分子水平上的虚拟仿真实验之思政元素的挖掘与提炼——以“高分子的构象、形态及尺寸的模拟与计算”项目为例

高分子的构象、形态及尺寸的模拟与计算,是分子水平上的虚拟仿真实验项目,结合诺贝尔奖获得者de Gennes和P.J.Flory的理论工作、由项目组自身教研成果转化、师生合作研发而成。与小分子化合物相比,高分子的研究方法有很大的不同,特别是需要采用统计方法来描述高分子链的构象、形态,计算高分子链的平均尺寸,这是经典的物理化学方法所不能完成的。本项目从研发到教学实践、再经改进,教学内容的更新优化中,自然融入了诺贝尔奖成果、哲学思想、科学思维、学科发展史、教研成果等多个维度的思政元素。

JNK3 involvement in nerve cell apoptosis and neurofunctional recovery after traumatic brain injury

Increasing evidence has revealed that the activation of the JNK pathway participates In apoptosis o1 nerve cells and neurological function recovery after traumatic brain injury. However, which genes inI the JNK family are activated and their role in traumatic brain injury remain unclear. Therefore, in this study, in situ end labeling, reverse transcription-PCR and neurological function assessment were adopted to investigate the alteration of JNK1, JNK2 and JNK3 gene expression in cerebral injured rats, and their role in celt apoptosis and neurological function restoration. Results showed that JNK3 expression significantly decreased at 1 and 6 hours and 1 and 7 days post injury, but that JNK1 and JNK2 expression remained unchanged. In addition, the number of apoptotic nerve cells surrounding the injured cerebral cortex gradually reduced over time post injury. The Neurological Severity Scores gradually decreased over 1,3, 5, 14 and 28 days post injury. These findings suggested that JNK3 expression was downregulated at early stages of brain injury, which may be associated with apoptosis of nerve cells. Downregulation of JNK3 expression may promote the recovery of neurological function following traumatic brain injury.

大物联网的小米胜经

小米在2010年凭借MIUI进入竞争激烈的中国手机市场,MIUI是一款基于安卓系统的第三方手机操作系统,也是小米的第一个产品。到2017年,小米已经成为全球领先的智能手机制造商,收入达到150亿美元。今天,小米是世界上最大的物联网(Io T)公司之一,2020年底收入超过370亿美元。小米如何实现如此非凡的增长?研究表明,小米的合作方式是其快速增长的关键因素。自成立以来,该公司一直致力于与消费者和合作伙伴建立互惠互利的关系。

Preparation and Characterization of lonic Conductive Eutectogels Based on Polyacrylamide Copolymers with Long Hydrophobic Chain

With the blooming development of electronic technology,the use of electron conductive gel or ionic conductive gel in preparing flexible electronic devices is drawing more and more attention.Deep eutectic solvents are excellent substitutes for ionic liquids because of their good biocompatibility,low cost,and easy preparation,except for good conductivity.In this work,we synthesized a reactive quaternary ammonium monomer(3-acrylamidopropyl)octadecyldimethyl ammonium bromide with a hydrophobic chain of 18 carbons via the quaternization of 1-bromooctadecane and N-dimethylaminopropyl acrylamide at first,then we mixed quaternary ammonium with choline chloride,acrylic acid and glycerol to obtain a hydrophobic deep eutectic solvent,and initialized polymerization in UV light of 365 nm to obtain the ionic conductive eutectogel based on polyacrylamide copolymer with long hydrophobic chain.The obtained eutectogel exibits good stretchability(1200%),Young's modulus(0.185 MPa),toughness(4.2 MJ/m^(3)),conductivity(0.315 S/m).The eutectogel also shows desireable moisture resistance with the maximum water absorption of 11.7 wt%after one week at 25℃and 60%humidity,while the water absorption of eutectogel without hydrophobic long chains is 24.0 wt%.The introduction of long-chain hydrophobic groups not only improves the mechanical strength of the gels,but also significantly improves moisture resistance of the eutectogel.This work provides a simpler and more effective method for the preparation of ionic conductive eutectogels,which can further provide a reference for the applications of ionic conductive eutectogels in the field of flexible electronic devices.

Co-application of energy uncoupling and ultrafiltration in sludge treatment:Evaluations of sludge reduction,supernatant recovery and membrane fouling control

Energy uncoupling is often used for sludge reduction because it is easy to operate and does not require a significant amount of extra equipments(i.e.no additional tank required).However,over time the supernatant extracted using this method can deteriorate,ultimately requiring further treatment.The purpose of this study was to determine the effect of using a low-pressure ultrafiltration membrane process for sludge water recovery after the sludge had undergone an energy uncoupling treatment(using 3,3’,4’,5-tetrachlorosalicylanilide(TCS)).Energy uncoupling was found to break apart sludge floe by reducing extracellular polymeric substances(EPS)and adenosine triphosphate(ATP)content.Analysis of supernatant indicated that when energy uncoupling and membrane filtration were coapplied and the TCS dosage was below 30 mg/L,there was no significant deterioration in organic component removal.However,ammonia and phosphate concentrations were found to increase as the concentration of TCS added increased.Additionally,due to low sludge concentrations and EPS contents,addition of 30-60 mg/L TCS during sludge reduction increased the permeate flux(two times higher than the control)and decreased the hydraulic reversible and cake layer resistances.In contrast,high dosage of TCS aggravated membrane fouling by forming compact fouling layers.In general,this study found that the co-application of energy uncoupling and membrane filtration processes represents an effective alternative method for simultaneous sludge reduction and sludge supernatant recovery.

A novel approach to the attitude stabilization structure for ducted-fan operative aerial robots:Finding improvements for modeling error and strong external transient disturbance

This research concerns a novel attitude stabilization structure for a ducted-fan aerial robot to work against modeling error and strong external transient disturbance,and it focuses on two main control targets:modeling error compensation,and the improvement of disturbance resistance along the rolling channel.For the first research objective,we proposed an adaptive nominal controller with the reconfigurable control law design based on the estimation of the modeling error found in the closed-loop.Results of simulations and corresponding flight tests verified that the proposed adaptive control structure is robust against both constant and time-varying modeling error.For the other research objective,a SAC(Stability Augmentation Control)structure was devised based on the CMG(Control Moment Gyroscope)theory in order to provide extra moment which effectively withstands the transient disturbance beyond the CDG(Critical Disturbance Gain).Furthermore,we studied the corresponding controller for the SAC via the SMC(sliding mode control)theory,while the working mechanism and performance of the SAC were verified through a specially devised prototype.

Superconductivity, electronic phase diagram, and pressure effect in Sr_(1-x)Pr_xFBiS_2

Based on a combination of X-ray diffraction, electrical transports, magnetic susceptibility, specific heat, and pressure-effect measurements, we report the results of experiments on a series of BiS_2-based Sr_(1-x)Pr_xFBiS_2 superconductors with the maximum Tcof 2.7 K for x=0.5 and at ambient pressure. Superconductivity appears only for 0.4≤x≤0.7 whereas the normal-state resistivity shows the semiconducting-like behaviors. The magnetic susceptibility χ(T) displays the low superconducting shielding volume fractions and C(T) shows no distinguishable anomaly near Tc, which suggests a filamentary superconductivity in the Pr-doped polycrystalline samples. By varying doping concentrations, an electronic phase diagram is established. Upon applying pressure on the optimally doped Sr_(0.5)Pr_(0.5)FBiS_2 system, Tcis abruptly enhanced, reaches 8.5 K at the critical pressure of P_c=1.5 GPa, and increases slightly to 9.7 K at 2.5 GPa. Accompanied by the enhancement of superconductivity from the low-to the high-Tc phases, the normal state undergoes a semiconductor-to-metal transition when under pressure. This scenario may be linked to enhanced overlap of the Bi-6 p and S-p orbitals, which contributes to the enhanced superconductivity above Pc. The pressuretemperature phase diagram for Sr_(0.5)Pr_(0.5)FBiS_2 is also presented.

Sign-reversed anomalous Nernst effect in the ferromagnetic Weyl-semimetal Fe_(3-δ)GeTe_(2): the role of Fe vacancies

Anomalous Nernst effect, as a thermal partner of anomalous Hall effect, is particularly sensitive to the Berry curvature anomaly near the Fermi level, and has been used to probe the topological nature of quantum materials. In this work, we report the observation of both effects in the ferromagnetic Weyl-semimetal Fe_(3-δ)GeTe_(2) with tunable Fe vacancies. With decreasing Fe vacancies,the anomalous Hall conductivity evolves as a function of the longitudinal conductivity from the hopping region to the region where the intrinsic Berry curvature contribution dominates. Concomitant evolutions in the anomalous Nernst signal and the anomalous off-diagonal thermoelectric coefficient are observed below the Curie temperature, displaying a unique sign change caused by the Fe vacancies. Combining these results with first-principles calculations, we argue that the Fe-vacancy concentration plays a unique role in simultaneously tuning the chemical potential and ferromagnetism, which in turn controls the Berry curvature contribution in this family of ferromagnetic topological semimetals.