Dramatic Tuning of the Topological Hall Effect in AxRhO2 (A = K,Rb, and Cs) Crystals by Electron Concentration or Cation

Topological Hall effect, being an unconventional anomalous Hall effect, is originated from the real-space Berry curvature caused by the nontrivial topological spin textures in materials. Manipulations of nontrivial magnetic structure and related topological Hall effect are very important for the study of the chiral magnet. Herein, it is experimentally observed that the significant topological Hall conductivity σ_xy in antiferromagnetic K_0.5RhO₂ can reach 3.5% of ν = 1 quantum conductivity below 20 K. Furthermore, by adjusting the concentration of K-cation different from 0.5 in K_xRhO₂ or substituting the K cations by Rb or Cs to form Rb_0.5RhO₂ or Cs_0.5RhO₂, it is observed that the topological Hall effect is much weakened or even disappeared. This evolution, verified by the theoretical calculations, is attributed to the unstable ground state of the non-coplanar spin structure in K_xRhO₂ (x = 0.4 and 0.6) and Cs_0.5RhO₂. The significantly tunable topological Hall effect in A_xRhO₂ makes it prospective on logical/sensor devices of spintronics.     

基于Kerberos变体的ad hoc网络安全认证研究

在Kerberos协议一个变体的基础上提出了一种称为KSAMAN的安全认证模型。该模型提供安全扩展来支持处于敌对环境中的移动adhoc网络更具挑战性的安全需求。KSAMAN将大量的特性从传统的、有线的Kerberos环境移植到移动的adhoc环境，包括结点身份伪造的预防，重放攻击的检测，安全通道的建立，终端的相互认证，以及用多个副本服务器进行临时会话密钥的安全分发。     

基于酸处理的产志贺毒素大肠埃希菌选择性增菌方法研究

目的开发一套基于酸处理的产志贺毒素大肠埃希菌(Shiga toxin-producing Escherichia coli,STEC)选择性增菌方法,提高食品中STEC菌株的检出率。方法 选择12株不同血清型STEC菌株以及13株常见干扰菌,评价其对不同酸处理条件(pH2.0、2.5、3.0)的耐受性;考察筛选的酸处理条件对营养胁迫和冷冻胁迫状态STEC菌株生长活性的影响;比较研究酸水解酪蛋白、酵母提取物和丙酮酸钠等成分对胁迫状态STEC菌株的促生长作用,优化酸处理后中和/促生长培养基配方;比较增菌前与增菌后两种酸处理方式对STEC菌株分离效果的影响;最后通过人工污染样品,评价本研究建立的STEC酸处理选择性增菌方法的检测效果。结果 本研究建立了一种不依赖于抑菌成分的STEC选择性增菌方法,样品在增菌前经酸处理培养基室温处理2 h,降低背景杂菌干扰,再通过中和/促生长培养基(TSB-1.5%Tris-0.1%丙酮酸钠)进行目标菌的增菌培养;人工污染试验结果表明,本方法与我国现行GB4789.36-2016标准方法相比,能够有效减少背景杂菌的干扰、获得更高的STEC分离效率。结论 本研究建立的基于酸处理的STEC选择性增菌方法能够有效提高食品中STEC菌株的检测效率和检测准确性。     

Intelligent fuzzy weighted input estimation method for the forces generated by an operating rotating machine

This paper presents a novel inverse method which efficiently and robustly estimates the vibration forces of a rotating machine mounted upon isolators under the operating condition. This new input estimation method includes the Kalman filter (KF) and the recursive least square estimator (RLSE), weighted by adopting a fuzzy weighting factor based on the fuzzy logic inference system. The excellent performance of this inverse method is demonstrated by solving the vibration problem and comparing it with constant weighting factors. The results reveal that this method has better feasibility and effectiveness in estimating vibratory forces.     

Protective Effect of Pioglitazone on Retinal Ganglion Cells in an Experimental Mouse Model of Ischemic Optic Neuropathy

The aim was to assess the protective effect of pioglitazone (PGZ) on retinal ganglion cells (RGCs) after anterior ischemic optic neuropathy (AION) in diabetic and non-diabetic mice. Adult C57BL/6 mice with induced diabetes were divided into three groups: group 1: oral PGZ (20 mg/kg) in 0.1% dimethyl sulfoxide (DMSO) for 4 weeks; group 2: oral PGZ (10 mg/kg) in 0.1% DMSO for 4 weeks; and group 3: oral DMSO only for 4 weeks (control group). Two weeks after treatment, AION was induced through photochemical thrombosis. For non-diabetic mice, adult C57BL/6 mice were divided into four groups after AION was induced: group 1: oral DMSO for 4 weeks; group 2: oral PGZ (20 mg/kg) in 0.1% DMSO for 4 weeks; group 3: oral PGZ (20 mg/kg) in 0.1% DMSO + peritoneal injection of GW9662 (one kind of PPAR-γ inhibitor) (1 mg/kg) for 4 weeks; group 4: peritoneal injection of GW9662 (1 mg/kg) for 4 weeks; One week after the induction of AION in diabetic mice, apoptosis in RGCs was much lower in group 1 (8.0 ± 4.9 cells/field) than in group 2 (24.0 ± 11.5 cells/field) and 3 (25.0 ± 7.7 cells/field). Furthermore, microglial cell infiltration in the retina (group 1: 2.0 ± 2.6 cells/field; group 2: 15.6 ± 3.5 cells/field; and group 3: 14.8 ± 7.5 cells/field) and retinal thinning (group 1: 6.7 ± 5.7 μm; group 2: 12.8 ± 6.1 μm; and group 3: 15.8 ± 5.8 μm) were also lower in group 1 than in the other two groups. In non-diabetic mice, preserved Brn3A⁺ cells were significantly greater in group 2 (2382 ± 140 Brn3A+ cells/mm², n = 7) than in group 1 (1920 ± 228 Brn3A+ cells/mm²; p = 0.03, n = 4), group 3 (1938 ± 213 Brn3A+ cells/mm²; p = 0.002, n = 4), and group 4 (2138 ± 126 Brn3A+ cells/mm²; p = 0.03, n = 4), respectively; PGZ confers protection to RGCs from damage caused by ischemic optic neuropathy in diabetic and non-diabetic mice.     

基于动力学与控制统一模型的蛇形机器人速度跟踪控制方法研究

对带有被动轮的蛇形机器人进行速度跟踪控制时,利用传统的动力学建模方法得到的动力学方程复杂且不利于控制器的设计. 本文基于微分几何的方法将带有被动轮的蛇形机器人动力学投影到速度分布空间中, 得到了动力学与控制统一模型, 更有利于速度跟踪控制器的设计. 考虑到蛇形机器人在进行速度跟踪时容易出现奇异位形, 提出增加头部扰动速度的方法. 基于头部扰动速度和统一模型, 提出避免奇异位形的速度跟踪控制方法, 最后通过逆向动力学得到控制力矩. 文中对速度跟踪控制进行了数值仿真和实验验证. 仿真和实验结果表明, 提出的速度跟踪控制方法能够跟踪想要方向的速度, 并且在跟踪过程中可以有效地避免奇异位形.     

移动社会网络中基于活动的消息机会转发

针对移动社会网络中节点移动形成的成簇特性和节点参与活动表现的周期特点,提出了一种基于活动的消息机会转发算法（activity-based message opportunistic forwarding,简称AMOF）.算法思想是：当消息携带节点与目的节点存在相同活动时,选择消息交付概率高的中继节点转发消息;当消息携带节点与目的节点不存在相同活动时,选择消息间接交付概率高的链路来转发消息.仿真结果表明,与经典路由算法（如Epidemic,PRoPHET,CMOT和CMTS）比较,所提出的路由算法不仅能够提高消息的传输成功率,还能有效地降低传输时延和网络负载.     

微波预处理提取黄芩中黄芩苷的研究

将微波预处理技术应用在黄芩中黄芩苷的提取中,采用单因素试验法,考察润湿时间、乙醇用量、乙醇浓度、微波功率以及微波作用时间对黄芩苷得率的影响.确定优化的提取工艺参数为:润湿时间50 min、乙醇用量14mL、乙醇浓度80%、微波功率800W、微波作用时间90 s.结果表明微波预处理提取黄芩中的黄芩苷,具有提取得率高、提取时间短的特点.     

Design and modeling of a combined embedded enhanced honeycomb with tunable mechanical properties

Honeycomb structures are increasingly being used in many important fields. A novel combined embedded enhanced honeycomb (CEEH) in developed in this paper based on the two existing embedded enhanced honeycombs, the single rib embedded enhanced honeycomb (SREEH) and the rhombic grid embedded enhanced honeycomb (RGEEH). Analytical model related to the in-plane Young’s modulus and Poisson’s ratio is built and validated by using two different finite element (FE) models (3D beam model and 3D solid model). The in-plane elastic behavior of the honeycomb is also investigated against the geometrical parameters by using the numerically validated analytical solutions. The results show that the new CEEH can achieve a wide range value of Poisson’s ratio and Young’s modulus by tailoring geometric parameters. The results also show that the new CEEH exhibits higher x- directional specific stiffness than SREEH while higher y- directional specific stiffness than RGEEH. Moreover, the new CEEH can weaken even eliminate the difference between the two principal directions which can be hardly achieved by the SREEH and RGEEH. Given these advantages, this new design may be promising in some applications. This work provides a new insight into the designs of embedded enhanced honeycombs.     

利用含有模板剂的SAPO-34分子筛制备高效铜基催化剂

氮氧化物污染已经成为一个严重的环境问题。利用分子筛催化剂进行选择性催化还原(SCR)处理氮氧化物是最有效的方法之一。为了降低现有催化剂的制备成本, 本工作直接利用含有模板剂的分子筛浆料为原料, 通过预处理、离子交换及一次焙烧的方法制备Cu-SAPO-34催化剂。采用XRD、BET、TG、ICP、XPS、SEM、TPR、TPD及NH₃-SCR等对制备的Cu-SAPO-34样品进行表征, 并对离子交换过程中的pH条件进行了优化。研究结果表明: 利用含模板剂的分子筛浆料制备得到催化剂含有2.43% Cu、立方晶型完整、酸性较强以及催化还原性能优秀。在200~450℃下, NO转化率超过80%, 并且在300℃时转化率达到最高97.8%。与使用商品化SAPO-34制备的催化剂相比, 两者具有相似的微观结构和SCR性能。SAPO-34分子筛中少量模板剂的存在对最终制备得到的Cu-SAPO-34催化剂的性能影响很小。因此采用含有模板剂的分子筛浆料制备高效Cu-SAPO-34催化剂是可行的。