首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
以顺酐和甲醇为原料,在浓盐酸的作用下采用一锅法合成富马酸二甲酯.通过正交实验考查了醇解和酯化过程中甲醇用量、时间、温度和异构化过程中浓盐酸用量、时间、温度等因素对反应的影响,得到最优化条件,收率达90.19%.  相似文献   

2.
The high input of agrochemicals into soils is a major agricultural technique for enhancement of plant crop production, but it is also an environmental hazard. Concern over health hazards related to agrochemicals, especially on radioactively polluted territories, as well as economic problems, have promoted fundamental research to search for new agrobiotechnologies. Nonsymbiotic plant growth-promoting Rhizobacteria (PGPR) are often used as inoculants; however, they are not as effective as endophytic bacteria. These bacteria have the advantage of living within the plant tissue, protecting the plant from superinfection by soil bacteria, and recolonizing the plant surface after some stress situations in the soil. Although the use of beneficial microorganisms is not a new idea, it is an idea that is not heavily utilized. Application of inoculants designed on the base of competitive endophytic bacteria may be a full or partial alternative to agrochemicals, and can diminish the level of penetration and accumulation of heavy metals and radionuclides inside plants. This study evaluates the input of the association of the bacteria, isolated from the plant interior, in the crop of corn (Zea mays) and develops inoculants on their base. Nitrogen-fixing Klebsiella oxytoca VN13 along with Xanthomonas maltophilia VN12 were found to be useful bacteria, the former capable of excreting auxins and antimicrobial substances, the latter promoting assimilation of soil phosphorous by the plants. As the association of the two bacteria has been chosen as an effective endophytic system for the inoculant development, the two are mixed to form an inoculant ‘Duet’ which is directly inoculated into seeds. Corn inoculated with this ‘Duet’ produced greater yields, and possessed a greater percentage of protein. In addition, experiments performed in Chernobyl, showed that the ‘Duet’ could protect the plant from radionuclides penetration. It is suggested that a novel inoculant, ‘Kleps’, be applied, as the formulation is simple, it is inexpensive, it can be produced on a large scale, and it can be stored for a long period of time in a relatively small volume. It is clear that simple formulations of novel inoculants can be designed on the base of the competitive endophytic bacteria for an environmentally friendly crop production on poor and polluted territories as an alternative to the use of agrochemicals.  相似文献   

3.
主要对用于印染废水处理的天然高分子型混凝剂、生产废物型混凝剂和微生物混凝剂的研究现状进行综述,分析了各类混凝剂的特点,并对混凝剂的发展趋势进行了展望。  相似文献   

4.
本文介绍了上海浦东新区新型太阳能小型无人值守水质自动监测系统的特点与组成,同时对水质自动监测数据和实验室分析数据进行比较分析,表明两者之间有很好的相关性和对比性。说明了新型太阳能小型无人值守水质自动监测站具有体积小、功能强、投入少、维护量小、监测参数多等优点,适用于不同水体的长期连续在线监测。  相似文献   

5.
In this paper, we have proposed a thermal cycle with the integration of chemical-looping combustion and solar thermal energy with the temperature of about 500-600°C. Chemical-looping combustion may be carried out in two successive reactions between a reduction of hydrocarbon fuel with metal oxides and a reduced metal with oxygen in the air. This loop of chemical reactions is substituted for conventional combustion of fuel. Methane as a fuel and nickel oxides as an oxygen carrier were employed in this cycle. Collected high-temperature solar thermal energy is provided for the endothermic reduction reaction. The feature of the proposed cycle is investigated through Energy-Utilization Diagram methodology. As a result, at the turbine inlet temperature of 1200°C, the exergy efficiency of the proposed cycle would be expected to be about 4 percentage points higher than that of a conventional gas turbine combined cycle. Compared to the previous study of chemical-looping combustion energy systems, the proposed cycle with the integration of green energy and traditional hydrocarbon fuels will offer the possibility of both greenhouse gas mitigation, with green energy, and a new approach to the efficient use of solar energy.  相似文献   

6.
通过化学分析、抗压强度、抗折强度等试验,研究了一种以矿渣为主要成分的新型建筑材料。试验结果表明:该种新型建筑材料的抗压强度和抗折强度能够达到525水泥相关要求,可满足实际工程的需要。  相似文献   

7.
茶皂素是一种从茶树籽中提取出的性能良好的天然非离子表面活性剂,将茶皂素与烷基酚聚氧乙烯醚类表面活性剂(OP)、硅酸钠(Na_2SiO_3)、脂肪醇聚氧乙烯醚(AEO)、仲烷基磺酸钠(SAS)进行复配,筛选出一种清洗效率高、环境友好的新型含油污泥清洗剂。该清洗剂茶皂素、Na_2SiO_3、AEO、NaHCO_3质量比为1∶3∶3∶3,最优清洗条件为热水浴温度65℃、搅拌时间40 min、转速100 r/min、溶液pH值为10、最佳处理量为2.0 g含油污泥/50 mL清洗剂,优化的二次清洗剂浓度为0.3 g AEO/50 mL蒸馏水。该清洗剂和二次清洗剂可以较好的处理含油污泥,脱油率最高可达95.35%。  相似文献   

8.
This study proposes a novel concept for designing a radio switch that can match workplace characteristics and personal needs by individually controlling the lighting group to save electricity. We use a microcontroller that can achieve the function of timing, turned-on and turn-off by setting the internal program to control the radio switch for convenient use, and electricity saving. As compared with the traditional mechanical switch, the radio switch reduced the electricity consumption by 38.64 kwh/week (86.25% of ideal condition or 1194.62% of practical condition), and the annual CO2 emission can be reduced by 1032.2 kg/year. Additionally, the cost of the radio switch to replace the traditional mechanical switch can be paid back in 1.72 years.  相似文献   

9.
Novel passive co-treatment of acid mine drainage and municipal wastewater   总被引:1,自引:0,他引:1  
A laboratory-scale, four-stage continuous-flow reactor system was constructed to test the viability of high-strength acid mine drainage (AMD) and municipal wastewater (MWW) passive co-treatment. Synthetic AMD of pH 2.6 and acidity of 1870 mg L(-1) as CaCO3 equivalent containing a mean 46, 0.25, 2.0, 290, 55, 1.2, and 390 mg L(-1) of Al, As, Cd, Fe, Mn, Pb, and Zn, respectively, was added at a 1:2 ratio with raw MWW from the City of Norman, OK, to the system which had a total residence time of 6.6 d. During the 135-d experiment, dissolved Al, As, Cd, Fe, Mn, Pb, and Zn concentrations were consistently decreased by 99.8, 87.8, 97.7, 99.8, 13.9, 87.9, and 73.4%, respectively, pH increased to 6.79, and net acidic influent was converted to net alkaline effluent. At a wasting rate of 0.69% of total influent flow, the system produced sludge with total Al, As, Cd, Cr, Cu, Fe, Pb, and Zn concentrations at least an order of magnitude greater than the influent mix, which presents a metal reclamation opportunity. Results indicate that AMD and MWW passive co-treatment is a viable approach to use wastes as resources to improve water quality with minimal use of fossil fuels and refined materials.  相似文献   

10.
Climate change communication to the Public is in general presented in a negative fashion and often depicts the resultant costs and impacts as distant. Its substantial gloom together with the less immediate consequences significantly weaken responses. Narratives and stories are potent arbiters of meaningful communication and are an important vehicle for communication in our information-rich lives. Importantly, they reduce jargon, gather and translate information, provide insight, reframe evidence and engage audiences. It has been argued by many observers that stories are potentially useful in driving change; presenting a way to value what is gone, expressing emotions, and helping us assert our determination to salvage something and work towards the future. This paper details the methods utilised by the authors to generate stories and case studies in a community in Ireland over a 4-year research period. The aim of the work was to identify and assess the salience and potency of storytelling – as part of a “co-creation” process – with regard to galvanising local action in the generation of sustainable models of lifestyle practice for residents. In this paper, co-creation includes the planning phase of co-design and the implementation phase of co-production. The demonstration of these sustainable lifestyle practices was a strong driver for the sustainable transition of this community supporting the reduction of its ecological footprint by 28% over 4 years, evidence of which is highlighted in this paper.  相似文献   

11.
清代小说家褚人获创作的小说<隋唐演义>表明我国历史演义小说创作进入了一个崭新的阶段.作者在继承前人创作的历史演义小说的基础上,又进行了很大的创新,主要在于拓展了历史演义小说创作的视野,具体表现在:体裁的拓宽、主题的创新、人物塑造复杂化等.创作视野的极大拓宽使小说更为大众化,也启迪了后世历史演义小说的创作方向.  相似文献   

12.
采用等体积浸渍法,制备了一系列含有相同含量活性组分(MoO3、CoO和NiO)不同USL沸石含量的加氢脱硫催化剂。通过X-射线衍射(XRD)、氮气吸附脱附、吡啶红外(Py-FTIR)和氨气程序升温脱附(NH3-TPD)等分析方法对样品进行了表征。结果表明:与Cat.0(参比剂,仅以γ-Al2O3为载体)相比,添加USL沸石催化剂所得加氢油的烯烃含量、芳烃含量和研究法辛烷值(RON)均增加;仅当催化剂载体中USL沸石加量在0~40m%之间变化时,加氢油的异构烷烃含量呈上升趋势;而当载体中USL沸石添加量在0~20m%之间变化时,催化剂的脱硫率有所升高。综合对比,当载体中USL沸石添加量约为40m%,催化剂具有最佳的综合性能指标,脱硫率达90%,RON损失仅为1.5左右。  相似文献   

13.
在我的读书生活中,我为能读到美国科学家蕾切尔·卡森所著的《寂静的春天》而感到幸运。这部1962年出版的划时代意义的作品,阐述了农药对环境的污染,它用生态学的原理分析了这些化学杀虫剂对人类赖以生存的生态系统带来的危害,指出人类用自己制造的毒药来提高农业产量,无异于饮鸩止渴。在这部惊世之作第一章“明天的寓言”中,蕾切尔·卡逊以她优美的文笔,描写了美国一个小镇在生态良好状态下的美丽和生气:“从前,在美国中部有一个城镇,这里的一切生物看来与其周围环境生活得很和谐。这个城镇座落在像棋盘般排列整齐的繁荣的农场中…  相似文献   

14.
Abstract

This article describes a novel flat plate heat-pipe solar collector, namely, the hybrid heat-pipe solar collector. An analytical model has been developed to calculate the collector efficiency as well as simulate the heat transfer processes occurring in the collector. The effects of heat pipes/absorber, top cover, flue gas channel geometry, and flue gas temperature and flow rate, on the collector efficiency were investigated based on three modes of operation, i.e., solar only operation, solar/exhaust gas combined, and solar, exhaust gas and boiler combined. Experimental testing of the collector was also carried out for each of these modes of operation under real climatic conditions. The results were used to estimate the efficiency of the collector and determine the relation between the efficiency and general external parameter. The modeling and experimental results were compared and a correlation factor was used to modify the theoretical predictions. It was found that the efficiency of the collector was increased by about 20–30% compared to a conventional flat-plate heat pipe solar collector.  相似文献   

15.
实验以处理金属表面所产生的磷化废水为研究对象,系统地分析了在新型混凝剂的使用过程中,pH值、温度、石灰投入量、沉降时间、助剂A等因素对脱磷效果的影响。结果表明,含磷量为18mg/L、COD为300mg/L、SS为150mg/L、pH值为5.7~6.5的废水,石灰投入量为300mg/L、沉降时间为10min左右、温度为25℃、pH值调节至9.0、加入5mL助剂A处理后,废水中磷含量为0.25~0.35mg/L、COD为80mg/L、SS为60mg/L,满足《污水综合排放标准》(GB8978—1996)中的一级标准。  相似文献   

16.
生物滴滤池是农村生活污水处理的主要技术之一,但其存在氮、磷去除能力有限,稳定性不高等缺点。为提高新型分层生物滴滤池的氮磷去除效率,探索最佳工艺条件,本文采用新型分层生物滴滤池为试验装置,考察了滤料种类、水力负荷、回流比等对装置去除污水中氮磷性能的影响。结果表明,当滤料为炉渣、水力负荷为4 m3&#183;m-2&#183;d-1、回流比为2:1时滤池去除氮磷的效果最好,对NH4+-N、TN、TP、COD的平均去除率分别可达到87.08%、57.37%、66.04%、80.78%;采用较高的回流比是滴滤池提高脱氮效果的一条有效途径。  相似文献   

17.
在家用空调系统的有源功率因数校正中,需要在输入电压的过零时刻开启功率因数校正功能,以避免非零相位时刻开启功率因数校正功能造成的输入电流超调冲击。提出一种频率自适应的过零检测方法,根据输入电流开环检测电网电压频率,在已知频率的基础上采用输入电流峰值闭环跟踪的方法进行过零检测。该方法不需要检测输入电压,能够自动适应50 Hz与60 Hz应用,同时该方法能够实时侦测电网电压短时中断。  相似文献   

18.
In this work several Li4SiO4-based sorbents from fly ashes for CO2 capture at high temperatures have been developed. Three fly ash samples were collected and subjected to calcination at 950 °C in the presence of Li2CO3. Both pure Li4SiO4 and fly ash-based sorbents were characterised and tested for CO2 sorption at different temperatures between 400 and 650 °C and adding different amounts of K2CO3 (0–40 mol%). To examine the sorbents performance, multiple CO2 sorption/desorption cycles were carried out. The temperature and the presence of K2CO3 strongly affect the CO2 sorption capacity for the sorbents prepared from fly ashes. When the sorption temperature increases by up to 600 °C both the CO2 sorption capacity and the sorption rate increase significantly. Moreover when the amount of K2CO3 increases, the CO2 sorption capacity also increases. At optimal experimental conditions (600 °C and 40 mol% K2CO3), the maximum CO2 sorption capacity for the sorbent derived from fly ash was 107 mg CO2/g sorbent. The Li4SiO4-based sorbents can maintain its original capacity during 10 cycle processes and reach the plateau of maximum capture capacity in less than 15 min, while pure Li4SiO4 presents a continual upward tendency for the 15 min of the capture step and attains no equilibrium capacity.  相似文献   

19.
A Framework for the Ethical Analysis of Novel Foods: The Ethical Matrix   总被引:6,自引:4,他引:2  
The paper addresses the issue of how indemocratic societies a procedure might be formulatedto facilitate ethical judgements on modernbiotechnologies used in food production. A frameworkfor rational ethical analysis, the Ethical Matrix, isproposed. The Matrix adapts the principles describedby Beauchamp and Childress for application to medicalissues, to interest groups (e.g., producers,consumers, and the biotic environment) affected bythese technologies. The use of the Matrix isillustrated by applying it to an example of a ``novelfood,' viz., a form of genetically modified maize.  相似文献   

20.
In the public debate concerning novel foods, someconsumer groups claim a consumer right to have accessto certain kinds of food in the market. To discusssuch statements, the paper identifies the reasons thatmay justify liberal states to regulate food. Althoughit defends certain paternalistic activities, itfavours an autonomy-centred food policy. Autonomy andconsumer sovereignty require that certain conditionsare fulfilled. It may be argued that one suchcondition is that the consumer should have choices.Against this position, the paper defends the view thatliberty rights to choose are limited to areas whichare of great importance for personal identity and thegood life. Local decisions in the area of foodconsumption do not have such importance, though globalones may have it. But even if this were true,government activity to protect such liberties shouldbe limited to the guarantee of formal conditions forthe good life of persons. It is not a legitimate taskof the government to safeguard specific conceptions ofthe good life.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号