The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simu...The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m.展开更多
Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy ...Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy on combustion and emission characteristics.Simultaneously,changing the way of exhaust gas recirculation(EGR)gas introduction forms uneven in-cylinder components distribution,and utilizing EGR stratification optimizes the combustion process and allows better emission results.The results show that the split-injection strategy can reduce the NO_(x)emissions and keep smoke opacity low compared with the single injection,but the rise in accumulation mode particles is noticeable.NO_(x)emissions show an upward trend as the injection interval expands,while soot emissions are significantly reduced.The increase in pre-injection proportion causes the apparent low-temperature heat release,and the two-stage heat release can be observed during the process of main combustion heat release.More pre-injection mass makes NO_(x)gradually increase,but smoke opacity reaches the lowest point at 15%pre-injection proportion.EGR stratification can optimize the emission results under the split injection strategy,especially the considerable suppression of accumulation mode particulate emissions.Above all,fuel stratification coupled with EGR stratification is beneficial for further realizing the in-cylinder purification of pollutants.展开更多
乳腺导管原位癌(ductal carcinoma in situ,DCIS)又称零期乳腺癌,是局限于导管-小叶系统的非浸润性上皮细胞恶性增殖,存在进展为浸润性癌的风险。为实现精准临床诊疗,需要对DCIS进行术前风险评估,其中影像学特征表现在DCIS筛查和个体化...乳腺导管原位癌(ductal carcinoma in situ,DCIS)又称零期乳腺癌,是局限于导管-小叶系统的非浸润性上皮细胞恶性增殖,存在进展为浸润性癌的风险。为实现精准临床诊疗,需要对DCIS进行术前风险评估,其中影像学特征表现在DCIS筛查和个体化诊疗中具有重要提示作用。本文就DCIS临床病理特征、多模态影像学特征以及人工智能(artificial intelligence,AI)在DCIS中的诊断、预后预测与评估应用现状予以总结,旨在提高影像医师对于DCIS的认识,为DCIS的早期诊断、治疗方案优化和个体化风险评估提供影像理论参考。展开更多
基金Project(50478113) supported by the National Natural Science Foundation of ChinaProject(J50502) supported by the Leading Academic Discipline Project of Shanghai Municipal Education Commission,China
文摘The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m.
基金Projects(51476069,51676084)supported by the National Natural Science Foundation of ChinaProject(2019C058-3)supported by the Jilin Provincial Industrial Innovation Special Guidance Fund Project,China+1 种基金Project(20180101059JC)supported by the Jilin Provincial Science and Technology Development Plan Project,ChinaProject(2020C025-2)supported by the Jilin Provincial Specific Project of Industrial Technology Research&Development,China。
文摘Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy on combustion and emission characteristics.Simultaneously,changing the way of exhaust gas recirculation(EGR)gas introduction forms uneven in-cylinder components distribution,and utilizing EGR stratification optimizes the combustion process and allows better emission results.The results show that the split-injection strategy can reduce the NO_(x)emissions and keep smoke opacity low compared with the single injection,but the rise in accumulation mode particles is noticeable.NO_(x)emissions show an upward trend as the injection interval expands,while soot emissions are significantly reduced.The increase in pre-injection proportion causes the apparent low-temperature heat release,and the two-stage heat release can be observed during the process of main combustion heat release.More pre-injection mass makes NO_(x)gradually increase,but smoke opacity reaches the lowest point at 15%pre-injection proportion.EGR stratification can optimize the emission results under the split injection strategy,especially the considerable suppression of accumulation mode particulate emissions.Above all,fuel stratification coupled with EGR stratification is beneficial for further realizing the in-cylinder purification of pollutants.
文摘目的探讨不同体积结节在微波消融过程中导致喉返神经(recurrent laryngeal nerve,RLN)损伤的独立危险因素,为临床风险分层提供依据。方法回顾性分析2022年9月至2024年8月接受微波消融治疗并发生喉返神经损伤的患者,根据结节体积分为大结节组(≥500 mm 3)和小结节组(<500 mm 3),每组按12匹配无RLN损伤病例。收集4类22项参数,通过单因素及多因素logistic回归分析筛选危险因素,并构建预测模型。结果大结节组(34例损伤/82例对照)中,Z结位置(OR=3.418,95%CI:1.326~8.809)、实性结构(OR=2.795,95%CI:1.066~7.360)及前被膜间距>2 mm(OR=5.097,95%CI:1.508~17.232)为喉返神经损伤的独立危险因素。小结节组(40例损伤/104例对照)中,较高的消融功率(OR=0.904,95%CI:0.828~0.986)是喉返神经损伤的独立保护因素,结节与气管食管沟(tracheoesophagealgroove,TEG)间距≤2 mm(OR=5.717,95%CI:2.402~13.605)为喉返神经损伤的独立危险因素。结论大结节RLN损伤风险与解剖位置及结节囊实性相关,而小结节风险受能量参数及邻近神经距离影响。分层评估可优化个体化消融策略。
文摘乳腺导管原位癌(ductal carcinoma in situ,DCIS)又称零期乳腺癌,是局限于导管-小叶系统的非浸润性上皮细胞恶性增殖,存在进展为浸润性癌的风险。为实现精准临床诊疗,需要对DCIS进行术前风险评估,其中影像学特征表现在DCIS筛查和个体化诊疗中具有重要提示作用。本文就DCIS临床病理特征、多模态影像学特征以及人工智能(artificial intelligence,AI)在DCIS中的诊断、预后预测与评估应用现状予以总结,旨在提高影像医师对于DCIS的认识,为DCIS的早期诊断、治疗方案优化和个体化风险评估提供影像理论参考。
