CO_2传感器的研究

采用ＮＡＳＩＣＯＮ（Ｎａ离子导体）与ＢａＣＯ＿３－Ｌｉ＿２ＣＯ＿３电极相结合的方式，使新型ＣＯ＿２传感器得到发展，据观察，其响应时间以及抗水湿性能都有了提高。对ＣＯ＿２浓度在１００～５×１０￣５ｐｐｍ这样宽的范围内，５００℃时测得的电动势与能斯特方程符合得很好。该元件几乎不受共存的Ｈ＿２Ｓ１００ｐｐｍ，ＮＯ＿２１００ｐｐｍ，ＣＯ１００ｐｐｍ，ＳＯ＿２１００ｐｐｍ，Ｃ＿２Ｈ＿５ＯＨ１００ｐｐｍ，ＣＨ＿４５０００ｐｐｍ以及ＮＨ＿３２０００ｐｐｍ的影响。电极材料在２０℃高湿状态下保持８００ｈ以上，其状态仍然没有大的变化．     

新型常温半导体气敏元件的研制及其特性研究

采用高活性的ＳｎＯ２为基体材料，选择适宜的掺杂剂，制成了性能独特的常温气敏元件．对其特性进行研究发现，其对ＣＯ，Ｈ２，Ｃ４Ｈ１０及混合气体具有不同的响应特征．     

金属－二氧化锡高选择CH_4气敏元件的研究

阐述了高选择ＣＨ４气敏元件的制造工艺，发现Ａｕ，Ｐｔ，Ｐｄ等金属超细粉的掺杂，可提高元件的抗干扰能力，对Ｃ２Ｈ５ＯＨ，Ｈ２，ＣＯ等干扰气体灵敏度＜２，而对ＣＨ４的灵敏度＞８．经２年多稳定性考核，＼Ｒ０≤±１０％，对金属超细粉在ＳｎＯ２晶粒表面状态进行了分析和探讨．     

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...     

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．     

中国专利文摘

专利申请号９９１１７４１０公开号１２５８７７８专利名称一种新型造纸施胶沉淀剂及其制造方法文摘本发明涉及的新型施胶沉淀剂由包括有铝、铝的氧化物、无机酸铝的盐类及它的化合物（Ａ）和碱金属盐及其化合物或氧化物（Ｂ）聚合,或再与含硅化合物（Ｃ）复聚合而成以下通式的聚合物：［Ａｌ２（ＯＨ）ｎ（ＳＯ４）３－ｎｘＨ２Ｏ］ｍ（１）式中：ｎ＝３－５ｍ＝１－１０或［Ａｌ２Ｓｉ（ＯＨ）ｎ（ＳＯ４）３－ｎｘＨ２Ｏ］ｍ·（２）式中：１≤ｎ≤５ｍ≤１０或［Ａｌ２（ＯＨ）ｎ（ＳＯ４）３－ｎｘＨ２Ｏ］ｍ·［Ａｌ２Ｓｉ（ＯＨ）ｎ…     

氨基酸衍生物和丙酮作混合底物的BZ振荡反应

报道氨基酸衍生物与丙酮作混合底物的ＢＺ类振荡反应－ＫＢｒＯ３／（ＣＨ３Ｏ）３ＣＣＨ（ＮＨ２）ＣＯＯＨ／ＣＨ３ＣＯＣＨ３／ＭｎＳＯ４／Ｈ２ＳＯ４体系振荡反应。给出了典型振荡波形及振荡浓度范围，分析了影响振荡反应的因素及振荡反应的温度效应。说明了丙酮及氨基酸的作用。     

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。     

蚕豆蛋白质抽提剂的初步评估及选择

选用１９种抽提剂和相应的抽提方法对蚕豆蛋白质的溶解特性进行初步研究。结果表明碱法和盐法都有较好的蛋白抽提效果。适合盐法的抽提剂有阴离子为Ｃｌ－．ＣＯ３２－，ＨＣＯ３－．ＰＯ４３－，ＨＰＯ４２－，ＳＯ３２－的钠盐，适合碱法的抽提剂为ＮａＯＨ．但为了避免蛋白质的变性和淀粉的破坏，必须控制碱液的ｐＨ＜１０，不适宜选用的抽提剂（抽提方法）有酸（法），醇（法），钙盐和阴离子为ＨＳＯ４－，ＨＳＯ３－，Ｈ２ＰＯ４－的钠盐。水溶法的蛋白提取率达７８％以上，有应用前景。     

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。     

Evaluation of peroxyacetic acid as a post-chilling intervention for control of Escherichia coli O157:H7 and Salmonella Typhimurium on beef carcass surfaces

Four experiments were conducted to test the efficacy of peroxyacetic acid as a microbial intervention on beef carcass surfaces. In these experiments, beef carcass surfaces were inoculated with fecal material (no pathogens) or fecal material containing rifampicin-resistant Escherichia coli O157:H7 and Salmonella Typhimurium. Inoculated surfaces were subjected to a simulated carcass wash with and without 2% l-lactic acid treatment before chilling. In Experiments 1 and 2, the chilled carcass surfaces were sprayed with peroxyacetic acid (200 ppm; 43°) for 15 s. Peroxyacetic acid had no effect on microbial counts of any organism measured on these carcass surfaces. However, lactic acid reduced counts of E. coli Type I (1.9log(10) CFU/cm(2)), coliforms (3.0log(10) CFU/cm(2)), E. coli O157:H7 (2.7log(10) CFU/cm(2)), and S. Typhimurium (2.8log(10) CFU/cm(2)) entering the chilling cooler and prevented growth during the chilling period. In Experiment 3, peroxyacetic acid at different concentrations (200, 600, and 1000 ppm) and application temperatures (45 and 55 °C) were used to investigate its effectiveness in killing E. coli O157:H7 and S. Typhimurium compared to 4% l-lactic acid (55 °C). Application temperature did not affect the counts of either microorganism. Peroxyacetic acid concentrations up to 600 ppm had no effect on these microorganisms. Concentrations of 1000 ppm reduced E. coli O157:H7 and S. Typhimurium by up to 1.7 and 1.3log(10) CFU/cm(2), respectively. However, 4% lactic acid reduced these organisms by 2.7 and 3.4log(10) CFU/cm(2), respectively. In Experiment 4, peroxyacetic acid (200 ppm; 43 °C) was applied to hot carcass surfaces. This treatment caused a 0.7log(10) CFU/cm(2) reduction in both E. coli O157:H7 and S. Typhimurium. The collective results from these experiments indicate that peroxyacetic acid was not an effective intervention when applied to chilled inoculated carcass piece surfaces.     

Alkaline biofiltration of H2S odors

Hydrogen sulfide (H2S) is a very common odor nuisance which is best controlled by chemical or biological scrubbing. Under alkaline pH, the amount of H2S that can be solubilized in a scrubbing liquid increases significantly, and therefore, gas-liquid mass transfer limitations can be reduced. To date, biological scrubbing of H2S has been limited to neutral or acidic pH, despite the potential benefit of reduced mass transfer limitations at alkaline pH. In the present paper, an alkaliphilic sulfoxidizing bacterial consortium was deployed in a laboratory-scale biotrickling filter treating H2S at pH 10. The gas contact time ranged from 1 to 6 s, and H2S inlet concentrations, from 2.5 to 18 ppm(v). The results showed that under most conditions, H2S removal exceeded 98% and the degradation end-product was sulfate. At the highest H2S concentrations and shortest gas contacttimes, when the loading exceeded 30 g m(-3) h(-1), the H2S removal efficiency decreased significantly due to biological reaction limitation, and incompletely oxidized sulfides were measured in the trickling liquid. An analysis of the process demonstrated that operating the biotrickling filter at high pH results in an enhancement of the mass transfer by a factor of 1700-11 000. Overall, alkaline biotrickling filtration was shown to be very effective at low concentration of H2S and very short gas contact time. This is the first demonstration of a biotrickling filter for air pollution control operated at high pH.     

Changes in landfill gas quality as a result of controlled air injection

Air addition has been proposed as a technique for rapid stabilization of municipal solid waste (MSW) in landfills. The objective of this study was to observe the change in concentration of trace constituents of landfill gas in response to air addition. Air injection tests were conducted at a MSW landfill in Florida, and the concentrations of several gaseous constituents at adjacent wells within the waste were measured. The concentrations of methane, carbon dioxide, and oxygen, as well as several trace constituents, were measured both prior to and during air addition. The trace components investigated included a suite of volatile organic compounds (VOCs), nitrous oxide (N20), carbon monoxide (CO), and hydrogen sulfide (H2S). A significant increase in CO was observed in 9 of 14 monitoring points; overall, CO concentrations were found to increase as the ratio of CH4 to CO2 decreased. A significant decrease in H2S was observed at 6 of 14 monitoring points. Air injection did not have a noticeable affect on VOC or N2O concentrations compared to initial levels.     

常温乙炔敏感振荡元件研究

报道了一种新型乙炔气体敏感元件。这种元件以Ｓｎｏ２为基体材料，工作在室温条件，对低浓度Ｃ２Ｈ２气体非常敏惑，对１０００ｐｐｍＨ２几乎没有气敏响应；其输出特性与一般加热元件明显不同，呈现为规律性极强的振荡波形，并对这种元件的气敏振荡机理进行了讨论．     

Influences of water vapor on Cr(VI) reduction by gaseous hydrogen sulfide

In Situ Gaseous Reduction (ISGR) using hydrogen sulfide (H2S) is a technology developed for soil remediation by reductive immobilization of contaminants such as hexavalent chromium (Cr(VI)). Deploying the technology requires us to obtain a much-improved understanding of the interactions among the contaminants, H2S, and various soil components. In this study, Cr(VI) reduction by gaseous H2S was examined under various relative humidities (0-96.7%), concentrations of Cr(VI) (127-475 microg/g of solid), and H2S (0-800 ppm(v)) and by using Cr(VI) compounds with different solubilities. Glass beads with various average diameters (GA = 0.600 mm; GB = 0.212-0.300 mm; and GC = 0.106 mm) and silica (SA = 0.075-0.150 mm) were used as matrices to support K2CrO4, CaCrO4, PbCrO4, or BaCrO4, and reduction of these compounds by gaseous H2S was monitored by Cr(VI) analysis following extractions with distilled water or hot alkali solution. The results showed that Cr(VI) reduction relied on both the relative humidity of the gaseous stream and the size of particles onto which Cr(VI) was deposited. The relative humidity required for fast Cr(VI) reduction was 85% for GA, 61% for GB, 6% for SA, and 0% for GC. It was believed that a water film formed on the particle surfaces under appropriate humidity conditions, resulting in Cr(VI) compound dissolution and subsequent reduction. For nonsoluble Cr(VI) compounds including PbCrO4 and BaCrO4, no reduction by H2S was observed, even at high relative humidity (96.7%), due to lack of dissolution. This study indicated that ISGR treatment in soils requires appropriate moisture content in the subsurface or maintaining a suitable humidity in the treatment gas stream to maximize chromium immobilization.     

Oxidation of H2S by iron oxides in unsaturated conditions

Previous studies have demonstrated that gas-phase H2S can immobilize certain redox-sensitive contaminants (e.g., Cr, U, Tc) in vadose zone environments. A key issue for effective and efficient delivery of H2S in these environments is the reactivity of the gas with indigenous iron oxides. To elucidate the factors that control the transport of H2S in the vadose zone, laboratory column experiments were conducted to identify reaction mechanisms and measure rates of H2S oxidation by iron oxide-coated sands using several carrier gas compositions (N2, air, and O2) and flow rates. Most experiments were conducted using ferrihydrite-coated sand. Additional studies were conducted with goethite- and hematite-coated sand and a natural sediment. Selective extractions were conducted at the end of each column experiment to determine the mass balance of the reaction products. XPS was used to confirm the presence of the reaction products. For column experiments in which ferrihydrite-coated sand was the substrate and N2 was the carrier gas, the major H2S oxidation products were FeS and elemental sulfur (mostly S8(0), represented as S(0) for simplicity) at ratios that were consistent with the stoichiometry of the postulated reactions. When air or O2 were used as the carrier gas, S(0) became the dominant reaction product along with FeS2 and smaller amounts of FeS, sulfate, and thiosulfate. A mathematical model of reactive transport was used to test the hypothesis that S(0) forming on the iron oxide surfaces reduces access of H2S to the reactive surface. Several conceptual models were assessed in the context of the postulated reactions with the final model based on a linear surface poisoning model and fitted reaction rates. These results indicate that carrier gas selection is a critical consideration with significant tradeoffs for remediation objectives.     

Capture of trace sulfur gases from binary mixtures by single-walled carbon nanotube arrays: a molecular simulation study

Adsorption of H(2)S and SO(2) pure gases and their selective capture from the H(2)S-CH(4), H(2)S-CO(2), SO(2)-N(2), and SO(2)-CO(2) binary mixtures by the single-walled carbon nanotubes (SWNT) are investigated via using the grand canonical Monte Carlo (GCMC) method. It is found that the (20, 20) SWNT with larger diameter shows larger capacity for H(2)S and SO(2) pure gases at T = 303 K, in which the uptakes reach 16.31 and 16.03 mmol/g, respectively. However, the (6,6) SWNT with small diameter exhibits the largest selectivity for binary mixtures containing trace sulfur gases at T = 303 K and P = 100 kPa. By investigating the effect of pore size on the separation of gas mixtures, we found that the optimized pore size is 0.81 nm for separation of H(2)S-CH(4), H(2)S-CO(2), and SO(2)-N(2) binary mixtures, while it is 1.09 nm for the SO(2)-CO(2) mixture. The effects of concentration and temperature on the selectivity of sulfide are also studied at the optimal pore size. It is found that the concentration (ppm) of sulfur components has little effect on selectivity of SWNTs for these binary mixtures. However, the selectivity decreases obviously with the increase of temperature. To improve the adsorption capacities, we further modify the surface of SWNTs with the functional groups. The selectivities of H(2)S-CO(2) and SO(2)-CO(2) mixtures are basically uninfluenced by the site density, while the increase of site density can improve the selectivity of H(2)S-CH(4) mixture doubly. It is expected that this work could provide useful information for sulfur gas capture.     

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.     

Reduction of Limonene Chlorohydrins in Commercial Citrus Oils

ABSTRACT: Commercial cold-pressed citrus oils containing terpene chlorohydrins may have quality and safety implications for end-users of these oils. Concentrations of (1S, 2S, 4R)-2-chloro-8- p -menthen-1-ol (1), (1 R , 2 R , 4 R )-2-chloro-8- p -menthen-1-ol (2), and (1 R , 2 R , 4 R )-2,9-dichloro-8- p -menthen-1-ol (3) in some citrus essential oils ranged from less than 1 ppm to 30 ppm measured by gas chromatography with a halogen detector. Reduction reactions of these compounds were accomplished by continuous mixing (reaction) of the oil with dilute solutions of KOH. Greater than 95% reduction of 1 and 3 were accomplished after reaction for 15 h with 0.5 N KOH or after 24 h with 0.25 N KOH in oils with either 25 or 30 ppm (1). Similar treatment of an oil containing 5 ppm (1) resulted in reduction to below the threshold limit of quantification (0.4 ppm). Sensory analyses of tasting solutions did not detect any flavor difference between untreated or KOH-treated oils.