Processing of alumina-coated clay–diatomite composite membranes for oily wastewater treatment

Crack-free alumina-coated clay–diatomite composite membranes were successfully prepared by a simple pressing and dip-coating route using inexpensive raw materials at a temperature as low as 1000 °C in air. The changes of porosity, flexural strength, pore size, flux, and oil rejection rate of the membranes were investigated while changing the diatomite content. A simple burn-out process subjected to the used membranes in air completely recovered the specific surface area, steady state flux, and oil rejection rate of the virgin membranes. The recycled membranes showed an exceptionally high oil rejection rate (99.9%) with a feed oil concentration of 600 mg/L at an applied pressure of 101 kPa. The typical porosity, pore size, flexural strength, oil rejection rate, and steady state flux of the recycled alumina-coated clay–diatomite composite membrane were 36.5%, 0.12 μm, 32 MPa, 99.9%, and 6.91×10⁻⁶ m³ m⁻² s⁻¹, respectively, at an applied pressure of 101 kPa.     

Identification of Human UDP-Glucuronosyltransferase 1A4 as the Major Isozyme Responsible for the Glucuronidation of 20(S)-Protopanaxadiol in Human Liver Microsomes

20(S)-protopanaxadiol (PPD), one of the representative aglycones of ginsenosides, has a broad spectrum of pharmacological activities. Although phase I metabolism has been investigated extensively, information regarding phase II metabolism of this compound remains to be elucidated. Here, a glucuronidated metabolite of PPD in human liver microsomes (HLMs) and rat liver microsomes (RLMs) was unambiguously identified as PPD-3-O-β-d-glucuronide by nuclear magnetic resonance spectroscopy and high resolution mass spectrometry. The chemical inhibition and recombinant human UDP-Glucuronosyltransferase (UGT) isoforms assay showed that the PPD glucuronidation was mainly catalyzed by UGT1A4 in HLM, whereas UGT1A3 showed weak catalytic activity. In conclusion, PPD-3-O-β-d-glucuronide was first identified as the principal glucuronidation metabolite of PPD in HLMs, which was catalyzed by UGT1A4.     

固溶处理对A286合金组织与硬度的影响

通过光学显微镜、扫描电镜和洛氏硬度计等研究了固溶温度(980、1000、1020℃)和保温时间(60、90、120 min)对A286合金微观组织和硬度的影响。结果表明,热轧态合金基体为再结晶的均匀奥氏体晶粒组织,同时存在一次碳氮化物。随着固溶温度的升高和保温时间的延长,再结晶晶粒优先从表面生长并逐渐向内部扩展,晶界有较大尺寸磷化物析出,合金硬度小幅度降低。     

Experimental and analytical investigation on seismic behavior of Q690 circular high‐strength concrete‐filled thin‐walled steel tubular columns

This paper proposed a new Q690 circular high‐strength concrete‐filled thin‐walled steel tubular (HCFTST) column comprising an ultrahigh‐strength steel tube (yield strength f_y ≥ 690 MPa). A quasi‐static cyclic loading test was conducted to examine the seismic behavior, and the obtained lateral load‐displacement hysteresis curves, skeleton curves, and ductility were analyzed in detail. Then, a numerical model based on a nonlinear fiber beam‐column element incorporating the modified uniaxial cyclic constitutive laws for concrete and steel was developed mainly to predict the seismic behavior of the tested Q690 circular HCFTST columns. The effects of the concrete cylinder compressive strength (f_c), steel yield strength (f_y), axial compression ratio (n), and diameter‐to‐thickness (D/t) ratio on the seismic behavior were investigated through a parametric study. Finally, a simplified hysteretic model incorporating the moment‐resisting capacity and deterioration of the unloading stiffness in addition to a normalized skeleton curve and hysteretic criterion was established. The results indicate the following: the proposed Q690 circular HCFTST columns can display reasonable hysteretic behaviors to some extent; the use of high‐strength steel can lead to a significantly larger elasto‐plastic deformation capacity and delay the appearance of post‐peak behavior, even if a lower ductility capacity is provided; moderately loosening the limitations on the D/t ratio can also result in ideal hysteretic behaviors; and the established numerical model and simplified hysteretic model can satisfactorily predict the experimentally observed load‐displacement hysteretic curves, including the deterioration of the strength and stiffness and can, thus, offer design references for the elasto‐plastic analysis of circular HCFTST columns.     

Tribological behavior of A356−CNT nanocomposites fabricated by various casting techniques

Tribological behaviors of monolithic A356 aluminum alloy castings and A356−CNT nanocomposite castings, fabricated by fully liquid and semisolid routes were examined. Samples were prepared by melt agitation, rheocasting, stir casting, and compocasting techniques. Effects of addition of carbon nanotubes (CNTs), casting process and the applied load on wear properties and mechanisms were investigated. It was found that wear loss, wear rate and friction coefficient of nanocomposite samples remarkably declined by the addition of CNTs. Moreover, changing the casting process from fully liquid to semisolid routes, plus increasing fractions of the primary phase were the two factors that improved the wear properties of the investigated samples, especially nanocomposite ones. In addition, it was revealed that adhesion and delamination were the dominant wear mechanism of the monolithic samples produced by fully liquid and semisolid routes, respectively. However, regardless of fabrication techniques, the abrasion was the main wear mechanism of nanocomposite samples.     

终轧温度对Q420qENH钢板组织性能的影响

研究了Q420qENH钢板显微组织与拉伸性能随终轧温度的变化规律。研究发现,随终轧温度的升高,Q420qENH钢板组织中粒状贝氏体的数量减少,多边形铁素体增多,屈服强度和抗拉强度均降低,屈强比降低。将屈服强度和晶粒尺寸进行Hall Petch拟合,得到的拟合式与试验结果吻合,能够反映出Q420qENH钢在不同终轧温度下的强度随晶粒尺寸的变化趋势。     

Q345NQR2铁路用高强度钢板的开发

通过低碳及微合金化学成分设计,研究了始冷温度对低屈强比铁路用Q345NQR2钢组织和性能的影响。结果表明,在相同终轧温度下,随着始冷温度的降低,钢板的屈服强度降低,抗拉强度变化不大。实验钢的组织为铁素体+珠光体,组织内珠光体与铁素体微区维氏显微硬度差不小于14HV时,钢板的屈强比不大于0.73,-40 ℃冲击功大于90 J,满足了铁路车辆用钢的性能要求。     

Q235钢搅拌摩擦焊接头微观组织与力学性能分析

在焊接速度为100 mm/min和搅拌头转速为450 r/min的工艺参数下,采用钨铼合金搅拌头对3 mm厚Q235钢进行了搅拌摩擦焊试验,并对接头的微观组织及力学性能进行了研究. 结果表明,在该工艺参数下可以获得表面无缺陷、成形良好的焊缝. 焊后搅拌头表现出一定程度的磨损及氧化. 接头截面各区域承受不同的热力联合作用,经历了不同的组织转变过程,但均保持铁素体和珠光体组织. 接头显微硬度最大值位于焊核区. 接头拉伸断裂位置处于热影响区,拉伸断口呈韧性断裂特征.     

腺苷A2AR拮抗剂对中枢炎症性小胶质细胞形态和功能的影响

目的:探讨腺苷A2A受体拮抗剂对实验性自身免疫性脑脊髓炎（EAE）的治疗作用及其对中枢炎症性小胶质细胞形态和功能的影响。方法:MOG35-55免疫诱导建立EAE模型,EAE小鼠出现神经功能缺损症状后开始腹腔注射腺苷A2AR拮抗剂至发病后第10天。ELISA法检测中枢神经系统内IFN-γ、IL-17、TGF-β、IL-10的表达情况,免疫荧光双重染色法检测小胶质细胞内M1型细胞标志物诱导型一氧化氮合酶（iNOS）和M2型细胞标志物精氨酸酶I（ArgI）的合成情况。离体培养BV-2小胶质细胞,LPS诱导的小胶质细胞炎症反应,并予A2AR拮抗剂干预,Real-time PCR和ELISA法检测M1型和M2型细胞相关的细胞因子RNA表达水平和分泌水平。Western Blot法检测各组小胶质细胞内M1型和M2型细胞标志物的表达量。结果:腺苷A2AR拮抗剂能有效缓解发病后EAE小鼠的神经功能缺损症状,降低IFN-γ的分泌水平,使M1型细胞相关的iNOS合成减少,M2型细胞相关的ArgI合成增多。腺苷A2AR拮抗剂能减少LPS刺激后BV-2小胶质细胞M1型细胞相关的细胞因子IL-1β的mRNA表达量和分泌量,对M2型细胞相关的细胞因子及蛋白无显著影响。结论:腺苷A2AR拮抗剂对发病后的EAE小鼠有肯定的治疗作用,其机制可能与改变中枢炎症过程中小胶质细胞的表型（M1/M2转换）改变（形态和功能）有关。     

KJ-15A机车运输监控屏蔽线路接线与维护

重点分析了KJ-15A矿井机车运输监控系统屏蔽线路的接线方法、常见故障类型及电缆检测和日常项目的维护。可为KJ-15A矿井机车运输监控系统屏蔽电缆的故障处理及系统的正常工作提供一定的理论参考,可为从事KJ-15A矿井机车运输监控系统日常维护的工作人员提供一些借鉴。