An incremental bundle method for portfolio selection problem under second-order stochastic dominance

Numerical Algorithms - We propose a preconditioner to accelerate the convergence of the GMRES iterative method for solving the system of linear equations obtained from discretize-then-optimize...     

非经典碳正离子简介

非经典碳正离子作为一种特殊的反应中间体,具有重要的理论和实际研究的意义。本文以碳正离子理论的发展为主线,以历史上非经典碳正离子(特别是降冰片基正离子)之争为中心,简要综述了Winstein、Brown和Olah三人的观点,并结合最新进展进行评述。此外,还对除降冰片基正离子之外的非经典碳正离子进行了适当的讨论。     

高中化学项目教学案例——探寻柠檬水中的维生素C

选取“维生素C”这一生活中常见的还原性物质,面向已经学习“氧化还原反应”基础知识的高一年级学生开展项目教学活动。通过提出项目问题、师生共同拆解项目问题设计研究方案和子任务、学生实施子任务研究等项目教学环节,在形成相应子任务成果的同时,进一步帮助学生巩固从氧化性和还原性视角认识化学物质性质的认识角度,建立基于物质性质定量分析目标物质含量的实验思路和思维框架,提升学生对于氧化还原反应功能和价值的认识。     

第30届中国化学奥林匹克(初赛)试题解析(一)

详细分析并解答了第30届中国化学奥林匹克(初赛)试题.对于每一道题目,都给出了详尽的讨论,引导读者综合运用所学的化学知识,通过推理、演算、论证等方法顺利解题.对于特定的题目,还给出了相关的科学背景介绍与知识拓展,鼓励读者了解题目背后的科学思想,感受化学学习与科研的乐趣.     

Review and new theoretical perspectives on active disturbance rejection control for uncertain finite-dimensional and infinite-dimensional systems

Nonlinear Dynamics - The active disturbance rejection control (AD RC), first proposed by Jingqing Han in late 1980s, is a powerful control technology being able to deal with external disturbances...     

Gallium Triggers Ferroptosis through a Synergistic Mechanism

The gallium ion (Ga³⁺) has long been believed to disrupt ferric homeostasis in the body by competing with iron cofactors in metalloproteins, ultimately leading to cell death. This study revealed that through an indirect pathway, gallium can trigger ferroptosis, a type of non-apoptotic cell death regulated by iron. This is exemplified by the gallium complex of the salen ligand ( Ga-1 ); we found that Ga-1 acts as an effective anion transporter that can affect the pH gradient and change membrane permeability, leading to mitochondrial dysfunction and the release of ferrous iron from the electron transfer chain (ETC). In addition, Ga-1 also targeted protein disulfide isomerases (PDIs) located in the endoplasmic reticulum (ER) membrane, preventing the repair of the antioxidant glutathione (GSH) system and thus enforcing ferroptosis. Finally, a combination treatment of Ga-1 and dietary polyunsaturated fatty acids (PUFAs), which enhances lipid peroxidation during ferroptosis, showed a synergistic therapeutic effect both in vitro and in vivo. This study provided us with a strategy to synergistically induce Ferroptosis in tumor cells, thereby enhancing the anti-neoplastic effect.     

第30届中国化学奥林匹克(决赛)理论试题解析(一)

详细分析并解答了第30届中国化学奥林匹克(决赛)理论试题。对于每一道题目,我们都给出了详尽的讨论,引导读者综合运用所学的化学知识,通过推理、演算、论证等方法顺利解题。对于特定的题目,我们还给出了相关的科学背景介绍与知识拓展,鼓励读者了解题目背后的科学思想,感受化学学习与科研的乐趣。     

Development of a prototype of the ME readout electronics onboard the HXMT satellite

A prototype of the ME readout electronics onboard the Hard X-ray Modulate Telescope （HXMT） satellite is developed. Application Specific Integrated Chip （ASIC） is used to construct the front end electronics due to a large number of detectors. Field Programmable Gate Array （FPGA） is connected to the ASIC as a state machine controller and data FIFO in the DAQ system. A USB board is designed to communicate between the DAQ system and the computer. The design goals and features, the operation of the system and the preliminary performance of the prototype are described. The testing results show that the design goals of the prototype system have been achieved.     

A Hydrogen-Bonded yet Hydrophobic Porous Molecular Crystal for Molecular-Sieving-like Separation of Butane and Isobutane

Porous molecular crystals sustained by hydrogen bonds and/or weaker connections are an intriguing type of adsorbents, but they rarely demonstrate efficient adsorptive separation because of poor structural robustness and tailorability. Herein, we report a porous molecular crystal based on hydrogen-bonded cyclic dinuclear Ag^I complex, which exhibits exceptional hydrophobicity with a water contact angle of 134°, and high chemical stability in water at pH 2–13. The seemingly rigid adsorbent shows a pore-opening or nonporous-to-porous type butane adsorption isotherm and complete exclusion of isobutane, indicating potential molecular sieving. Quantitative column breakthrough experiments show slight co-adsorption of isobutane with an experimental butane/isobutane selectivity of 23, and isobutane can be purified more efficiently than for butane. In situ powder/single-crystal X-ray diffraction and computational simulations reveal that a trivial guest-induced structural transformation plays a critical role.     

学科能力导向的“物质构成的奥秘”教学研究

以王磊提出的化学学科能力框架为理论依据,对“物质构成的奥秘”主题进行分析,从核心知识经验、认识角度思路、认识对象及问题、能力活动要素等4个维度构建了“物质构成的奥秘”主题的学科能力模型。运用实验法进行教学实践,证实了本研究设计的教学方式更有利于学生学科能力的发展提升。最后提出学科能力导向的“物质构成的奥秘”教学设计模式和教学实施的有效策略:(1)单元整体系统化设计,有层次有梯度的发展学生学科能力;(2)侧重应用实践型任务的解决,外显知识的输出性功能和价值;(3)重视核心知识和认识角度的建立过程;(4)追问、外显学生的认识角度和认识思路。