Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

Carbon-and silica-based nanomaterials possess a set of merits including large surface area,good structural stability,diversified morphology,adjustable structure,and biocompatibility.These outstanding features make them widely applied in different fields.However,limited by the surface free energy effect,the current studies mainly focus on the symmetric structures,such as nanospheres,nanoflowers,nanowires,nanosheets,and core-shell structured composites.By comparison,the asymmetric structure with ingenious adjustability not only exhibits a larger effective surface area accompanied with more active sites,but also enables each component to work independently or corporately to harness their own merits,thus showing the unusual performances in some specific applications.The current review mainly focuses on the recent progress of design principles and synthesis methods of asymmetric carbon-and silica-based nanomaterials,and their applications in energy storage,catalysis,and biomedicine.Particularly,we provide some deep insights into their unique advantages in related fields from the perspective of materials’structure-performance relationship.Furthermore,the challenges and development prospects on the synthesis and applications of asymmetric carbon-and silica-based nanomaterials are also presented and highlighted.

Research on Robust Cooperative Dual Equilibrium with Ellipsoidal Asymmetric Strategy Uncertainty

In this paper,we investigate robust cooperative dual equilibria with two players in which each player minimizes the opponent’s cost and can not evaluate his own strategy while may estimate an asymmetric bounded set of the mixed strategy.Using dual theory and robust optimization technique,we obtain a result that the counterpart of the primitive uncertainty with ellipsoidal norm for each player can be formulated as a second-order cone programming(SOCP)and solving the corresponding equilibrium can be converted to solving a second-order cone complementarity problem(SOCCP).Then we present a numerical experiment to illustrate the behavior of robust cooperative dual equilibrium.

Research of matrix converter based on asymmetric regular sampling method SPWM control strategy

Based on the topological analysis of three-phase matrix AC to AC conversion circuit, an AC to AC nine-switch matrix isequivalent to rectification part and conversion part. The Matrix converter can be viewed as AC-DC-AC converter, the asymmetricregular sampling method SPWM(Sine Pulse Width Modulation) is studied and applied in the three-phase matrix AC to AC converter,Based on Matlab/simulink the simulation of the matrix converter with such strategy is carried out. Inductive load simulation is carriedout on the matrix converter prototype. The simulation results verify the workability of the asymmetric regular sampling method SPWMstrategy for matrix converter.

Equalizer Zero-Determinant Strategy in Discounted Repeated Stackelberg Asymmetric Game

This paper focuses on the performance of equalizer zero-determinant(ZD)strategies in discounted repeated Stackelberg asymmetric games.In the leader-follower adversarial scenario,the strong Stackelberg equilibrium(SSE)deriving from the opponents’best response(BR),is technically the optimal strategy for the leader.However,computing an SSE strategy may be difficult since it needs to solve a mixed-integer program and has exponential complexity in the number of states.To this end,the authors propose an equalizer ZD strategy,which can unilaterally restrict the opponent’s expected utility.The authors first study the existence of an equalizer ZD strategy with one-to-one situations,and analyze an upper bound of its performance with the baseline SSE strategy.Then the authors turn to multi-player models,where there exists one player adopting an equalizer ZD strategy.The authors give bounds of the weighted sum of opponents’s utilities,and compare it with the SSE strategy.Finally,the authors give simulations on unmanned aerial vehicles(UAVs)and the moving target defense(MTD)to verify the effectiveness of the proposed approach.

New strategies for asymmetric photocatalysis: asymmetric organocatalytic/photoredox relay catalysis for efficient synthesis of polycyclic compounds containing vicinal amino alcohols

An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.

New Asymmetric Fuzzy PID Control for Pneumatic Position Control System

A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused by asymmetric structures and different friction characteristics in two directions. On the basis of this algorithm, a traditional PID control is used to improve dynamic performance. Furthermore, a new asymmetric fuzzy PID control with α factor is advanced to improve the self-adaptability and robustness of the system. Both the theoretical analyses and experimental results prove that, with this control strategy, the dynamic performance of the system can be greatly improved. The system using this control algorithm has strong robustness and it obtains desired overshoot and repeatability in both transient and steady-state responses.

An Evolutionary Catch-up Strategy of Innovation： Knowledge Transfer of Chinese Hi-t：ech Multinationals Through Firm-University Cooperation

Chinese hi-tech multinationals strengthen their technological competitiveness in their internationalization process. Their strategic emphasis on cooperation with academic institutes to develop professional knowledge is an important yet underexplored issue in the extant literature. Based on the comparison between a pair of hi-tech companies--HUAWEI from China and CISCO from the US, this study analyzes the process of technological evolution of the former during 1998-2014, which ihas already become one of strategic solutions for Chinese multinationals （CMNE） to catch up with traditional counterparts in technological field. This study contributes to the present theory of CMNE by disclosing the Firm-University Cooperation （FUC） strategy, as well as its significance and implications for later-corner＇s catch-up trajectory in international business.

一种低输入电流总谐波畸变率的三相Buck整流器不对称调制策略

传统空间矢量脉宽调制(SVPWM)三相Buck整流器没有考虑直流链电流纹波对输入电流的影响,且在扇区切换点处输入电流存在严重畸变,导致输入电流总谐波畸变率(THD)升高。该文分析直流链电流纹波对三相Buck整流器输入电流的影响,分析输入电流扇区切换点畸变产生的原因,提出一种新型不对称SVPWM策略,显著降低了三相Buck整流器的输入电流THD。最后,通过仿真和1 kW的实验样机验证了理论分析的正确性以及所提调制策略的有效性。

线上竞合供应链制造商合作策略选择研究

在由制造商、零售商和平台商组成的线上零售供应链中,考虑下游零售商和平台商之间既竞争又合作的竞合关系,研究了渠道初始市场需求不对称对制造商合作策略选择的影响。运用博弈方法从制造商的视角分别构建了不合作、与零售商合作、与平台商合作三种策略模型。在此基础上,首先,以不合作模型为基准,分析了制造商是否有动机与下游成员合作;然后,比较了不同策略下的合作动机大小问题。研究结果表明:制造商与零售商、平台商均有合作的动机。然而,其合作动机大小与佣金费率以及渠道初始市场需求比率有关。当佣金费率较低且初始市场需求比率较大时,制造商更倾向与零售商合作;否则,其与平台商合作动机更大。有趣的是,制造商与零售商(平台商)合作并非总是损害平台商(零售商)的利润。当佣金费率满足一定条件时,若初始市场需求比率较大,则平台商(零售商)可以从制造商与零售商(平台商)的合作中获益。最后,讨论了数量竞争和平台商为领导者两种情形下制造商的合作策略选择。

永磁直驱型风机海上风电送出系统不对称接地及甩负荷电磁暂态研究

为明确海上风电交流送出系统过电压的特征与水平,需考虑风电机组的故障穿越特性。该文结合永磁直驱风机变流器的控制原理,提出海上风电送出系统不对称接地过电压的解析计算方法。基于PSCAD对风电机组进行精确电磁暂态建模与故障电压穿越测试,以国内某500 kV大规模海上风电工程为背景,仿真计算送出系统不对称接地及甩负荷过电压。结果表明:系统不对称接地过电压大小与风机正负序控制策略有关;海缆电网侧甩负荷将产生持续百ms的1.3 pu以上的暂态过电压,风机过电压保护动作延时越长,暂态过电压越严重。实际海上风电工程计算需紧密联系风机控制保护策略及其参数,并综合关键设备耐压水平进行评估,通过风机控制策略优化可以降低系统过电压水平。

一种双有源桥变换器单侧非对称占空比调制策略

针对双有源桥变换器在单移相调制策略中宽电压范围情况下的低效率问题,文中提出了一种单侧非对称占空比调制策略,显著的提升了双有源桥变换器的效率,尤其是在轻载情况下。首先描述了单侧非对称占空比调制方式的原理,并根据控制自由度的关系得到了两种工作模式。第二,基于时域分析,推导了两种工作模式的稳态特性,包括电感电流以及传输功率。第三,为了寻求控制自由度的最优组合,选择电感电流峰峰值作为优化目标,应用KKT条件得到了最优的单侧非对称占空比调制策略。最后,搭建了一台基于碳化硅器件的双有源桥变换器实验平台,实验验证了单侧非对称占空比调制策略的有效性。

三单元不对称级联H桥调制策略及推广

3:1:1型不对称级联H桥多电平逆变器输出电压谐波性能优异,但是在传统的调制策略下,存在高低压单元间电流倒灌问题,且传统调制策略仅仅适用于3:1:1型不对称级联H桥,不能推广应用。该文基于部分区间上高低压单元控制信号互补和移相载波调制策略提出了一种改进型混合频率载波调制策略。该文提出的调制策略不仅解决了传统调制策略下存在的高低压单元间的电流倒灌问题,而且可推广至n:1:1…型多电平逆变器的调制策略,同时给出各级联单元开关管控制信号的通用表达式,且可以实现所有低压单元间的功率均衡。仿真与实验结果证明了该调制策略的可行性,正确性与易推广性。

考虑智能制造技术补贴的新能源汽车制造商定价策略

“双碳”目标的提出进一步明确了将新能源汽车作为汽车行业的发展方向,要求新能源汽车在智能制造技术下实现创新与突破。从新能源汽车的智能制造技术补贴政策入手,将消费者对新能源汽车的购买偏好纳入考虑范围,构建了传统型汽车生产商和新能源汽车生产商的竞争性定价决策模型,求解在不同补贴程度下汽车企业的最优定价及生产策略,并分析了社会福利情况,最后对模型进行了数值仿真与分析。研究结果表明:新能源汽车智能制造技术补贴政策加剧了传统型汽车生产商和新能源汽车生产商的市场竞争,从而拉低了两种类型汽车价格。在补贴政策下的新能源汽车竞争环境中,虽然传统型汽车价格不断降低,但消费者对其需求却持续下降。政府在侧重考虑环境污染影响时,应当提高新能源汽车的补贴水平,且当消费者出现对新能源汽车和传统型汽车的不对称偏好时,政府应当降低技术补贴水平以获取社会福利最大化。

Technology Progress Path and Catchup Strategy for Late-Moving Large Countries

Based on the endogenous technology progress framework for late-moving large countries,this paper simulates the effects of market size on technology progress path and technology catch-up,and finds that under the strategy of combining innovation with imitation,the increase of market size will restrain the convergence of economies towards technology frontier and deepen their reliance on imitation.Under the strategy of replacing imitation with innovation,there is a non-uniform U-shaped threshold effect for market size to influence technology progress path and catch-up,and the threshold for the shift of technology progress path lags behind that for technology catch-up.Hence,we should follow technology catch-up as the benchmark and timely adjust our innovation strategy to unleash the advantages of economies of scale for innovation.The innovation-driven development strategy is a choice compatible with China’s changing market size.However,since China remains in a transition from a super-large economy to a super-strong one,the contribution of innovation will decrease at first before increasing afterwards.

非对称Colonel Blotto博弈模型下的多信道功率分配抗干扰

针对智能干扰条件下传输速率固定的通信系统多信道功率分配问题,建立了非对称Colonel Blotto博弈模型。在完全信息条件下,推导出了各种功率预算约束下通信方和干扰方的等效单信道最优功率分配策略,进而证明了通信方和干扰方存在唯一混合纳什均衡策略,并求得了纳什均衡收益。基于等效单信道最优功率分布,提出了一种多重扫描直接列元素交换算法,可以快速构建多信道混合功率分配矩阵,且相比于线性规划方法,可适应更多的信道数和更广的功率分布范围。通过数值仿真,验证了所提多信道混合功率分配矩阵构造算法的有效性及多信道功率分配策略的最优性。

Asymmetric molecular engineering in recent nonfullerene acceptors for efficient organic solar cells

Nonfullerene acceptors(NFAs),which usually possess symmetric skeletons,have drawn great attention in recent years due to their pronounced advantages over the fullerene counterparts.Moreover,breaking the symmetry of NFAs could fine tune the molecular dipole,solubility,energy level,intermolecular interaction,molecular packing,crystallinity,etc.,and give rise to improved photovoltaic performance.Currently,there are three main strategies for the design of asymmetric NFAs.This review highlights the recent advances of high-performance asymmetric NFAs and briefly outlooks the materials exploration for the future.

基于递推最小二乘法的阀控缸液压系统控制策略

阀控缸液压系统存在建模不准确、动态控制精度较低和控制算法调试困难的问题,为此,提出了一种基于递推最小二乘法(RLS)的反步法动态面控制策略,并采用半实物仿真平台对其控制算法进行了调试验证。首先,建立了阀控缸液压系统非线性状态空间模型,推导了该系统的最小二乘矩阵形式和递推算法公式;然后,基于李雅普诺夫稳定性理论和动态面控制技术,建立了阀控非对称缸系统的控制模型,设计了一种基于RLS的反步法动态面控制器;最后,基于半实物仿真平台,对改造后的Linux操作系统进行了实时性验证,完成了阀控非对称缸系统参数辨识和基于RLS的反步法动态面控制试验任务。试验结果表明:RLS算法不仅能用于准确地估计系统模型参数,更能有效地适应系统模型参数的变化;相比于常规PID控制方法,基于RLS反步法动态面控制策略在阀控非对称缸系统稳定状态和换向的过程中,其动态控制精度分别提高了72.9%和20.3%,可为今后阀控缸液压系统建模及非线性控制策略研究提供较高的理论参考。

Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill

It is a complicated problem for cold-rolled strip to improve asymmetric strip shape in strip production. A roll system and strip coupled model of six-high cold rolling mill was established with finite element method to estimate the effect of intermediate roll shifting, tilting, symmetric and asymmetric bending technologies on strip profile. To reduce asymmetric defects of strip shape as much as possible, some control strategies were proposed, including tilting and asymmetric bending of intermediate roll and work roll. The combinations of these three control strategies can effectively eliminate asymmetric strip shape defects. Finally, the closed-loop control model of asymmetric flat- ness at the last stand was given, and the flatness control system with the function of asymmetric strip shape control was also designed for cold tandem mill.

Technological Breakthrough and Domestic Substitution of Key Products Based on Asymmetric Competition:Taking the Integrated Circuit Industry as an Example

Integrated circuit is a typical key product in the digital economy era.Given external containment,breakthroughs in core technologies of integrated circuit are confronted with barriers of first movers in underlying technological ecology and with their threats of decoupling from the supply chain.Currently,China has various bottlenecks in the proprietary industrial ecosystem,and domestic substitution lacks effective overall planning.Therefore,it is essential to apply the underlying logic of asymmetric competition and to leverage a relatively complete industrial system,abundant application scenarios,solid talent base,and the institutional advantages of the new system for mobilizing resources nationwide to break through in integrated circuit manufacturing technologyand in domestic substitution.As such,it is necessary to further strengthen the top-level design,leverage the advantages of the new system for mobilizing resources nationwide to enhance the institutiona1lguarantee for domestic substitution of bottlenecks,and enhance basic research to consolidate the technological foundation for domestic substitution.Moreover,we should implement talent strategy to enhanceethe driving force of human resource for domestic substitution development.We should also further opening-up and cooperation policy to create an open domestic substitution ecology.In addition,we should increase counter-cyclical investment to nurture leaderssin asymmetric competition,and seize the demand window to drive domestic substitution with"epoch-making products."

Ir-Catalyzed Asymmetric Hydrogenation of Unprotected Indoles:Scope Investigations and Mechanistic Studies

Transition metal-catalyzed asymmetric hydrogenation(AH)of unprotected indoles has mainly been applied to alkyl substituted unprotected indoles.However,the challenging aryl substituted unprotected indoles with poor reactivity and enantioselectivity(≤42%ee)could not be hydrogenated well.In this work,a highly efficient Ir/bisphosphine-thiourea ligand ZhaoPhos catalytic system for the AH of challenging aryl substituted unprotected indoles has been successfully developed for the first time with high reactivity and excellent stereoselective control.Moreover,a series of 2-alkyl-substituted and 2,3-disubstituted unprotected indoles were also well tolerated in this catalytic system.A wide variety of chiral indoline derivatives were obtained in good to high yields with excellent stereoselectivities(75–99%yields,>20:1 dr,and 86–99%ee).The anion-binding activation strategy played an important role in accessing both high reactivity and excellent stereoselectivity,which was formed between the catalyst and unprotected indoles in situ-generating iminium ion with the assistance of Brønsted acid.A possible catalytic mechanism was proposed for this Ir-catalyzed AH according to density functional theory calculations and control experiment results.Readily available substrates,a broad range of substrate tolerance,an efficient chiral catalytic system,and a gram-scale protocol further demonstrated the potential practicality of this methodology.