微观组织演变对细晶Mg-Y-Nd合金超塑性性能的影响

在初始应变速率为2×10^-2~4×10^-4 s^-1,温度为683~758 K的条件下,对用水下搅拌摩擦加工制备的细晶Mg-Y-Nd合金进行高温拉伸实验,研究了微观组织演变对其超塑性性能的影响。结果表明:因为具有细小均匀的微观组织和良好的热稳定性,Mg-Y-Nd合金在733 K和3×10^-3 s^-1初始应变速率下表现出最大的伸长率(967%),在758 K和2×10^-2 s^-1条件下表现出最优的高应变速率超塑性(900%)。在高温下暴露时间过长导致α-Mg晶粒和第二相颗粒显著长大,使试样的伸长率明显降低;因为第二相颗粒与镁基体之间有良好的变形协调性,在相界处不会产生明显的应力集中,裂纹主要在晶界生成。     

超声作用下刚性壁面附近的双气泡脉动

在实际应用时,空化泡可能位于刚性壁附近。对刚性壁附近的空化泡脉动进行研究有利于更好地利用声空化。文章研究了刚性壁附近双气泡的动力学规律。研究结果表明,当两气泡与刚性壁距离相同时,气泡与壁之间的距离越大,刚性壁对辐射声波的反射越小,气泡脉动时能够达到的最大半径与最小半径的比值(即压缩比)也越大。若改变单个气泡与刚性壁的距离,则当两个气泡距离接近时,位置固定的气泡压缩比会减小。增大单个气泡的平衡半径,会使得两气泡脉动时的压缩比变小。此外,文章还对两气泡间距固定情况下,气泡压缩比与两气泡中心连线和壁面所成夹角之间的关系进行了讨论。     

环境相对湿度对牛皮纸垫缓冲性能影响的研究

目的 探究环境相对湿度对新型牛皮纸垫缓冲性能的影响。方法 基于静、动态压缩试验,分析叠加层数分别为2、3、4的牛皮纸垫在环境相对湿度分别为30%、50%、70%、90%条件下的缓冲性能。结果 在静态压缩试验中,牛皮纸垫静压承载能力随着环境相对湿度的增大而减弱、叠加层数的增多而增强。不同规格纸垫存在对应的湿度应力分界值,当材料所受外力小于湿度应力分界值时,其缓冲性能随着湿度的增大而提高;当外力大于湿度应力分界值时,缓冲性能随湿度的增大而减弱。一定湿度条件下,叠加层数对牛皮纸垫缓冲性能也存在影响：相对湿度为30%时,缓冲性能随叠加层数的增多而减弱;相对湿度为50%、70%、90%时,存在层数应力分界值,当材料所受外力小于层数应力分界值时,其缓冲性能随叠加层数的增多而减弱,当外力大于层数应力分界值时,缓冲性能随叠加层数的增多而增强。在动态压缩试验中,随着环境相对湿度的增加,牛皮纸垫传递给产品的最大加速度增大,缓冲性能减弱;叠加层数的增多,使其传递给产品的最大加速度减小,缓冲性能增强。结论 研究结果对牛皮纸垫缓冲包装的设计和材料选择存在潜在的指导意义。     

微波杀菌及包装材料的微波穿透性对湿豆皮保鲜品质的影响

目的 探究不同包装材料结合微波杀菌对湿豆皮保鲜效果的影响,为湿豆皮提供新的保鲜方案。方法 将湿豆皮分别装入OPP/PE和PET/PE/CPP材料的包装袋中,经密封后进行微波杀菌处理,测定其贮藏期间的指标。结果 经微波处理后,湿豆皮在OPP/PE中的表面温度比在PET/PE/CPP中高8 ℃,菌落总数少0.66 lg(CFU/g),说明微波更易穿透OPP/PE材料,更能有效延缓长期贮藏中因微生物活动造成的氧气含量下降和二氧化碳上升,延缓湿豆皮的pH值、水分含量和拉伸性的下降,抑制其TVB-N含量的上升,从而抑制组织结构的破坏,减缓脂质酸败的速率,还可减小色差的变化幅度,维持更高的感官评价得分。结论 采用微波处理能够有效延长湿豆皮的保鲜期,OPP/PE和PET/PE/CPP材料组湿豆皮的保鲜期分别延长了15、12 d左右,且对不同材料包装的湿豆皮品质的影响差异显著。采用微波穿透性更好的包装材料,其微波作用强度更大,杀菌效果更明显,保鲜效果更好。     

隔热疏水功能涂料研究进展

目的 归纳隔热疏水涂料的功能实现方法,分析疏水隔热功能涂料在包装中的潜在的应用价值,为新型多功能涂料的制备及其在纸包装领域的应用提供参考和借鉴。方法 梳理并归纳阻隔型、反射型、辐射型等3种类型隔热涂料的工作原理及实现方式,系统介绍几种常见的疏水表面形成机理模型以及制备方法,综述疏水隔热功能涂料的应用研究进展。结果 涂料的制备以及涂布技术已经成熟,疏水隔热功能涂料可涂布于瓦楞纸箱、白卡纸等表面用于食品保温包装。结论 将隔热疏水功能涂料用于纸包装箱,用来保护温敏食品品质和节约冷链运输成本,具有巨大的潜力和广阔的发展前景。     

Highly Exposed ?NH2 Edge on Fragmented g-C3N4 Framework with Integrated Molybdenum Atoms for Catalytic CO2 Cycloaddition: DFT and Techno-Economic Assessment

This study focuses on the applicability of single-atom Mo-doped graphitic carbon nitride (GCN) nanosheets which are specifically engineered with high surface area (exfoliated GCN),  NH₂ rich edges, and maximum utilization of isolated atomic Mo for propylene carbonate (PC) production through CO₂ cycloaddition of propylene oxide (PO). Various operational parameters are optimized, for example, temperature (130 °C), pressure (20 bar), catalyst (Mo₂GCN), and catalyst mass (0.1 g). Under optimal conditions, 2% Mo-doped GCN (Mo₂GCN) has the highest catalytic performance, especially the turnover frequency (TOF) obtained, 36.4 h⁻¹ is higher than most reported studies. DFT simulations prove the catalytic performance of Mo₂GCN significantly decreases the activation energy barrier for PO ring-opening from 50–60 to 4.903 kcal mol⁻¹. Coexistence of Lewis acid/base group improves the CO₂ cycloaddition performance by the formation of coordination bond between electron-deficient Mo atom with O atom of PO, while  NH₂ surface group disrupts the stability of CO₂ bond by donating electrons into its low-level empty orbital. Steady-state process simulation of the industrial-scale consumes 4.4 ton h⁻¹ of CO₂ with PC production of 10.2 ton h⁻¹. Techno-economic assessment profit from Mo₂GCN is estimated to be 60.39 million USD year⁻¹ at a catalyst loss rate of 0.01 wt% h⁻¹.     

Peptidyl Virus-Like Nanovesicles as Reconfigurable “Trojan Horse” for Targeted siRNA Delivery and Synergistic Inhibition of Cancer Cells

The self-assembly of peptidyl virus-like nanovesicles (pVLNs) composed of highly ordered peptide bilayer membranes that encapsulate the small interfering RNA (siRNA) is reported. The targeting and enzyme-responsive sequences on the bilayer's surface allow the pVLNs to enter cancer cells with high efficiency and control the release of genetic drugs in response to the subcellular environment. By transforming its structure in response to the highly expressed enzyme matrix metalloproteinase 7 (MMP-7) in cancer cells, it helps the siRNA escape from the lysosomes, resulting in a final silencing efficiency of 92%. Moreover, the pVLNs can serve as reconfigurable “Trojan horse” by transforming into membranes triggered by the MMP-7 and disrupting the cytoplasmic structure, thereby achieving synergistic anticancer effects and 96% cancer cell mortality with little damage to normal cells. The pVLNs benefit from their biocompatibility, targeting, and enzyme responsiveness, making them a promising platform for gene therapy and anticancer therapy.     

钢铁企业能源中心系统设计

在钢铁企业生产过程中,能源的稳定供给是保证正常生产的必备条件之一.如何高效、合理利用能源,已成为当今钢铁企业必须面对和亟待解决的战略问题.为了加强对钢铁企业复杂多样的能源介质和能源设施的综合管理,以国内某大型钢铁联合企业为背景,针对该企业能源管理分散和调度系统独立等问题,从系统总体结构和系统主要功能等方面介绍了能源中心...     

普通本科院校信息与计算科学专业实习实训方案设计

分析当前普通高校信息与计算科学专业学生实习实训模式存在的主要问题,并针对这些问题提出一些解决方案;探讨适合学生实习实训要求的企业实训模式,以安庆师范学院信息与计算科学专业学生实习实训模式为例,对学生实习实训的计划和实施过程进行了阐述。实践表明,新的实训模式能够使学生取得良好的实习实训效果。     

Piecewise output feedback control for affine systems with disturbances based on linear temporal logic specifications

In the paper,we investigate the problem of finding a piecewise output feedback control law for an uncertain affine system such that the resulting closed-loop output satisfies a desired linear temporal logic (LTL) specification.A two-level hierarchical approach is proposed to solve the problem in a triangularized output space.In the lower level,we explore whether there exists a robust output feedback control law to make the output starting in a simplex either remains in it or leaves via a specific facet.In the higher level,for the triangularization,we construct the transition system according to the reachability relationship obtained in the lower level and search for feasible paths that meet the LTL specification.The control approach is then applied to solve a motion planning problem.