摘要：Dermal substitutes have provided a template for the regeneration and reconstruction of the ***,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and *** this study,a composite bioink composed of methacrylated gelatin(GelMA)and chitosan oligosaccharide(COS)was proposed for printing a dermal scaffold using digital light processing(DLP)*** GelMA/COS bioink exhibited suitable porosity,swelling,degradation rate,and mechanical *** inclusion of COS demonstrated antibacterial effects against both Gram positive and Gram-negative bacteria,while simultaneously fostering the proliferation of human dermal fibroblasts(HDFs).Additionally,the application of COS could effectively reduce the expression levels of fibrosis-related genes,such as collagen I,collagen III,and fibronectin *** three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability,facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix ***,the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure,reduce inflammation,and improve wound ***,the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.

摘要：Traditional tumor models do not tend to accurately simulate tumor growth in vitro or enable personalized treatment and are particularly unable to discover more beneficial targeted *** address this,this study describes the use of threedimensional(3D)bioprinting technology to construct a 3D model with human hepatocarcinoma SMMC-7721 cells(3DP-7721)by combining gelatin methacrylate(GelMA)and poly(ethylene oxide)(PEO)as two immiscible aqueous phases to form a bioink and innovatively applying fluorescent carbon quantum dots for long-term tracking of *** GelMA(10%,mass fraction)and PEO(1.6%,mass fraction)hydrogel with 3:1 volume ratio offered distinct pore-forming characteristics,satisfactorymechanical properties,and biocompatibility for the creation of the 3DP-7721 *** analysis and quantitative real-time fluorescence polymerase chain reaction(PCR)were used to evaluate the biological properties of the *** with the two-dimensional culture cell model(2D-7721)and the 3D mixed culture cell model(3DM-7721),3DP-7721 significantly improved the proliferation of cells and expression of tumor-related proteins and ***,we evaluated the differences between the three culture models and the effectiveness of antitumor drugs in the three models and discovered that the efficacy of antitumor drugs varied because of significant differences in resistance proteins and genes between the three *** addition,the comparison of tumor formation in the three models found that the cells cultured by the 3DP-7721 model had strong tumorigenicity in nude *** evaluation of the levels of biochemical indicators related to the formation of solid tumors showed that the 3DP-7721 model group exhibited pathological characteristics of malignant tumors,the generated solid tumors were similar to actual tumors,and the deterioration was *** research therefore acts as a foundation for the application of 3DP-7721 models in drug devel

摘要：论述了一种基于并行质量工程的分析、优化机械装配公差的方法———6σ公差设计方法。以面向6σ设计为导向,通过实例探讨了如何在公差设计中将6σ质量设计到产品之中,进而给出设计和优化的流程。

摘要：目前大多数研究在进行二维质保期和价格的联合优化时,往往将预防性维护策略作为已知方案进行考虑,忽略了对质保期内预防性维护策略的联合设计。针对该问题,从制造商的视角,对二维基础质保期、预防性维护策略和产品价格进行联合设计与优化。考虑不同使用率顾客在二维质保结束时间和使用量上的差异性,构建基于二维质保期的需求模型和考虑周期预防性维护的质保成本模型。以制造商的期望利润最大化为目标,对基础质保时间和使用量限制、预防性维护次数和水平,以及产品价格进行优化。最后,通过算例和敏感性分析验证了模型方法的有效性。该研究能够为制造商开展二维质保政策联合设计与优化提供理论和实践指导建议。

摘要：针对不同编织角、不同纤维体积分数的三维五向炭纤维/酚醛编织复合材料在不同温度下进行了纵向(编织方向)压缩和横向压缩试验,获得了其主要压缩力学性能,分析了编织参数、温度对材料压缩力学性能的影响。对试件断口进行了宏观及扫描电镜观察,从宏、细观角度研究了材料的变形及其破坏机制。结果表明,三维五向炭纤维/酚醛编织复合材料的压缩应力-应变曲线呈现明显的非线性特征,且温度效应明显;编织角和纤维体积分数是影响材料压缩性能的主要参数。三维五向炭纤维/酚醛编织复合材料的纵向压缩与横向压缩具有完全不同的破坏机制。

摘要：产品市场竞争的加剧对二维质保内维修策略与质保期的系统设计提出了迫切需求。当前二维质保期设计与优化研究主要基于市场弹性,存在关联函数建模困难、参数拟合准确性差、未有效结合预防性维修策略优化等问题。针对以上不足,首先,在分析一维质保效用模型不足的基础上,建立了基于质保服务时间与里程的二维质保效用模型;其次,在分析不同预防性维修策略对产品失效率与质保服务成本影响的基础上,构建了等成本下考虑预防性维修策略的二维质保期设计与优化模型,将二维质保期设计与质保内预防性维修策略优化进行了有效结合;最后,采用算例分析对模型的有效性和适用性进行了验证。

摘要：恰当的随访策略对于预防不良后果、控制医疗服务成本具有重要意义。现有研究采用马尔可夫模型、数学规划等运筹学方法设计随访策略,缺乏对患者不守时随访行为的考虑,所得策略无法满足不同患者的差异化需求。本文利用Cox-Frailty模型构建不良后果风险函数,并将患者分为不同风险组别;引入一组独立同分布的随机变量对策略规定的随访时间和患者实际的随访时间的差值进行建模;结合virtual age和随机过程方法精准核算计划时间区间的医疗服务成本,并构建以该成本最小为目标函数的混合整数非线性规划模型。利用所提模型得到不同风险水平的儿童1型糖尿病患者在1年内的最优随访次数和随访时间间隔,以及患者守时和不守时情况下的策略变化规律,从而为医疗机构进行策略动态调整提供依据。

摘要：互联网技术的发展促成了新营销方式的形成,乳制品销售开始转向线上。本研究设计了调查问卷,以了解河北省城镇居民乳制品线上消费的现状,通过二元Logistic模型分析影响河北省城镇居民乳制品线上消费的影响因素。结果表明:河北省城镇居民乳制品线上消费支出偏低,每月乳制品消费200元以下的占80%;线上消费平台偏好淘宝,产品类别偏好酸奶,产品品牌偏好伊利、蒙牛。并构建了影响因素的指标体系,分别分析了个人因素、乳制品产品因素、社会因素、认知因素对于乳制品线上消费的影响。据此提出增强乳制品质量安全信息的及时性和透明度、规范乳制品线上销售市场、提高乳制品质量安全水平、借助新兴媒体平台进行销售、引导消费者转变消费观念和方式等对策建议。

摘要：根据大型对日定向装置的结构特点和受力特性,调整传力结构,充分利用纤维增强复合材料结构的可设计性,开展优化设计。在保证高刚度和轻量化的同时,克服结构大开口带来的承载能力不足,设计出结构质量与承载比仅为5.2%,集舱段和壳体功能于一体的大型对日定向装置复合材料主承力架结构。建立有限元模型,分别采用Tsai-Wu和最大应变2种纤维增强复合材料的强度失效准则,对其进行校核。开展静力试验,采集应变等信息,与有限元仿真分析结果展开对比。结果表明:其整体趋势一致,顺利通过试验考核。

摘要：铁相对水泥混凝土耐久性具有显著的积极作用,为拓宽铁相来源,本文研究了铁盐对铝酸盐水泥性能及水化产物的影响。通过将铝酸盐水泥和硫酸盐(二水石膏和硫酸亚铁)复合,使铝酸盐水泥水化生成以钙矾石为主的产物,在此基础上,研究了硫酸盐中硫酸亚铁比例对铝酸盐水泥浆体凝结时间、抗压强度以及体积稳定性的影响规律,并采用XRD和SEM分析水化产物类型以及微观形貌,阐明硫酸亚铁对水泥浆体性能的影响机理。结果表明:适量的硫酸盐可提升铝酸盐水泥浆体的抗压强度;硫酸亚铁对铝酸盐水泥表现出轻微的促凝作用,对膨胀率具有显著的抑制作用;硫酸亚铁对钙矾石的形成具有明显的抑制作用,适量的硫酸亚铁使得所生成的钙矾石尺寸较小,且分布均匀,有利于提升硬化浆体的抗压强度。