．利用表面处理法在开发Ｈ２Ｓ元件，Ｃ２Ｈ５ＯＨ元件方面也取得了良好效果．     

测定维生素C的提取剂的研究

发现了一种新的Ｖｃ提取剂（２％草酸＋１％盐酸溶液），并与２％Ｈ＿３ＰＯ＿３溶液、２％Ｈ＿２Ｃ＿２Ｏ＿４溶液，１０％三氯乙酸溶液及３％Ｈ＿３ＰＯ＿３＋８％ＨＡＣ溶液作了比较。这种提取剂在Ｖｃ含量测定中将有很好的前景。     

印染助剂实用指南（十二）

印染助剂实用指南（十二）吴庆源（常州化工研究所常州２１３００１）３５柔软剂ＫＳ─２０３５．１结构或组份Ｃ＿１７Ｈ＿３５ＣＯＮ（Ｃ＿２Ｈ＿４ＯＨ）＿２将硬脂酸和乙二醇胺缩合成硬脂酸酰胺，然后冷却，加入非离子乳化剂进行乳化而得。３５．２规格及标准外观为乳...     

食品中牛磺酸的稳定性研究

食品中牛磺酸的稳定性研究张平伟杨祖英卫生部食品卫生监督检验所（１０００２１）牛磺酸的结构式为ＮＨ２—ＣＨ２—ＣＨ２—ＳＯ３Ｈ，化学性质不活泼。ＳＵＢＢＡＲＡＯ报道〔１〕维生素配方中的牛磺酸经１００℃加热８８ｈ或高强度紫外灯照射７ｈ、ｐＨ为３，７，１０...     

掺杂镍酸镧材料的气敏特性研究

研究了ＴｉＯ＿２掺杂ＬａＮｉＯ＿３的气敏特性，实验表明，在中等掺杂时，材料的电导适中，气敏性能最好；ＸＲＤ证实，掺杂后ＬａＮｉＯ＿３仍属于ＡＢＯ＿３钙钛矿结构，且有新相生成。还对掺杂ＳｎＯ＿２，Ｓｂ＿２Ｏ＿３及Ｖ＿２Ｏ＿５进行了研究，指出ＳｎＯ＿２中等掺杂及Ｓｂ＿２Ｏ＿３，Ｖ＿２Ｏ＿５低掺杂时，同样能使ＬａＮｉＯ＿３的气敏性质有所改善。     

造纸污泥流化床焚烧的环境分析

研究了造纸污泥在流化床中焚烧的排放情况。在大型热态流化床上，测定了污泥和煤以不同比例混烧时，烟气中的ＮＯ＿ｘ、ＳＯ＿２、ＣＯ、Ｃｌ＿２、ＨＣｌ的含量，同时还测定了纯污泥灰样中某些重金属的含量。     

Remote identification and quantification of industrial smokestack effluents via imaging Fourier-transform spectroscopy

Industrial smokestack plume emissions were remotely measured with a midwave infrared (1800-3000 cm(-1)) imaging Fourier-transform spectrometer operating at moderate spatial (128 × 64 with 19.4 × 19.4 cm(2) per pixel) and high spectral (0.25 cm(-1)) resolution over a 20 min period. Strong emissions from CO(2), H(2)O, SO(2), NO, HCl, and CO were observed. A single-layer plume radiative transfer model was used to estimate temperature T and effluent column densities q(i) for each pixel's spectrum immediately above the smokestack exit. Across the stack, temperature was uniform with T = 396.3 ± 1.3 K (mean ± stdev), and each q(i) varied in accordance with the plume path length defined by its cylindrical geometry. Estimated CO(2) and SO(2) volume fractions of 8.6 ± 0.4% and 380 ± 23 ppm(v), respectively, compared favorably with in situ measurements of 9.40 ± 0.03% and 383 ± 2 ppm(v). Total in situ NO(x) concentration (NO + NO(2)) was reported at 120 ± 1 ppm(v). While NO(2) was not spectrally detected, NO was remotely observed with a concentration of 104 ± 7 ppm(v). Concentration estimates for the unmonitored species CO, HCl, and H(2)O were 14.4 ± 0.3 ppm(v), 88 ± 1 ppm(v), and 4.7 ± 0.1%, respectively.     

Impact of CO2 addition to milk on selected analytical testing methods

The addition of CO2 to raw milk and dairy products controls the growth of psychrotrophic bacteria at refrigeration temperatures. The objective of this study was to determine the effects of dissolved CO2 in milk on the performance of four important routine testing methods: antibiotic residue test, freezing point test, infrared milk component analysis, and alkaline phosphatase test. Raw or pasteurized whole milk was carbonated at <4 degrees C to contain approximately 0 (control), 200, 400, 600, and 1000 ppm of CO2. The addition of CO2 to raw milk up to 1000 ppm had no effect on the performance of the three antibiotic (beta-lactams) residue tests: IDEXX SNAP, Charm II Sequential Tablet, and Delvo-P Ampule. Milk freezing point decreased linearly with increasing concentration of dissolved CO2, from -0.543 degrees H (control) to -0.595 degrees H (1000 ppm). Carbonation to 1000 ppm decreased milk pH (measured at 38 degrees C) from 6.61 (control) to 6.15 (1000 ppm). The effects of CO2 on milk freezing point and pH were reversible upon removal of dissolved CO2. Increased CO2 levels in milk changed the infrared absorption spectrum of milk and caused the corrected lactose readings to decrease and the corrected fat B readings to increase. For the alkaline phosphatase tests, 0 (none), 0.05, 0.1, and 0.2% raw milk were deliberately added to pasteurized milks of six levels of carbonation (0 to 1000 ppm). The addition of CO2 did not influence the ability of Fluorophos, Charm PasLite, and Scharer Modified Rapid tests to differentiate between a pasteurized milk and a pasteurized milk with raw milk contamination.     

Carbon dioxide capture by functionalized solid amine sorbents with simulated flue gas conditions

A novel solid amine sorbent was prepared using KIT-6-type mesoporous silica modified with tetraethylenepentamine (TEPA). Its adsorption behavior toward CO(2) from simulated flue gases is investigated using an adsorption column. The adsorption capacities at temperatures of 303, 313, 333, 343, and 353 K are 2.10, 2.29, 2.58, 2.85, and 2.71 mmol g(-1), respectively. Experimental adsorption isotherms were obtained, and the average isosteric heat of adsorption was 43.8 kJ/mol. The adsorption capacity increases to 3.2 mmol g(-1) when the relative humidity (RH) of the simulated flue gas reaches 37%. The adsorption capacity is inhibited slightly by the presence of SO(2) at concentrations lower than 300 ppm but is not significantly influenced by NO at concentrations up to 400 ppm. The adsorbent is completely regenerated in 10 min at 393 K and a pressure of 5 KPa, with expected consumption energy of about 1.41 MJ kg(-1) CO(2). The adsorption capacity remains almost the same after 10 cycles of adsorption/regeneration with adsorption conditions of 10 vol % CO(2), 100 ppm SO(2), 200 ppm NO, 100% relative humidity, and a temperature of 393 K. The solid amine sorbent, KIT-6(TEPA), performs excellently for CO(2) capture and its separation from flue gas.     

Effects of water-soluble natural antioxidants on photosensitized oxidation of conjugated linoleic acid in an oil-in-water emulsion system

ABSTRACT:  The effect of photosensitized oxidation of conjugated linoleic acid in an oil-in-water (o/w) emulsion system was studied. Water-soluble natural antioxidants, including apple polyphenols from apple extract, green tea extract, 4-hydroxy-2(or 5)-ethyl-5(or2)-methyl-3(2H)-furanone(HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), and ascorbic acid, were tested for antioxidant activity in this system. The green tea extract showed the highest antioxidant activity followed by ascorbic acid. Apple polyphenols did not give significant antioxidant activity. HEMF and HDMF exhibited a prooxidant effect. The antioxidant activity of tea catechins was also investigated. Of them, EGCG and ECG exhibited antioxidant activity at 50 ppm, but the antioxidant activity between them was not significantly different ( P < 0.05). Comparatively, EC, EGC, and GCG showed no significant antioxidative effect at 50 ppm. When the concentration increased to 100 ppm, the antioxidant activity of ECG and EGCG significantly increased compared with that at 50 ppm, and EGCG had higher antioxidant activity than ECG. GCG also showed significant antioxidant activity at 100 ppm. EGCG exhibited the highest antioxidant activity among the tea catechins in the emulsion system at 100 ppm.     

Influence of ammonia and carbon dioxide on the sorption of a basic organic pollutant to carpet and latex-painted gypsum board

Sorptive interactions with indoor surfaces strongly influence indoor exposure to organic pollutants. Adsorption itself may be influenced by indoor levels of common indoor gases such as CO2, NH3, and H2O. We quantified sorption characteristics of trimethylamine (TMA) on carpet and painted wallboard, while challenging the surface with gas-phase CO2, NH3 and H2O. We show that the capacity of the carpet to sorb TMA, doubles when the CO2 mixing ratio is increased from 0 to 1000 ppm CO2 at 90% relative humidity. In contrast, NH3 decreases the surface capacity of both carpet and latex paint. Sorption of TMA to these indoor materials is primarily caused by interactions at one or more interfaces. Dissolution of TMA and aqueous acid-base chemistry appear to also contribute to the overall sorptive capacity of carpet at high relative humidity. The reduction in the distribution coefficient, k(e), in the presence of NH3 is explained by competition between TMA and NH3 molecules for sites on the substrates at low-to-medium relative humidity conditions.     

Effect of chemical sanitizer combined with modified atmosphere packaging on inhibiting Escherichia coli O157:H7 in commercial spinach

Escherichia coli O157:H7 contaminated spinach has recently caused several outbreaks of human illness in the USA and Canada. However, to date, there has been no study demonstrating an effective way to eliminate E. coli O157:H7 in spinach. Therefore, this study was conducted to investigate the effect of chemical sanitizers alone or in combination with packaging methods such as vacuum and modified atmosphere packaging (MAP) on inactivating E. coli O157:H7 in spinach during storage time. Spinach inoculated with E. coli O157:H7 was packaged in four different methods (air, vacuum, N(2) gas, and CO(2) gas packaging) following treatment with water, 100 ppm chlorine dioxide, or 100 ppm sodium hypochlorite for 5 min at room temperature and stored at 7+/-2 degrees C. Treatment with water did not significantly reduce levels of E. coli O157:H7 in spinach. However, treatment with chlorine dioxide and sodium hypochlorite significantly decreased levels of E. coli O157:H7 by 2.6 and 1.1 log(10)CFU/g, respectively. Levels of E. coli O157:H7 in samples packaged in air following treatments grew during storage time, whereas levels were maintained in samples packaged in other packaging methods (vacuum, N(2) gas, and CO(2) gas packaging). Therefore there were significant differences (about 3-4 log) of E. coli O157:H7 populations between samples packed in air and other packaging methods following treatment with chemical sanitizers after 7 days storage. These results suggest that the combination of treatment with chlorine dioxide and packaging methods such as vacuum and MAP may be useful for improving the microbial safety of spinach against E. coli O157:H7 during storage.     

Elimination of Listeria monocytogenes biofilms by ozone, chlorine, and hydrogen peroxide

This study evaluated the efficacy of ozone, chlorine, and hydrogen peroxide to destroy Listeria monocytogenes planktonic cells and biofilms of two test strains, Scott A and 10403S. L. monocytogenes was sensitive to ozone (O3), chlorine, and hydrogen peroxide (H2O2). Planktonic cells of strain Scott A were completely destroyed by exposure to 0.25 ppm O3 (8.29-log reduction, CFU per milliliter). Ozone's destruction of Scott A increased when the concentration was increased, with complete elimination at 4.00 ppm O3 (8.07-log reduction, CFU per chip). A 16-fold increase in sanitizer concentration was required to destroy biofilm cells of L. monocytogenes versus planktonic cells of strain Scott A. Strain 10403S required an ozone concentration of 1.00 ppm to eliminate planktonic cells (8.16-log reduction, CFU per milliliter). Attached cells of the same strain were eliminated at a concentration of 4.00 ppm O3 (7.47-log reduction, CFU per chip). At 100 ppm chlorine at 20 degrees C, the number of planktonic cells of L. monocytogenes 10403S was reduced by 5.77 log CFU/ml after 5 min of exposure and by 6.49 log CFU/ml after 10 min of exposure. Biofilm cells were reduced by 5.79 log CFU per chip following exposure to 100 ppm chlorine at 20 degrees C for 5 min, with complete elimination (6.27 log CFU per chip) after exposure to 150 ppm at 20 degrees C for 1 min. A 3% H2O2 solution reduced the initial concentration of L. monocytogenes Scott A planktonic cells by 6.0 log CFU/ml after 10 min of exposure at 20 degrees C, and a 3.5% H2O2 solution reduced the planktonic population by 5.4 and 8.7 log CFU/ml (complete elimination) after 5 and 10 min of exposure at 20 degrees C, respectively. Exposure of cells grown as biofilms to 5% H2O2 resulted in a 4.14-log CFU per chip reduction after 10 min of exposure at 20 degrees C and in a 5.58-log CFU per chip reduction (complete elimination) after 15 min of exposure.     

Comparison of chemical treatments to eliminate enterohemorrhagic Escherichia coli O157:H7 on alfalfa seeds.

The focus of this study was to determine the efficacy of various chemicals in eliminating 2.04 to 3.23 log10 CFU/g of Escherichia coli O157:H7 from alfalfa seeds and to determine the survivability of the pathogen on seeds stored for prolonged periods at three temperatures. Significant (P < or = 0.05) reductions in populations of E. coli O157:H7 on inoculated seeds were observed after treatments with 500 and 1,000 ppm of active chlorine (as Ca[OCl]2) for 3 but not 10 min and with > or =2,000 ppm of Ca(OCl)2 regardless of pretreatment with a surfactant. Treatment with 20,000 ppm of active chlorine failed to kill 2.68 log10 CFU/g of seeds. Acidified NaClO2 (500 ppm) was effective in reducing populations of the pathogen by >2 logs per g. Acidified ClO2 significantly reduced populations of E. coli O157:H7 on seeds at concentrations > or =100 ppm, and 500 ppm of ClO2 reduced the pathogen from 2.7 log10 CFU/g to <0.5 CFU/g. Chlorine (as NaOCl) was not effective at concentrations < or =1,000 ppm; significant reduction was achieved only after treatment with 2,000 ppm for 3 or 10 min. Notable reduction in populations was observed after treatment with 30 or 70% C2H3OH, but there was a dramatic decrease in germination percentage. Treatment with 0.2% H2O2 significantly reduced populations, and the organism was not detected by direct plating after treatment with > or =1% H2O2. Significant reduction in population of E. coli O157:H7 occurred after treatment with 1% trisodium phosphate, 40 ppm of Tsunami and Vortexx, and 1% Vegi-Clean. A significant decrease in the number of E. coli O157:H7 on dry seeds was observed within 1 week of storage at 25 and 37 degrees C, but not at 5 degrees C. Between 1 and 38 weeks, populations on seeds stored at 5 degrees C remained relatively constant. The pathogen was recovered from alfalfa seeds initially containing 3.04 log 10 CFU/g after storage at 25 or 37 degrees C for 38 weeks but not 54 weeks.     

Accumulation of carbon monoxide and carbon dioxide in stored canola

Production of carbon monoxide (CO) and carbon dioxide (CO(2)) from canola was studied in the laboratory and in commercial storage. Canola rapidly produced amounts of CO and CO(2) far exceeding those reported for dry cereal grain and dried peas and at levels dangerous to human health. In the laboratory, canola (5.8% m.c.) was stored in sealed flasks at 25, 35 and 45 degrees C for 12 weeks. Levels of CO, CO(2) and oxygen (O(2)) were then measured by gas chromatography. Average levels of CO and CO(2) increased with storage temperature. Levels of CO peaked at 6 weeks, exceeding 10,000 ppm v/v (1%) at 45 degrees C. CO(2) levels peaked at 11.9% after 10 weeks storage at 45 degrees C. In field measurements, CO levels in a steel bin (7000 tonne capacity) filled with canola ranged from 1100 to 800 ppm in the grain bulk before sealing, 1050-370 ppm in the grain bulk after sealing, and 290-440 ppm in the head space of the sealed bin. CO(2) concentrations were >3% in the grain bulk and averaged 1.5% in the headspace. CO production rate was estimated at 200 ng g(-1) day(-1). Canola storage poses a greater potential safety hazard than storage of cereals.