矿山多属性环境协同作用对锚杆腐蚀的影响

锚固材料失效造成围岩失稳呈现多元化特征,其中锚固材料在服役过程中受到多属性腐蚀环境协同作用造成其腐蚀越来越严重。锚杆腐蚀开裂频繁发生在富黏土地带,反映出多属性环境(包括含氧率、地下水、矿物质等)协同作用是锚杆腐蚀的重要影响因素。为了掌握锚杆在多属性环境协同作用影响下的腐蚀规律,将锚杆服役环境以"腐蚀细胞"的方式进行了实验室模拟试验。研究表明:环境中的矿物质通过离子交换增加水溶液离子溶度,间接加速了锚杆的腐蚀,证明了溶液中离子浓度与腐蚀速率成正相关关系;腐蚀是长期的过程,经过3个月的试验后,大部分腐蚀产物形成于螺纹和锚杆端部,以及被黏土与煤包裹的部位,反映出矿物质能加速锚杆的腐蚀;相比于腐蚀介质仅为去离子水,锚杆在包含黏土或者煤的试验环境中腐蚀后的抗拉强度均有所降低;锚杆在煤和黏土共同作为腐蚀介质且开放的环境下,抗拉强度最小,这也间接说明矿物质材料能加速锚杆的腐蚀。上述研究进一步表明:环境中煤、黏土、地下水可通过增加溶液总离子浓度提高环境腐蚀性,因此在含有矿物质与地下水的区域,矿山支护设计与维护时需进行防腐蚀方面的考虑。     

Identification of Darunavir Derivatives for Inhibition of SARS-CoV-2 3CLpro

The effective antiviral agents that treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed around the world. The 3C-like protease (3CL^pro) of SARS-CoV-2 plays a pivotal role in virus replication; it also has become an important therapeutic target for the infection of SARS-CoV-2. In this work, we have identified Darunavir derivatives that inhibit the 3CL^pro through a high-throughput screening method based on a fluorescence resonance energy transfer (FRET) assay in vitro. We found that the compounds 29# and 50# containing polyphenol and caffeine derivatives as the P2 ligand, respectively, exhibited favorable anti-3CL^pro potency with EC50 values of 6.3 μM and 3.5 μM and were shown to bind to SARS-CoV-2 3CL^pro in vitro. Moreover, we analyzed the binding mode of the DRV in the 3CL^pro through molecular docking. Importantly, 29# and 50# exhibited a similar activity against the protease in Omicron variants. The inhibitory effect of compounds 29# and 50# on the SARS-CoV-2 3CL^pro warrants that they are worth being the template to design functionally improved inhibitors for the treatment of COVID-19.     

JSD220型变速器后盖铸件裂纹缺陷分析与改进

JSD220型变速器在服役过程中后盖铸件会出现裂纹,甚至开裂现象,最终导致变速器功能失效。针对这个问题,从材料的化学成分、力学性能、金相组织以及断口的铸造缺陷等方面综合分析,排除以上相关因素。运用有限元方法对该产品的结构设计更改前、后的结构强度做了对比分析,优化了铸件结构设计。结果表明,改进后的后盖铸件整体强度明显提升,得到了市场实际批量验证,基本消除了JSD220型变速器后盖铸件因裂纹导致的失效现象。工艺改进后,后盖铸件装机服役效果良好。     

Unveiling the roles of alumina as a sintering aid in Li-Garnet solid electrolyte

The superiority of garnet-type solid electrolyte makes it one of most promising candidates for all-solid-state lithium batteries. Several studies show that introduction of alumina during synthesis can greatly improve the density and ionic conductivity of garnet electrolyte Li₇La₃Zr₂O₁₂ (LLZO), but the reason of poor sinterability of LLZO is still unclear. In this study, we reveal that lithium carbonate, which has a high decomposition temperature and covers on the particle surface of LLZO, is the underlying reason that handicaps the sinterability of Li-Garnet electrolyte in air. The addition of alumina promotes the decomposition of Li₂CO₃ (down to 400°C) and the concomitant product LiAlO₂, as a fast Li-ion conductor, facilitates the sintering process and bulids a fast Li-ion conducting network along the grain-boundaries, significantly increasing the ionic conductivity of Li-Garnet electrolyte. By the conventional solid state sintering, the 10 mol% Al₂O₃ modified Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZT-10Al₂O₃) electrolyte reaches a relative density of 96% and shows a conductivity of 0.31 mS cm⁻¹ at room temperature. The prepared LLZT-10Al₂O₃ electrolyte exhibits a good wetting property toward metallic Li electrode with an interfacial resistance of 59 Ω cm² compared to 1270 Ω cm² for LLZT/Li. This work provides a fundamental understanding and a valuable strategy for developing high performance garnet-type electrolyte for all-solid-state lithium batteries.     

Fabrication of graphitic carbon spheres and their application in Al2O3‐SiC‐C refractory castables

Graphitic carbon spheres (GCS) with an average diameter of about 0.8 μm were prepared via hydrothermal carbonization combined with catalytic graphitization using glucose and in situ formed Fe nanoparticles (NPs) as, respectively, a carbon precursor and catalyst. They were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and thermogravimetric analysis/differential scanning calorimetry (TG/DSC). The optimal content of Fe catalyst for graphitization of amorphous CS was found to be 1.0 wt%, and the optimal temperature and soaking time were, respectively, 1473 K and 3 hours. The transformation from CS to GCS was considered to be dominated by the “dissolution‐precipitation” mechanism. Using as‐prepared GCS instead of flake graphite (FG) as a carbon source, not only reduced water demand for casting Al₂O₃‐SiC‐C samples and decreased their final apparent porosity, but also enhanced their modulus of rupture and cold crushing strength. In addition, castable samples using GCS showed better oxidation resistance than those using FG.     

绿-黄可逆电热致变色织物的制备及其性能

石墨烯因其优异的导电性、优越的柔韧性和环境稳定性, 在可穿戴电子纺织品领域发挥了重要作用。本工作通过丝网印刷技术分别将自制的石墨烯浆料和复合热致变色油墨印在聚酯织物的正反面, 构筑了一种石墨烯基绿-黄可逆电热致变色织物。采用SEM、XRD以及FTIR等分析了织物的结构性质和变色原理, 采用红外热成像仪及全色差色度仪研究了织物的热学以及变色性能。结果表明：石墨烯电热致变色织物厚度约为250 μm, 在12 V电压下逐渐加热超过45 ℃, 焦耳热主要通过热传导至变色层, 结晶紫内酯的闭开环实现绿-黄可逆变色, 其变色响应时间约为15 s, 褪色响应时间约为27 s。石墨烯电热致变色织物经历30°~180°的弯曲角度后, 电压-电流曲线保持稳定。经200次加热/冷却循环后, 性能未发生明显衰退。本研究成功制备了颜色在绿-黄之间变化、响应迅速、循环性能良好的可逆电热致变色织物：石墨烯膜‖聚酯织物‖热致变色膜, 在军事伪装和可穿戴显示领域有一定的应用前景。     

Green lignin-based polyester nanofiltration membranes with ethanol and chlorine resistance

As the main water treatment material, polymeric membranes inevitably suffer from membrane fouling. In this work, novel lignin-based polyester composite nanofiltration membranes (NFM) with ethanol and chlorine resistance were fabricated via interfacial polymerization. Lignin alkali (LA), a green lignin derivative, typically treated as chemical waste in the paper industry, was employed as the aqueous monomer, trimesoyl chloride (TMC) is served as the organic monomer. The structure and separation properties of the lignin-based NFM were studied, revealing that the dense polyester separation layer may show good performance for dye removal. The rejections of the optimized LA/TMC-3 membrane with an excellent permeation flux of 13.9 kg m^?2?h^?1 for rose Bengal sodium salt, brilliant blue, congo red, rhodamine B, MgSO₄, and NaCl are 97.6%, 97.3%, 97.8%, 71.34%, 51.4%, and 31.8%, respectively. Moreover, the LA/TMC-3 membrane also shows long-term tolerance in ethanol and sodium hypochlorite solution; the rejection of LA/TMC-3 to dye only decreases 8% after 8 days when immersed in alcohol, while the normalized rejection maintains 94% after 4000 ppm-hours of continuous exposure to chlorine. This lignin-based polyester membrane may broaden the sustainable utilization sphere of lignin derivatives, at that provide a referable direction for the development of membrane materials.     

基于改进DBN的回转支承寿命状态识别

为了解决大型回转支承背景噪声大,特征信号微弱,寿命状态难以识别等问题,提出了一种基于改进深度信念网络(Deep Belief Network,DBN)的回转支承寿命状态识别方法。DBN网络拥有强大的深度学习能力,能够有效挖掘回转支承运行状态信息,解决了传统浅层网络过度依赖特征提取效果和识别精度不高的问题。在DBN学习训练中,采用新的优化学习方法FEPCD(Free Energy in Persistent Contrastive Divergence),解决了DBN在长期学习中近似和分类能力下降的问题。然后利用自主研发试验台的试验数据对所提方法的优越性进行验证。将改进的DBN算法与浅层分类算法的识别结果进行比较。结果表明改进DBN网络比原始DBN网络和浅层算法能更精确反映回转支承寿命特征,所提方法具有稳定性和智能性的特点。     

固相接枝法制备聚丙烯相容剂

通过固相接枝法将甲基丙烯酸缩水甘油酯（GMA）、苯乙烯（St）接枝到聚丙烯（PP）主链上制得聚丙烯相容剂。讨论了界面剂、引发剂、GMA、St、反应时间与反应温度对产物接枝率的影响,结果发现这些实验条件均对聚丙烯相容剂接枝率产生较大的影响,最佳的制备条件为m（PP）：m（GMA）：m（St）：m（BPO）：m（二甲苯）=100：15：15：1：10,反应温度为120℃,反应时间为1h。