葡萄糖氧化酶与6-脱氧-D-葡萄糖作用机制的模拟分析

葡萄糖氧化酶(GOx)具有多种用途,它是一种氧化还原酶,也是一种需氧脱氢酶,与生命的重要物质葡萄糖和氧有密切联系,且对人体无毒无害。本文基于分子动力学模拟手段,对GOx以及含有底物6-脱氧-D-葡萄糖的GOx复合物分子进行了计算分析,通过分析复合物体系中能量、回转半径、二级结构等相关数据,探究了GOx与底物6-脱氧-D-葡萄糖的催化机理和作用机制

基于3D＿ResUnet肝脏CT图像分割的临床应用研究

目的:为解决传统肝实质分割方法在阈值分割方面存在的分割精度低的问题。方法:采用AI自动识别算法,通过Unet与Resnet相结合的3D_ResUnet网络对肝脏CT图像进行分割,并对分割结果通过最大联通分量的方法去除杂质,得到较为精确的肝脏区域,实现肝实质自动分割。结果:基于3D_ResUnet的肝脏CT图像分割,其分割的平均Dice为96.12%,高于3D_Unet的分割精度。结论:基于3D_ResUnet的肝脏CT图像分割提高了肝实质分割的精度,实现了无需人工交互的全自动分割,通过应用在肝癌手术计划系统中,为临床医生的肝癌手术规划提供了可视化依据。国家自然科学基金(编号：61327001)~

壁面微通道冷却对旋流燃烧室性能影响实验

为了探索微通道高效换热技术在低污染燃烧室壁面冷却中的应用,实验研究了壁面微通道冷却对模型旋流燃烧室性能的影响。结果表明:微通道结构对燃烧室热壁面具有显著的冷却效果,在雷诺数小于350时,雷诺数增加对壁面冷却有明显提升作用,在雷诺数大于350后,雷诺数的增大对冷却效果提高的促进作用减小;雷诺数增大对相同进气工况下CH*化学发光信号表征的火焰时均结构几乎不产生影响,但在个别工况下会使火焰产生黄色火星,甚至间歇地产生黄色火焰,带来不完全的燃烧;雷诺数增大会增强微通道对流换热程度,加大壁面传热速率,加剧火焰和微通道换热间的相互作用,使火焰表面发生较大的热量损失,最终造成CO排放量增加,NOx排放量降低,并使整体燃烧效率下降。国家自然科学基金(51406171);;福建省自然科学基金(2016J06011);;中央高校基本科研业务费(20720180058);;航空科学基金(20152868006

WSMR非能动安全系统在全厂断电事故下的事故缓解能力分析

先进的小堆设计广泛地采用一体化结构设计与非能动安全理念,使小堆固有安全性显著提升。然而,在实现小堆广泛商用化之前,其安全性需要得到全面的评估。本研究利用严重事故分析软件MELCOR,对WSMR小堆进行建模,以全厂断电事故为基础事故序列,分析了全厂断电事故在WSMR小堆中的事故进程;同时对非能动安全系统在全厂断电事故下的缓解能力进行了研究,其中着重探讨堆芯补水箱的事故缓解作用,并针对堆芯补水箱的有效运行数量与启用时间进行了敏感性分析。研究结果表明:全厂断电事故会导致堆芯冷却能力下降,从而造成堆芯坍塌失效;而堆芯补水箱能够为反应堆提供额外的冷却剂,且利用余热移除热交换器将堆芯余热移至外部最终热阱水箱中,从而保证堆芯的长期冷却。相关敏感性分析结果表明:在其他非能动安全设施全部失效的情况下,至少需要两个正常运行的堆芯补水箱才能有效缓解事故;在堆芯补水箱启动失败的情况下,若考虑重新启用堆芯补水箱,重启时间应不晚于52.5 ks,才能避免堆芯结构损坏。该研究结果可为相关小堆的严重事故管理导则的制定和改进提供参考,从而增强对全厂断电事故的应对能力,同时有利于提升模块化小堆非能动安全系统的事故缓解能力。厦门大学能源学院发展基金(2017NYFZ01

Progress in Proton-Exchange Membranes for Direct Methanol Fuel Cells

本文对直接甲醇燃料电池 (DMFC)质子交换膜的要求及目前的研究状况作了简要的概述 ,特别是从基膜材料结构角度进行分类 ,较详细地介绍分析以Nafion膜为代表的全氟磺酸膜的各种改性研究及以PBI、PEEK、PSU等基膜材料为代表的聚芳环系列的DMFC质子交换膜的研究情况。总结了质子交换膜的一些研究方法 ,对直接甲醇燃料电池质子交换膜的发展前景进行了探讨The recent research progress of the proton exchange membranes for direct methanol fuel cells (DMFC) including the requests and the methods were briefly reviewed in this paper. The details of the Nafion membrane and its modifications, the arylene main chain polymers such as polybenzimidazole (PBI), polyetherketone (PEEK) and polyethersulfone(PSU) membranes and their modifications, based on the structures of the membrane materials, were especially described. The research methods and their development foreground of the proton exchange membranes were also discussed.国家自然科学基金资助项

The Characteristic of Calcium Distribution in Developing Female Gametophyte of Allium tuberosum

对韭开花前1 d到开花后2 d的发育胚囊中CA2+分布特征进行研究,结果显示:在开花前1 d游离核胚囊形成细胞,CA2+主要分布在极核周围的细胞质小液泡中,与中央细胞的大液泡形成有关;在开花当天,卵细胞大液泡体中CA2+增多,与其大液泡形成有关;开花后1 d,卵细胞大液泡中钙沉淀颗粒减少,助细胞珠孔段的CA2+增多,合点端较少,呈极性分布;开花后2 d,卵细胞大液泡和中央细胞大液泡珠孔部位CA2+再次明显增加。助细胞珠孔端丝状器中CA2+也增加,一个助细胞退化,呈现接受花粉管状态。韭发育胚囊中CA2+分布特征显示其参与调控胚囊细胞的分化,揭示雌配子体中CA2+分布的时空特征是深入研究胚囊细胞分化的基础。Characteristic of Ca2+ distribution in developing female gametophyte of Allium tuberosum was studied from 1 d before anthesis to 2 d a fter anthesis.At 1 d before anthesis, the nuclear embryo sac differentiates gametophyte cells.Calcium precipitates of young embryo sac were few and mainly located in the small vacuoles surrounding polar nuclei, suggesting Ca2+ relating with the formation of the large vacuole of central cell.At anthesis, the precipitates in large vacuole of egg increased, also suggesting Ca2+ relating with formation of the large vacuole of egg cell.At 1 d after anthesis, the precipitates in egg cell decreased and increased in synergid cells, in which the precipitates displayed polarity distribution: more in the micropyle end of the cell than in the chalazal end.At 2 d after anthesis, the precipitates in the large vacuole of egg and the micropyle part of central cell appeared again.The precipitates in filiform apparatus of both synergids also increased.One synergid cell degenerated, which prepared to accept pollen tube.The characteristic of calcium distribution in developing embryo sac of A.tuberosum suggests that Ca2+ may regulate cell differentiation of embryo sac.Exploring the spatial-temporal feature of Ca2+distribution in developing embryo sac is a base of further study of cell differentiation of embryo sac.国家自然科学基金(31170289); 公益性行业(农业)科研专项课题(200903016

Content and Structure of Tannins in Different Parts of Bayberry (Myrica rubra (Lour.) Sieb. et Zucc.)

对杨梅的叶、枝和树皮的总酚含量与可溶缩合单宁含量进行了测定,并利用基质辅助激光解吸附飞行时间质谱(MALDI-TOFMS)详细研究了不同部位中缩合单宁的类型、聚合度及聚合物的分布情况。结果表明:树皮的总酚含量最高(43.56%),叶次之(34.69%),枝最低(18.53%);树叶的可溶缩合单宁含量最高(25.67%),皮次之(17.93%),枝最低(8.01%);3组分的缩合单宁都以(表)棓儿茶素-3-O-棓酸酯(EGCG/GCG)为基本结构单元的原翠雀定,且大部分聚合物的结构单元之间存在A型和B型两种连接方式,但其中叶和枝缩合单宁的聚合度要大于树皮。Contents of total phenolics and extractable condensed tannins in leaves,branches and bark of Myrica rubra(Lour.)Sieb.et Zucc.were determined.In addition,type of condensed tannins,degree of polymerization and distribution of polymer were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS).The results were showed as follows:total phenolics content was the highest in bark(43.56 %),followed by leaves(34.69 %),and then branches(18.53 %);while extractable condensed tannins content was the highest in leaves(25.67 %),followed by bark(17.93 %),and then branches(8.01 %).Epigallocatechin-3-O-gallate was invariably the basic unit occurring in the three condensed tannins.A-type and B-type linkages were the common types among the structural units of polymers.Meanwhile tannins in leaves and branches had the larger highest polymerization degree than bark.国家自然科学基金(40376026;30671646);; 教育部新世纪优秀人才支持计划(NCET-07-0725

Analysis on gene detection results of 3715 cases with thalassemia in Xiamen

目的:调查厦门地区地中海贫血基因的携带率、基因突变类型及其频率分布。方法:对2013年1月~2014年8月在该院住院或门诊治疗的患者及健康体检人员共3 715例进行地中海贫血基因检测,对检测结果进行统计分析。结果:检测出静止型α-地中海贫血200例(5.4%),中间型α-地中海贫血44例(1.2%),标准型α-地中海贫血1 213例(32.6%),β-地中海贫血787例(21.2%),α-合并β-地中海贫血69例(1.8%)。结论:不同就诊对象地中海贫血检出率具有明显差异,血常规是筛查地中海贫血高危孕妇的一个有效手段,但也存在一些缺陷,需引起重视。Objective: To survey the carrying rate,types of gene mutation,and frequency distribution of thalassemia gene in Xiamen.Methods: Thalassemia gene detection was conducted among 3 715 patients treated in the hospital or in outpatient department of the hospital and healthy cases receiving physical examination,the results were analyzed statistically.Results: Among the cases,200 cases( 5.4%) were diagnosed as silent α-thalassemia,44 cases( 1.2%) were diagnosed as intermediate α-thalassemia,1 213 cases( 32.6%)were diagnosed as standard α-thalassemia,787 cases( 21.2%) were diagnosed as β-thalassemia,69 cases( 1.8%) were diagnosed as α-thalassemia combined with β- thalassemia.Conclusion: The detection rates of thalassemia among different objects vary,blood routine screening is an effective means for screening high-risk pregnant women,but there are some defects,which should be paid more attention to

Action recognition based on the angle histogram of key parts

当前的姿态表示的行为识别方法通常对姿态的准确性做了很强的假设,而当姿态分析不精确时,这些现有方法的识别效果不佳。提出了一种低维的、鲁棒的基于关键肢体角度直方图的人体姿态特征描述子,用于将整个动作视频映射成一个特征向量。同时,还在特征向量中引入共生模型,用以表示肢体间的关联性。最后,设计了分层的SVM分类器,第1层主要用于选择高判别力的肢体作为关键肢体,第2层则利用关键肢体的角度直方图并作为特征向量,进行行为识别。实验结果表明,基于关键肢体角度直方图的动作特征具有较好的判别能力,能更好地区分相似动作,并最终取得了更好的识别效果。The current pose-based methods usually make a strong assumption for the accuracy of pose,but when the pose analysis is not precise,these methods cannot achieve satisfying results of recognition.Therefore,this paper proposed a low-dimensional and robust descriptor on the gesture feature of the human body based on the angle histogram of key limbs,which is used to map the entire action video into an feature vector.A co-occurrence model is introduced into the feature vector for expressing the relationship among limbs.Finally,a two-layer support vector machine( SVM) classifier is designed.The first layer is used to select highly discriminative limbs as key limbs and the second layer takes angle histogram of key limbs as the feature vector for action recognition.Experiment results demonstrated that the action feature based on angle histogram of key limbs has excellent judgment ability,may properly distinguish similar actions and achieve better recognition effect.国家自然科学基金资助项目(61202143); 福建省自然科学基金资助项目(2013J05100;2010J01345;2011J01367); 厦门市科技重点项目资助项目(3502Z20123017

C/SiC表面SiC涂层氧化的显微CT无损检测与分析

对C/SiC复合材料表面SiC涂层在1300℃干氧和湿氧环境中退火处理60 h,利用显微CT技术对高温氧化后的SiC涂层进行无损检测。通过重构SiC涂层不同深度的氧化形貌,并利用SEM、EDS和XRD进行辅助验证,得到沿SiC涂层表面和厚度方向的氧化形貌。结果表明:显微CT能有效地检测氧化后SiC涂层中存在的氧化产物SiO2及其氧化深度,其在表面及深度方向均呈非均匀分布;在干氧环境中SiC涂层的氧化面积沿着涂层的深度方向呈减少趋势,而在湿氧环境中SiC涂层的氧化面积沿着涂层的深度方向呈先增加后递减的趋势,验证了C/SiC复合材料表面SiC涂层在干氧和湿氧中不同的氧化机制