Re-Looking into the Active Moieties of Metal X-ides (X- = Phosph-, Sulf-, Nitr-, and Carb-) Toward Oxygen Evolution Reaction

Non-precious metal-based catalysts for oxygen evolution reaction (OER) have been extensively studied, among which the transition metal X-ides (including phosph-ides, sulf-ides, nitr-ides, and carb-ides) materials are emerging as promising candidates to replace the benchmark Ir/Ru-based materials in alkaline media. However, it is controversial whether the metal Xides host the real active sites since these metal Xides are thermodynamically unstable under a harsh OER environment—it has been reported that the initial metal Xides can be electrochemically oxidized and transformed into corresponding oxides and (oxy)hydroxides. Therefore, the metal Xides are argued as “pre-catalysts”; the electrochemically formed oxides and (oxy)hydroxides are believed as the real active moieties for OER. Herein, the recent advances in understanding the transformation behavior of metal Xides during OER are re-looked; importantly, hypotheses are provided to understand why the electrochemically formed oxides and (oxy)hydroxides catalysts derived from metal Xides are superior for OER to the as-prepared metal oxides and (oxy)hydroxides catalysts.     

致密砂岩油藏能量补充方式评价及优化

针对致密砂岩油藏大规模体积压裂开发后能量补充困难的问题,利用自主设计制作的大型人造三维岩心物理模型和物理模拟实验舱,开展致密砂岩油藏能量补充方式优化研究。实验结果表明:致密砂岩油藏压裂开发过程中,地层能量损耗严重,采取注水或注气的方式可有效进行能量补充;地层中裂缝规模越大,越有利于原油渗流,后续补充能量的传播范围越广,有助于进一步提高原油采收率;从提高驱油效率和扩大波及系数方面优选吞吐渗吸介质,CO₂均优于活性水,CO₂吞吐开发在矿场试验中取得了显著的增油效果,因此,CO₂吞吐作为一种有效的能量补充方式在致密油开发中展现了良好的应用前景。该文分析了致密砂岩储层水平井压裂开发的渗流规律,优选出致密砂岩储层大规模压裂开发后最佳渗吸介质,可为致密砂岩油藏开发设计提供重要的理论依据。     

坚硬顶板下巷道锚网索喷联合支护技术实践

干河煤矿+80水平三采区皮带巷上部赋存坚硬岩层,围岩压力较大;针对坚硬顶板条件,拟定以强主动支护为主的对策,即采用锚网索喷联合支护技术;应用表明,该巷道围岩变形量不大,验证了该支护技术安全可靠。     

Physiologically Active Molecules and Functional Properties of Soybeans in Human Health—A Current Perspective

In addition to providing nutrients, food can help prevent and treat certain diseases. In particular, research on soy products has increased dramatically following their emergence as functional foods capable of improving blood circulation and intestinal regulation. In addition to their nutritional value, soybeans contain specific phytochemical substances that promote health and are a source of dietary fiber, phospholipids, isoflavones (e.g., genistein and daidzein), phenolic acids, saponins, and phytic acid, while serving as a trypsin inhibitor. These individual substances have demonstrated effectiveness in preventing chronic diseases, such as arteriosclerosis, cardiac diseases, diabetes, and senile dementia, as well as in treating cancer and suppressing osteoporosis. Furthermore, soybean can affect fibrinolytic activity, control blood pressure, and improve lipid metabolism, while eliciting antimutagenic, anticarcinogenic, and antibacterial effects. In this review, rather than to improve on the established studies on the reported nutritional qualities of soybeans, we intend to examine the physiological activities of soybeans that have recently been studied and confirm their potential as a high-functional, well-being food.     

Influences of the inner diameter of the solid shielding tube on the characteristics of the radio-frequency cold atmospheric plasma jet

Active control of the local environment of the cold atmospheric plasma (CAP) jet is of great importance in actual applications since the CAP operates in an open atmosphere with the inevitable entrainment of the surrounding cold air. In this paper, the solid shielding effects of the cylindrical quartz tubes with different inner diameters on the characteristics of the CAP jets driven by a radio-frequency (RF) power supply are studied experimentally. The experimental results show that the total length of the shielded plasma jet can be increased significantly by an appropriate combination of the quartz tube inner diameter and that of the plasma generator nozzle exit with other parameters being unchanged. This phenomenon may be qualitatively attributed to the loss of diffusion of the charged particles in the radial direction under different inner diameters of the quartz tubes. Compared with the plasma free jet, the plasma shielding jet is produced with optimized parameters including longer plasma jet length, higher concentrations of chemically reactive species, higher rotational, vibrational, and electron excitation temperatures when the inner diameters of the solid shielding tube and the generator nozzle exit are the same. A maximum plasma jet length of 52.0 cm is obtained in contrast to that of 5.0 cm of the plasma free jet in this study. The experimental results indicate that the solid shielding effect provides a new method for the active control of the local environment of the RF-CAP jet operating in an open atmosphere.     

淀粉/聚乙烯醇活性包装薄膜及其在食品包装应用中的研究进展

综述了淀粉/聚乙烯醇（PVA）活性包装薄膜及其在食品包装中的研究进展，主要对从不同比例共混、疏水改性、增强改性等方面对淀粉/PVA薄膜的改性研究，从功能特性和活性物质对薄膜性能的影响2个方面对淀粉/PVA活性薄膜研究和薄膜在食品包装中的应用3个方面进行了归纳总结，旨在为以淀粉/PVA为基材的活性包装薄膜研究提供参考。     

射电望远镜主动面促动器的电磁辐射分析

主动面控制技术是当前大口径、高精度射电望远镜广泛使用的主动补偿技术,其包含的促动器在补偿面形精度的同时也辐射电磁波并影响射电天文观测。文中结合目前研究现状,对极低电磁辐射要求下的促动器进行辐射源分析,重点针对促动器控制板上信号建立数学模型,并选取晶振回路计算,合理设定印制板及器件的参数,通过Ansys 软件进行频域有限元分析,得到控制板晶振回路的辐射结果和规律。用近场测试验证了文中方法的有效性。该研究为促动器控制板的电磁兼容优化设计提供了验证方法,为降低主动面控制系统的电磁辐射奠定了基础。     

羟基(—OH)对煤自燃侧链活性基团氧化反应特性的影响

针对煤结构及其氧化反应机理不明等问题,以羟基(—OH)和煤自燃侧链活性基团—OCH,—CHOHCH 3和—OCH 3为研究对象,采用密度泛函理论(DFT)的B3LYP-311G(d,p)方法,构建出了羟基(—OH)处于侧链活性结构邻位的小分子结构模型。基于前线轨道理论和量子化学理论,采用Gaussian 16软件对小分子模型的静电势、前线轨道的能级和电荷分布及煤氧复合反应过程中的热力学参数进行了模拟计算,探究了侧链活性基团的低温氧化特性和羟基(—OH)对其的影响。计算结果显示,在侧链活性结构中,氢原子周边呈强正电势,为亲核反应活性位点,而氧原子附近呈强负电势,为亲电反应活性位点。当羟基(—OH)处于侧链活性基团邻位时,会削弱侧链活性基团的亲电反应能力,增加—CHO和—CHOHCH 3的亲核反应能力,而使—OCH 3的亲核反应能力消失;通过分析各活性基团最高占据轨道(HOMO:Highest Occupied Molecular Orbital)和最低未占轨道(LUMO:Lowest Unoccupied Molecular Orbital)可知,侧链活性基团的稳定性与其前线轨道的成键能力并不一致,而活性基团与氧气发生复合反应的难易程度主要取决于该基团前线轨道中LUMO的成键能力,成键能力越强,复合反应越容易发生;由于羟基(—OH)改变了侧链活性基团前线轨道上的电子特性,故当其与侧链基团共存时,会使—CHO和—CHOHCH 3与氧气的复合反应更容易发生,而使—OCH 3与氧气的复合由自发的放热反应转变为非自发的吸热反应。该研究成果可为揭示煤自燃微观作用机理和研发煤自燃新型高效阻化材料提供参考。     

基于近似测地线的分层次自动铺带轨迹规划方法

自动铺带技术是一种增量制造技术，适用于制造翼面、壁板等大尺寸、小曲率复合材料构件，具有加工成本低、效率高等特点。轨迹规划是自动铺带技术的关键环节，它直接关系到复合材料构件的成型精度与质量。现有的自动铺带轨迹规划方法难以便捷兼顾调控铺放间隙与防止铺放褶皱，保证铺带产品的最终质量。有鉴于此，提出了一种基于近似测地线的分层次铺放轨迹规划方法。主要目标是合理利用预浸带允许变形能力，在防止铺放褶皱产生的前提下，保证相邻带料不产生覆盖，且间隙不超过2.5 mm。首先，研究了铺放间隙的产生与演化规律，给出了几种典型曲面上初始铺放间隙的优化方法。接下来，提出了近似测地线的数学模型与求解格式。然后，基于铺放褶皱的产生机制与铺放间隙的演化规律，确定了近似测地线的测地曲率大小与符号。最后，在双曲面模具以及自由曲面模具上验证了所提出方法的有效性。     

Three-phase four-wire shunt active power filter based on the SOGI filter and Lyapunov function for DC bus control

The three-phase four-wire shunt active power filter (SAPF) was developed to suppress the harmonic currents generated by nonlinear loads, and for the compensation of unbalanced nonlinear load currents, reactive power, and the harmonic neutral current. In this work, we consider instantaneous reactive power theory (PQ theory) for reference current identification based on the following two algorithms: the classic low-pass filter (LPF) and the second-order generalized integrator (SOGI) filter. Furthermore, since an important process in SAPF control is the regulation of the DC bus voltage at the capacitor, a new controller based on the Lyapunov function is also proposed. A complete simulation of the resultant active filtering system confirms its validity, which uses the SOGI filter to extract the reference currents from the distorted line currents, compared with the traditional PQ theory based on LPF. In addition, the simulation performed also demonstrates the superiority of the proposed approach, for DC bus voltage control based on the Lyapunov function, compared with the traditional proportional-integral (PI) controller. Both novel approaches contribute towards an improvement in the overall performance of the system, which consists of a small rise and settling time, a very low or nonexistent overshoot, and the minimization of the total harmonic distortion (THD).