Dynamics and control designs for internal thermally coupled distillation columns with different purities, Part 2: close loop analysis and control designs

Interaction between overhead and bottom composition loops of internal thermally coupled distillation columns (ITCDIC) with four purities are analyzed by means of relative gain array, condition number and singular value decomposition, which indicates that high- and very high-purity ITCDIC are well coupled and ill-conditioned systems with severe gain directionality problem. Based on the above dynamic behaviors, suitable control schemes of four different purity systems are studied. In low-purity system, internal model control (IMC) is better than decentralized proportion integral differential (D-PID) control in terms of response speed and remaining errors. In moderate-purity system, D-PID can effectively reject large load disturbances while IMC fails due to severe mismatch between model and plant. In high-purity system, neither IMC nor D-PID can provide satisfactory control so that modified IMC and multivariable PID with singular value decomposition scheme are presented respectively to improve control performances. Finally, in very high-purity systems, the combined feed-forward and feedback control scheme is proposed to deal with extremely sluggish responses to load disturbances.     

模具细节结构的设计与模具寿命

针对实际生产中模具寿命低的情况，我们通过对相关的因素进行分析，在材料、热处理等条件相同的情况下，经过完善模具细节结构的设计，降低了应力集中，模具的寿命大幅度提高。     

教育设施重大安全事故罪之解读--一个实证的分析

在教育设施重大安全事故罪的犯罪构成要件中,“不采取措施或者不及时报告”是相容的两个选项;“明知”包括“已经明知”和“应当明知”;正在进行具体教学活动和管理的教师也是本罪的主体。教育设施安全意识和制度的缺失是本罪发生的深层次原因。“灾缘政而生,灾变应人,要在责己”,“居安思危,思则有备,有备无患”是本罪发生的实效性预防措施。     

计算均质等截面柱体微幅摆动固有频率的一般方法

本文应用曲率圆弧近似一般曲线的方法，导出了具复杂截面曲线的等截面柱体在另一柱体上微幅摆动时固有频率的一般计算式。该式简单实用，既可用于判定平衡点是否稳定，也能方便地计算出微摆固频。     

一种快速模拟退火矢量量化图像编码算法

模拟退火是解决全局优化问题的随机搜索技术,它在工程领域有着广泛应用。将模拟退火技术与LBG算法有机结合,通过对LBG算法中的空胞腔码书进行适当处理,并设置适当参数使LBG与模拟退火交替进行,提出了一种快速模拟退火矢量量化图像编码算法,以降低计算量和进一步提高码书性能。实验结果表明,算法具有对初始码书选取依赖性小、不容易陷入局部极小、收敛速度快等优点。与随机竞争学习矢量量化及进化模拟退火矢量量化算法相比,峰值信噪比改善超过0.6dB。     

实施专利战略积极迎接挑战——关于尽快建立山西省专利申请资助资金的建议

面对中国加入WTO参与未来市场竞争的挑战，只有积极实施专利战略，切实强化专利管理和保护，迅速提高知识产权管理和保护的能力与水平，才能趋利避害，变压力为动力，为经济的发展提供更大的空间。     

Densification Mechanism of Si_3N_4 with AZ-Type Non-Toxic, Non-Oxide Additives

Si3N4 ceramics with AZ-type non-toxic, non-oxide additives canbe highly densified. In this work densification behavior and mechanism ofSi3N4 with AZ-type additives were investigated.     

高校职称评聘中必须引起重视的若干问题

目前高校所采用的职称评聘制度，对专业技术队伍的建设、成长发挥着相当重要的作用，但仍然存在一些问题，需要引起重视并着手解决。     

PERSPECTIVES ON URBAN WATER INFRASTRUCTURE IN CHINA FOR THE 21~(ST) CENTURY: SDMUWEIC MODEL

Based on system dynamics approach, SDMUWEIC model is developed in order to evaluate future dynamics of urban water infrastructure development in China. Firstly, this paper presents the basic structure and characteristics of the model, focusing on water infrastructure's dynamic relationships with population increase, economic development, water resources shortage and water conservation practices. Secondly, model veracity and robustness tests based on behavior reproduction and uncertainty analyses are illustrated. Thirdly, based on the model, future patterns of China's urban water infrastructure investment requirements are simulated, and effectiveness of two different policy scenarios are evaluated. Finally, conclusions and policy implications are drawn, allowing insights into China's sustainable water infrastructure policies and managements.