科创中国

在综合比较知识管理成熟度模型的基础上,充分借鉴诸多知识管理成熟度模型的特性,结合我国企业知识管理实践,提出企业知识管理成熟度整合模型,并深入剖析其逻辑结构、成熟等级、关键过程领域以及实施程序,为现代企业有效实施知识管理项目,提升知识管理能力和绩效提供借鉴和帮助.

基于PKI的WTLS协议涉及复杂的证书操作,需耗费较大的通信和计算开销,且缺乏对服务器证书的有效性检查.引入可信证书验证代理(TCVP)和证书有效性凭据(CVT)等概念,由TCVP为无线通信节点(WN)生成短时有效的CVT,WN通过交换CVT来完成证书的有效性检查和公钥交换.基于此,提出了一种通用无线认证协议(GWAP).在GWAP框架下,采用ECC算法设计了一种具体的无线安全认证协议,并进行了效率分析.结果表明,该协议在确保安全的前提下降低了通信开销.

探究了Vectran长丝纱在剑杆小样机上试织平纹织物的主要工艺设计和上机织造情况.研究Vectran长丝纱的可织性,探索利用Vectran长丝纱开发新型产业用纺织品的途径.结果表明其可织性与芳纶类似,主要问题是其织造张力难以均匀控制,且易钩丝,应对长丝纱作前处理并合理控制织造工艺.

Several typical flexible pneumatic actuators(FPA) and different mechanical models describing their behaviors have been proposed, however, it is difficult to balance compliance and load capacity in conventional designs, and these models still have limitations in predicting behavior of FPAs. A new flexible pneumatic bending joint(FPBJ) with special anisotropic rigidity structure is proposed. The FPBJ is developed as an improvement with regard to existing types of FPA, and its principal characteristic is derived from the special anisotropic rigidity structure. With this structure, the load capacity in the direction perpendicular to bending plane is strengthened. The structure of the new FPBJ is explained and a mathematical model is derived based on Euler-Bernoulli beam model and Hook's law. To obtain optimum design and usage, some key structure parameters and input-output characteristics are simulated. The simulation results reveal that the relationship between the structure parameters and FPBJ's bending angle is nonlinear. At last, according to the simulation results, the FPBJ is manufactured with optional parameters and tested. The experimental results show that the joint's statics characteristics are reflected by the mathematical model accurately when the FPBJ is deflated. The maximum relative error between simulation and experimental results is less than 6%. However, the model still has limitations. When the joint is inflated, the maximum relative error reaches 20%. This paper proposes a new flexible pneumatic bending joint which has sufficient load capacity and compliance, and the mathematical model provides theoretical guidance for the FPBJ's structure design.

地下水数值模拟是目前定量研究地下水的重要手段.分析了数值法求解地下水流数学模型的基本步骤,对于采用试估一校正法进行模型识别率定和验证过程中,在遵循模型的识别率定和验证的基本要求和四个基本原则基础上,对于如何评价模型率定和验证的效果、定量分析模型精度、以及达到模型可实际应用的要求,总结众多地下水数值模型调试的经验,提出了地下水数值模型识别率定和验证的定量评价标准.

Most researches on transient fuel control of port fuel injection S.I. engine are carried out from the perspective of advanced mathematical theories. When it comes to practical control, there exist many limitations although they are more intelligent. In order to overcome the fuel wetting effect of PFI engine, the application-oriented transient fuel control is studied by analyzing the key parameters which are closely related with the engine transient characteristics. Both validity and simplicity are taken into consideration. Based on the fuel wall-wetting theory and popular fuel compensation strategy, short-term transient fuel(STF) and long-term transient fuel(LTF), as well as their individual decay approaches, are introduced. STF is to compensate the drastic fuel film loss caused by sudden throttle change, while the function of LTF is to compensate the fuel film loss by manifold air pressure(p) fluctuation. Each of them has their respective pros and cons. The engine fuel mass and air mass are also calculated for air-fuel ratio(AFR) according to ideal gas state equation and empirical equations. The vehicle acceleration test is designed for model validation. The engine experiences several mild and heavy accelerations corresponding to the gear change during vehicle acceleration. STF and LTF control are triggered reliably. The engine transient fuel control simulation adopts the same inputs as the test to ensure consistency. The logged test data are used to check the model output. The results show that the maximum fuel pulse width(FPW) error reaches 2 ms, and it only occurs under engine heavy acceleration condition. The average FPW error is 0.57 ms. The results of simulation and test are close overall, which indicates the accuracy of steady and transient fuel. The proposed research provides an efficient approach not only suitable for practical engineering application, but also for AFR prediction, fuel consumption calculation, and further studies on emission control.

Parallel kinematic machines have drawn considerable attention and have been widely used in some special fields.However,high precision is still one of the challenges when they are used for advanced machine tools.One of the main reasons is that the kinematic chains of parallel kinematic machines are composed of elongated links that can easily suffer deformations,especially at high speeds and under heavy loads.A 3-RRR parallel kinematic machine is taken as a study object for investigating its accuracy with the consideration of the deformations of its links during the motion process.Based on the dynamic model constructed by the Newton-Euler method,all the inertia loads and constraint forces of the links are computed and their deformations are derived.Then the kinematic errors of the machine are derived with the consideration of the deformations of the links.Through further derivation,the accuracy of the machine is given in a simple explicit expression,which will be helpful to increase the calculating speed.The accuracy of this machine when following a selected circle path is simulated.The influences of magnitude of the maximum acceleration and external loads on the running accuracy of the machine are investigated.The results show that the external loads will deteriorate the accuracy of the machine tremendously when their direction coincides with the direction of the worst stiffness of the machine.The proposed method provides a solution for predicting the running accuracy of the parallel kinematic machines and can also be used in their design optimization as well as selection of suitable running parameters.

结合南水北调天津干线工程建设管理具体工作实践,对南水北调中线天津干线施工控制体系构建、主要做法和成功经验进行了分析梳理总结,结果表明南水北调天津干线工程施工中的土方工程、混凝土工程,施工受季节影响以及施工工期受资源配置、施工方案的选择影响较大,在建设实施过程中通过合理安排施工,配置资源合理,优化施工方案,充分发挥整体钢模台车的整体优势,对加强工程实体质量控制等方面的实践是成功的,对进一步提高南水北调天津干线工程以及其它大型水利工程建设水平具有一定的借鉴意义.

The existing research of process capability indices of multiple quality characteristics mainly focuses on nonconforming of process output, the concept development of univariate process capability indices, quality loss function and various comprehensive evaluation methods. The multivariate complexity increases the computation difficulty of multivariate process capability indices(MPCI), which makes them hard to be used in practice. In this paper, a new PCA-based MPCI approach is proposed to assess the production capability of the processes that involve multiple product quality characteristics. This approach first transforms the original quality variables into standardized normal variables. MPCI measures are then provided based on the Taam index. Moreover, the statistical properties of these MPCIs, such as confidence intervals and lower confidence bound, are given to let the practitioners understand the capability indices as random variables instead of deterministic variables. A real manufacturing data set and a synthetic data set are used to demonstrate the effectiveness of the proposed method. An implementation procedure is also provided for quality engineers to apply our MPCI approach in their manufacturing processes. The case studies demonstrate the effectiveness and feasibility of this new kind of MPCI, which is easier to be used in production practice. The proposed research provides a novel approach of MPCI calculation.

本文认为,基层税收征管体系改革,必须以明确征纳双方法律权责、切实提高纳税遵从度和科学可控为目标.在改革原则上,要后移控制措施,前置应需服务;注重分析预警,加强税源管控;强化激励监督,健全内部管理.在整体架构设计上,应划分为宣导办税、税务管理和检查内控3个环节,其工作重点分别为满足需求、预警控制和监督考核.