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Student-centered teaching has become increasingly common in higher education as researchers have demonstrated its efficacy in recent decades. Herein, we hope to establish an efficient problem-based learning (PBL) method, which can help upper-division students learn organic chemistry content by combining teaching materials, experimental literature, and computational methods in a self-directed way, systematically and deeply. We aim to cultivate the critical-thinking skills of students and to expand modern research methods to analyze, predict, and understand organic chemical processes. On the basis of such goals and ideas, we take the practical Friedel-Crafts alkylation reaction as a model reaction. We focus on two key points, the pre-equilibrium and the rate-determining step (RDS). In combination with the textbook knowledge and DFT calculation method, we attempt to promote the upper-division students to further discuss and understand reaction details, including kinetic-controlled reactions, the Hammond-Leffler postulate, and the Curtin-Hammett principle, etc. Following this approach, we achieve our goals to discuss the Friedel-Crafts alkylation reaction and provide juniors with a deep understanding of the carbon-carbon bond formation reaction. Furthermore, students initially master the DFT calculation method and make a direct connection between experimental observations and computational results. This approach activates students' study interests to further use core ideas of structures and bonding to rationalize complex chemical reaction phenomena for their future learning career.

Hydraulic fracturing technology is a crucial technique for effectively developing shale oil reservoirs. In field fracturing treatment operations, these reservoirs are often consisting of a combination of various rock types that making them complex. Therefore, this study specially focuses on the sandstone–shale layers in the G zone of the Daqingzi Well G Area in the southern part of the Songliao Basin. It aims to provide essential parameter support for subsequent theoretical and numerical research through laboratory mechanical experiments. Using the finite discrete element method, we have established four different numerical models for the hydraulic fracturing of shale oil with varying geological conditions, (including transition zones). The study reveals that when the vertical stress difference is 6 MPa, the crack height increases, and the offset distance decreases. At 8 and 10 MPa, crack propagation exhibits a "forking" phenomenon. A decrease in rock cohesion leads to increased offset distances in the transition zone, along with an increase in crack height. For type a and b transition zones, it is recommended to use a fracturing fluid with a viscosity of approximately 10 mPa s and a flow rate of 12 m3/min for fracturing. For type c transition zones, it is advisable to select fracturing fluid with a viscosity in the range of 10–30 mPa s and use a flow rate of 12 m3/min for fracturing. For the type d transition zones in the fracturing reservoir, it is recommended to use fracturing fluid with a viscosity of around 10 mPa s and a flow rate of 15 m3/min for optimal field fracturing operations. [ABSTRACT FROM AUTHOR]

Currently, mainstream quantum computing simulators are generally based on numerical calculations, which suffer from precision loss, lack of intuitive representation of quantum states, and difficulty in supporting parameterized quantum circuits. Although symbolic quantum computing simulators have been proposed, they are limited in describing parameterized quantum states, constructing custom quantum gates, and integrating with quantum programming environments. To address this issue, this paper proposes a symbolic quantum computing simulator, SymQC. SymQC can use either full amplitude vectors or Dirac symbols to represent quantum states, calculate the equivalent matrix of symbolically parameterized quantum circuits, simulate the evolution of quantum states under quantum circuits, and output the execution results of quantum algorithms in different forms. This paper describes the software structure of SymQC and provides a mathematical proof of a commonly used quantum state update algorithm. Algorithm instances including variational quantum eigensolver (VQE) algorithm are used to verify the ability of SymQC. [ABSTRACT FROM AUTHOR]