Recycling and depolymerization of waste polyethylene terephthalate bottles by alcohol alkali hydrolysis

In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymerization rate of waste PET bottles and the yield of TPA were conducted to determine the optimized experimental conditions,in terms of reaction time,reaction temperature,dosage of ethylene glycol and sodium bicarbonate,amount of distilled water and stirring rate.Then IR spectra and elemental analysis were carried out for the characterization of obtained product.Under optimal experimental conditions,over 98%PET can be depolymerized into the target product(TPA)and the purity and yield of TPA are over 97%and 94%,respectively.Both the experimental and analytical results support a feasible process for the preparation of TPA from waste PET.It is expected that this alcohol alkali hydrolysis method can promise an effective way for the sustainable recycling of waste PET.

建筑能耗预测与建筑节能分析模型构建研究

针对大型商场建筑动力设备多、结构复杂、能耗高的问题,为了解大型研究商场的能耗状况,提升广州地区商场建筑的能源利用效率,通过对13家商场建筑能耗调查,建立了能耗预测模型进行建筑能耗预测。选择内扰因素、围护结构影响因素、空调系统参数三类13个影响因子进行敏感度分析,其中空调系统COP值、室内设计温度和风机效率的敏感度最高,后期节能改造的潜力最大,天窗传热系数、冷冻水供水温度、新风量指标的敏感度最低。通过极差分析法建立包含9个影响因子的商场建筑节能预测模型对13家商场能耗进行预测对比,预测能耗值与实测能耗值的平均相对偏差为6.79%,相对最大偏差为13.28%,说明选定的商场能耗主要影响因素能较好地反应商场能耗水平,建立预测模型具有较高的预测精确度。

西藏自治区全科住院医师规范化培训委托培养的探索

为解决西藏自治区基层全科医生人才培养之困,四川大学华西医院全科医学科通过“以需求为导向,以临床能力培养为核心”的培训计划构建教学框架、基于“全科理论-临床实践-社区运用”设置轮转计划、闭合环路机制完善教学管理体系、创新培训考核和教学活动4个方面,归纳了西藏自治区委托培养全科住院医师规范化培训的实践经验,旨在为培训方案设计提供参考。