纸箱包装机连续高速纸板供给机构的设计探讨

纸板供给是高速纸箱包装机的瓶颈之一,为了满足80箱/min纸箱包装机的供板需求,提出垂直与水平相结合的解决方案。垂直输送技术比较成熟,实际应用比较普遍,为了提高水平输送速度,提出采用纸板水平短距离移动机构和对辊输送机构相配合的设计方案,对各部件工作原理及结构原理进行分析,论述设计的合理性和实用性,实现快速输送。     

面向快递业服务质量评估的组合评价方法研究

针对快递业发展现状以及在服务质量方面存在的问题,通过市场调研和数据分析,采用科学的分析方法,构建快递业服务质量评价指标体系。在该体系上应用层次分析法、民意调查法、专家定见法等获取各项的指标权重,对查询的快递企业用模糊综合评价法进行服务质量的分析评价,以获取快递型企业的服务满意度,以此提升整体服务绩效。     

基于坡面径流输沙模型的湘中红壤丘陵区土壤有机碳流失模拟研究

坡面径流是泥沙和土壤有机碳(soil organic carbon,SOC)流失的主要动力.本研究以典型湘中红壤丘陵区坡耕地(翻耕和免耕)为研究对象,通过野外径流小区模拟降雨试验,对已建立的以径流率为变量的对数线性回归坡面径流输沙模型进行修正,并结合泥沙中SOC的富集特性,建立湘中红壤丘陵区的坡面SOC流失模型.研究结果表明:坡面SOC流失模型能够有效地应用于湘中红壤丘陵区次降雨过程中坡面SOC流失的模拟中,且具有较好地模拟效果,SOC流失率模拟平均误差在30%左右,决定系数在0.85以上;同时模拟结果表明,泥沙和SOC流失过程在坡面径流侵蚀影响下呈现波动状态,表现为产流开始后10min泥沙和SOC流失呈增加趋势,其后在波动中逐渐趋于平稳;通过比较翻耕和免耕条件坡面径流输沙和SOC流失模型,结果显示侵蚀性降雨条件下,翻耕方式泥沙和SOC流失率大于免耕方式.非侵蚀性降雨条件下,翻耕方式泥沙和SOC流失状况与免耕方式一致.     

糖复合物的生物应用

糖类化合物是一类很重要的生物大分子,它在细胞膜表面通过形成各种复合物参与许多重要的生理活动。主要讨论了近几年糖类复合物在药物靶向传递及肿瘤成像/检测等方面的研究进展,综述了叶酸、寡糖等作为靶向基团的药物靶向传递体系,同时探讨了各种糖类复合物在细胞成像及生物检测方面的应用,指出了未来糖化学的发展前景。     

未成年子女作为探望权主体之伦理考察

家庭成员之间的权利与义务关系主要根据血缘亲情而构建,涉及到一系列伦理价值判断。2001年婚姻法仅规定离婚后未与子女共同生活一方父或母有探望权,忽略了子女主动与父母进行亲情沟通的伦理需要,将子女置于被动的客体地位。笔者认为,被探望的子女绝非探望权的义务主体,法律进一步明确未成年子女作为探望权的权利主体,符合探望权的伦理价值取向。     

优先队列在物流配送管理中的应用研究

针对物流企业在配送管理业务流程中的要求与特点，提出了采用优先级队列来实现分拣配货的动态调度观点，并对涉及动态调度过程中的相关数据结构与算法进行了设计，采用此技术可以提高企业的经济与社会效益．     

病的隐喻与城市批判--李佩甫《城市白皮书》的"病相"解读

<城市白皮书>作为李佩甫整个小说创作中较为独特的一部,其潜在意义远值得深刻的挖掘,其叙事策略的独异性也值得合理有效的阐释."病孩"明明作为小说的视点人物,使小说批判城市的主题得到了更为恰切有效的表达."病孩"在叙述功能中显现出来的矛盾性与深刻性,尤其值得关注.     

带二维装箱约束的需求可拆分车辆路径问题模型及算法研究

车辆配送计划时通常会考虑货物易损、易碎的可能性,以及如何充分利用有限的运输资源对货物进行配送以满足顾客的需求。在车辆有限、货物易损坏、顾客需求可进行拆分等环境下,实现车辆配送总路径最短,即考虑二维装箱约束的客户需求可拆分的车辆路径问题。对问题进行详细定义,建立了2L-SDVRP模型。将遗传算法与BLF算法的结合求解模型;并用数值案例验证算法有效性。     

Preparation and cellular uptake of PLGA particles loaded with lamivudine

Poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles loaded with lamivudine and coated with bovine serum albumin (BSA) were prepared via a double emulsion method. The influences of experiments parameters such as volume of inner aqueous phase, concentration of organic phase and ultrasonication time on the particle size and drug entrapment efficiency were investigated, obtaining PLGA particles with a diameter of ~260 nm and drug entrapment efficiency of ~35%. The particles were observed by scanning electron microscopy and transmittance electron microscopy, showing a core-shell structure. BCA assay found that 58 mg BSA was present on/in 1 g LPB particles. The loaded lamivudine showed a burst release at beginning and sustained release until 24 h in physiological conditions. Low pH could accelerate the release of lamivudine from PLGA particles, making the PLGA particles potential intelligent intracellular drug carriers. The PLGA particles were readily internalized into the human liver cells within a short time and increased gradually with the prolongation of incubation time regardless of the loading of lamivudine. The particles either resided within lysosomes or transferred to cytoplasm, but could not enter into the cell nucleus. The cell viability was not significantly influenced in the presence of the particles regardless of lamivudine encapsulation, suggesting that this kind of particles may be a good candidate for the intracellular anti-hepatitis B drug delivery.     

Enhancement of the efficiency of PEI/liposome transfection by magnetofectins formed via electrostatic self-assembly

One of the major challenges for successful gene therapy is improving the transfection efficiency of non-viral vectors. Magnetic nanoparticles (MNPs) have been developed as enhancers of non-viral vehicles. We prepared MNPs and modified them with polyethyleneimine (PEI), citric acid (CA) or carboxylmethyl-dextran (CMD). Both positively charged MNPs (MNPs@PEI) and negatively charged MNPs (MNPs@CA, MNPs@CMD) could spontaneously form transfection complexes (magnetofectins) with plasmid DNA and PEI/liposome via electrostatic self-assembly. Our results showed as-prepared magnetofectins apparently enhanced PEI/liposome transfection efficiency and/or gene expression level into COS-7 cells with reduced transfection time from 4 h to 15 min under a magnetic field in vitro. Meanwhile, the effect of magnetofection was cell line-dependant. These results suggest that charged MNPs could improve transfection efficiency for non-viral vectors by simply mixing with them and by exerting a magnetic force. Thus such MNPs provide a convenient platform for further applications of gene delivery.