并行工程环境下面向装配的设计系统

提出了一种在并行工程下面向装配的产品设计方法,通过对面向装配设计中的关键技术问题,如产品的装配模型、装配顺序规划、机构运动分析与综合、装配过程仿真及产品可装配性评价等方法的探讨,实现了面向装配的设计目标.     

Comprehensive, in operando, and correlative investigation of defects and their impact on device performance

Despite the long history of research that has focused on the role of defects on device performance, the studies have not always been fruitful. A major reason is because these defect studies have typically been conducted in a parallel mode wherein the semiconductor wafer was divided into multiple pieces for separate optical and structural characterization, as well as device fabrication and evaluation. The major limitation of this approach was that either the defect being investigated by structural characterization techniques was not the same defect that was affecting the device performance or else the defect was not characterized under normal device operating conditions. In this review, we describe a more comprehensive approach to defect study, namely a series mode, using an array of spatially-resolved optical, electrical, and structural characterization techniques, all at the individual defect level but applied sequentially on a fabricated device. This novel sequential approach enables definitive answers to key questions, such as: (i) how do individual defects affect device performance? (ii) how does the impact depend on the device operation conditions? (iii) how does the impact vary from one defect to another? Implementation of this different approach is illustrated by the study of individual threading dislocation defects in GaAs solar cells. Additionally, we briefly describe a 3-D Raman thermometry method that can also be used for investigating the roles of defects in high power devices and device failure mechanisms.     

Interlocked MXene/rGO aerogel with excellent mechanical stability for a health-monitoring device

Two-dimensional (2D) materials have attracted considerable interest thanks to their unique electronic/physical–chemical characteristics and their potential for use in a large variety of sensing applications. However, few-layered nanosheets tend to agglomerate owing to van der Waals forces, which obstruct internal nanoscale transport channels, resulting in low electrochemical activity and restricting their use for sensing purposes. Here, a hybrid MXene/rGO aerogel with a three-dimensional (3D) interlocked network was fabricated via a freeze-drying method. The porous MXene/rGO aerogel has a lightweight and hierarchical porous architecture, which can be compressed and expanded several times without breaking. Additionally, a flexible pressure sensor that uses the aerogel as the sensitive layer has a wide response range of approximately 0–40 kPa and a considerable response within this range, averaging approximately 61.49 kPa^–1. The excellent sensing performance endows it with a broad range of applications, including human-computer interfaces and human health monitoring.     

新型凝胶泡沫材料阻化性能实验研究

为研究新型凝胶泡沫对煤体阻化作用的效能与影响,基于程序升温实验,对凝胶泡沫处理前后的不同粒径煤样组进行实验,分析煤样升温过程中的耗氧速率、CO与CH₄气体体积分数及其产生率,以及凝胶泡沫对煤样的阻化率。研究结果表明：煤的粒径不同,其耗氧速率也不同,经新型凝胶泡沫处理煤样的CO、CH₄气体的体积分数及其产生率均明显低于未经处理的煤样;在100 ℃时,粒径小于0.9 mm煤样的阻化率为59.23%,粒径3~5 mm煤样的阻化率为61.69%,粒径6~10 mm煤样的阻化率为65.63%,各粒径煤样受凝胶泡沫的阻化影响顺序为大粒径> 中粒径> 小粒径;新型凝胶泡沫材料能有效延缓煤的氧化过程、抑制煤氧复合反应、延迟煤体蓄热进程,对防治煤自燃具有十分积极的作用。     

基于回采巷道破碎程度的浆液性能选型研究

工作面回采巷道围岩破碎程度不同,应采用不同性能的注浆材料对围岩进行分区、分类加固。采用BP神经网络算法,建立了回采巷道围岩破碎程度与注浆材料性能的“地质条件—浆液性能”互馈模型。该模型选取顶板岩层强度、煤层强度、底板岩层强度等7个地质条件参数作为输入因子,选取注浆材料7 d抗压强度、初凝时间和初始黏度作为输出因子。利用34组数据对模型进行训练,8组数据作为测试样本开展误差分析。结果表明：训练集拟合系数达到0.999 95,测试集输出因子相对误差低于13%,训练和测试效果较好,能够满足基于围岩破碎程度进行浆液参数选型及预测的要求。     

非热杀菌在NFC果汁上的应用前景

为探究浓缩还原（From concentrate,FC）和非浓缩还原（Not from concentrate,NFC）杨梅汁成分的差异,本文借助超高效液相色谱-四极杆飞行时间质谱的代谢组学技术分析二者的代谢产物。通过正交偏最小二乘-判别分析实现了对NFC和FC杨梅汁的区分,根据变量投影重要度和差异倍数筛选出9个差异较大的代谢物,经对比发现,FC杨梅汁中对磺基苯甲酸、5-甲基四氢叶酸、矢车菊素、西瑞香素、花椒毒酚和异黄蝶呤等抗氧化活性成分的含量相对较低,而苦味物质（新橙皮苷、橙皮苷和槲皮素-3-O-新橙皮苷）含量相对较高。通过对差异代谢物的代谢途径分析,筛选出5条差异较大的代谢通路,其中苯丙氨酸代谢、黄酮和黄酮醇的生物合成是NFC与FC杨梅汁中差异代谢物的关键代谢途径。本研究揭示了NFC与FC杨梅汁代谢产物的差异性,为NFC杨梅汁的加工与鉴别提供理论参考。     

鱼香味的烹饪应用

为了优化鱼香肉丝方便菜肴配方,并探究其最佳灭菌条件和储藏方式、鉴定挥发性风味成分,通过单因素试验及正交试验探究辅料添加量对菜肴品质的影响,探讨不同灭菌条件及储藏方式对产品汁液流失率、色差、菌落总数、挥发性盐基氮、pH、丙二醛含量、感官评分的影响,采用顶空固相微萃取−全二维气相色谱−质谱联用技术研究挥发性成分,最终优化得到产品配方（以里脊肉100 g计）：蒜添加20 g,醋添加4 g,泡椒添加20 g,糖添加8 g,盐添加1.2 g。最佳灭菌工艺：121 ℃,灭菌15 min。储藏期：−18 ℃条件下储藏15 d。共检测到136种风味化合物,其中含量较高并且对风味有重要贡献的化合物有α-姜黄烯、(反,反)-2,4-癸二烯醛、反-2-己烯醛、反-2-辛烯醛、反-2-癸烯醛、4-乙基-2-甲氧基苯酚、3-乙烯基-1,2-二硫代环己-4-烯、二烯丙基二硫、二烯丙基硫醚、二烯丙基三硫醚。本研究为鱼香肉丝方便菜肴工业化生产及其风味评价提供了一定的理论依据。     

螺带几何参数对反应釜内混合性能的影响

为提高螺带式搅拌器的混合性能,基于均匀试验设计方法对偏心式和对心式螺带搅拌器进行方案设计,通过数值模拟对各方案进行计算和分析,选取最优方案并与原始方案的混合时间、混合效果、功率以及单位体积混合能进行对比。结果表明：偏心式螺带搅拌器相较于对心式的混合时间减少1.25~17.5 min,但其混合效果降低2.1%~9.1%;对心式螺带搅拌器相较于偏心式消耗功率高0.02~0.53 kW,单位体积混合能高120~931 kJ/m³;螺带数5条、螺距1200 mm、转速35 rad/min的对心式螺带搅拌器为最优方案,其混合效果与原始方案相比提升8.5%,混合时间减少20 min,消耗功率增加4.43 kW,单位体积混合能减少54.09 kJ/m³。     

pH对生物脱硫系统的性能及菌群结构的影响

为探究pH对生物脱硫反应器性能、生物量及微生物种群结构的影响, 一座生物滴滤池(bio-trickling filter, BTF)分别运行在中性偏碱(6.0 < pH < 9.5)、弱酸(2.6 < pH < 5.5)和极酸(pH < 1.0)环境下。结果表明, BTF获得对H₂S的最大脱硫性能分别为246.5、142.8和164.6 g/(m³·h)。中性偏碱下BTF的脱硫性能最佳, 这是由于较低的H₂S气液传质阻力及较高的硫氧化菌活性。保持此pH范围需消耗大量碱性试剂, 这导致反应器的运行成本升高和操作过程变得复杂。在极酸环境中, 耐酸的硫氧化菌——Mycobacterium逐渐占据主导(79.2%), 且生物膜拥有高硫氧化活性(比耗氧速率1.35 mg/(g·min)), 非耐酸的微生物被淘汰, 这维持了系统内生物量的稳定(生物量质量浓度10~11 g/L), 避免了反应器的堵塞, 降低了生物量控制和pH调整的成本。综上, 通过富集高丰度且高活性嗜酸的Mycobacterium, BTF在极酸环境(pH < 1.0)下仍可获得较高的脱硫性能, 扩大了生物反应器运行的pH范围。

     

四川乐山几个李子品种的品质特征研究

为了解不同品种李子的品质特性,本文选取12个品种李子作为研究对象,分别从外观、理化及糖酸组成等方面对果实品质进行了对比分析,同时采用主成分分析和聚类分析对李子品质性状进行综合评价。结果表明,不同品种李子外观、理化和糖酸组成等指标均表现出丰富的多样性。糖酸组成、色泽、单果重、果实密度和果形指数等是评价李子综合品质的关键性指标。12个品种中‘紫皇’（ZH）‘圣雪珀’（SXP）‘爱丽丝’（ALS）‘香李’（XL）‘香甜李’（XTL）5个品种综合评分为正值,品质较好。其中,ZH和SXP品质特征为出汁率、可溶性固形物、总糖含量及色泽品质高;ALS品质特征为总糖、总甜度、甜酸比和糖酸比最高;XL和XTL品质特征为可溶性固形物含量、糖酸比、甜酸比高,但出汁率低。该研究结果可作为不同用途李子品种筛选的重要参考依据。