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Synthesis and Gas-sensing Performance of Nanosized SnO2
Nanosized tin dioxide particles were prepared by sol-gel dialytic processes with tin(Ⅳ) chloride and alcohol as start materials. The nanoparticles of tin dioxide were charactered by thermogravimetry and differential thermal analysis(TG-DTA), X-ray diffraction(XRD), transmission electron microscopy (TEM) and BET. The results show that the average diameter of tin dioxide particles dried at 353 K was about 2 nm. Even if the tin dioxide particles were calcined at 873 K, the average diameter of particles was less than 10 nm. The removal of Cl- was solved by using this kind of method. The mechanism of the formation of tin dioxide nanosized particles was proposed and analyzed in this paper. We also measured the sensitivity of the sensor based on the tin oxide powder calcined at 673 K to NH3, alcohol, acetone, hexane and CO. The gas-sensing performance results indicate that this sensor has a higher sensitivity to alcohol and acetone, and selectivity for NH3, hexane and CO at an operating temperature of 343 K....
2020-09-15 12:28:59浏览：55
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Directional solidification of metal-gas eutectic and fabrication of regular porous metals
Directional solidification of metal-gas eutectic (Gasar) is a novel process for making regular porous metals.This process is based on a solid-gas eutectic reaction involving a gaseous medium and a metal or a ceramic phase, and allows an easy control of the porosity, such as its pore size, pore orientation and morphology in a wide range by properly adjusting its melting and solidification conditions. The latest progress and our research work in this field are reviewed in this paper....
2020-09-15 12:28:59浏览：65
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KDNBF的热分解过程及非等温反应动力学
利用DSC,TG-DTG及FT-IR技术对4,6-二硝基-7-羟基-7-氢化苯并氧化呋咱钾(KDN-BF)的热分解过程进行了研究.结果表明,230℃时,固体残渣中含有RCOOK,KNCO,RNO2,KNO3,而在306℃时则含有KNC,RCOOK及KNO3.利用Kissinger法与Ozawa-Doyle法对KDNBF的热分解过程进行了动力学计算.两种方法所得结果互相吻合,结合本文及文献结果,Arrhenius方程可表达为:lnk=45.2-192600/RT....
2020-08-30 18:25:27浏览：55
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SHELL煤气化金属滤芯的安装和检查
Shell的粉煤气化技术在中国得到了广泛的应用，作为气化核心装置的S－1501高温高压飞灰过滤器陶瓷滤芯断裂的问题，严重影响了系统的长周期运行，力学性能更优的金属滤芯渐渐得到了更多的应用，正确的安装可以保证金属滤芯和系统的长周期运行。...
2020-07-12 21:36:56浏览：69
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浅析城镇生活污水处理
随着我国城镇化进程的加快，小城镇建设迅猛发展。城镇污水治理已经成为城镇化进程建设过程中的一个重要因素。本文从当前我国城镇污水治理面临的严峻形势，以及现实情况出发，提出适合各新建城镇的污水处理技术工艺。...
2020-07-10 14:39:05浏览：42
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污水处理系统的仪表设计
大型污水处理系统的仪表，种类多且较为特殊，多为压力、流量、液位及分析类仪表，它们在污水厂中发挥着很重要的作用。本文就污水厂典型自动化仪表的配置、设计选型、设计要点进行了详细阐述。...
2020-07-10 14:39:05浏览：38
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活性生物KO菌在污水处理中的应用
由于600 kt/a醇氨项目各装置开、停车频繁,高浓度氨氮污水冲击SBR污水处理系统,导致污泥死亡、出水浑浊。为了保证处理后的污水合格排放,在SBR池内投加了KO多功能复合微生物制剂( KO菌)。小试结果表明,投加KO菌后,SBR池出水氨氮含量达标,且具有一定的耐高浓度氨氮冲击的效果。...
2020-07-09 15:51:42浏览：54
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Treatment of methanol wastewater with two-stage and two-phase anaerobic process
The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanolwastewater. Test results show that TSTP process is quick start-up in 51 d, and the maximum VFA of hydrolytic acidification reactor effluent reaches 876 mg/L. Under the condition of volume loading of 6. 56 kgCOD/m~3·d,COD removal rate of the first-order EC reactor is about 85%, and under the condition of volume loading of 1.02 kgCOD/m~3·d, COD removal rate of the second-order EC reactor is about 50%. When the inflow COD of TSTP process is between 7000-11000 mg/L, its effluent COD is lower than 600 mg/L. In the biological conversion process of methanol into methane, the production of acetic acids as an intermediate product can be ignored and the direct production of methane from methanol is predominant....
2020-07-08 21:52:19浏览：41
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Study on Technology for Quenching Catalytic Pyrolysis Gas
This article describes the application of technology for quenching catalytic pyrolysis gas at the Daqing commercial CPP test unit and the Shenyang commercial CPP production unit. On the basis of results for application of the Shenyang CPP unit this paper puts forward an improved process flow scheme for quenching the pyrolysis gas and made calculations using the process fiowsheet software. Case Ⅰ of the process flow scheme, which is designed for full circulation of slurry, intends to use the pyrolysis light oil and fresh feed oil as the quenching media with the product slurry oil and fresh feedstock being discharged from the quench cooler bottom and routed directly to the reactor so that the fresh feed oil can be preheated prior to pyrolysis. Case Ⅱ of the process flow scheme intends to adopt recycle oil as the quenching medium with the product slurry and recycle oil being discharged from the quench cooler bottom to the fractionator, which then delivers the slurry from the bottom. These two cases for improving the process flow diagram can all effectively control the density and viscosity of the quenching medium to secure the smooth operation of quench cooler....
2020-07-08 21:52:19浏览：40
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A reduced thermodynamic model on the formation of the Nansha warm water
A reduced vertically integrated upper mixed layer model is set up to numerically study the thermodynamic process of the formation of the "Nansha warm water"(NWW) in the Nansha Islands sea areas in spring. According to the numerical experiments, it is shown that, in spring, the formation of the NWW is mainly due to the sea surface net heat flux and the local weak current strength; the contribution from temperature advection transport and warm water exchange with the outer seas (Sulu Sea or south of Sunda shelf) is very little. In the sea areas where the current is strong, the advection may also play an important role in the temperature field....
2020-07-08 21:52:19浏览：62
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A Physicoempirical Model for Soil Water Simulation in Crop Root Zone
To predict soil water variation in the crop root zone,a general exponential recession (GER) model was developed to depict the recession process of soil water storage.Incorporating the GER model into the mass balance model for soil water,a GER-based physicoempirical (PE-GER) model was proposed for simulating soil water variation in the crop root zone.The PE-GER model was calibrated and validated with experimental data of winter wheat in North China.Simulation results agreed well with the field experiment results,as well as were consistent with the simulation results from a more thoroughly developed soil water balance model which required more detailed parameters and inputs. Compared with a previously developed simple exponential recession (SER) based physicoempirical (PE-SER) model,PE-GER was more suitable for application in a broad range of soil texture,from light soil to heavy soil.Practical application of PE-GER showed that PE-GER could provide a convenient way to simulate and predict the variation of soil water storage in the crop root zone,especially in case of insufficient data for conceptual or hydrodynamic models....
2020-07-08 21:52:19浏览：35
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AHP Comprehensive Evaluation on Sustainable Utilization of Water Resources in Hengshui City, China
In order to investigate the sustainable utilization of water resources in Hengshui City, quantitative analysis and comprehensive evaluation on 15 indexes of Hengshui City, such as the perspectives of social and economic devel-opment condition, water resource condition, environment condition, development and utilization of water resources, were conducted by using the analytic hierarchy process(AHP) method from 2004 to 2008. Although the sustainable utilization has been growing from 2004 to 2008, the situation and environment of water resources were not optimistic because of the severe water shortage in Hengshui. In the future, improving the supply capacity is the key target for promoting sustainable utilization of water resources....
2020-07-08 21:52:19浏览：50
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A Water Movement Study in Lianzhou Bay, Guangxi Province,China
This study investigates the physical conditions (water depth, current speed, salinity, temperature) in Lianzhou Bay, a shallow coastal bay in southern China, during two expeditions in the dry and wet seasons of 2011. Based on these expedition data, basic hydrodynamic parameters like Brunt-V?is?l? Frequency, Richardson Number, Rossby radius, and Resonance Period are calcu-lated. The results show that Lianzhou Bay is characterized by comparatively small quantity of freshwater input and weak stratifica-tion. Strong tides, which are spatially uniform within the bay, cause turbulent mixing. Residence time of the water is shorter in winter due to a stronger coastal current in that season. Consideration of the water movement may help to reduce the harmful ecological impact of aquaculture waste water discharge....
2020-07-08 08:49:41浏览：36
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Establishment of water quality index (Na+, Ca2+) for purified water reused to zinc electrolysis proc
The effects of Na+ and Ca2+ in the purified water on the conductivity of zinc electrolyte and the current efficiency of zinc electrolysis were studied by the alternating current bridge method and the simulated electrolysis experiments, and the water quality index of reused water was established. The results show that the conductivity of the solution and the current efficiency decrease as these two kinds of positive ions are added in the electrolyte. The effect of Ca2+ is much more remarkable than that of Na+. ρ(Na+)≤ 8 g/L and ρ(Ca2+)≤20 mg/L are the quality indexes in the zinc electrolysis process and the concentrations of Na+ and Ca2+ in the purified water reused to the process should be less than the limited values, i.e. the water quality index of the purified water should be controlled by its reused amount....
2020-07-08 08:49:41浏览：46
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Quantificational analysis on progress of river water quality in China
In order to understand the dynamic change of water quality in a specific period of time,a type of possibility transition matrix based on the theory of Markov process was established.The transition possibility with a weight to calculate the degree of absolute advancement was given based on the result of water quality evaluation,the concept of relative advancement was presented.It was used to evaluate the extent of water quality changed in a period of time.The method was used to calculate the degrees of relative advancement for 4 rivers in China,and the results were analyzed....
2020-07-08 08:49:41浏览：32
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