-
In situ time-resolved FTIRS study of adsorption and oxidation of ethylene glycol on Pt(100) electrod
Adsorption and oxidation of ethylene glycol (EG) on Pt(100) electrode were studied by in situ time- resolved FTIRS (TRFTIRS). The TRFTIR spectra recorded at 0.10 V illustrate that an IR band appears near 2050 cm-1 at t > 5 s, corresponding to linearly bonded CO formed in dissociative adsorption of EG. The TRFTIR results have confirmed also that CO species are distributed uniformly on Pt(100) surface. Another band appears near 2342 cm-1 at t > 70 s, associating with IR absorption of CO2 produced in the direct oxidation of EG. With the increase of electrode potential, the direct oxidation of EG becomes gradually the main reaction. When the potential is above 0.40 V, the oxidation of EG occurs mainly via the reactive intermediates, i.e. species containing -COOH determined by in situ TRFTIRS....
2020-12-22 21:24:13瀏覽：41
查看 -
Stability Analysis for Stochastic Optimization Problems
Stochastic optimization offers a means of considering the objectives and constrains with stochastic parameters. However, it is generally difficult to solve the stochastic optimization problem by employing conventional methods for nonlinear programming when the number of random variables involved is very large. Neural network models and algorithms were applied to solve the stochastic optimization problem on the basis of the stability theory. Stability for stochastic programs was discussed. If random vector sequence converges to the random vector in the original problem in distribution, the optimal value of the corresponding approximation problems converges to the optimal value of the original stochastic optimization problem....
2020-12-06 21:11:24瀏覽：31
查看 -
Isolation and phylogenetic analysis of heterotrophic nitrobacteria
A method about the isolation of heterotrophic nitrosebactria and the characteristics of heterotrophic nitrosobaetria were studied, it can be seen from the fluorescence in situ hybridization results of the bio-mem-brahe sample from the bio-ceramic reactor, the spots of green nitrosobacteria are obviously more than those of orange nitrohaeteria. Two heterotrophic nitrohacteria were isolated from the bio-ceramic reactor. By sequencing 16SrDNA and establishing the phylogenic tree, they were identified physiologically and biochemically as Pseudomonas sp.. After 12 d, the COD removal efficiency of wgy55 and wgy68 were 45.03% and 50.85% , the NH4-N removal efficiency of them were 80.12% and 85.93%, and the TN removal efficiency of them were 69.71% and 64.7%. The final concentration of NO2-N of wgy55 and wgy68 was 0.753 mg/L and 0.601 mg/ L, and that of NO3-N was 3.21 mg/L and 3.38 mg/L. These results show that wgy55 and wgy68 have the ca-pability of nitrification and they are heterotrophic nitrobacteria....
2020-11-22 17:58:37瀏覽：28
查看 -
Analysis on the Individual Discrepancy in English Teaching
Pecently,a great tide of English teaching reform swept across China,advocating the innovation of educational concept and teaching mode.However,the phenomenon of rigid uniformity in teaching process is still commonly seen,neglecting the individual discrepancy of students.The individual discrepancy is manifested by both the congenital heredity and the acquired disposition.Supported by the Chinese traditional theory of teaching students in accordance with their aptitude and Vygotsky's "the zone of proximal development" theory,this paper illustrates the importance of paying attention to the individual discrepancy from the perspective of students' growing background and personality.In addition,standing on the point of view of relevant authority and English teacher,the author tries to put forward some countermeasures....
2020-11-22 17:58:37瀏覽：29
查看 -
河南省糧食“九連增”后的思考
在分析河南省糧食“九連增”影響因素的基礎上，指出了糧食持續增產面臨的問題，提出了促進河南省糧食持續增產的相關對策。...
2020-11-06 10:55:48瀏覽：29
查看 -
-
Amplification process of a gas electron multiplier simulated by PIC-MCC model
The performance of a single gas electron multiplier (GEM) in pure Xe at an atmospheric pressure is investigated by Particle in Cell-Monte Carlo Collision (PIC-MCC) model.The micro development processes with electrons and ions distributions in space have been revealed.Based on the micro development processes,the macroscopic parameters such as GEM gain and the effective efficiency have also been obtained.The simulation results indicate that after tens of nanoseconds,electrons are collected by the readout electrode while the ions still exist in the gas space for several microseconds.The main signal current is formed by the electrons arriving at the readout electrode,but electrons and ions are also collected by the copper electrodes near the GEM hole and the thin Kapton film boundary.The simulated gain of GEM exponentially increases with the applied GEM voltage.With the PIC-MCC simulations,both the physical amplification and charging mechanisms in the GEM device can be well understood,which is beneficial to the device design....
2020-09-15 12:28:59瀏覽：34
查看 -
Study of 3-D Numerical Simulation for Gas Transfer in the Goaf of the Coal Mining
In order to simulate field distribution rules, mathematical models for 3-D air flows and gas transfer in the goaf of the coal mining are established, based on theories of permeability and dynamic dispersion through porous media. A gas dispersion equation in a 3-D field is calculated by use of numerical method on a weighted upstream multi-element balance. Based on data of an example with a U type ventilation mode, surface charts of air pressure distribution and gas concentration are drawn by Graphtool software. Finally, a comparison between actually measured results in the model test and the numerical simulation results is made to proves the numerical implementation feasible....
2020-09-15 12:28:59瀏覽：27
查看 -
Surface performance of workpieces processed by electrical discharge machining in gas
The surface performance of workpieces processed by electrical discharge machining in gas (dry EDM) was studied in this paper. Firstly, the composition, micro hardness and recast layer of electrical discharge machined (EDMed) surface of 45 carbon steels in air were investigated through different test analysis methods. The results show that the workpiece surface EDMed in air contains a certain quantity of oxide, and oxidation occurs on the workpiece surface. Compared with the surface of workpieces processed in kerosene, fewer cracks exist on the dry EDMed workpiece surface, and the surface recast layer is thinner than that obtained by conventional EDM. The micro hardness of workpieces machined by dry EDM method is lower than that machined in kerosene, and higher than that of the matrix. In addition, experiments were conducted on the surface wear resistance of workpieces processed in air and kerosene using copper electrode and titanium alloy electrode.The results indicate that the surface wear resistance of workpieces processed in air can be improved, and it is related with tool material and dielectric....
2020-09-15 12:28:59瀏覽：38
查看 -
Riemann problem for the zero-pressure flow in gas dynamics
The Riemann problem for zero-pressure flow in gas dynamics in one dimension and two dimensions is investigated. Through studying the generalized Rankine-Hugoniot conditions of delta-shock waves, the one-dimensional
Riemann solution is proposed which exhibits four different structures when the initial density involves Dirac measure. For
the two-dimensional case, the Riemann solution with two pieces of initial constant states separated at a smooth curve is
obtained....2020-09-15 12:28:59瀏覽：42
查看 -
Physical Simulation of Water Dissolved Gas (WDG)During Migration
By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as Δ13c,Δd,and Ic4/Nc4 in water-dissolved gas (WDG) during migration) was performed. The result shows that, with the increase of distance, 1) the relative abundance of non-hydrocarbon (CO2) and hydrocarbon (CH4) increase while the relative abundance of hydrocarbon (C2+) decreases (the relative abundance of hydrocarbon (C5+) can be basically negligible); 2) the relative abundance of benzene and methylbenzene increase in the initial time and then decrease. The carbon and hydrogen isotopes of methane vary slightly, which can be regarded as indicators of gas dissolved in water formation....
2020-09-15 12:28:59瀏覽：36
查看 -
Source-Contacting Gas:Accumulation Mechanism and Distribution in China
Source-contacting gas, which is also called basin-center gas, deep basin gas, is the tight-sand gas accumulation contacting closely to its source rocks. Having different accumulation mechanisms from conventional gas reservoirs that are formed by replacement way, the typical source-contacting gas reservoirs are formed by piston-typed migration forward way. Source-contacting gas accumulations exhibit a series of distinctly mechanic characteristics. According to the valid combination of these characteristics, the estimation for the type of discovered gas reservoirs or distributions of source-contacting gas reservoirs can be forecasted. The source-contacting gas is special for having no edge water or bottom water for gas and complicated gas-water relationships, which emphasizes the intimate association of reservoir rocks with source rocks, which is called the root of the gas reservoir. There are many basins having the mechanic conditions for source-contacting gas accumulations in China, which can be divided into three regions. Most of the basins with favorable accumulation conditions are located mainly in the central and western China. According to the present data, basins having source-contacting gas accumulations in China can be divided into three types, accumulation conditions and configuration relationships are the best in type A basins and they are the larger basins in central China. Type B basins with plain accumulation conditions exist primarily in eastern China and also the basins in western China. Accumulation conditions and exploration futures are worse in type C basins, which refer mainly to the small basins in southern China and China Sea basins. Main source-contacting gas basins in China are thoroughly discussed in this paper and the distribution patterns of source-contacting gas in five huge basins are discussed and forecasted....
2020-09-13 23:35:02瀏覽：49
查看 -
Division of Gas Accumulation System and Laws Controlling Distribution of Natural Gas in Typical Petr
Considering the existing problems of the petroleum system, this paper brings forward the concept of natural gas accumulation system and presents the dividing principles. Then detailed statistics on the accumulation factors of the 32 typical natural gas accumulation systems in China and studies on the laws controlling distribution of gas are collected. The research shows that the petroleum accumulation system is the basic unit controlling petroleum generation, migration and accumulation. Generating intensity, generating amount, accumulating efficiency and migration distance plays an important role in the distribution of natural gas. Through analysis on results of resources evaluation, discovered reserves and residual reserves, potential areas in middle-scaled petroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basins are found out to be the main basins developing and enriching gas accumulation systems....
2020-09-13 23:35:02瀏覽：31
查看 -
聚乙二醇6000對間尼索地平溶解性能的影響
目的：研究聚乙二醇6000對間尼索地平溶解度和體外溶出度的影響,為間尼索地平劑型的選擇提供參考。方法以聚乙二醇(PEG)6000為載體,采用溶劑-熔融法制備間尼索地平固體分散體。應用差示掃描量熱分析法( DSC)、X射線粉末衍射光譜( XRD)對固體分散體進行鑒定,紫外分光光度法測定固體分散體的溶解度和體外溶出度。結果固體分散體的DSC、XRD圖譜與原料藥及其物理混合物均不同,不同比例的間尼索地平-聚乙二醇固體分散體的溶解度及體外溶出度均高于原料藥,2 h的溶出百分率：原料藥26.80%,固體分散體(13,15,17)分別為35.31%,38.71%,41.48%,比例相同的固體分散體的溶出率高于其物理混合物。結論間尼索地平與聚乙二醇6000形成了低共熔物,聚乙二醇6000作為間尼索地平的載體,可加速其體外溶出。...
2020-07-10 14:39:05瀏覽：29
查看 -
寶鋼電廠4號機組循環水泵房控制系統
該文介紹了寶鋼電廠4號機組循環水泵房現場控制系統設計,內容主要包括監控內容、控制原則、PLC現場站設計、主要控制功能和控制系統供電設計.由于所涉被監控設備地理位置分散和電廠運行要求高可靠性,系統設計與常規市政泵站相比有一定的復雜性及特異性.系統采用遠方DCS及就地PLC相結合的構架,各環節均采用冗余系統,采用符合循環水泵特點的控制邏輯及有效的保護措施,實現了泵房的可靠運行.幾年來運行結果表明,該控制系統設計符合使用方的要求....
2020-07-10 14:39:05瀏覽：39
查看 -
強自吸雙吸循環水泵故障多發的原因分析與對策
泵軸的斷裂原因涉及操作環境、材質、軸負荷、汽蝕以及裝配質量等多個方面,其中之一或更多方面的共同作用都會導致泵軸在運行時斷裂,通過對循環水場兩臺雙吸泵的斷軸故障原因分析,提出改造措施,消除了斷軸現象,保證了水泵的長周期安全運行....
2020-07-10 14:39:05瀏覽：34
查看 -
Simultaneous operation of dibenzothiophene hydrodesulfurization and methanol reforming reactions ove
In the current study simultaneous reactions of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic ( Co-Mo/Al2O3 and Ni-Mo/Al2O3 ) and tri-metallic ( Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3 ) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 ＞ Ni-Mo/Al2O3 ＞ Pd-Co-Mo/Al2O3＞ Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91％ DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism....
2020-07-08 21:52:19瀏覽：40
查看 -
Aviation-oriented Micromachining Technology-Micro-ECM in Pure Water
This article proposes a precise and ecofriendly micromachining technology for aerospace application called electrochemical machining in pure water (PW-ECM). On the basis of the principles of water dissociation, a series of test setups and tests are devised and performed under different conditions. These tests explain the need for technological conditions realizing PW-ECM, and further explore the technological principles. The results from the tests demonstrate a successful removal of electrolytic slime by means of ultrasonic vibration of the workpiece. To ensure the stability and reliability of PW-ECM process, a new combined rnachining method of PW-ECM assisted with ultrasonic vibration (PW-ECM/USV) is devised. Trilateral and square cavities and holes as well as a group of English alphabets are worked out on a stainless steel plate. It is eonfirmed that PW-ECM will be probably an efficient new aviation precision machining method....
2020-07-08 21:52:19瀏覽：32
查看 -
Applications of Water Sensitivity In Situ Remediation at Saltwater-Freshwater Interface
Based on the laboratory experiments with the saltwater and freshwater replacing each other in the level sand column, taking the kaolin, illite, smectite, bivalent hydrargyrum ion (Hg2+) and phenol (C6H5OH) as exam-ples, this paper studies the applications of water sensitivity in situ remediation in saltwater-freshwater transition zone. In the water sensitivity process, the release and migration of clay minerals can make the hydraulic conductiv-ity (HC) decrease and pollutants remove. A new type of low penetrable or impenetrable purdah can be built by adding clay minerals into the sand media to replace the underground concrete impenetrable wall to prevent seawater intrusion, and a number of the heavy metals and organic pollutants in the sand media can be removed by in situ remediation. The results show that the content of kaolin and illite influences the water sensitivity process slightly, and HC of the sand columns descends from 0.011 cm/s to 0.001 4 cm/s and 0.001 2 cm/s respectively even if the content reaches 12% (weight ratio, sic passim). However, for smectite, HC descends sharply to about 1×10-8 cm/s when its content reaches 4%, and no water can flow through the sand columns beyond 5%. The particle release and migration processes can remove the Hg2+ and C6H5OH out of the sand columns efficiently, the removing rate of Hg2+ is 31.68% when the freshwater and saltwater are filtered through the sand columns polluted by Hg2+, while it is 67.55% when the water sensitivity occurs. With the same method, the removing rates of C6H5OH under the fluid flow and water sensitivity are 55.71% and 43.43% respectively....
2020-07-08 21:52:19瀏覽：24
查看 -
Mining-induced variation in water levels in unconsolidated aquifers and mechanisms of water preserva
Phreatic water resources are widely found in thick unconsolidated surface layers in western China, where water levels respond sensitively and quickly to large-scale underground mining in conjunction with shallow coal seams. Longwall face #32201 of the Bulianta Coal Mine, in the Shendong coalfield was selected as an industrial trail base, where field observations on ground-water levels were conducted when the working face was below a water-rich area. The space-time variation in the behavior of un-consolidated water levels in response to underground mining and its relation with of advance were observed through the field trials. The basic conditions for water preservation in mines are presented and the mechanisms of water preservation in mining analyzed, given the geological condition of two key strata and a severely weathered layer buried in the overburden. The field trails show that water preservation in mining shallow coal seams can be successful under suitable conditions, providing new technology for envi-ronmental protection in the desert coalfields of northwestern China....
2020-07-08 08:49:41瀏覽：16
查看 -
Water content distribution in the surface layer of Maoping slope
The water content distribution in the surface layer of Maoping slope has been studied by testing the water content at 31 control sites. The water content profiles at these sites have also been determined. The water content distributions at different segments have been obtained by using the Kriging method of geostatistics. By comparing the water content distributions with the landform of the slope, it was shown that the water content is closely dependent on the landform of the slope. The water content distribution in the surface layer provided a fundamental basis for landslide predication and treatment....
2020-07-08 08:49:41瀏覽：31
查看 -
Research on the Sustainable Utilization of Water Resources of Jinan City
The study on the sustainable utilization of water resources of Jinan city is a research hotspot in the urban sustainable development field.How to use a scientific and rational evaluation index system to analyze the sustainable utilization of water resources of Jinan city and then guide the development and utilization of water resources becomes particularly important.Based on the theory of sustainable development this study introduces the method,basic steps and evaluation indexes of the assessment of the development and utilization of water resources.By systemic analyzing the exploitation and utilization standards of water resources and economy and society in Jinan city,the evaluation and index system of sustainable utilization of water resources in Jinan city can be constructed and index weight can be confirmed,and then,the standard of sustainable utilization of water resources in different years can be analyzed comparably.Thus,the deficiency of lack of reflection of coordination extent in water resources development standard,society and economy in traditional evaluation method is settled efficiently.The paper takes the sustainable utilization of water resources of Qingdao City in 2008 as the standard to compare and assess the water resources utilization in Jinan City.The paper also collects data of water resources in Jinan City from2001 to 2007.The result indicates that evaluation method is of feasibility and it is effective to the implementation of sustainable utilization strategy water resources in Jinan City....
2020-07-08 08:49:41瀏覽：27
查看 -
Experimental study on total dissolved gas supersaturation in water
More and more high dams have been constructed and operated in China.The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish.Through a series of experiments,the conditions and requirements of supersaturated TDG generation were examined in this study.The results show that pressure (water depth),aeration,and bubble dissolution time are required for supersaturated TDG generation,and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG.The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines.Furthermore,the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs.These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection....
2020-07-08 08:49:41瀏覽：21
查看 -
Timing of advanced water flooding in low permeability reservoirs
It is very important to design the optimum starting time of water injection for the development of low permeability res-ervoirs. In this type of reservoir the starting time of water injection will be affected by a reservoir pressure-sensitive effect. In order to optimize the starting time of water injection in low permeability reservoirs, this effect of pressure change on rock permeability of low permeability reservoirs was, at first, studied by physical simulation. It was shown that the rock permeability decreases expo-nentially with an increase in formation pressure. Secondly, we conducted a reservoir engineering study, from which we obtained analytic relationships between formation pressure, oil production rate, water production rate and water injection rate. After our physical, theoretical and economical analyses, we proposed an approach which takes the pressure-sensitive effect into consideration and designed the optimum starting time of water injection, based on the principle of material balance. Finally, the corresponding software was developed and applied to one block of the Jiangsu Oilfield. It is shown that water injection, in advance of production, can decrease the adverse impact of the pressure-sensitive effect on low permeability reservoir development. A water-flooding pro-ject should be preferably initiated in advance of production for no more than one year and the optimum ratio of formation pressure to initial formation pressure should be maintained at a level between 1.05 and 1.2....
2020-07-08 08:49:41瀏覽：23
查看 -
Radioactivity monitoring in environmental water and air around QNPP
Results of environmental radioactivity monitoring around Qinshan Nuclear Power Plant (QNPP) are reported in this paper. From 1992 to 2005, concentrations of 90Sr, 137Cs and 3H in terrestrial freshwater are (4.4±1.7) mBq·L-1, (0.3±0.1) mBq·L-1 and (1.6±0.5) Bq·L-1, respectively, and (2.8±2.4) Bq·L-1 of 3H in rainwater. Concentrations of 90Sr, 137Cs and 3H in the seawater samples collected from sea area nearby QNPP are (5.4±4.1) mBq·L-1,(0.7±0.2) mBq·L-1 and (1.0±0.5) Bq·L-1, respectively. Concentrations of 90Sr, 137Cs and 3H in the total waste water discharged from NPP-I are (4.0±1.8) m Bq·L-1, (1.0±0.5) mBq·L-1 and (2.8±2.2) Bq·L-1, respectively, and (1.4±0.4)Bq·L-1 of 3H in seawater sampled from No.1 outlet. Atomspheric 3H concentration in 1993 ～ 2005 at two monitoring sites is (78.9±96.3) and (64.2±40.2) mBq·m-3, respectively, with an increasing trend after 2003. Atmospheric 14C concentrations at the two sites are in the same levels as the background and data of the reference site....
2020-07-08 08:49:41瀏覽：19
查看
