Microheterogeneous Thoria-Urania Fuels for Pressurized Water Reactors

A thorium-based fuel cycle for light water reactors will reduce the plutonium generation rate and enhance the proliferation resistance of the spent fuel. However, priming the thorium cycle with ²³⁵U is necessary, and the ²³⁵U fraction in the uranium must be limited to below 20% to minimize proliferation concerns. Thus, a once-through thorium-uranium dioxide (ThO2-UO2) fuel cycle of no less than 25% uranium becomes necessary for normal pressurized water reactor (PWR) operating cycle lengths. Spatial separation of the uranium and thorium parts of the fuel can improve the achievable burnup of the thorium-uranium fuel designs through more effective breeding of ²³³U from the ²³²Th. Focus is on microheterogeneous fuel designs for PWRs, where the spatial separation of the uranium and thorium is on the order of a few millimetres to a few centimetres, including duplex pellet, axially microheterogeneous fuel, and a checkerboard of uranium and thorium pins. A special effort was made to understand the underlying reactor physics mechanisms responsible for enhancing the achievable burnup at spatial separation of the two fuels. The neutron spectral shift was identified as the primary reason for the enhancement of burnup capabilities. Mutual resonance shielding of uranium and thorium is also a factor; however, it is small in magnitude. It is shown that the microheterogeneous fuel can achieve higher burnups, by up to 15%, than the reference all-uranium fuel. However, denaturing of the ²³³U in the thorium portion of the fuel with small amounts of uranium significantly impairs this enhancement. The denaturing is also necessary to meet conventional PWR thermal limits by improving the power share of the thorium region at the beginning of fuel irradiation. Meeting thermal-hydraulic design requirements by some of the microheterogeneous fuels while still meeting or exceeding the burnup of the all-uranium case is shown to be potentially feasible. However, the large power imbalance between the uranium and thorium regions creates several design challenges, such as higher fission gas release and cladding temperature gradients. A reduction of plutonium generation by a factor of 3 in comparison with all-uranium PWR fuel using the same initial ²³⁵U content was estimated. In contrast to homogeneously mixed U-Th fuel, microheterogeneous fuel has a potential for economic performance comparable to the all-UO2 fuel provided that the microheterogeneous fuel incremental manufacturing costs are negligibly small.

中国自由生活线虫新记录(色矛目、嘴刺目和窄咽目)

本文报道淡水、土壤自由生活线虫国内新记录11种，即：田园素矛线虫Achromadoraruricola，半棘素矛线虫Achromadorasemiarmata,叉齿烙线虫Ironusdentifurcatus，好逸烙线虫Ironusignavus，亲邻三孔线虫Tripylaaffinis，球形三孔线虫Tripylaglomerans，谢氏小三孔线虫Tripylinasheri,墙根绕线虫Plectusparietinus,似疑绕线虫Plectusinquirendus,愁容筒咽线虫Cylindrolaim

亚硒酸钠对四氯化碳损伤草鱼肝原代细胞与肝组织的保护作用

不同浓度四氯化碳（ＣＣｌ４）对草鱼肝原代细胞的损伤实验中，ＣＣｌ４浓度为１０μｌ／ｍｌ可引起细胞血清中丙氨酸氨基转移酶（ＡＬＴ）、天门冬氨酸氨基转移酶（ＡＳＴ）、乳酸脱氢酶（ＬＤＨ）逸出量与细胞破损率显著增高，培养液中添加亚硒酸钠（Ｎａ２ＳｅＯ３）０．２μｇ／ｍｌ，则可降低ＡＬＴ、ＡＳＴ、ＬＤＨ的逸出量，减轻细胞破损程度。Ｎａ２ＳｅＯ３保护实验中，Ｎａ２ＳｅＯ２＋ＣＣｌ４组预先腹腔注射（ｉｐ）０．１ｍｇ／ｋｇ．ｂｗ连续三日，末次ｉｐＣＣｌ４混合液１ｍｌ／ｋｇ．ｂｗ，２４ｈ内肝组织超氧物歧化酶（ＳＯＤ）相对

太平湖水库藻类演替与营养侦别研究

本文报告了1992～1993年间对安徽省太平湖水库藻类的演变以及库水营养侦别试验的研究结果。与1985～1986年资料相比,整个水库的藻类种类多样性下降,总种类数由175种降为112种,减少了1/3。藻类种类小型化现象十分明显,相隔6～7年,小型藻类的种类及其数量越来越多,单个藻细胞鲜重的平均值在敞水区和库湾区分别减少了63.6％和75.4％;平均细胞密度则分别增长了3.6和5.6倍;生物量的变化不大,增长不足1倍。营养侦别试验结果表明,磷仍然是该水库的主要限制因子,库水的藻类生长潜力约为对照培养基的1/

Product intelligence in warehouse management: A case study

The need for more flexible, adaptable and customer-oriented warehouse operations has been increasingly identified as an important issue by today's warehouse companies due to the rapidly changing preferences of the customers that use their services. Motivated by manufacturing and other logistics operations, in this paper we argue on the potential application of product intelligence in warehouse operations as an approach that can help warehouse companies address these issues. We discuss the opportunities of such an approach using a real example of a third-party-logistics warehouse company and we present the benefits it can bring in their warehouse management systems. © 2013 Springer-Verlag.

Exploring an effective model of new product development in medical devices: A knowledge cluster approach

This study proposes a new product development (NPD) model that aims to improve the effectiveness of innovative NPD in the medical devices. By adopting open innovation theory and applying an in-depth investigation methodology, this paper proposes a knowledge cluster that improves the integration of interdisciplinary human resources and enhances the acquirement of innovative technologies. A knowledge cluster approach helps gather, organise, synthesise, and accumulate knowledge in order to become the impetus for innovation. Although enterprises are no longer the principals of research and development, they should still be capable of integrating professional physicians, external groups, and individuals through the knowledge cluster platform. However, in order to support an effective NPD model, enterprises should provide adequate incentives and trust to external individuals or groups willing to contribute their expertise and knowledge to this knowledge cluster platform. Copyright © 2013 Inderscience Enterprises Ltd.

中国淡水轮虫新资料

<正> 1978年7月下旬至9月中旬,作者到华南地区13个水库进行湖沼学调查,共采集了浮游动物定性样品27个,定量样品38个。经初步鉴定,发现轮虫种类非常丰富,共有57种,其中包括新种1个,新亚种3个,新纪录3个。现描述于下。模式标本均存中国科学院水生生物研究所。

武昌的秀体溞

<正> 秀体溞(Diaphanosoma)是枝角类栉足族仙达溞科(Sididae)中包括种类最多的一个属,根据已往的记录,共计约有20种。关于我国秀体溞的计载,总共只有7种。最早是由 Spandl 在广东记述了镰角秀体溞(D.excisum Sars)一种。上野益三曾发表过有关我国枝角类的文章多篇,他报告了浙江、四川、台湾、黑龙江、吉林以及内蒙古等地的秀体溞共有6种,即:短尾秀体溞[D.brachyurum(Liévin)],长肢秀体溞

Modeling the carbon nanofiber addressed liquid crystal microlens array from experimentally observed optical phenomena

This paper presents a novel method of using experimentally observed optical phenomena to reverse-engineer a model of the carbon nanofiber-addressed liquid crystal microlens array (C-MLA) using Zemax. It presents the first images of the optical profile for the C-MLA along the optic axis. The first working optical models of the C-MLA have been developed by matching the simulation results to the experimental results. This approach bypasses the need to know the exact carbon nanofiber-liquid crystal interaction and can be easily adapted to other systems where the nature of an optical device is unknown. Results show that the C-MLA behaves like a simple lensing system at 0.060-0.276 V/μm. In this lensing mode the C-MLA is successfully modeled as a reflective convex lens array intersecting with a flat reflective plane. The C-MLA at these field strengths exhibits characteristics of mostly spherical or low order aspheric arrays, with some aspects of high power aspherics. It also exhibits properties associated with varying lens apertures and strengths, which concur with previously theorized models based on E-field patterns. This work uniquely provides evidence demonstrating an apparent "rippling" of the liquid crystal texture at low field strengths, which were successfully reproduced using rippled Gaussian-like lens profiles. © 2014 Published by Elsevier B.V.

Aerobic biodegradation of hexachlorobenzene by an acclimated microbial community

The aerobic degradation of hexachlorobenzene (HCB) by an acclimated microbial community which isolated from a contaminated site and acclimated in our laboratory was investigated. The enriched microbial community was capable of biodegrading HCB when cultivated in minimal salts medium and supplied HCB as the sole carbon source. The efficiencies of microbial community in the degradation of HCB under different pH and temperatures were examined. The phylogenetic analysis for the nearly complete sequences of 16S rDNA demonstrated that the bacteria assemblage in the microbial community was dominated by Azospirillum and Alcaligenes groups.

Molecular characterization and expression profiles in response to bacterial infection of Chinese soft-shelled turtle interleukin-8 (IL-8), the first reptilian chemokine gene

In this study, an IL-8 homologue has been cloned and identified from a reptile, Chinese soft-shelled turtle for the first time. The full-length cDNA of turtle IL-8 was 1188 bp and contained a 312 bp open reading frame (ORF) coding for a protein of 104 amino acids. The chemokine CXC domain, which contained Glu-Leu-Arg (ELR) motif and four cysteine residues, was well conserved in turtle IL-8. The 4924 bp genomic DNA of turtle IL-8 contained four exons and three introns. Phylogenetic analysis showed that the amino acid sequence of turtle IL-8 clustered together with birds. RT-PCR analysis showed that turtle IL-8 mRNA was constitutively expressed liver, spleen, kidney, heart, blood and intestine tissues of control turtles. Real-time quantitative PCR analysis further indicated that the turtle IL-8 mRNA expression was apparent in various tissues at 8 h and up-regulated significantly during 8 h-7 d after Aeromonas hydrophila infection. The present studies will help us to understand the evolution of IL-8 molecule and the inflammatory response mechanism in reptiles. (C) 2009 Elsevier Ltd. All rights reserved.

Simultaneous determination of microcystin contaminations in various vertebrates (fish, turtle, duck and water bird) from a large eutrophic Chinese lake, Lake Taihu, with toxic Microcystis blooms

This is the first to conduct Simultaneous determination of microcystin (MC) contaminations in multi-groups of vertebrates (fish, turtle, duck and water bird) from Lake Taihu with Microcystis blooms. MCs (-RR, -YR, -LR) in Microcystis scum was 328 mu g g(-1) DW. MCs reached 235 mu g g(-1) DW in intestinal contents of phytoplanktivorous silver carp, but never exceeded 0.1 mu g g(-1) DW in intestinal contents of other animals. The highest MC content in liver of fish was in Carassius auratus (150 ng g(-1) DW), followed by silver carp and Culter ilishaeformis, whereas the lowest was in common carp (3 ng g(-1) DW). In livers of turtle, duck and water bird, MC content ranged from 18 to 30 ng g(-1) DW. High MC level was found in the gonad, egg yolk and egg white of Nycticorax nycticorax and Anas platyrhynchos, suggesting the potential effect of MCs on water bird and duck embryos. High MC contents were identified for the first time in the spleens of N. nycticorax and A. platyrhynchos (6.850 and 9.462 ng g(-1) DW, respectively), indicating a different organotropism of MCs in birds. Lakes with deaths of turtles or water birds in the literatures had a considerably higher MC content in both cyanobacteria and wildlife than Lake Taihu, indicating that toxicity of cyanobacteria may determine accumulation level of MCs and consequently fates of aquatic wildlife. (C) 2009 Elsevier B.V. All rights reserved.

A global model for effective use and evaluation of e-learning in health.

Healthcare systems worldwide face a wide range of challenges, including demographic change, rising drug and medical technology costs, and persistent and widening health inequalities both within and between countries. Simultaneously, issues such as professional silos, static medical curricula, and perceptions of "information overload" have made it difficult for medical training and continued professional development (CPD) to adapt to the changing needs of healthcare professionals in increasingly patient-centered, collaborative, and/or remote delivery contexts. In response to these challenges, increasing numbers of medical education and CPD programs have adopted e-learning approaches, which have been shown to provide flexible, low-cost, user-centered, and easily updated learning. The effectiveness of e-learning varies from context to context, however, and has also been shown to make considerable demands on users' motivation and "digital literacy" and on providing institutions. Consequently, there is a need to evaluate the effectiveness of e-learning in healthcare as part of ongoing quality improvement efforts. This article outlines the key issues for developing successful models for analyzing e-health learning.