呼出气挥发性有机化合物研究进展

人类的呼出气体中蕴含丰富的挥发性有机化合物（VOCs），其种类可达数千种之多。除外界空气携带进入体内的VOCs外，绝大部分的VOCs来自于人体代谢以及人体内微生物的代谢。所以呼出气VOCs携带了大量人体内部的信息，这些信息类似于个体代谢状况的呼出气物质的“指纹”，从而使其有潜力成为健康监测和疾病诊断的理想工具。近年来大量关于疾病和呼出气VOCs的研究展示出有价值的结果。人体内诸多疾病均和体内氧化应激反应具有密切关联，氧化应激反应同样会产生大量VOCs通过肺部排出，这成为了监测疾病的一个新的窗口。今后利用呼出气VOCs分析开展针对感染性疾病、代谢性疾病以及肿瘤等疾病的检测和诊断可能成为一种新的趋势。本文将从呼出气VOCs的概念、采集、检测、临床应用以及VOCs和疾病的关系5个方面展开综述

公序良俗:代孕技术限制的法理基础

由于现代科技的发展,立法上完全杜绝代孕几无可能,视而不见也绝非明智。代孕技术立足于生育权的保障,其针对的对象主要是不能生育或生育有缺陷的主体。对于代孕,必须进行必要的限制或规范。从公共秩序的层面,国家立法和公共政策对代孕技术的实施进行了限制,并从合法性的角度对代孕行为提出了质疑。从善良风俗的层面,宪法道德、契约法道德和家庭法道德亦对代孕技术的实施进行了限制,并从合理性的角度对代孕行为提出了质疑。公序良俗原则是代孕技术限制的法理基础

Theoretical Study on Novel Refrigerant Mixture R1270/R152a/R13I1

A new refrigerant mixture,R1270/R152a/R13I1,is proposed as a substitute for R22 in this paper.The thermophysical properties of this environment-friendly mixture and its refrigeration system performance are theoretically analyzed with the software Refprop 8.0.The results show that the COP and the unit volume refrigerating capacity of the system with the new refrigerant mixture is equivalent to those with R22 under the standard working condition.Under the variable working condition,the temperature glide of th..

应用Python改进信号处理类实验教学

信号处理类课程具有概念抽象、推导复杂、内容枯燥等教学难题,实验课程的设置尤为重要,软硬件实验配套理论课程的方式已经被广泛应用。而随着新工科建设的需求,Python在信号处理类实践应用教学方面应当引起关注。分析信号处理类实验课程的发展,给出Python信号处理类实验教学案例,希望能促进此类课程的改进,做好新工科学科建设,增强学生应用设计能力

Simulation of surface topography considering process-machine interaction in grinding

磨削加工方法是保证加工表面质量的重要手段,机床结构与磨削过程之间存在的交互作用会对工件表面质量产生不利影响。以砂轮端面磨削加工过程为研究对象,在研究磨削工件表面形貌仿真方法的基础上,深入分析了机床结构与磨削过程之间交互作用对工件表面形貌的影响。首先基于砂轮表层磨粒的随机分布特性建立了虚拟砂轮形貌,然后通过对磨削过程中砂轮磨粒与工件几何干涉作用的分析,建立了磨粒运动轨迹方程和工件表面形貌方程。考虑砂轮变形对磨削过程的反向作用,建立了主轴-砂轮结构与磨削过程间的交互模型,采用耦合仿真的方法对机床-磨削交互过程进行了仿真,并考虑磨削过程中的交互作用提出了一种新的磨削工件表面形貌仿真模型,实验结果验证了所给算法的正确性和有效性,该方法为进一步优化磨削工艺参数提供了依据。Grinding is an important means to guarantee the quality of the machined surface,however,the interaction between machine and grinding process reduces surface quality. Focusing on face grinding,the influence of process-machine interaction on ground surface was analyzed based on the investigation of surface topography simulation. A visual wheel topology was simulated based on the random nature of grains located on the wheel surface. The grain trajectory equation and workpiece topography equation were established based on the analyses of interference between grains and workpiece. The interaction between grinding process and spindle-wheel was modeled considering the inverse influence of wheel deformation on process and simulated by adopting a coupling simulation method. Taking the processmachine interaction into account,a novel simulation model for surface topography of the grinding process was proposed.Grinding test verifies the accuracy and effectiveness of the given algorithm. The method can be further used to optimize the grinding process parameters.福建省高校产学合作科技重大项目“高效、高精度可转位刀片周边刃磨关键技术研究”(2014H6025

Spindle Thermal Error Comprehensive Prediction Model Based on Information Granulation and SVM

主轴热变形是影响数控机床加工精度的主要因素。为提高主轴热误差的预测精度,提出了基于信息粒化支持向量机（SVM）的主轴热误差综合预测模型。使用信息粒化方法对采样温度数据与主轴热误差数据进行预处理,分别建立基于SVM的主轴热误差的回归预测模型和时间序列模型,通过计算两个模型权重系数,最终建立主轴热误差综合预测模型。以2MZK7150五轴数控可转位刀片工具磨床为研究对象,实验表明,较之于单一模型该模型具有良好的泛化能力和较高建模精度。Spindle thermal deformation has an extraordinary influence on the NC machining precise. Aiming to the im- provement of the spindle thermal deformation predict ability, the spindle thermal error comprehensive predict model is pro- posed on the basis of the information granulation and support vector machine（SVM）. Information granulation method is em- ployed to pretreat the sampling temperature and spindle thermal error. The regression prediction model and time series mod- el of spindle thermal error are also carried out based on the SVM. Finally, the spindle thermal error comprehensive predict model is established using the weight coefficients of the two models. The 2MZK7150 five-axis NC indexable insert tool grinding lathe machining experiment shows that the established model has better generalization ability and higher modeling precision compared with the unitary model.陕西省科技统筹创新工程计划（2014KTD201-04-03

A Flux Control System Based on Single Chip

介绍一种以PIC16F876为核心的流量控制系统,通过单片机与计算机通讯,实现远距离的自动控制,控制系统经使用效果良好。文章给出了系统设计原理、单片机程序流程图和硬件电路。This paper presents a flux control system based on the single chip PIC16F876.The system realizes the long distance auto control by the communication between single chip and computer.The result has been proved to be good.The design principle of the system,flow chart of single chip and the related circuits are introduced in detail

Significado político-constitucional do direito penal

Através do Direito Penal o Estado ganha o poder de retirar da pessoa humana os direitos constitucionalmente assegurados, quais sejam: vida, liberdade e patrimônio, configurados como cláusulas pétreas da Constituição. O que se atinge no Direito Penal são os bens assegurados pela Carta Política, cuja aplicação e interpretação devem ser feitas em consonância com os Princípios Constitucionais. A discussão aqui empreendida quer demonstrar que, além do caráter técnico-dogmático, o Direito Penal tem um caráter político e este é o condicionante do objeto e do método do Direito Penal, fazendo com que os mesmos apresentem uma relação substancial com os princípios constitucionais

A New Approach to the Surface Reconstruction of Corneal Based on Slit-lamp Imaging

角膜是人眼的重要组成部分,眼外科中对角膜表面检查一般采用基于Placido盘的角膜地形图法和裂隙扫描角膜地形图法,但这两种方法的结果都未能获得直观的角膜表面三维模型。本研究设计的一种基于裂隙扫描图像的角膜表面三维重建算法,实现了对角膜前后表面的重建,并能快速地计算出角膜前后表面的几何参数以及转换成传统的等高线图和地形图,方便了医生的诊断。该算法首先采集角膜的裂隙扫描图像序列,然后在图像集中提取出每层角膜的轮廓,进而采用轮廓线重构算法得到角膜表面模型。在对裂隙图像提取闭合轮廓线时,根据角膜区域的颜色差异,采用了色彩分割的算法;针对角膜轮廓线是凹的特点,对轮廓线重构算法做了改进,以便能构造出正确的角膜表面三角形网格。Cornea is an important part of eyeball. There are two clinical methods that are commonly used in measuring corneal shape. One is Placido-based corneal topography,and the other is Orbscan corneal topography. By using both technologies, 3D corneal surface model can not be obtained. In this paper,a new approach to the surface reconstruction of corneal based on slit-lamp imaging was proposed,which realize visualization for 3D structure of corneal anterior and posterior surface and gain the geometric parameters of its shape fast. At the meantime the results can be transferred the hypsographic map and the topography map to diagnose easily. The algorithm firstly acquires an image series using slit-lamp,secondly extracts the contour of the corneal,at last the corneal surface model is produced using algorithm of contour reconstruction. In abstracting the contour,we adopt color segmentation method according to the difference of the corneal zone. Against the concave characteristics of corneal contour,we improve the algorithm of contour reconstruction to increase the robust of algorithm and obtain the triangle mesh of corneal surface.国家自然科学基金 (60 3 710 12 ) ;; 福建省科技重点项目 (2 0 0 2Y0 2 1);; 面向 2 1世纪教育振兴行动计划项目的支持

化学气相沉积SiC–B_xC涂层在高温模拟环境中的微观结构

将化学气相沉积在石墨基片上的SiC-BxC复合涂层在O2(8kPa)/H2O(14kPa)/Ar(78kPa)的模拟气氛中,分别加热到700,1000℃和1200℃处理10h。利用扫描电镜、X射线衍射、能谱分析、显微Raman和Fourier变换红外光谱仪研究其微观结构。结果表明:复合涂层中的BxC层在700～1000℃的模拟环境中会被完全氧化成B2O3和H3BO3;在1000～1200℃的模拟环境中,BxC层的氧化产物迅速挥发。经高温模拟环境处理后,复合涂层中生成了硼硅酸盐玻璃,且各氧化产物和SiC层的结晶度随处理温度的升高而下降。基于微观分析结果,对SiC-BxC复合涂层的自愈合抗氧化性能进行了分析