铍材料精密电火花加工工艺研究

针对铍材料机械加工性能较差的缺点,进行了电火花精密加工工艺的探索;通过负极性和以较低放电能量的加工方式,突破了机械加工极限,得到了厚度为0.05mm左右的铍薄膜。     

Polydimethylsiloxane wrapped aluminum diethylphosphinate for enhancing the flame retardancy of polyamide 6

Aluminum diethylphosphinate (ADP) was wrapped with polydimethylsiloxane (PDMS) by a facile method to improve its hydrophobic properties. The morphology and properties of PDMS-modified ADP (PDMS-ADP) were investigated by thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and water contact angle tests. The water contact angle of PDMS-ADP was increased from 126° to 151° as compared with that of ADP, which indicates that PDMS-ADP showed good hydrophobic properties. Then, ADP and PDMS-ADP were introduced into polyamide 6 (PA6) matrices to study the flame retardancy of the composites. The flammability of the PA6/ADP and PA6/PDMS-ADP composites was much lower than that of pure PA6. The composites PA6-1 (with the addition of 15 wt% ADP) and PA6-4 (with the addition of 12 wt% PDMS-ADP) could pass the UL-94 V-0 in the vertical burning test. Meanwhile, the peak heat release rates of PA6-1 and PA6-4 were 212 and 192 kW/m², with reductions of 67.3 and 70.4%, respectively, compared with pure PA6. These results indicated that the coating of PDMS could enhance the flame-retardant efficiency of ADP.     

DRD2和5-HTR2A基因多态性及其交互作用对奥氮平治疗精神分裂症疗效的影响

目的：探讨多巴胺D2受体（dopamine D2 receptor, DRD2）和5-羟色胺2A受体（5-hydroxytryptamine 2A receptor, 5-HTR2A）基因多态性及其交互作用与奥氮平治疗精神分裂症疗效的关系。方法：纳入147例接受单一奥氮平治疗的精神分裂症住院患者为研究对象，采用阳性与阴性症状量表（PANSS）评定药物疗效，按PANSS减分率≥50%和<50%，分为有效组和无效组。采用多重高温连接酶检测反应技术（iMLDR）检测DRD2（rs1799978、rs1800497）和5-HTR2A（rs6311、rs6313）基因多态性；采用多因素Logistic回归分析各基因型和奥氮平疗效的关联性，采用多因子降维法（MDR）分析基因-基因的交互作用。结果：有效组和无效组rs1799978、rs6313位点基因型和等位基因频率分布差异均有统计学意义（P<0.05），而两组rs1800497、rs6311位点基因型和等位基因频率分布差异均无统计学意义（P>0.05）；rs1799978位点GA和GG型患者奥氮平疗效较野生AA型好，其比值比（OR）及95%CI分别为5.101（1.118～23.267）、6.051（2.454～14.925）；rs6313位点CT和CC型患者奥氮平疗效较野生TT型好，其OR及95%CI分别为2.623（1.054～6.528）、3.412（1.180～9.869）；rs1799978、rs1800497和rs6313位点间存在交互作用，其交互模型为最优基因-基因交互作用模型（P<0.05），该模型检验样本准确度为0.727 3，交叉验证一致性为10/10。结论：DRD2（rs1799978）和5-HTR2A（rs6313）基因多态性可能与奥氮平治疗精神分裂症疗效相关，DRD2（rs1799978、rs1800497）和5-HTR2A（rs6313）对奥氮平疗效的影响存在交互作用。     

高韧性环氧沥青及混合料性能影响因素分析

开发了一种新型高韧性环氧沥青,研究了树脂用量、相容剂种类及用量、高温固化复配体系对高韧性环氧沥青及混合料性能的影响。试验结果表明,随着树脂用量增加,高韧性环氧沥青及混合料的性能随之增强,合适的树脂用量为40%;自制的相容剂能有效改善树脂与基质沥青的相容性,其最佳用量为10%;采用高温固化剂与中温固化剂复配体系,当其用量比为9∶1时,高韧性环氧沥青及混合料能获得良好的力学性能,且常温养护7 d即可形成最终强度。高韧性环氧沥青及混合料具有与进口材料同样优异的性能。     

Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.     

Designing Champion Nanostructures of Tungsten Dichalcogenides for Electrocatalytic Hydrogen Evolution

Fine-tuning strain and vacancies in 2H-phase transition-metal dichalcogenides, although extremely challenging, is crucial for activating the inert basal plane for boosting the hydrogen evolution reaction (HER). Here, atomically curved 2H-WS₂ nanosheets with precisely tunable strain and sulfur vacancies (S-vacancies) along with rich edge sites are synthesized via a one-step approach by harnessing geometric constraints. The approach is based on the confined epitaxy growth of WS₂ in ordered mesoporous graphene derived from nanocrystal superlattices. The spherical curvature imposed by the graphitic mesopores enables the generation of uniform strain and S-vacancies in the as-grown WS₂ nanosheets, and simultaneous manipulation of these two key parameters can be realized by simply adjusting the pore size. In addition, the formation of unique mesoporous WS₂@graphene van der Waals heterostructures ensures the ready access of active sites. Fine-tuning the WS₂ layer number, strain, and S-vacancies enables arguably the best-performing HER 2H-WS₂ electrocatalysts ever reported. Density functional theory calculations indicate that compared with strain, S-vacancies play a more critical role in enhancing the HER activity.     

Revealing Electrical-Poling-Induced Polarization Potential in Hybrid Perovskite Photodetectors

Despite recent rapid advances in metal halide perovskites for use in optoelectronics, the fundamental understanding of the electrical-poling-induced ion migration, accounting for many unusual attributes and thus performance in perovskite-based devices, remain comparatively elusive. Herein, the electrical-poling-promoted polarization potential is reported for rendering hybrid organic–inorganic perovskite photodetectors with high photocurrent and fast response time, displaying a tenfold enhancement in the photocurrent and a twofold decrease in the response time after an external electric field poling. First, a robust meniscus-assisted solution-printing strategy is employed to facilitate the oriented perovskite crystals over a large area. Subsequently, the electrical poling invokes the ion migration within perovskite crystals, thus inducing a polarization potential, as substantiated by the surface potential change assessed by Kelvin probe force microscopy. Such electrical-poling-induced polarization potential is responsible for the markedly enhanced photocurrent and largely shortened response time. This work presents new insights into the electrical-poling-triggered ion migration and, in turn, polarization potential as well as into the implication of the latter for optoelectronic devices with greater performance. As such, the utilization of ion-migration-produced polarization potential may represent an important endeavor toward a wide range of high-performance perovskite-based photodetectors, solar cells, transistors, scintillators, etc.     

Collective reflection strategy for moderating conformity tendency and promoting reflective judgment performance

Reflective judgement is crucial for medical-related practitioners in dealing with controversial issues. However, the conformity phenomenon is likely to occur and interfere with reflective judgement learning during interactive activities. Effective strategies are required to moderate the conformity behaviour tendency (CBT) and improve reflective judgement performance (RJP). This study demonstrates two significant results: (a) Compared with the guided self-reflection learning strategy, the online collective reflection (OCR) learning strategy effectively weakened the learners' general CBT while dealing with professional controversial issues; and (b) a significantly negative correlation between the RJP achieved and the change of CBT in online environment was detected in the OCR group. The implications and potential applications in higher education were discussed. Further studies are needed to confirm the long-term effects and the extending application to other professional studies.