Pancytopenia in children with brucellosis: clinical manifestations and bone marrow findings

Among 276 paediatric cases of brucellosis seen over a 7-year period, 16 patients (5.8%) with pancytopenia were identified. The most frequent presentations were fever, malaise, anorexia, weight loss, arthralgia, and hepatosplenomegaly. Fourteen patients (87.5%) had positive blood and/or bone marrow cultures for Brucella melitensis. Bone marrow aspiration specimens showed hypercellularity in 14 patients and normocellularity in 2. Histiocytes, eosinophils and plasma cells were increased in every marrow aspirate, and haemophagocytosis was observed in 14 patients (87.5%). Non-caseating granulomas were present in the bone marrow biopsy of 11 patients (68.8%). The pancytopenia was transient, and resolved on treatment of the Brucella infection.     

压接IGBT器件并联子模组热阻分布实验研究

在刚性压接型IGBT模块中,并联芯片的压力分布直接决定了接触热阻和接触电阻的大小。通常无法测量器件正常工作时的压力分布及其引起的热阻分布。为了分析压接IGBT模块内部各子模组的压力分布情况和热阻分布情况,提出一种利用器件特性和热阻实验测量压接IGBT模块并联子模组热阻分布的方法。在此方法基础上,详细研究不同压力和电流条件下的热阻分布。实验结果表明,由于外部压力、器件特性和连接导体的差异,压接IGBT模块内部并联子模组间的结温、电流和热阻分布具有很大的分散性。提出的测量方法可以有效验证压接IGBT模块在一定封装条件下的结温、热阻和压力分布特性。     

A method for modelling photovoltaic modules under non-standard conditions of solar radiation and ambient temperature in Quibdó, Colombia

This work describes a mathematical model developed to estimate the I–V and P–V curves of photovoltaic modules operating under non-standard conditions of irradiance and temperature in Quibdó, Colombia.

The model was implemented using the Matlab? software using an equivalent circuit of a diode for a photovoltaic panel. The input parameters of solar radiation and ambient temperature were obtained from a monitoring station installed in the city of Quibdó. The average annual solar radiation was 256.96?W/m² while the annual average temperature was 27.59°C in 2015. The model resulted in curves for I–V and P–V. These were compared with simulated results from the information reported by the manufacturer of a polycrystalline 250?W silicon solar panel (reference AS-6P30), which is part of a photovoltaic system 2?kW interconnected with the grid. This resulted in an average error of 0.5% for the I–V curve and 0.3% for the P–V curve.     

连拱隧道动态施工模型试验与三维数值仿真模拟研究

连拱隧道作为公路隧道新的结构型式，理论上还不成熟。以云南省元磨高速公路的一座连拱隧道作为工程背景，按弹性阶段相似原则进行连拱隧道室内模型试验，模拟连拱隧道的施工工况，采用压力盒、数码摄像、沉降板等仪器量测施工过程中隧道围岩应力和位移分布，采用三维连续介质快速拉格朗日元模拟连拱隧道的施工工况，得出施工过程中隧道围岩位移、应力和塑性区分布规律，其结果与模型试验所得结果基本一致。     

把人参二醇类皂苷转化为Rg3的特种人参皂苷糖苷酶生成的细菌筛选

采用TLC、HPLC等酶活力检测方法对Arthrobacter sp．3、Rhodanobacter sp．14、Rhodopseudomonas sp．18和Enterobacter sp．20菌进行了菌种筛选。其中Arthrobacter sp．3、Rhodopseudomonas sp.18和Enterobncter sp．20菌发酵生成把人参二醇类皂苷PPD转化为Rg3、Rh2和苷元的特殊人参皂苷糖苷酶，Arthrobacter sp．3菌发酵产酶速度相对快一些。Rhodanobacter sp．14发酵主要生成能把人参二醇类皂苷PPD转化为Rd的人参皂苷糖苷酶。Rhodanobacter sp．14发酵生成的人参皂苷糖苷酶对丙酮抗性较好，Arthrobacter sp．3、Rhodopseudomonas sp．18和Enterobacter sp．20菌所生成的人参皂苷糖苷酶对丙酮抗性略差。综合各因素，选取Arthrobacter sp．3为目标菌种。     

Identification of microbial flora in kefir grains produced in Turkey using PCR

Kefir grains might have different ratios and/or content of microflora according to their origin. The purpose of this study was to determine microbial flora of kefir grains produced in three regional universities in Turkey using polymerase chain reaction (PCR) and consensus sequence primers. According to the results of PCR products with the specific primers, the following were identified as the natural inhabitants of the kefir grains: Lactobacillus acidophilus, Lactobacillus helveticus, Streptococcus thermophilus, Bifidobacterium bifidum and Kluyveromyces marxianus kefir. The results of this study revealed that traditional kefir produced by using kefir grains as natural starter cultures contains lactic acid bacteria especially Lactobacillus spp. One of the sources also contained B. bifidum. This is the first record on the presence of B. bifidum in kefir grains.     

基于PLM的装备项目管理模式分析

通过分析PLM思想的发展应用，论述了PLM系统对制造业企业项目管理的推动与支持，以及在装备采办中的应用前景，研究探讨了PLM系统与装备项目管理结合对提高装备采办效益的意义及实施对策。     

带路径约束的聚烯烃牌号切换操作优化方法

产品多样化需求使得聚烯烃生产过程中经常需要进行牌号切换操作。以往关于牌号切换优化的研究大多只关心切换过程结束后聚合物质量指标是否达到目标牌号值,对过渡过程中质量指标及状态变量的波动情况缺少关注,而过程的波动会影响到最终产物的质量性质和操作平稳性。为此,本文以聚乙烯气相流化床反应器为对象,通过在牌号切换优化命题中加入关于熔融指数等的路径约束,防止过渡过程中的状态变量剧烈波动影响聚合物树脂质量。为求解此类带路径约束的动态优化问题,对常规的控制变量参数化方法进行了改进,通过求解微分代数方程(DAE方程)将路径约束转化为控制变量约束。仿真结果表明,加入路径约束可以有效避免牌号切换中变量的剧烈波动,增强过程平稳性。     

机器人机构结构综合方法的基本思想、特点及其发展趋势

对机器人机构结构综合3种方法(基于螺旋理论的方法、基于位移子群/子流形的方法和基于方位特征的方法)的基本思想与特点进行比较研究。研究表明,基于方位特征的方法具有显著的特点:可得到非瞬时机构和非瞬时自由度,机构存在的几何条件具有一般性(以上不同于基于螺旋理论的方法);结构学基本方程揭示了机构的拓扑结构、运动方位特征和自由度三者之间的显式映射关系,运算规则较少,且几何意义明确,易于操作,只使用简单的数学工具(矢量代数等),便于设计者理解和应用,适用于所有机构(不含Bennett等一类机构)的结构综合(以上不同于基于位移子群的方法)。研究亦表明,基于单开链单元的结构组成原理,构建机构结构学、运动学和动力学三者密切相关的系统理论与方法是机构拓扑结构学发展的重要方向之一。     

iCutter: a direct cut‐out tool for 3D shapes

We present a novel sketch‐based tool, called iCutter (short for intelligent cutter), for cutting out semantic parts of 3D shapes. When a user performs a cutting task, he only needs to draw a freehand stroke to roughly specify where cuts should be made without much attention. Then, iCutter intelligently returns the best cut that meets the user's intention and expectation. We develop a novel scheme for selecting the optimal isoline from a well‐designed scalar field induced from the input stroke, which respects the part saliency as well as the input stroke. We demonstrate various examples to illustrate the flexibility and applicability of our iCutter tool. Copyright © 2011 John Wiley & Sons, Ltd.