SiCW/Zn-22Al复合材料的组织与高温变形

对低压浸渗、挤压比为10：1的热挤压以及固溶处理制备的SiCw／Zn-22Al复合材料的组织与高温变形行为进行了研究。结果表明：SiCw的复合使材料中出现了熔点为655K的低熔点共晶组织。显著提高了变形抗力，降低了塑性，并使材料丧失了在共析温度区的超塑性；在出现适量液相的共晶温度区，复合材料具有超塑性。     

基于图像重建的黄连根系-土壤复合体力学特性仿真与试验

针对黄连（Coptis chinensis）收获过程机械化程度低，根土复合体力学特性研究缺乏的问题，该研究以收获期黄连为研究对象，运用增量式运动恢复结构（incremental structure from motion，ISFM）和多视图立体（multi-view stereo，MVS）算法，通过多视角图像三维重构，将建立的高保真根系形态模型应用于不同条件下的根系-土壤复合体力学特性研究中。首先，通过田间采样和室内力学特性试验，得到根茎的平均剪切模量和泊松比，并测得不同深度的土壤和根土复合体的平均抗剪强度等物理力学参数。再以试验获得的入土深度为0～30 mm的土壤和根土复合体的平均抗剪强度作为响应值，采用Plackett-Burman试验和Central Composite试验等进行离散元仿真参数标定，并在EDEM软件中进行不同深度的土壤和根土复合体直剪试验数值模拟。结果表明：当土壤含水率在49.58%～62.96%、根系含水率在80%～230%的范围内时，在不同入土深度下，收获期黄连根土复合体离散元模型的内聚力和内摩擦角与试验结果的平均误差分别为3.48%和5.21%，标准差分别为3.44%和1.63%，验证表明通过图像重建根系模型可靠，并可用于模拟根土复合体力学行为。模拟方法可为黄连机械化收获关键工作部件设计和工作参数优化等提供理论依据。     

CaM拮抗剂W7对PEG胁迫下番茄幼苗根系生长和ABA、多胺动态变化的影响

以耐旱性不同的两个番茄品种为试材,采用营养液水培,研究了CaM拮抗剂W7〔N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide〕预处理对聚乙二醇(PEG-6000)模拟干旱胁迫下番茄幼苗根系生长及内源ABA、游离态多胺含量的影响。结果表明,用200 mmol/L W7预处理24 h,然后进行干旱胁迫处理,番茄根系内源ABA和多胺含量低于未经W7预处理的PEG胁迫处理下的值,W7处理削弱了番茄对胁迫逆境的抵抗能力,幼苗生长变弱,表明Ca2+-CaM信使系统通过影响多胺的含量参与调节干旱胁迫下多胺的代谢过程,对抵抗干旱逆境胁迫有积极作用。两个品种相比较,‘毛粉802’在PEG胁迫下可以积累更多的亚精胺(Spd)和精胺(Spm),受W7的影响小于‘皇冠’,表现出较强的耐旱性。     

Retrospective evaluation of the impact of hypoxemia during thoracic surgery in dogs on outcome: a multicenter analysis of 94 cases

ObjectiveTo investigate the statistical association of severe intraoperative hypoxemia in thoracic surgery with mortality, postoperative hospitalization times and cost of care.Study designRetrospective study.AnimalsDogs that underwent thoracic surgery in three veterinary hospitals between October 1, 2018 and October 1, 2020.MethodsAnesthesia and hospitalization records from 112 dogs were reviewed and 94 cases met inclusion criteria. Recorded data included signalment, disease etiology, pulmonary or extrapulmonary nature of disease, surgical procedure performed, episodes of severe intraoperative hypoxemia defined as a pulse oximetry reading (SpO₂) <90% of 5 minutes or longer duration, survival to discharge, time from extubation to hospital discharge and total invoice cost for clinical visit. Dogs were divided into two groups, those that experienced severe hypoxemia (group A) and those in which SpO₂ reading <90% was not observed throughout the procedure (group B).ResultsGroup A had a greater risk of mortality (odds ratio 10.6, 95% confidence interval 1.9–106.7; p = 0.002), prolonged hospitalization (median 62 hours versus 46 hours; p = 0.035) and more expensive cost of care (median US$10,287 versus $8506; p = 0.056) than group B. No significant difference was found for the type of surgical procedure or pulmonary versus extrapulmonary nature of disease.Conclusions and clinical relevanceSevere intraoperative hypoxemia was statistically associated with an increased risk of mortality and longer postoperative hospitalization times. Although not achieving statistical significance, there was a trend toward increased costs to the client for animals with intraoperative hypoxemia.     

哲学与艺术的共同抵抗——阿多诺对于现代美学的构想及意义

阿多诺美学的出发点在现代艺术，落脚点在拯救现实。他认为，只有把哲学和艺术二者有机结合，才足以让传统美学重新焕发活力，促进艺术的发展，进而挽救处于颓势的人类文明。阿多诺注意挖掘传统美学的潜力、从现代艺术现实出发构建现代美学理论、注重美学理论的开放性，对我国当代美学理论的构建具有借鉴意义。