新型回转式曲面分层 3D 打印机设计与实验研究

3D 打印技术在航天、军工、机器人等领域应用广泛，但也存在诸多问题，如阶梯效应所带来的叠层误差、2.5D 制造原理导致的打印零件各向异性、支撑结构的打印及后处理导致的耗时和耗能等问题。针对上述不足，该文提出一种回转式曲面分层 3D 打印方法，对多自由度回转式 3D 打印设备的设计方法进行研究，通过构型综合和尺度综合确定了打印机构型及结构参数，提出了曲面打印路径规划方法。通过联合仿真与样机实验，验证了 3D 打印设备构型综合与尺度设计的有效性，为打印装备创新设计、曲面打印过程规划策略及相关实验研究提供了新思路。     

组氨酸共价修饰咕啉的计算机模拟

利用计算机模拟,分别以咕啉-咪唑(Corrin-Im)和咕啉-组氨酸(Corrin-His)配合物为研究对象,采用分子力学MM2、MM ,以及半经验量子化学ZINDO/1,考察两种配合物在分子构型、分子轨道、分子能量,以及轴向配体效应方面所存在的差别,以探讨组氨酸对咕啉分子的共价修饰,在配合物的结构、性质及功能方面所产生的影响。文章对于设计与构建人工咕啉配合物,以及这些功能配合物的应用,会有一定的指导意义。     

氧分子O_4的结构与性能的密度泛函理论研究

采用密度泛函理论(DFT中的B3LYP方法,在LANL2DZ基组水平上对On0,±(n=2～4)分子的各种可能构型进行了几何结构优化,预测了它们的基态构型,并对O40,±分子基态结构的能量、振动光谱和芳香特性进行了理论研究.结果表明:O4分子的基态结构为对称性为D2d的非平面的四边形,阴阳离子的基态结构都为对称性为D4h的平面正四边形;O4具有芳香性,O4和O4+具有反芳香性;O40,±分子的基态结构均具有红外活性和拉曼活性;红外光谱均出现1个较强的振动峰,拉曼光谱中O4、O4+、O4-分别有4个、3个和1个较强的振动峰.     

一种高分子化合物的合成、结构表征及荧光性能

设计并合成了1种含有吡唑啉发光功能基团的化合物,采用凝胶色谱(GPC)对其分子量进行了测定,确定其为高分子。通过对比测得的核磁共振图谱(~(1)H NMR)与Chem3D Ultra 10.0对其~(1)H NMR的模拟图谱,对其结构进行了确证。进而研究了高分子化合物的发光性能,结果表明其在溶液及固体薄膜中具有良好的荧光发光能力,在电致发光器件中有潜在的用途。     

寻找失落的宠物——《猎人MM》的诱惑

《猎人MM》是由韩国XaiMedia公司推出的一款有动漫风格画面和Q版人物造型的网游大作，是通过与怪兽之战解决问题的一款在线游戏。因为游戏走的是“可爱”路线，所以必定会吸引大批MM参与其中，玩游戏的同时，说不定还会认识知心的MM哟。虽然《猎人MM》采用的只是2D画面，     

氨基酸His或二肽Cys-His共价修饰Fe(Ⅲ)-salophen的计算机模拟

通过比较天然血红素蛋白中血红素与多肽链进行共价连接的结构,我们对组氨酸(His)或二肽半胱氨酰-组氨酸(Cys-His)共价修饰人工配合物Fe(III)-salophen进行了计算机模拟,旨在为设计包含非天然辅基的金属蛋白分子提供有用的信息。修饰物采用分子力学MM 方法进行了分子构型优化,而且在最低能量构型的基础上,采用半经验量子化学ZINDO/1方法进行了单点计算。结果阐明,当His形成Fe(III)-salophen的第五轴向配体时,通过与His形成酰胺键进行共价修饰,引入丙酸根要比甲酸根使分子更加稳定;同时,在Fe(III)-salophem的位置a进行His或Cys-His共价修饰,均比在位置b进行修饰使分子更加稳定。此外,在所有修饰物分子中,最稳定的分子为:通过Cys与a位置所引入的乙烯基之间形成硫醚键的二肽Cys-His修饰物。这一结构与自然界中c型细胞色素一致。本研究提供了一些初步的理论研究结果,它能够指导功能性Fe(III)-salophen配合物的构建以及在人工金属蛋白设计中的应用。     

(SP-4-2)-[(1R,2R)-环己基-1,2-二胺-N,N′]双(十四烷酸-O)合铂(Ⅱ)的合成、表z征及量子化学计算

为深入研究(SP-4-2)-[(1R,2R)-环己基-1,2-二胺-N,N′]双(十四烷酸-O)合铂(II)(又称米铂),本文采用(1R,2R)-1,2-环己二胺与氯亚铂酸钾为原料进行合成,精制得到纯度99.5%的目标化合物;通过红外光谱,高分辨质谱,核磁共振氢谱及碳谱对目标化合物的结构进行表征和分析。采用Gaussian03程序包,在B3LYP/LANL2DZ基组水平上对体系进行几何全优化及相关计算。对于计算结果进行了稳定性分析和振动频率分析,通过实验值和计算值的对比,证实软件优化的分子构型与实验制备的分子构型一致;根据QTAIM理论,采用AIMALL程序包对目标分子中的化学键进行了拓扑分析,其结果对分子构型给出了合理的解释。通过本文的研究,对(SP-4-2)-[(1R,2R)-环己基-1,2-二胺-N,N′]双(十四烷酸-O)合铂(II)有了更深入的了解,为其相关性质研究提供了理论依据,并且对于其他类似的分子研究均有一定的借鉴价值。     

铁卟啉化合物与氧气分子形成的体系的密度泛函理论研究(英文)

采用密度泛函理论B3LYP方法在6-31G(d)基组水平下对氯化铁(+3)卟啉与氧气分子形成的体系进行了研究,得到了几何构型,电子性质及分子轨道结构等相关数据.对两个体系不同自旋状态下的几何构型参数和电子性质对比发现:受体系立体构型对称性的影响,在两个体系中凡是与卟啉环上N原子相关的几何参数及电子性质均呈现出相同规律性.又采用密度泛函理论UB3LYP/6-311G*//UB3LYP/6-31G*方法对这两个体系不同自旋状态下的能量进行了计算,分析表明自旋多重度越高体系越稳定.然后分别分析了两个体系在最稳定自旋状态下的分子轨道占据情况及中心Fe原子最外层3d轨道的电子分布情况,结果表明Fe原子的3d二和3dxz/3dyz与氧气分子的单占据反键轨道HOMO π*2px/π*2py之间存在相互作用,这种相互作用引起铁卟啉环与O2分子间的电子转移并使O2活化.然而,根据分析在通常状态下铁卟啉对O2分子的活化作用是微弱的.     

环体聚硅氧烷D4H的密度泛函研究

采用B3LYP/6-311++G(d,p)方法,对环体聚硅氧烷D4H进行了量子化学研究。优化了D4H的几何构型,研究了目标化合物在几何结构、电子结构、偶极距、前线轨道等方面的性质。结果表明,D4H分子中Si-O八元环采取"椅式-船式"低能构象。Si原子上集中了大部分的正电荷,而O、C原子则带负电荷。各原子对分子HOMO、LUMO贡献的区别并不明显,HOMO、LUMO能量差较大,表明分子具有一定的稳定性。溶剂效应分析表明,随着溶剂极性的增加,分子的能量越来越小,稳定性增加。     

财务人员补补课——用好Word表格求和

我工作过的几个公司都有一个特点。财务部门的小MM使用Excel的水平大多神乎其神,一向自诩Office应用专家的我也绝不敢在他们面前摆弄Excel。不过今天终于出了口气，原来那些Excel高手们对Word一窍不通，很多Excel里简单的应用在Word中竟然让她们寸步难行。     

An evaluation of the effectiveness of symbolic testing

The effectiveness in discovering errors of symbolic evaluation and of testing sad static program analysis are studied. The three techniques are applied to a diverse collection of programs and the results compared. Symbolic evaluation is used to carry out symbolic testing and to generate symbolic systems of path predicates. The use of the predicates for automated test data selection is analysed. Several conventional types of program testing strategies are evaluated. The strategies include branch testing, structured testing and testing on input values having special properties. The static source analysis techniques that are studied include anomaly analysis and interface analysis. Examples are included which describe typical situations in which one technique is reliable but another unreliable. The effectiveness of symbolic testing is compared with testing on actual data and with the use of an integrated methodology that includes both testing and static source analysis. Situations in which symbolic testing is difficult to apply or not effective are discussed. Different ways in which symbolic evaluation can be used for generating test data are described. Those ways for which it is most effective are isolated. The paper concludes with a discussion of the most effective uses to which symbolic evaluation can he put in an integrated system which contains all three of the validation techniques that are studied.     

Asymptotic shape of the Erlang capacity region of a multi-service shared resource

We consider a loss model of an unbuffered resource having C channels, which are shared by several different types of service connections. Connections of each type arrive in a Poisson stream and request a number of channels, which depends on the type. An arriving connection is blocked and lost if there are not enough free channels. Otherwise, the channels are held for the duration of the connection, and the holding period is generally distributed. It is assumed that C and the traffic intensities are proportionately large. The admission control problem is considered for specified upper bounds on the blocking probabilities, and the boundary of the admissible set is investigated asymptotically. Characterization of admissible sets is extremely useful, not only for connection-level admission control, which is the context in which this topic has typically been considered in the past, but also for higher level objectives, such as network economics, network design, and network control. The asymptotic view of the admissible set is particularly appropriate for the higher level objectives, where the fine details are not as important as the qualitative properties of the shape of the set and tractability of the numerical calculations for large systems. Our results are derived by investigating the local behavior with respect to the tangent hyperplane at a point on the boundary of the admissible set. The lowest order results that hold in the asymptotic limit C→∞ are given first. Importantly, the boundary is linear for the key critically loaded and also for the overloaded regimes, and weakly convex for the underloaded regime. Next, refined results that hold for C1 are given, which indicate that the boundary is not convex, although only slightly so.     

Quantitative lithostratigraphic correlation of subsurface sequences

A quantitative method for geologic correlation of two electric-log sequences of unequal length is proposed which calculates scaling factors that are applied to Fourier transformations of each time series. Correlations thus are made in the frequency domain and are based on an assumed recognizable, unique periodicity in correlative geologic units. A FORTRAN IV program is presented and application is demonstrated for two wells in Texas. The method is useful for stratigraphic correlations that are to be performed by automated procedures and which may not be visually obvious.     

基于XML的结构化电子病历系统设计

阐述了两种结构化数据采集的方法:自然语言处理(NLP)和结构化数据输入(SDE).基于上述两种方法,设计了一个结构化电子病历系统(EPR)的原型,用XML技术来描述和实现知识库,使用Microsoft.NET的XML数据流技术实现病历数据的输入、存储和展现,并使用XSL技术实现Web方式的病历浏览.设计表明,利用XML技术解决病历的自由输入并和结构化输入相结合,是可行的技术方案;它为电子病历的研究提供了新的途径.     

回转窖无线测温系统的设计

本文是回转窖无线测温系统的设计,热电偶测量窖内温度产生的电压信号,通过无线电传设备送至操作室,直接显示窖头、窖中和窖尾温度;同时将信号转发到中控室,并转换成4～20mA电流送其它仪表或控制系统显示,无线测温系统是回转窖无线测温的理想工具和最佳手段。     

超导转子旋转轴位置测量的影响因素分析

介绍了一种用于低温装置中超导球形转子旋转轴线位置测量的反射式强度调制(R IM)型光纤传感器。在转子端面刻划矩形漫反射图形,利用该刻线图形对反射光的强度调制来获取旋转轴线位置偏移的大小和方向。用M atlab软件进行了仿真,由输出波形分析了转子刻线精度和光斑大小对光纤传感器信号拾取的影响。仿真结果为光纤传感器的设计提供了依据,对传感器在实际应用中提高信号拾取的精度具有参考价值。     

Irreversibility and Limiting Possibilities of Macrocontrolled Systems: I. Thermodynamics

In this paper, two types of systems — thermodynamic and economic — are considered, which include a large number of micro subsystems and are controlled on the macro level (macrocontrolled systems). The analogy between the maximal work problem in thermodynamics and the maximal profit problem in a microeconomic system is investigated. The notion of exergy is generalized for the systems which do not contain reservoirs, and the conditions of maximal power of heat engines are generalized for systems with arbitrary structure. The notion of system profitability and the measure of irreversibility of an microeconomic processes are introduced. The extremal principle which determines an equilibrium state of open microeconomic system, is formulated. The conditions of optimality of resource trading and the expression for profitability of resource exchange are formulated for systems which include market with perfect competition, and for systems which do not include it. Economic analogues of the second law of thermodynamics are formulated using introduced concepts. The first part of the paper is devoted to thermodynamic systems and the second to microeconomic systems.     

Numerical evaluation of the asymptotic energy behavior of intermediate shells with application to two classical benchmark tests

We consider the class of shell problems which are neither purely bending neither purely membrane dominated. In such cases the asymptotic energy norm behavior (which is useful not only because it represents the structure stiffness, but also for numerical comparison purposes) is not a priori known. In this work we apply a numerical procedure in order to estimate the energy behavior of a general shell problem. In order to test its reliability, the method is applied to various problems for which the theoretical energy behavior is known and the results can be compared. Among the problems tested, we have two classical engineering shell benchmarks which are neither bending neither membrane dominated, and for which an analytical evaluation has been obtained in a recent work. All the energy behavior estimates obtained with the numerical method are in perfect agreement with the theoretical values.     

Autonomous longitudinal motion of a paraglider. Mathematical simulation, synthesis of control

Mathematical model of motion of a paraglider in the longitudinal plane is constructed. The vehicle consists of a sail and a gondola. Both bodies are assumed to be perfectly rigid. They are connected by slings which are assumed to be perfectly rigid rods. Thus, the considered model of the paraglider represents one rigid body with three degrees of freedom. An engine, which develops thrust using a propeller, is mounted rigidly on the gondola of the vehicle. The orientation of the thrust vector with respect to the gondola is constant. The steady-state regimes of motion of the paraglider for the constant thrust are found. The law of automatic thrust control for which the flight of the vehicle is stabilized at the given altitude is designed. The domains of asymptotic stability of the paraglider motion at a constant altitude, including with account of delay, are constructed in the plane of the feedback coefficients. In this plane the domains in which a given stability factor is ensured are constructed. Some results of numerical simulation of the flight of the vehicle are presented.     

Control of asynchronous sampled data systems

This paper is concerned with the problem of controller design in the case of asynchronous sampled data systems. Optimal LQG controllers are obtained for the class of two-rate systems where all the control inputs are held at a rate which is asynchronously related to the rate with which all of the outputs are sampled. Furthermore for this class, a parameterization of all stabilizing controllers is provided