Low power laser trigger switching of a solid insulated spark gap

The feasibility of reliably triggering solid dielectric insulated spark gaps by low power ( approximately 6 MW) lasers has been demonstrated. Breakdown of 10-mil Lexan dielectric sheets stressed to 70 kV was initiated by a focused 6 MW, Nd in YAG laser emitting 40 mJ in a pulse 6 ns wide at the half-peak intensity height. Delays achieved were in the tens of ns. Slight increases in laser power or electrical stress should produce shorter delays (<10 ns) and subnanosecond jitter.     

慢性乙肝的综合治疗方案

乙型肝炎,特别是慢性乙肝,是最常见的慢性传染病之一。据统计目前全球每年有100万以上的人死于HBV感染及其相关疾病,在我国,有超过1．2亿的乙肝感染者,其中慢性乙肝病人数至少2000万,每年约有28万人死于与乙肝相关的疾病,是世界上受乙肝茶毒最深的国家。但迄今对慢性乙肝尚缺乏理想的治疗方法和药物。本文就这综合治疗方法作些综述。     

天津市造纸工业概况

2009年,天津市造纸行业在经历多年来的兴衰与变迁、调整和震荡之后,正在逐渐步入振兴和发展.目前,天津市造纸工业总产值超过6亿元人民币,其产品种类以各等级的高强瓦楞原纸为主,包括部分高级证券纸、防伪纸等高附加值产品.     

Adsorptive performance of penta-bismuth hepta-oxide nitrate, Bi?O?NO?, for removal of methyl orange dye

The adsorption of methyl orange dye from aqueous solution onto penta-bismuth hepta-oxide nitrate, Bi(5)O(7)NO(3), synthesized by precipitation method, was studied in a batch adsorption system. The effects of operation parameters such as adsorbent dose, initial dye concentration, pH and temperature were investigated. The adsorption equilibrium and mechanism of adsorption was evaluated by Langmuir and Freundlich isotherm and different kinetic models, respectively. The results indicate that adsorption is highly dependent on all operation parameters. At optimum conditions, the adsorption capacity was found to be 18.9 mg/g. The adsorption data fits well with the Langmuir isotherm model indicating monolayer coverage of adsorbate molecules on the surface of Bi(5)O(7)NO(3). The kinetic studies show that the adsorption process is a second-order kinetic reaction. Although intra-particle diffusion limits the rate of adsorption, the multi-linearity plot of intra-particle model shows the importance of both film and intra-particle diffusion as the rate-limiting steps of the dye removal. Thermodynamic parameters show that the adsorption process is endothermic, spontaneous and favourable at high temperature.     

Mycoflora of two types of Portuguese dry-smoked sausages and inhibitory effect of sodium benzoate, potassium sorbate, and methyl p-hydroxybenzoate on mold growth rate

The mycoflora of chouriqo types Alentejano and Ribatejano, two varieties of Portuguese dry-smoked sausages, have been investigated after a producer-defined shelf life period (120 days at 20 +/- 5 degrees C) in modified atmosphere packaging (55% N2 and 45% CO2). On the basis of morphological and physiological characteristics, the isolates were identified as Penicillium, Aspergillus, Fusarium, Rhizopus, Monilia, Absidia, and Cephalosporium. The species identified were as follows: Penicillium terrestres (43.4%), Penicillium sp. (13.3%), Fusarium sp. (10%), Aspergillus glaucus (10%), Aspergillus versicolor (6.8%), Monilia fruticola (3.3%), Absidia sp. (3.3%), Cephalosporium sp. (3.3%), Rhizopus stolonifer (3.3%), and Fusarium tricinctum (3.3%). Additionally, the effects of three preservatives (potassium sorbate [PS], sodium benzoate [SB], and methyl p-hydroxybenzoate [MHB]) were studied on the growth rate of mold representative isolates. MHB showed a greater inhibitory effect than SB and PS in all fungi isolates, except in A. glaucus [Tm30(A)], in which the inhibitory effect of MHB was similar to PS. At 0.05% (wt/vol), all fungi were inhibited with MHB, except for R. stolonifer [Tm25(A)], which started to decrease the growth rate only at a concentration higher than 0.1%. PS was more effective at inhibiting mold growth than SB, except in Absidia sp. [Tm16(R)], in which both showed a similar inhibitory effect. MHB showed great promise as an application to the surface at 0.1% (wt/vol) to improve the stability and safety of the product through the inhibition of potential spoilage and toxigenic molds.     

光催化氧化法处理漂白废水

文章介绍了制浆造纸过程中漂白废水的产生、特点和危害,对光催化氧化法处理漂白废水的原理、研究现状及其在漂白废水中的应用进行了较详细的阐述,并对其今后的发展方向进行了展望。     

Biodegradation of synthetic base fluid surrogates in Gulf of Mexico sediments under simulated deep-sea conditions

In this study, an anaerobic marine biodegradability test was adapted to study the fate of synthetic base fluid (SBF) surrogates, ethyl oleate and tetradecene, by deep-sea microorganisms. Sediment samples from hundreds of meters deep in the Gulf of Mexico were incubated at low temperatures (4 degrees C) and high hydrostatic pressure in steel vessels. Stimulation of indigenous microbial communities to SBF biodegradation was evident in the fact that the rate of removal of ethyl oleate was greater in sediments that had some previous exposure to SBF (first-order decay coefficient kof -0.22 +/- 0.02 week(-1)) compared to unexposed control sediments (first-order decay coefficient k of -0.11 +/- 0.02 week(-1)). When sulfate-linked tetradecene degradation occurred within the test period, the activity could also be modeled as a first-order decay following an initial lag phase, with an average decay coefficient of k = -0.05 +/- 0.01 week(-1). This study also revealed that the degradation of SBF surrogates by microorganisms collected from deep-sea sediments was not significantly effected by the hydrostatic incubation pressure.     

黄河流域河流水化学特征分布规律及对比研究

河流水化学的变化可以从一定程度上反映出人类活动对水环境的影响。根据近10年来黄河流域的水化学监测资料,分析了河川径流矿化度、总硬度和水化学类型的地区分布,统计了黄河干流沿程变化及主要支流水化学变化情况。并与20世纪80年代初第一次黄河流域水资源评价的结果进行了对比。对比结果表明：除个别站点外,大多数测站的矿化度和总硬度均有不同程度的增大,个别站点水化学类型有所改变,显示水质变差。     

振冲碎石桩在海塘软基处理中的应用

利用振冲碎石桩处理软土地基,对地基具有置换、排水、加筋等作用,与原土基构成复合地基,可提高地基承载力。结合台州市海堤工程实例,对振冲碎石桩的技术工艺、设计、施工和检测等方面进行介绍。