摘要：The extended state observer (ESO) is a novel observer for a class of uncertain systems. Since ESO adopts the continuous non-smooth structure, the classical observer design theory is hard to use for ESO analysis. In this note, the self-stable region (SSR) approach, which is a nonlinear synthesis method for nonlinear uncertain systems, will be used for ESO design and its stability analysis. The advantages of the non-smooth structure in ESO for improving the convergence properties and the estimation precision will be shown.

摘要：A reverse-conducting lateral insulated-gate bipolar transistor （NI.2-LltJlS｜） with a trench oxide layer （IUL）, teaturlng a vertical N-buffer and P-collector is proposed. Firstly, the TOL enhances both of the surface and bulk electric fields of the N-drift region, thus the breakdown voltage （BV） is improved. Secondly, the vertical N-buffer layer increases the voltage drop VpN of the P-collector/N-buffer junction, thus the snapback is suppressed. Thirdly, the P-body and the vertical N-buffer act as the anode and the cathode, respectively, to conduct the reverse current, thus the inner diode is integrated. As shown by the simulation results, the proposed RC-LIGBT exhibits trapezoidal electric field distribution with BV of 342.4 V, which is increased by nearly 340% compared to the conventional RC-LIGBT with triangular electric fields of 100.2 V. Moreover, the snapback is eliminated by the vertical N-buffer layer design, thus the reliability of the device is improved.

摘要：7075 aluminum alloy is often used as an important load-bearing structure in aircraft industry due to its superior mechanical *** the process of deep hole boring,the boring bar is prone to vibrate because of its limited machining space,bad environment and large elongation induced low *** reduce vibration and improve machined surface quality,a particle damping boring bar,filled with particles in its inside damping block,is designed based on the theory of vibration *** theoretical damping coefficient is determined,then the boring bar structure is designed and *** studies through impact testing show that cemented carbide particles with a diameter of 5 mm and a filling rate of 70% achieve a damping ratio of 19.386%,providing excellent vibration reduction capabilities,which may reduce the possibility of boring ***,experiments are setup to investigate its vibration reduction performance during deep hole boring of 7075 aluminum *** observe more obviously,severe working conditions are adopted and carried out to acquire the time domain vibration signal of the head of the boring bar and the surface morphologies and roughness values of the *** comparing different experimental results,it is found that the designed boring bar could reduce the maximum vibration amplitude by up to 81.01% and the surface roughness value by up to 47.09% compared with the ordinary boring bar in two sets of experiments,proving that the designed boring bar can effectively reduce *** study can offer certain valuable insights for the machining of this material.

摘要：It is commonly known that riblets with sharper tip generally have better turbulent drag reduction capacity,which,however,poses great challenges for manufacturing and makes the riblets vulnerable to tip *** this study,we show that a scalloped riblet which is not as sharp in the tip as corresponding triangular riblet with same height-width ratio,nevertheless has a larger protrusion height,a quantity solely depending on the riblet shape and calculated through a boundary element algorithm in this study,and thus a higher projected drag reduction *** addition,it is found that,when subjected to tip rounding,this scalloped riblet performs better in terms of protrusion height than corresponding parabolic riblet,which indicates stronger resilience to riblet tip *** the class of scalloped riblets,designed by smoothly connecting two third-order polynomials and thus the tip sharpness and valley curvature can be well defined,it is revealed that two mechanisms,one for the valley curvature at the viscous limit and one for the tip sharpness at infinite deep limit,determine the protrusion height,and thus the projected drag reduction *** numerical simulations are then carried out to investigate controlled boundary layer transition with the scalloped riblet of width s+=20 and 5+=60.A 7.8%drag reduction in the turbulent region is found for the smaller riblet with a preferable transition delay,while for the larger riblet transition is promoted and drag is increased in the turbulent *** is also found that the area fraction of high drag region around the riblet tips is basically the same for the two ***,even higher drag is found around the tip region for the smaller drag-reducing *** the other hand,a much smaller drag coefficient is found in the valley of the smaller riblet,which results in the reduction of turbulent *** is thus inferred that the issue of sharp riblet tip,that hard to manufacture and deteriorate substantially

摘要：A room-temperature electrochemical strategy for hydrogenation(deuteration)and reverse dehydrogenation of N-heterocycles over a bifunctional MoNi_(4)electrode is developed,which includes the hydrogenation of quinoxaline using H2O as the hydrogen source with 80%Faradaic efficiency and the reverse dehydrogenation of hydrogen-rich 1,2,3,4-tetrahydroquinoxaline with up to 99%yield and *** in situ generated active hydrogen atom(H^(*))is plausibly involved in the hydrogenation of quinoxaline,where a consecutive hydrogen radical coupled electron transfer pathway is ***,the MoNi_(4)alloy exhibits efficient quinoxaline hydrogenation at an overpotential of only 50 mV,owing to its superior water dissociation ability to provide H^(*)in alkaline *** situ Raman tests indicate that the Ni^(Ⅱ)/Ni^(Ⅲ)redox couple can promote the dehydrogenation process,representing a promising anodic alternative to low-value oxygen ***,electrocatalytic deuteration is easily achieved with up to 99%deuteration ratios using *** method is capable of producing a series of functionalized hydrogenated and deuterated quinoxalines.

摘要：产业创新空间是我国创新战略的重要空间载体,也是实现地区产业升级和创新竞争的重要途径。文章基于创新的产业属性、创新属性与空间属性之间的关联,以创新型企业为表征载体,并结合大数据空间分析手段,对杭州城西科创大走廊地区进行空间测度,研究其时空演化特征及形成机制。结果表明:(1)静态特征上,大走廊地区空间格局呈现“东密西疏,集群连片,多中心发展”的格局;创新活动主体以中小微企业为主,以互联网和数字经济为主导,行业集聚性显著;创新产业空间集聚于政府主导的邻近高校院所的园区中,创新成果以软件著作权、专利为主,复合化趋势明显。(2)动态特征上,大走廊地区经历了“零星—缓慢—快速”3个发展阶段,呈现“零散—集中—扩散”的演化态势,反映出创业领先于创新、产业培育领先于政策落地的演化规律。(3)形成机制上,“市场+创新主体+政府”是地区产业创新空间时空演化形成的主要动因,包括需求溢出机制、内在生成机制和社会支持机制。

摘要：多组分组装包含多个可以形成自组装的组分,这在自然过程中是很常见的现象。可以通过分析嵌入天然超分子结构中的结构特点,并根据预测的分子相互作用设计创新材料,但因为对于分子本身性质的理解有限,设计可控层级结构的小分子水凝胶目前仍然面临一定困难,距离自然形成的多层级复杂可控组装体系也比较远。在多组分的超分子化学领域,我们有必要利用系统论的方法研究多组分自组装网络的结构与功能,除了理解组分分子单体的性质,还需要对组分分子形成的化学网络进行研究,才能更好地理解自然。当在多组分系统中触发自组装时,通常产生三种组装方式,即共组装(Co⁃assembly)、自分类(Self⁃sorting)和异质多维组装(Multidimensional hierarchical combination of assemblies or heterojunction)。这三种组装体系相互竞争但也可能并存,导致多组分组装体系的复杂性与多元响应性,因此对多组分组装构建块或组装体系的设计与组装结构预测也就具有很大挑战性。多层次的多组分组装过程允许多个自组装体协同和正交运行,并具有精确的空间和时间控制。而自分类现象是多种相关(生物)化学过程(如相分离、动力学解析或自我复制等)的基础,自分类现象可以是自恋的,也可以是社会的,对多组分组装体系中自分类组装进行研究,对于加深理解组分分子相互关系实现对网络的控制,从而实现多层级复杂组装体系的可控构建具有重大意义。本文将就多组分组装体系的特点、研究方法展开综述,并展示多组分组装体系的自分类组装的特点、控制等领域研究成果,讨论小分子凝胶剂在多组分自分类组装水凝胶组装体系的研究进展,以期促进对该领域的理解和深入研究。

摘要：窄间隙激光焊作为核电领域大型厚壁构件的先进连接工艺,具有热输入小、焊接效率高、接头质量高等优点。然而,受现场复杂施焊环境影响,焊缝内部易因污染物清理不尽而产生气孔缺陷。传统的焊后无损检测费时耗力,且检测结果受零部件尺寸结构制约及检测人员主观判断影响,因此亟待发展气孔缺陷在线检测技术。本文设计研制了基于发射光谱的窄间隙激光焊质量检测系统,探究工艺参数及水、油等污染物对气孔缺陷的影响规律,分析水对激光致等离子体电子温度、光谱强度的作用机制,开发因污染物导致的气孔缺陷在线预警软件系统。结果表明,窄间隙激光焊时由于受工件侧壁拘束使得等离子体密度高,对激光反射、散射作用强,测得光谱强度值较弱。窄间隙填丝焊时由于激光能量存在损耗、不能完全被母材和丝材吸收,其测得的光谱强度小于窄间隙自熔焊。采用Boltzmann作图法求得窄间隙激光填丝焊光致等离子体电子温度为7201.1 K,电子密度为5.2797×10^(15)cm^(-3),均小于窄间隙激光自熔焊时的热力学状态参数。在本文的6组自熔焊工艺参数范围内,X射线探伤未检测到密集气孔缺陷。当母材表面有水时,焊缝表面有气孔产生,通过X射线探伤观察到焊缝中有大量密集气孔存在。与正常工艺下获得的光谱数据相比,光谱仪全波段上的相对光强均降低,电子温度也下降至6900~7200 K范围内动态波动,但电子密度会增大。采用神经网络模型对主成分分析降维后的光谱数据进行训练,可对窄间隙激光填丝焊时因水、油等污染物导致的气孔缺陷进行高准确率的预测。开发的气孔检测系统可对因污染物导致的气孔缺陷进行有效识别,准确率达90%,响应时间在0.1 s内。

摘要：计算机交互式评价以计算机模拟的形式呈现学科知识及其系统结构,并支持新颖的交互形式。评价学生的科学探究能力不仅需要创设丰富的任务情境,同时也要收集和分析学生的行为和作答数据。鉴于交互式评价与科学探究评价的契合性,文章基于以证据为中心(Evidence-Centered Design,ECD)的评价设计理念,解析了交互式科学探究评价的设计流程。首先,介绍了评价设计的理论基础--ECD框架。其次,结合科学探究评价的典型研究项目,以评价设计流程的任务分析、任务创设和数据分析为主线,总结了任务分析的领域信息来源、任务情境标准、任务创设的界面形式、学生作品和系统响应,以及数据分析中使用的多种数学模型。最后,讨论了交互式评价在评价的标准、实用性、非认知因素以及协同开发等方面应关注的问题和未来的发展方向,旨在丰富我国有关交互式评价开发的理论和实践研究。

摘要：The innovative Next Generation Subsea Production System(NextGen SPS)concept is a newly proposed petroleum development solution in ultra-deep water *** definition of NextGen SPS involves several disciplines,which makes the design process *** this paper,the definition of NextGen SPS is modeled as an uncertain multidisciplinary design optimization(MDO)*** deterministic optimization model is formulated,and three concerning disciplines—cost calculation,hydrodynamic analysis and global performance analysis are *** model technique is applied in the latter two *** optimization(CO)architecture is utilized to organize the concerning disciplines.A deterministic CO framework with two disciplinelevel optimizations is proposed *** the uncertainties of design parameters and surrogate models are incorporated by using interval method,and uncertain CO frameworks with triple loop and double loop optimization structure are established *** optimization results illustrate that,although the deterministic MDO result achieves higher reduction in objective function than the uncertain MDO result,the latter is more reliable than the former.