39 research outputs found

    入侵植物互花米草上的蚜虫新纪录:一条蚜及其种群分化

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    本研究报道了一条蚜Hysteroneura setariae在中国华南地区取食入侵植物互花米草,这是该植物上的首个蚜虫纪录。结合DNA条形码和系统发育分析,探究了互花米草上一条蚜种群的来源,并基于中国华南、印度、巴基斯坦、美国等地区样品的序列数据,分析了一条蚜种群遗传分化格局。结果显示:华南地区互花米草上的一条蚜来自周边其他寄主植物上一条蚜种群的扩散;北美本土一条蚜种群与亚洲地区种群具有一定程度的遗传分化。国家重点研发计划项目(2016YFE0203100);;国家自然科学基金项目(31772504);;福建省杰出青年科学基金项目(2015J06005

    Classification method of diabetes based on integration of characteristic classifier

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    目的:结合医用电子鼻技术,探讨糖尿病患者及其口腔呼气的气味图谱特征。方法:选择180例糖尿病患者和100例健康者,用医用电子鼻采集280例口腔呼气的气味图谱,采用基于数据特征划分的方法,用支持向量机和随机森林集成模型对糖尿病患者进行分类预测。结果:1线性核函数的支持向量机(SVM1)分类结果不是很理想,低于多项式核(SVM2)、径向基函数核(SVM3)和随机森林(RF)3种分类器,说明分类超平面显然是非线性的;2集成分类器对糖尿病患者和健康者的气味图谱特征的识别准确率可达88.04%。结论:基于特征划分的分类器集成方法预测性能明显好于单一分类器,为使用医用电子鼻进行糖尿病诊断分析提供了一种有效手段。Objective: To discuss the proi le features of oral odor of diabetic patients based on medical electronic nose technology. Methods: 180 patients of diabetes and 100 healthy people were selected, and the proi le features of oral odor of 280 volunteers were collected by using medical electronic nose. The classii cation forecasting was carried out on diabetic patients by using support vector machine(SVM) and random forest integration model based on partitioning method of data characteristics. Results: 1The classii cation result of SVM1 was not very good, which was lower than that of SVM2, SVM3 and RF, and the result showed that the classii cation hyperplane is nonlinear. 2The accurate rate of recognition of integrated classii er on diabetic patients and healthy people is 88.04%. Conclusion: The forecasting performance of classii er integration method based on feature division is superior to that of single classii er signii cantly, which provided an ef ective means for the diagnostic analysis of diabetes based on medical electronic nose.国家自然科学基金项目(No.81373552);; 福建省教育厅A类项目(No.JA14212);; 福建工程学院科研启动项目(No.GY-Z12079)~

    湿地变形菌门甲烷氧化菌群的缺氧能量代谢

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    甲烷氧化菌以甲烷作为碳源和能源,在全球甲烷平衡和温室效应控制中扮演着重要角色。甲烷生物氧化过程跨越不同氧化还原生态位,近年来的研究表明,在湿地缺氧生态位下变形菌门甲烷氧化菌具有代谢潜力,但其能量代谢机制尚不清楚。本研究基于生物电化学技术、矿物学实验及微生物组学方法,结果表明变形菌门甲烷氧化菌主导的菌群具有直接和间接胞外电子传递潜力;在氧气耗尽时,甲烷氧化菌群可利用水铁矿作为电子受体完成能量代谢过程,缺氧体系中γ-Proteobacteria纲的甲烷氧化菌和非甲烷氧化微生物共同驱动铁矿还原。本研究探讨了变形菌门甲烷氧化菌主导菌群的缺氧能量代谢过程,拓展了反硝化厌氧甲烷氧化菌及厌氧甲烷氧化古菌主导的缺氧甲烷氧化理论,为甲烷生物控制提供了理论支持

    Electroless Copper Deposition Using Sodium Hypophosphite as Reductant

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    研究了以次磷酸钠为还原剂、硫酸镍为再活化剂的化学镀铜工艺和镀层结构,指出工艺的基本特性。结果表明,在含有次磷酸钠和硫酸镍的镀液中,化学镀铜过程可以持续进行并呈现自催化特性;只有在合适的镀液pH范围内才可获得铜镀层;铜镀层为面心立方结构,没有明显的晶面择优取向现象,镀层结构的晶面间距d和晶胞参数a与标准Cu粉末的相比均较大,说明铜镀层仍存在应力和缺陷。The primary characterstics for the process of electroless copper deposition, using sodium hypophosphite as reducing agent and nickel sulfate as re-activation agent, and the deposit structure were studied. The results showed that in the solution containing sodium hypophosphite and nickel sulfate the copper deposition was sustainable and was presented in self-catalyzation. The deposit could only be obtained in a proper pH range. The deposit was in face-centered cubic structure without obvious crystal face preferred orientation. Its lattice distanced and lattice parameter a were larger than those of standard copper powder, which indicated that the obtained deposit was still present internal stress and defects

    New method of variable excitation MFL testing under the condition of small magnetizing apparatus

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    为解决常规储罐和管道的漏磁检测(Mfl)方法中磁化器体积大、耗能多的缺点,提出了一种小型磁化器条件下的变励磁Mfl检测新方法。首先,分析了小磁化器条件下被测钢板磁化状态随外部励磁强度的变化特性,推导了偏置磁化条件下励磁通变化量与漏磁场变化率的关系模型;其次,根据所建立的关系模型,设计了一种新型变励磁Mfl检测探头,并给出变励磁Mfl法的系统实现方案;再次,结合实现方案,搭建了变励磁Mfl相应的实验平台;最后,在该平台上,开展了一系列的物理实验并对实验结果进行了深入讨论。实验结果表明,所提变励磁Mfl法无需对被测钢板进行局部饱和磁化,适合小型磁化器条件并具有较高的灵敏度。变励磁Mfl法为漏磁检测领域提供了一种新的检测思路。In the conventional method of magnetic flux leakage( MFL) testing,the magnetizer is in big volume and with more energy consumption.To solve the problem,a new method of variable excitation MFL testing under the condition of small magnetizer is proposed.First of all,the state of magnetized steel along with the change of the external excitation's intensity under the condition of small magnetizer is analyzed.Secondly,according to the established model,a new type of testing probe for the variable excitation of MFL is designed and a new implementation scheme is proposed.Furthermore,combining with the implementation scheme,an appropriate testing platform of the variable excitation MFL is set.Finally,a series of physical experiments on the platform are carried out and the results of the experiment were discussed.The experimental results show that the proposed method don't need to make local saturation magnetization of tested steel plate,which is suitable for the condition of small magnetizer with higher sensitivity.The new method provides a new testing idea for MFL testing field.国家自然科学基金(51177141); 中央高校基本科研业务项目(2010121041); 航空基金(2012ZD68003)资助项

    New nondestructive test method with empirical research using local hysteretic loop characteristics

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    提出了一种利用局部磁滞回线特性的无损检测新方法。首先,研究了钢板内部缺陷对其动态磁导率分布的影响规律。其次,探讨了变励磁条件下局部磁滞回线的形成机理,并建立了动态磁导率与局部磁滞回线之间的关系模型。再次,根据所建立的关系模型,提出了一种利用局部磁滞回线特性实现对钢板缺陷进行无损检测的新方法,并给出检测系统的实现方案。最后,通过3d有限元法对实验模型进行仿真,并开展了一系列的物理实验进行了验证。结果表明,缺陷对钢板动态磁导率分布的影响显著,可利用局部磁滞回线特性来检测磁导率变化,从而达到检测内部缺陷,甚至背面缺陷的目的。所提新方法无需检测静态漏磁场磁感应强度,因此有效减小了磁化器体积。A new nondestructive test method based on local hysteretic loop characteristics is proposed in this paper.First of all,the influence law of the steel plate internal defects on the dynamic permeability distribution is studied,and the formation mechanism of the local hysteretic loop under the variable magnetic excitation condition is discussed.Secondly,the relation model between the dynamic permeability and local hysteretic loop is established.Furthermore,according to the proposed relation model,a new nondestructive test method of steel plate defects based on the local hysteretic loop characteristics is proposed,and the implementation scheme of the test system is given.Finally,the 3D finite element method was used to simulate the experiment model and a series of physical experiments were carried out to verify the proposed method.The results show that the steel plate defects have significant influence on the dynamic permeability distribution; the local hysteretic loop characteristics can be used to detect the permeability variation,and achieve the goal of detecting the internal defects of the steel plate,even the defects on the back of the steel plate.The proposed new method does not require to test the static leakage magnetic field,which reduces the volume of the magnetizing apparatus effectively.国家自然科学基金(51177141); 中央高校基本科研业务项目(2010121041); 航空基金(2012ZD68003)项目资

    CdS量子点表面巯基酸分子排列方式的宽带和频光谱研究

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    巯基酸是一种常用的量子点表面配体,对量子点的光电属性和催化活性具有重要影响。用宽带和频光谱(BB-SFG)研究巯基酸分子(HS-(CH2)n-COOH,n = 2,5,10)在金膜和硫化镉(CdS)量子点表面的排列方式。结果表明:在金表面上3种自组装巯基酸单分子膜,都可以检测到与巯基和羧基相连的两个亚甲基的C-H振动和频谱峰。而在CdS量子点表面,短链的HS-(CH2)2-COOH和HS-(CH2)5-COOH处于较无序的混乱包覆状态,检测不到C-H振动和频谱峰;但长链的HS-(CH2)10-COOH在CdS量子点表面是较有序的类似反胶束状的排列,可以检测到与羧基相连的亚甲基的C-H振动谱峰。国家重点研发计划项目(2017YFA0206500,2016YFA0200702)国家自然科学基金(21327901)

    Ge/GeO/多层石墨纳米复合物锂离子电池负极材料性能研究

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    由于其高容量、快速锂离子扩散速率和高电导性的优点,锗被认为是一种非常有前景的锂离子电池负极材料.本研究利用GeO2和石墨作为前驱体,通过水热法制备Ge/GeO/多层石墨复合物并将其应用于锂离子电池负极材料进行电化学性能研究.实验结果表明,Ge/GeO2纳米粒子的粒径约为40 nm.该复合物电极的第一次充放电容量分别是2045和1146 mA h g.1,库仑效率为56.0%.50圈充放电循环后,当电压范围为0.01.50 V时,容量保持在1008 mAhg.倍率实验表明,该电极在1C(1C=1000mAg)和2 C倍率大电流下,虽然容量略有衰减,但仍保持790和710 mAhg的高容量.教育部新世纪优秀人才计划(编号:NCET-13-0879);福建省闽江学者特聘教授计划;泉州市桐江学者特聘教授计划;福建省自然科学基金(编号:2016J01069)资助项目

    散发型戊型肝炎与急性乙肝临床特征比较

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    目的比较散发型急性戊型肝炎与乙肝临床特征。方法分析戊肝和急性乙肝间年龄、性别、肝脏损伤、症状体征以及病程的差异。结果急性肝炎病例中,戊型肝炎最常见(28.0%),急性乙肝次之(9.2%);戊肝平均发病年龄为56.3±13.1岁,急性乙肝为43.0±12.5岁,平均发病年龄戊肝较急性乙肝大(t=4.4723,P<0.0001),均为男性多发;两者常见的临床症状和体征基本相当,但戊肝患者黄疸症状更多见(P<0.05);戊肝病程较急性乙肝长(t=3.7249,P=0.0003);通过年龄性别进行1:1匹配分析,戊肝比急性乙肝对肝脏的损伤程度严重(t=3.5978,P=0.0019)。结论戊肝多见于中老年,急性乙肝多见于中青年,均为男性多于女性。临床特征比较戊肝较急性乙肝更为严重

    生物质气化灰的肥效试验研究

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    通过试验对生物质气化发电的副产物——生物质气化灰的肥效进行研究。结果表明,在施肥量相同的条件下,添加生物质气化灰的试样,除黄瓜外,空心菜、油麦菜、樱桃萝卜、上海青试样的发芽时间都略早于单施化学肥料的试样;后期长势也明显优于单施化学肥料的试样,叶片厚而有光泽;前者在生长过程中没有虫害现象,后者有虫害现象。在生物质气化灰中添加氮、磷的试样比施单一肥料的试样长势好。研究表明,生物质气化灰具有替代钾肥的广阔市场前景
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