纳米C-S-H/PCE对蒸养UHPC力学性能增强机理研究

目前超高性能混凝土(UHPC)制品的力学性能有待进一步提升,采用纳米C-S-H/PCE对UHPC进行增强在理论上是一种可行的技术途径。本文研究了蒸养条件下掺入以聚羧酸(PCE)为分散剂的纳米水化硅酸钙(C-S-H/PCE)对UHPC力学性能的影响,通过测试水化热、水化产物、微观形貌和孔结构等对其机理进行了分析。结果表明,掺入3.0%(质量分数)纳米C-S-H/PCE可以显著提高蒸养UHPC的抗压强度和抗折强度。掺入纳米C-S-H/PCE可以促进UHPC的早期水化,生成更多的水化硅酸钙(C-S-H)凝胶,使水化放热温峰增高,并缩短达到水化温峰的时间。掺入纳米C-S-H/PCE可有效改善蒸养UHPC的孔结构,在掺量为3.0%(质量分数)时总孔隙率最小,有害孔比例最低。该研究可为纳米C-S-H/PCE在蒸养UHPC中的应用提供参考。

Preparation and electrochemical properties of LiFePO_4/C composite with network structure for lithium ion batteries

The bare LiFePO4 and LiFePO4/C composites with network structure were prepared by solid-state reaction. The crystalline structures, morphologies and specific surface areas of the materials were investigated by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and multi-point brunauer emmett and teller(BET) method. The results show that the LiFePO4/C composite with the best network structure is obtained by adding 10% phenolic resin carbon. Its electronic conductivity increases to 2.86×10-2 S/cm. It possesses the highest specific surface area of 115.65 m2/g, which exhibits the highest discharge specific capacity of 164.33 mA·h/g at C/10 rate and 149.12 mA·h/g at 1 C rate. The discharge capacity is completely recovered when C/10 rate is applied again.

Using Neural Networks to Predict Secondary Structure for Protein Folding

Protein Secondary Structure Prediction (PSSP) is considered as one of the major challenging tasks in bioinformatics, so many solutions have been proposed to solve that problem via trying to achieve more accurate prediction results. The goal of this paper is to develop and implement an intelligent based system to predict secondary structure of a protein from its primary amino acid sequence by using five models of Neural Network (NN). These models are Feed Forward Neural Network (FNN), Learning Vector Quantization (LVQ), Probabilistic Neural Network (PNN), Convolutional Neural Network (CNN), and CNN Fine Tuning for PSSP. To evaluate our approaches two datasets have been used. The first one contains 114 protein samples, and the second one contains 1845 protein samples.

Effect of C/S Ratio on Morphology and Structure of Hydrothermally Synthesized Calcium Silicate Hydrate

The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of （002）, （110） and （020） decreased, the d-spacing of （200） increased, and the d-spacing of （310） varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.

A welding document management software package based on a Client/Server structure

According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.

Adaptive evolvement of information age C^4ISR structure

Command, control, communication, computing, intel- ligence, surveillance and reconnaissance （C^4ISR） in information age is a complex system whose structure always changes ac- tively or passively during the warfare. Therefore, it is important to optimize the structure, especially in ambiguous and quick-tempo modern warfare. This paper proposes an adaptive evolvement mechanism for the C^4ISR structure to survive the changeable warfare. Firstly, the information age C^4ISR structure is defined and modeled based on the complex network theory. Secondly, taking the observe, orient, decide and act （OODA） model into consideration, four kinds of loops in the C^4ISR structure are pro- posed and their coefficient of networked effects （CNE） is further defined. Then, the adaptive evolvement mechanisms of the four kinds of loops are presented respectively. Finally, taking the joint air-defense C^4ISR as an example, simulation experiments are im- plemented, which validate the evolvement mechanism and show that the information age C41SR structure has some characteristics of small-world network and scale-free network.

Effect of Polymer on Morphology and Structure of Calcium Silicate Hydrate Prepared via Precipitation Method

The effects of polyaerylamide （PAM） and polyvinyl alcohol （PVA） on morphology and structure of calcium silica~ hydrate with C/S 1.0-1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TEM techniques. The results show that incorporation of the polymers decreased the order degree, increased the interlayer spacing and disturbed the layered stacking of C-S-H. Interlayer spacing expansion depended on C/S ratios and type of polymer. Interlayer spacing expansion had a minimum at C/S 1.0 and a maximum at C/S 1.3 and 1.5. Interlayer spacing expansion of PAM was bigger than that of PVA with the same C/S. C-S-H added with PVA mainly exhibited foil-like and fibrillar morphology. The fibrils were of variable length from a few tens of nanometers to a few hundreds of nanometers. Fibrils or foils seemed to be longer in the presence of PVA.

Electronic Structure and Optical-absorption Properties of C-, N-, and S-doped BiOCl: the First-principles Calculations

Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.

SYNTHESIS AND STRUCTURE OF COMPLEX(PPh3)_2Ni[S_2C=C(CN)_2]

(PPh_3)_2Ni(i-mnt),(i-mnt=S_2C=C(CN)_2),Mr=613.43,monoclinic,Pn,a=9.167(3),b=10.872(3), c=18.209(7) ,β=101.46(3)°,V=1779(1) ,Z=2,Dc=1.15 g/cm^3,λ(Moka)=0.71069 ,μ=7.67 cm^(-1), F(000)=648,T=296K,final R=0.060,Rw=0.073 for 1909 observed reflections with Ⅰ≥3σ(Ⅰ).The complex adopts a square planar geometry as its coordination unit,the mean Ni-S and Ni-P distances are 2.216 and 2.221 ,respectivety.

Effect of solid solution modification on structure and properties of dicalcium silicate

In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing of BaSO4in cement clinker improved crystal plane distance of C2S as well as the relations of coordination. The performance tests show that the strength of C2S modified by BaSO4 changes and the reactivity of C2S increases significantly.

CRYSTAL STRUCTURE OF SEVEN-COORDINATE ZIRCONOCENE COMPLEX (CH_3C_5H_4) Zr(S_2CNBz_2)_3 (Bz=CH_2C_6H_5)

(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm^(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm^(-1), R=0.069, Rw=0.078 for 6100 reflections. The title complex has pentagonal bipyramid configuration in which the zirconium atom is coordinated by one CH_3C_5H_4 group and three bidentate dibenzyldithiocarbamate ligands.

CRYSTAL STRUCTURE OF FIVE-COORDINATE ZIRCONOCENE COMPLEX CP_2ZrCl(S_2CNBz_2) (Bz=C_6H_5CH_2)

Cp;ZrCl（S;CNBz;） is a five-coordinate bent zirconocene in which the dibenzyldithiocarbamate is a bidentate ligand (Zr-Cl 2.549（1）A; Zr-C 2.489-2.533; Zr-S 2.667（1）, 2.734（1）; Zr-Cl-S1 137.6（1）;; Zr-Cl-S2 73.3（1）;).

Crystal Structure of Phenol,2-[4(S)-4-Dihydro-4-benzyl-2-ozazolinyl]

The compound phenol,2-[4（S）-4,5-dihydro-4-phenyl-2-ozazolinyl（1,C15H13NO2） was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786（5）,b = 10.730（5）,c = 19.722（5）,C15H13NO2,Mr = 239.26,V = 1224.4（12）3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ（Ⅰ） and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS.

RCEP成员国国际旅游经济网络结构演化及中国角色分析

融入国际旅游经济网络是中国旅游国际化发展的重要路径,也是推进中国双循环新发展格局构建的重要举措。以RCEP 15个成员国为研究对象,从国际旅游经济的规模、增长、结构与效率4个维度构建国际旅游经济发展水平评价体系,并借助修正的引力模型构建国际旅游经济网络,运用社会网络分析方法对2000—2018年RCEP成员国国际旅游经济网络结构演化及中国角色展开分析。结果表明:①2000—2018年RCEP成员国国际旅游经济整体网络结构变动剧烈,呈现紧密度增强、通达度提升、等级度下降趋势,网络结构趋于稳定;网络中单个节点发展差异明显,对中国、新加坡、泰国等少数核心节点依赖性强。②RCEP成员国国际旅游经济网络可划分为4个凝聚子群,节点间国际旅游经济联系主要在子群内建立,“小群体”现象显著;中国的网络角色演变经历了从一般的旅游贡献者逐步发展为网络“领头羊”和重要“中间人”,现已成为RCEP成员国国际旅游经济网络中最具影响力的国家。

Data-Driven Structural Design Optimization for Petal-Shaped Auxetics Using Isogeometric Analysis

Focusing on the structural optimization of auxetic materials using data-driven methods,a back-propagation neural network(BPNN)based design framework is developed for petal-shaped auxetics using isogeometric analysis.Adopting a NURBSbased parametric modelling scheme with a small number of design variables,the highly nonlinear relation between the input geometry variables and the effective material properties is obtained using BPNN-based fitting method,and demonstrated in this work to give high accuracy and efficiency.Such BPNN-based fitting functions also enable an easy analytical sensitivity analysis,in contrast to the generally complex procedures of typical shape and size sensitivity approaches.

基于C/S结构的学生心理健康信息采集管理系统

为解决采集学生心理健康信息时采集时间较长、处理效率较低、成本耗费较大等问题,以C/S结构为基本框架,设计出一种学生心理健康信息采集管理系统。硬件设计方面,通过网络实现客户机与服务器间通信,利用前端客户机与后台数据库服务器,组建系统总体框架;通过多个处理模块,整合、导出学生的心理健康信息,完成信息采集子系统架构。软件设计方面,基于数据存储的安全算法,实现信息的加解密操作。实验结果表明,所建系统功能较为全面,具有可靠性、有效性。

基于C/S结构的计算机辅助诊断系统设计

根据医学影像临床诊断实际需求,基于C/S结构设计了计算机辅助诊断系统的整体架构和系统工作流程。使用Python编程语言,并通过TCP/IP协议、Twisted异步框架、RabbitMQ消息中间件等技术实现了所设计的服务器端和客户端的主要模块与功能。所开发的计算机辅助诊断系统具有影像读取浏览、影像手动分割、影像自动分割、影像诊断、诊断报告生成等功能,能够辅助医生进行医学影像诊断,降低医生的工作负担,提高诊断准确率和速度。

基于模糊神经网络的SCR脱硝效率预测模型研究

针对火电厂选择性催化还原(SCR)系统存在变量多、耦合性强等特点,造成脱硝效率难以准确实时监测的问题,提出利用Takagi-Sugno(T-S)模糊神经网络算法,建立多输入单输出预测模型,以研究未来时间脱硝效率的变化。将模糊C均值(FCM)聚类算法用于结构辨识、模糊神经网络的混合学习算法用于参数辨识,构造T-S模糊预测模型。在分布式控制系统(DSC)上采集连续48 h实时数据,并利用MATLAB进行模型训练与检验。试验结果显示:训练集98%点的相对误差在±1.5%之间,最大误差小于2%,检测集99%点的相对误差在±0.5%之间,最大误差小于2.5%。该模型能够较好地反映SCR烟气脱硝效率,可以为脱硝效率的控制优化提供依据。

基于C++的ANSYS RST文件中节点力数据读取方法

通过C++程序以及ANSYS提供的应用编程接口,给出了一种提取ANSYSRST结果文件中节点力数据的方法。使用ANSYS对某地铁车辆焊接构架的有限元模型进行静力学求解,获得包含节点力数据的RST文件,并将该方法读取的节点力数据与疲劳寿命计算软件WeldFatigue的计算结果进行对比,验证了利用该方法提取数据的准确性与适用性。