Auto-scanning and visualizing system for the acoustic field of transducer

This paper presents an automatic scanning and visualizing system for ultrasound field of a planar piston transducer. This system consists of a water tank with wedge absorber, stepper motors driver, system controller, a planar piston transducer, a needle-type hydrophone and data processing software. Our software realizes the processing and displaying of ultrasonic data, which are acquired by adjusting accurately positions of the hydrophone and transducer that are driven by stepper motors. And the ultrasonic field is represented by employing 1D, 2D or 3D graphs of data, respectively. Experimental results show that this auto-scanning and visualizing system provides a more spatial structure of ultrasonic field and reveals a more characteristic of ultrasonic beam radiated by the planar piston transducer.     

A parallel matrix factorization based recommender by alternating stochastic gradient decent

Collaborative Filtering (CF) can be achieved by Matrix Factorization (MF) with high prediction accuracy and scalability. Most of the current MF based recommenders, however, are serial, which prevent them sharing the efficiency brought by the rapid progress in parallel programming techniques. Aiming at parallelizing the CF recommender based on Regularized Matrix Factorization (RMF), we first carry out the theoretical analysis on the parameter updating process of RMF, whereby we can figure out that the main obstacle preventing the model from parallelism is the inter-dependence between item and user features. To remove the inter-dependence among parameters, we apply the Alternating Stochastic Gradient Solver (ASGD) solver to deal with the parameter training process. On this basis, we subsequently propose the parallel RMF (P-RMF) model, of which the training process can be parallelized through simultaneously training different user/item features. Experiments on two large, real datasets illustrate that our P-RMF model can provide a faster solution to CF problem when compared to the original RMF and another parallel MF based recommender.     

基于SVG流程图的设备管理系统的设计与实现

为解决现有企业设备管理系统图形交互能力差且图形格式不一的现状,在分析流程图技术的基础上,提出了一种基于SVG流程图进行设备管理的实现方法和途径,并给出了一种基于SVG(可扩展矢量图形)流程图的设备管理系统的实现.通过建立基于JS (JavaScript)与DOM(文本对象模型)的SVG图形编辑系统,构建了SVG设备图元库以及SVG流程图库.该系统采用三层B/S架构,基于流程图提供了可解析与交互的设备图形信息应用平台,具有较好的扩展性,为流程企业提供了更加直观、便捷、高效的设备管理功能.     

基于SSM框架的智能web系统研发设计

为了解决传统CMS系统不能对web布局进行修改的局限性,降低维护web系统成本及风险,提高管理效率,提出了集建站和维护系统于一体智能web系统设计。设计中使用了SSM框架,很大程度上提高了开发效率及系统的可靠性和易用性;Ajax、jQuery、jqGrid等技术的采用实现了拖动页面布局修改web布局的效果。此外还对传统的菜单管理和内容管理等功能进行了改进,从而提高了web系统维护效率,降低维护风险,更方便管理人员。     

任务管理系统模型类的抽象与设计

针对以往任务管理系统开发效率低、系统可维护性不强的情况,对任务管理系统模型类进行抽象与设计,分析了模型类的通用性和适用性,详细介绍了模型类抽象与设计的思路和方法。最后把抽象出的模型类应用到现有的任务管理系统中,验证设计思路,改进、优化了现有系统,降低了开发类似系统的成本,对任务管理系统的平台化研究和实现有一定的帮助。     

反应性化学品泄漏扩散的三维数值模拟

多晶硅副产物四氯化硅泄漏后形成重气云,易与水蒸气发生反应,生成四氯化硅、氯化氢和硅酸的混合有毒气云,威胁人类安全,导致严重的生态和环境危害。针对四氯化硅泄漏后形成的重气云的三维大气扩散与反应迁移过程建立了传递转化模型并采用计算流体力学(CFD)进行模拟研究,化学反应模型采用漩涡破碎模型(Eddy-Break-UpModel)。模拟研究了四氯化硅气体与水蒸气反应过程中四氯化硅、氯化氢、硅酸等有毒物质的空间分布与迁移转化情形。四氯化硅受重力作用下沉并向周围扩展,迎风面处的四氯化硅下沉触碰到地面后向上风侧移动,但主体向下风向迁移;生成的毒害性氯化氢覆盖范围较四氯化硅广泛;反应物和生成物在近地面的浓度较大,威胁环境安全;水解反应消耗水分导致脱水效应和反应放热升温,会对该区域生态造成严重危害。研究结果为反应性化学品事故处理提供了依据。     

用临界功率表征多相搅拌槽中搅拌效果

多相搅拌过程中常常根据临界搅拌转速表征搅拌效果。由于各种搅拌桨的功率准数不同,低临界转速的搅拌桨对应的搅拌功耗可能大于高临界转速的搅拌桨,因此,本文提出用临界功率作为表征手段。选取表面曝气和固体悬浮2个典型的多相搅拌过程进行了验证,结果表明:(1)在表面曝气过程中,达到临界曝气时六斜叶下推圆盘涡轮(PBRTD)桨的搅拌功耗比标准Rushton(RT)桨低,相同功耗下PBRTD桨的kLa也更高,与临界曝气转速的判定结果不同,临界功率法认为PBRTD桨更适合作表面曝气桨,这与表面曝气机理的认识相符;(2)下推折叶透平(PBTD)桨和三叶后掠(TBHA)桨的固体颗粒悬浮实验结果也表明TBHA桨的临界离底悬浮转速高但功耗更低,TBHA桨的整体循环能力更强,有利于固体悬浮。     

一种有效的多关键词词频统计方法

针对词频统计的特点，设计了一种多关键词词频统计方法。该方法以一种树形的数据结构来存储待处理关键词集合的信息。实现了多关键词的高效匹配，扫描一次文档就可统计出全部关健词词频信息。通过理论分析与实验表明，其性能比传统的关键词词频统计方法有较大的提高。     

基于VBA的可扩展专家控制系统的研究

针对传统专家控制系统存在的灵活性不够，不能允许用户自定义过程操作的不足，提出了一种新型的可扩展专家控制系统。该系统是在传统的专家控制系统的基础上，引入VBA技术，通过将过程对象定义为VBA对象模型，由用户对其进行触发操作的自定义，并可在操作中引入数值计算，以增强系统的数值计算能力，然后由主应用程序中的消息来触发执行这些方法。仿真实验表明，该专家控制系统的应用使得操作人员对过程的控制更加地灵活多变。     

Porous hollow silica nanoparticles as controlled delivery system for water-soluble pesticide

Porous hollow silica nanoparticles (PHSNs) were prepared and applied as controlled delivery system of water-soluble pesticide validamycin. PHSNs were loaded with validamycin through a specially designed supercritical fluid loading method. It was demonstrated that a high loading capacity (36 wt.%) of validamycin could be achieved, which was found to be more effective than that of the simple immersing method in this study. The loaded PHSNs were characterized by TG, IR and XPS analysis. The validamycin release profile from PHSNs was investigated and showed a multi-staged release pattern probably due to the different adsorption locations of validamycin on PHSNs. This release behavior makes PHSNs a promising carrier in agriculture, especially for pesticide controlled delivery whose immediate as well as prolonged release is needed. In addition, factors influencing the validamycin release rate, including pH and temperature, were investigated.