Heavy metal levels in seafood from Honghai Bay and its human dietary exposure assessment

分析了广东红海湾13种海产品肌肉组织中8种重金属铬(Cr)、钴(CO)、镍(nI)、铜(Cu)、锌(zn)、砷(AS)、镉(Cd)和铅(Pb)的浓度水平,并利用单因子污染指数法(Pn)评价其污染状况。利用美国环保署提出的人体健康风险评价模式进行人体重金属暴露风险评估,同时利用金属污染指数(XMPI)研究生物体的重金属富集效应。结果显示:红海湾生物总体污染水平较低,Cr在软体类生物中属于轻度污染;nI在甲壳类生物中属于轻度污染;Cu和zn在鱼类中属于轻度污染;Cr在鱼类和甲壳类中都属于中度污染。口虾蛄OrATOSQuIllA OrATOrIA对Cd、Cu、zn存在潜在的严重积累作用,且AS含量超过了食用的参考剂量,需引起重视。人体暴露风险评估表明,食用红海湾海产品(口虾蛄除外)对人体潜在的健康风险相对较低,建议食用海产品量控制在25 g·d？1以内。Concentrations of 8 kinds of heavy metals including Cr, Co, Ni, Cu, As, Zn, Cd and Pb in the muscles of thirteen seafood from Honghai Bay were determined.Single factor pollution index(Pn) was applied to evaluate the contamination status of these organisms.Human health risk assessment model by US EPA was employed to evaluate the human dietary exposure.Metal pollution index(XMPI) was used for the enrichment effect of heavy metals on seafood.The results showed that the level of heavy metal in the marine organisms from Honghai Bay was low.Ni in crustacean and Cu, Zn in fish and Cr in mollusk were slightly polluted while Cr in fish and crustacean was moderately polluted.It should be highlighted that Oratosquilla oratoria showed a strong accumulative capacity for Cu, Zn and Cd.The level of As was beyond the reference dose.The results of human exposure risk assessment indicated that consumption of seafood(except Oratosquilla oratoria) would not pose a risk to humans.Suggested daily amount of seafood consumption should be limited to be less than 25 g·d?1.中国博士后科学基金(2012M510201); 中国科学院百人计划资助项

Research and Implementation on Enterprise Operation Management Software System Based on KPI

中国大多数企业目前所面临的主要问题正是目标不能够得到有效的执行，执行是一个集成了目标、制度、流程、信息与人的经营管理过程，本文提出了一套基于KPI，具备有效的监控与调整能力的企业经营计划与业绩跟踪的管理流程体系，以闭环的、持续改进的自适应运营管理系统保证执行过程中贯彻企业的战略意图，实现既定的目标；并且将其信息系统相应的纳入企业信息化的整体框架中，成为联系战略规划层和业务操作层的桥梁。在软件系统的开发过程中，利用ARIS的企业建模体系构造组织模型，建立面向过程的功能树模型，进一步的细化业务流程模型，并通过功能分配图模型、面向业务对象的功能树模型，ER模型等进行具体的软件分析与设计；接着，在软件开发平台GeneXus上以增量开发的方式实现软件系统，并归纳一套ARIS与GellXus结合的软件开发过程的方法。最后结合某服装企业的应用实证分析该系统的在企业中的应用和推广的价值。Nowadays, most Chinese enterprises are focusing on how to effectively execute to get things well done. Execution is a management procedure that integrates the objective, discipline, business processes, information and persons. An enterprise planning and performance tracing architecture based KPI is put forward to assuring that during the executive procedure, the enterprise's strategy intention is effectively carried out and implemented, which means a closed-loop, continually-improved and self-adaptive operation management system should be set up. Correspondingly, the enterprise operation software system based KPI is added into the enterprise informationization's framework to link the strategy layer and the business execution layer. In the process of developing the software system, the software system's analysis and design are finished in ARIS and it is implemented in GeneXus with an incremental philosophy. Whereafter, the methodology for software development procedure with ARIS and GenuXus is summarized. At last, the system's value for enterprise application is demonstrated by the practise in a famous garment combine of China

Numerical Study on Pilot Ignition of a Thermally-Thick Solid Fuel with Low-Velocity Airflow in Microgravity

The mechanisms controlling the dependence on low-velocity flow of the piloted ignition of a solid material under external radiant heating is investigated through a numerical modeling. The poly (methyl methacrylate) (PMMA) was used as the fuel. The objective of the present study is to gain insight into the intrinsic ignition mechanisms of a solid fuel, as well as to gain a more comprehensive understanding of the dynamical characteristics of the ignition process near the extinction limit. For this purpose, a two-dimensional numerical model has been developed using the Fire Dynamic Simulator (FDS5) code, in which both solid-phase and gas-phase reactions are calculated. Two radiant heat flux, which are 16 and 25 kW/m2 were studied, and an external air flow was varied from 3 to 40 cm/s. The simulation results showed that transient gas reaction flashed before a continuous flame was attached to the sample surface for gas flow velocities lower than a critical value. As the flow velocity is reduced, the flashing time, which is defined as the time when any flame is seen above the sample surface, decreases, while the duration of flashing increases. The solid surface temperature and mass flow rate increase rapidly during flashing. The ignition time, which is defined as the time when a continuous flame is attached to the fuel surface, decreases, reaches a minimum, and then increases until ignition cannot occur. Mechanisms were considered to explain the ''V-shaped" dependence of ignition time on flow-velocity, and two regimes were identified each having a different controlling mechanism: the mass transport regime where the ignition delay is controlled by the mixing of oxygen and pyrolyzate; and the heat transfer regime where the ignition delay is controlled by changes in convection heat losses and critical mass flux for ignition. With the decrease of the airflow velocity, the critical mass flux shows a trend of decreasing and then increasing, which is dominated by the mixing of the pyrolyzate and the oxidizer, while the critical temperature monotonically decreases, which is dominated by a reduction of the net heat flux at the fuel surface. The results provide further insight into the ignition behavior of solid fuel under low-velocity flow environment, and guidance about fire safety in microgravity environments

金属粉末激光成形扫描间距优化方法

金属粉末激光成形技术是一种新的快速成形技术,扫描间距是金属粉末激光成形工艺过程关键参数之一, 将扫描线截面轮廓形状近似看作一段圆弧、以相邻扫描线重叠面积与凹沟面积相等为原则进行扫描间距优化计算,从理论上确定MPLS工艺最佳扫描间距。通过平面扫描试验分析可知,在扫描间距等于理论计算值时,扫描平面相对平整、沟痕较浅,截面厚度保持单道扫描截面高度值且十分均匀,可实现精确多层连续扫描

research on supply chain exception event management system

对供应链系统的管理,关键在于对例外事件的及时处理,以确保系统的正常运作。为迅速发现供应链系统中的例外事件并协同处理,达到快速响应、提高竞争力的目的,提出了供应链例外管理系统。该系统将供应链管理的焦点集中到对一组流程关键节点的例外控制上,以量化的性能指标为基础来构建一套信息、过程与人的集成框架和一套可配置、可扩展的软件架构,并通过一个例外管理的流程实例展示了系统在实际中的应用

Typhoon Wind Field Model Based on the Radii of Wind Circle

首先用JElESnIAnSkI台风风场模型及美国联合台风警报中心(JTWC)整编的台风资料,计算10级和7级风圈半径,并与气象部门的发布值相比,发现两者存在较大误差.进而,在JElESnIAnSkI台风风场模型的基础上,提出一种基于最大风速半径、10级和7级风圈半径的台风风场模型,并比较两种台风风场模型的风速剖面.结果表明:该模型比包括被广泛应用的JElESnIAnSkI台风风场模型在内的前人提出的台风风场模型都更接近台风风场实况,其中10级和7级风圈半径与气象部门的发布值是一致的.The wind radii of level ten and level seven were calculated by Jelesnianski typhoon wind field model with typhoon data from Joint Typhoon Warning Center(JTWC).The error was considerable when compared to the release value of meteorological department.Thus a new typhoon wind filed model,which was based on the radii of maximum、level ten and level seven wind speed was proposed referring to Jelesnianski model.Then the wind profiles of the two models were compared.The result showed that the typhoon wind field calculated by the new model was more closer to reality than by any other models include the Jelesnianski model,which was popular used.And the wind radii of level ten and level seven in the new model were the same to the release value of meteorological department.海洋公益性行业科研专项(200905013-7

The Composite Based on Graphene and Its Application in Energy Storage

能源问题是人类社会未来面临的重大挑战,从实现电能与化学能相互转换的角度而言,作为一种二维结构材料,石墨烯不仅可以构筑电子导电网络,也可实现对反应活性物种状态的设计和调控,进而改变反应的热力学和动力学,在电化学储能系统中具有十分重要的意义.本文主要介绍了石墨烯的制备方法及其在构筑电子导电网络以实现对反应活性物种状态的设计和调控方面的作用和功能,分别就其在构筑硫复合材料、氧化物复合材料、导电聚合物复合材料等方面进行了讨论,并结合相应的电化学储能系统评价这些复合材料的性能.The energy crisis is a major challenge for the human society in the future.As a material with two-dimensional structure,graphene can not only build electronic conductive network,but also realize the design and control of the status of reactive species,and then change the thermodynamics and kinetics of reactions.Thus,graphene is of great significance in electrochemical energy storage systems in terms of realizing the transformation from chemical energy to electric energy.This paper mainly reviews the preparation methods of graphene and its functions in constructing electronic conductive network to realize the design and regulation of the status of reactive species.We discuss the construction of sulfur composite materials,oxide composite materials,and conductive polymer composites,and evaluate the performances of these composite materials in corresponding electrochemical energy storage systems.国家自然科学基金(U1305246;21321062); 厦门市电动车重大专项(3502Z20121002

提高高马赫数超燃冲压发动机推力的理论方法

斜爆轰发动机和激波诱导燃烧冲压发动机在高马赫数吸气式发动机中具有重要应用前景,但是斜爆轰发动机是否具有足够大的净推力,还是一个未知的问题,因此需要对高马赫数冲压发动机的推进性能以及提高推力的方法进行理论研究.本文主要分为3部分.第1部分理论研究了超燃冲压发动机中的爆燃波和爆轰波的传播特性.保证发动机稳定燃烧是提高推力的前提.通过对爆燃波和爆轰波传播特性研究,得到了影响发动机燃烧稳定性的关键参数和物理规律.第2部分研究了发动机处于热壅塞临界状态下的燃烧规律和推力特性.在临界状态下,燃烧室入口气流速度正好等于爆轰波传播速度,二者处于平衡状态,这是发动机推进性能的理论上限.第3部分研究了提高高马赫数超燃冲压发动机推力的理论方法.对于高马赫数冲压发动机,燃烧室入口气流速度远远大于爆轰波的传播速度,这部分速度差就是提高推力的理论空间.对于马赫数Ma≥12的超燃冲压发动机,理论上燃烧产生的爆燃波或激波不会引起发动机不起动,因此可以通过进一步添加燃料和氧化剂的方法来提高其推力.理论分析结果表明,对于高马赫数超燃冲压发动机,不但燃烧流场是容易稳定的,而且可以有很多方法来进一步提高推力

斜爆轰发动机燃烧机理试验研究

为了研究斜爆轰发动机的稳定燃烧机理,开展了飞行马赫数9的斜爆轰发动机的数值模拟研究和试验研究。设计了全尺度斜爆轰发动机模型,发动机的总长度为2.8m。采用两级进气道压缩,每级压缩角度均为15°。利用三个小支板在进气道前缘主流核心区中进行氢气的喷射和混合。采用带化学反应的雷诺平均N-S方程、SST k-ω模型以及9组分19步反应的基元反应模型,对氢气混合过程和发动机燃烧过程进行了数值模拟研究。结果表明,氢气在进气道内混合得比较均匀,在燃烧室内获得了稳定的斜爆轰流场和正爆轰流场。在激波风洞中开展了马赫数9状态下的斜爆轰发动机稳定燃烧机理试验研究,在50ms的风洞有效试验时间内获得了持续稳定的斜爆轰流场,试验结果与数值模拟结果吻合较好,表明在试验中形成了斜爆轰波。研究结果证明了斜爆轰发动机的技术可行性