In-situ-reduced synthesis of cyano group modified g-C3N4/CaCO3 composite with highly enhanced photocatalytic activity for nicotine elimination

Graphite carbon nitride has many excellent properties as a two-dimensional semiconductor material so that it has a wide application prospect in the field of photocatalysis. However, the traditional problems such as high recombination rate of photogenerated carriers limit its application. In this work, we introduce nitrogen deficiency into g-C₃N₄ to solve this problem a simple and safe in-situ reduction method. g-C₃N₄/CaCO₃ was obtained by a simple and safe one-step calcination method with industrial-grade micron particles CaCO₃. Cyano group modification was in-situ reduced during the thermal polymerization process, which would change the internal electronic structure of g-C₃N₄. The successful combination of g-C₃N₄ and CaCO₃ and the introduction of cyanide have been proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer. The formation of the cyano group, an electron-absorbing group, promotes the effective separation of photogenic electron hole pairs and inhibits the recombination of photogenic carriers. These advantages result in the generation of more •O₂⁻ and ¹O₂ in the catalytic system, which increases the photocatalytic efficiency of nicotine degradation by ten times. Furthermore, the degradation process of nicotine has been studied in this work to provide a basis for the degradation of nicotine organic pollutants in the air.     

超临界二氧化碳流体萃取土壤中有机污染物的研究进展

就近年来人们利用超临界二氧化碳流体对有机污染物污染的土壤所做的研究工作以及所取得的成果进行了总结。     

清洁的胡椒基T醚生产工艺的研究I,5-丙基-1,3-苯并二氧杂茂的氯甲基化废水的处理

报道了胡椒基丁醚生产中５－丙基－１，３－苯并二氧杂茂的氯甲基化的废水处理，该废水经蒸馏可回收９４％的盐酸，此酸吸收氯化氢后浓度在３６％以上，可再用于氯甲基化反应。蒸馏残液经分油、Ｆｅｎｔｏｎ试剂处理和五次生炭柱吸附后ＣＯＤＣｒ等项指标均可国家二类污染物的一级排放标准。     

减排温室气体的经济手段：许可证交易和税收政策

温室气体的减排是当前国际社会关心的热点环境问题。本文首先从分析采用经济手段减排温室气体的潜在利弊出发，对温室气体排放交易和国际碳税进行了深入的分析比较。最后，提出了我国响应减排温室气体经济政策的若干建议。     

汽车内二氧化碳污染与通风模式

不同车速下,对四种通风模式(A关闭通风口和风扇、B关闭通风口打开风扇、C打开通风口关闭风扇、D打开通风口和风扇)车内二氧化碳浓度进行分析研究。通风口关闭的状态,无论是否打开风扇及车速快慢,车内CO2浓度严重超标。通风口打开:不开风扇,以50km/h速度行驶,车内CO2浓度高于标准限量;速度提高到80km/h,车内CO2浓度可低于标准限量,通风口和缝隙的换气可以保障车内的空气质量;而打开风扇可以有效排除车内污染物。车速提高,各种通风模式的换气量都增加,属于缝隙换气贡献的比例增加,属于风扇换气贡献的比例减小,属于通风口换气贡献比例变化不大。基于研究结果,提出了一些减少车内污染的通风方式建议。     

精品意识在教学过程中的实施

以教师、课程与教材、课堂、科研等要素为出发点,提出了精品意识在教学过程中的实施方法。     

海水环境下玻璃纤维增强复合材料力学性能演化规律研究

目的 研究海水环境下海流能发电机组叶片用玻璃纤维复合材料力学性能的变化规律.方法 在实验室内通过海水浸泡试验、拉伸试验、弯曲试验以及剪切试验,测定叶片用玻璃纤维树脂基复合材料的吸水特性,以及在人工海水介质中各项力学性能参数的演变规律.结果 随着浸泡时间的增加,玻璃纤维树脂基复合材料吸水率先逐步增大、后趋于稳定,总吸水率约0.075％.抗拉强度呈先降低、后提高、又降低的趋势,抗拉强度最高可超过1100 MPa,最小值约为940 MPa.弹性模量和弯曲强度呈逐渐降低的趋势,弹性模量降幅约9.5％,弯曲强度降幅约为30％.弯曲模量变化起伏不定,变化幅度在15％以内.材料剪切强度呈先增大、后降低的趋势,最小值为189 MPa,较初始值高10 MPa.剪切模量呈先降低、后提高的现象,在浸泡28 d时,剪切模量最小,为16.4 GPa.结论 玻璃纤维增强树脂基复合材料经过长期海水浸泡后,拉伸及抗剪切性能略有降低,但降幅不大,抗弯性能下降明显,需要在叶片结构设计和强度计算时,充分考虑抗弯性能衰减的负面影响.     

基于神经网络的压铸合金选择

在归纳总结压铸合金选择经验和知识的基础上 ,对压铸合金性能进行评价。采用BP神经网络方法建立了快捷的压铸合金材料选择系统 ,提出了一种将模糊化性能要求量化 ,增加训练样本集的方法。     

含硫污水系统耐蚀材料的筛选与应用

针对西北地区一综合炼油厂含硫污水管线的严重腐蚀问题，分析了腐蚀原因，确立了材料筛选方案，通过实验室静态挂片试验绘制了重量损失率变化曲线和现场挂片等试验手段，筛选推荐出了树脂玻璃钢耐蚀材料。工业生产应用结果表明，MFE-2型树脂玻璃钢是适用于该厂含硫污水系统的耐蚀材料，为类似装置的长周期运行提供了借鉴和经验。     

Carbon Budget Implications of the Transition from Natural to Managed Disturbance Regimes in Forest Landscapes

Land-use change from an unmanaged to a managed forested landscape in northern forests is associated with a reduction of the area annually affected by natural disturbances (wildfires and forest insects) and the introduction of harvesting as a new disturbance. This study examined the impacts of changes in the disturbance regime-the frequency and type of disturbance-on landscape-level carbon (C) content and fluxes. The Carbon Budget Model of the Canadian Forest Sector was used to assess these impacts in six representative landscapes (100,000 ha each) with a range of disturbance regimes that are characteristic of conditions in coastal British Columbia, the interior of British Columbia, and the eastern boreal forest in Canada. The model was used to simulate ecosystem C fluxes during a period of natural disturbances, a 50-year transition period during which harvesting replaced natural disturbances, followed by 150 years of harvesting. The initial landscape-level biomass C content under natural disturbance regimes in the six example landscapes was 22 to 75% of their potential maximum content which is often used as the reference or baseline case. After 200 years of forest management, the C stored in the landscape plus the C retained in forest products manufactured from harvested biomass was between 58 and 101% of the landscape C content prior to the onset of harvesting. Landscape-level ecosystem C content was found to be affected by changes in the disturbance frequency, the age-dependence of the disturbance probabilities, and the disturbance-specific impacts on ecosystem C content. The results indicate that using the potential maximum C content of a landscape as the baseline always overestimates the actual C release due to land use change. A more meaningful procedure would be to assess the actual differences in landscape-level C content between the natural and the managed disturbance regime.