Quercetin: Its Antioxidant Mechanism,Antibacterial Properties and Potential Application in Prevention and Control of Toxipathy

Quercetin, as a flavonol compound found in plants, has a variety of biological activities. It is widely present in nature and the human diet, with powerful oxidative properties and biological activities. In this review, the antioxidant mechanism and broad-spectrum antibacterial properties of quercetin are revealed; the intervention effects of quercetin on pesticide poisoning and the pathway of action are investigated; the toxic effects of main mycotoxins on the collection and the detoxification process of quercetin are summarized; whether it is able to reduce the toxicity of mycotoxins is proved; and the harmful effects of heavy metal poisoning on the collection, the prevention, and control of quercetin are evaluated. This review is expected to enrich the understanding of the properties of quercetin and promote its better application in clinical practice.     

Building Polymeric Framework Layer for Stable Solid Electrolyte Interphase on Natural Graphite Anode

The overall electrochemical performance of natural graphite is intimately associated with the solid electrolyte interphase (SEI) layer developed on its surface. To suppress the interfacial electrolyte decomposition reactions and the high irreversible capacity loss relating to the SEI formation on a natural graphite (NG) surface, we propose a new design of the artificial SEI by the functional molecular cross-linking framework layer, which was synthesized by grafting acrylic acid (AA) and N,N′−methylenebisacrylamide (MBAA) via an in situ polymerization reaction. The functional polymeric framework constructs a robust covalent bonding onto the NG surface with —COOH and facilitates Li⁺ conduction owing to the effect of the —CONH group, contributing to forming an SEI layer of excellent stability, flexibility, and compactness. From all the benefits, the initial coulombic efficiency, rate performance, and cycling performance of the graphite anode are remarkably improved. In addition, the full cell using the LiNi_0.5Co_0.2Mn_0.3O₂ cathode against the modified NG anode exhibits much-prolonged cycle life with a capacity retention of 82.75% after 500 cycles, significantly higher than the cell using the pristine NG anode. The mechanisms relating to the artificial SEI growth on the graphite surface were analyzed. This strategy provides an efficient and feasible approach to the surface optimization for the NG anode in LIBs.     

Improved Stretchable and Sensitive Fe Nanowire-Based Strain Sensor by Optimizing Areal Density of Nanowire Network

Flexible strain sensors, when considering high sensitivity and a large strain range, have become a key requirement for current robotic applications. However, it is still a thorny issue to take both factors into consideration at the same time. Here, we report a sandwich-structured strain sensor based on Fe nanowires (Fe NWs) that has a high GF (37–53) while taking into account a large strain range (15–57.5%), low hysteresis (2.45%), stability, and low cost with an areal density of Fe NWs of 4.4 mg/cm². Additionally, the relationship between the contact point of the conductive network, the output resistance, and the areal density of the sensing unit is analyzed. Microscopically, the contact points of the conductive network directly affect the sensor output resistance distribution, thereby affecting the gauge factor (GF) of the sensor. Macroscopically, the areal density and the output resistivity of the strain sensor have the opposite percolation theory, which affects its linearity performance. At the same time, there is a positive correlation between the areal density and the contact point: when the stretching amount is constant, it theoretically shows that the areal density affects the GF. When the areal density reaches this percolation threshold range, the sensing performance is the best. This will lay the foundation for rapid applications in wearable robots.     

Designing a deep-UV nonlinear optical monofluorophosphate

As structural variants of famous hexagonal tungsten bronzes, hexagonal tungsten oxides(HTO) represent an important family with fascinating functional properties, such as piezoelectric, ferroelectric, pyroelectric, and nonlinear optical(NLO) properties.However, none of them are transparent in the deep-UV spectral region, which limits their applications. Herein, we report the first HTO-type monofluorophosphate K₃Sc₃(PO₄)(PO₃F)₂F₅(I)...     

Superconvergence of local discontinuous Galerkin methods with generalized alternating fluxes for 1D linear convection-diffusion equations

This paper investigates superconvergence properties of the local discontinuous Galerkin methods with generalized alternating fluxes for one-dimensional linear convection-diffusion equations. By the technique of constructing some special correction functions, we prove the(2k + 1)-th-order superconvergence for the cell averages, and the numerical traces in the discrete L~2 norm. In addition, superconvergence of orders k + 2 and k + 1 is obtained for the error and its derivative at generalized Radau points. All the theoretical findings are confirmed by numerical experiments.     

同轴虚阴极振荡器实验研究

 介绍了中国工程物理研究院应用电子学研究所关于同轴虚阴极振荡器实验的最新进展。实验结果表明,带阳极反射板结构的同轴虚阴极振荡器比不带阳极反射板结构的同轴虚阴极振荡器输出微波功率更高,频谱更纯。在二极管电压350 kV,电流23 kA条件下,输出微波峰值功率500 MW,能量转换效率约6.2%,工作频率为3.3 GHz。对实验结果进行了理论分析。     

An Exploration of the Effect of the Kleier Model and Carrier-Mediated Theory to Design Phloem-Mobile Pesticides Based on Researching the N-Alkylated Derivatives of Phenazine-1-Carboxylic Acid-Glycine

The Kleier model and Carrier-mediated theory are effective for molecularly designing pesticides with phloem mobility. However, the single Kleier model or Carrier-mediated theory cannot achieve a reliable explanation of the phloem mobility of all exogenous substances. A detailed investigation of the two models and the scope of their applications can provide a more accurate and highly efficient basis for the guidance of the design and development of phloem-mobile pesticides. In the present paper, a strategy using active ingredient-amino acid conjugates as mode compounds is developed based on Carrier-mediated theory. An N-alkylated amino acid is used to improve the pesticide’s physicochemical properties following the Kleier model, thus allowing the conjugates to fall on the predicted and more accessible transportation region of phloem. Moreover, the influence of this movement on phloem is inspected by the Kleier model and Carrier-mediated theory. To verify this strategy, a series of N-alkylated phenazine-1-carboxylic acid-glycine compounds (PCA-Gly) were designed and synthesized. The results related to the castor bean seeds (R. communis L.) indicated that all the target compounds (4a–4f) had phloem mobility. The capacity for phloem mobility shows that N-alkylated glycine containing small substituents can significantly improve PCA phloem mobility, such as 4c(i-C₃H₇-N) > 4a(CH₃-N) ≈ 4b(C₂H₅-N) > 4d (t-C₄H₉-N) > PCA-Gly > 4e(C₆H₅-N) > 4f(CH₂COOH-N), with an oil–water partition coefficient between 1.2~2.5. In particular, compounds 4a(CH₃-N), 4b(C₂H₅-N), and 4c(i-C₃H₇-N) present better phloem mobility, with the average concentrations in phloem sap of 14.62 μΜ, 13.98 μΜ, and 17.63 μΜ in the first 5 h, which are 8 to 10 times higher than PCA-Gly (1.71 μΜ). The results reveal that the Kleier model and Carrier-mediated theory play a guiding role in the design of phloem-mobile pesticides. However, the single Kleier model or Carrier-mediated theory are not entirely accurate. Still, there is a synergism between Carrier-mediated theory and the Kleier model for promoting the phloem transport of exogenous compounds. Therefore, we suggest the introduction of endogenous plant compounds as a promoiety to improve the phloem mobility of pesticides through Carrier-mediated theory. It is necessary to consider the improvement of physicochemical properties according to the Kleier model, which can contribute to a scientific theory for developing phloem-mobile pesticides.     

Combine Harvester Bearing Fault-Diagnosis Method Based on SDAE-RCmvMSE

In the fault monitoring of rolling bearings, there is always loud noise, leading to poor signal stationariness. How to accurately and efficiently identify the fault type of rolling bearings is a challenge. Based on multivariate multiscale sample entropy (mvMSE), this paper introduces the refined composite mvMSE (RCmvMSE) into the fault extraction of the rolling bearing. A rolling bearing fault-diagnosis method based on stacked auto encoder and RCmvMSE (SDAE-RCmvMSE) is proposed. In the actual environment, the fault-diagnosis method use the multichannel vibration signals of the bearing as the input of stacked denoising autoencoders (SDAEs) to filter the noise of the vibration signals. The features of denoise signals are extracted by RCmvMSE and the rolling bearing operation-state diagnosis is completed with a support-vector machine (SVM) model. The results show that in the original test data, the accuracy rates of SDAE-RCmvMSE, RCmvMSE, and commonplace features of vibration signals combined with SVM (CFVS-SVM) methods are 99.5%, 100%, and 96% respectively. In the data with noise, the accuracy rates of RCmvMSE and CFVS-SVM are 97.75% and 93.08%, respectively, but the accuracy of SDAE-RCmvMSE is still 100%.     

Ⅰ型裂纹中低速冲击荷载下起裂韧度测试新方法

为了探寻更加合理的构型试件来研究纯Ⅰ型裂纹在冲击荷载下的起裂及扩展行为, 提出一种新构型试件, 即双倾斜底边中心裂纹试件(double inclined bottom central cracked, DIBCC)。借助于中低速落锤式冲击实验装置进行冲击实验, 通过应力波来使试件内预制裂纹起裂并扩展, 同时利用应变片测试系统监测裂纹起裂时刻, 并采用AUTODYN有限差分软件对实验过程进行数值模拟, 最后计算裂纹的动态应力强度因子, 利用实验测得的起裂时刻, 确定试件的起裂韧度。结果表明:(1)在反射拉伸波作用下, 预制裂纹两侧会产生垂直于裂纹面向外的位移, 使预制裂纹扩张, 从而使裂纹起裂。(2)数值模拟结果与实验结果在裂纹扩展路径上具有一致性, 说明本文中提出的DIBCC构型试件有效, 可以用来测试裂纹在冲击载荷下的断裂韧度。

     

柴油爆炸性能外场实验研究

通过Ø30 mm杀爆燃弹外场炮击实验,模拟车辆、装备油箱被炮火击中后二次爆炸场景,采用高速照相机、红外热成像仪分别记录引爆柴油过程和爆炸火球的温度场,对比评估普通柴油、含水型柴油和抑爆型柴油的爆炸特性。实验结果显示：炮弹射击油箱瞬间,柴油液滴被抛撒出油箱,与空气快速混合形成气溶胶,并在炸药能量作用下引发爆炸,形成爆炸火球;不同类型柴油的爆炸火球均经历3个发展阶段,但其尺寸、扩展速率和表面温度等有较大差别,普通柴油和含水型柴油的火球这3个参数比较接近,都大于抑爆型柴油;含水型柴油的油箱毁伤容积为108.00 dm³,远高于普通柴油的57.65 dm³和抑爆型柴油的38.15 dm³。研究表明,抑爆柴油中的高分子聚合物能起到较好的抑爆作用。