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      • 添加劑EDTA對KDP晶體快速生長的影響研究

        在添加不同濃度(0~5×10-3)EDTA 的KDP飽和溶液中,采用“點籽晶”快速生長技術生長了KDP晶體,生長速度約20 mm/d.研究了不同濃度的EDTA對KDP晶體快速生長的影響.實驗發現,隨著溶液中EDTA添加量的增加,KDP 晶體(100)面的生長速度是先增加經過一個最大值然后減??;晶體宏觀外形高寬比則是先減小經過一個最小值然后增加.在溶液中添加適量濃度的EDTA(5×10-5~5×10-4)可以有效地提高生長溶液的穩定性;而過量的添加 ED-TA(>1×10-3)反而會破壞溶液的穩定性,當溶液中EDTA濃度增至5×10-3時,溶液甚至發生“雪崩”,晶體出現母液包藏、添晶和粉碎性裂紋等缺陷.結合KDP的晶體結構和EDTA的分子特點,對其影響機理進行了討論....

        2020-12-22 21:24:13瀏覽:16 KDP晶體添加劑快速生長溶液穩定性KDPcrystaladditiveRapidgrowthsolutionStability

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      • Fatigue reliability analysis of kiln welded shell

        This paper presents a probabilistic reliability method for the welded shell during crack growth. The crack growth model incorporated with a failure assessment diagram(FAD), which can provides a better estimation of the critical crack length, is developed to describe fatigue failure. All variables for particular welded joints of the shell are studied. Among them, the stress variables are based on the calculated stress by using the finite element (FE) code ANSYS. Fatigue reliability analysis of the welded shell is performed by using the Monte Carlo simulation method. The failure probability curve of the example kiln is significantly useful to determine the repair schedule of shell cracks....

        2020-12-06 21:11:24瀏覽:38 FatiguereliabilityweldedShellcrackgrowthFADMonteCarloANSYS

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      • Crystallographic Analysis of Tapering of ADP Crystallites

        On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, the growth rate of prismatic faces is slower and more sensitive to the additives and impurities for ADP crystals. When the supersaturation is low, the advance of growth steps on prismatic face can be blocked by ethanol or impurities, the crystal morphology is changed from the tetragonal prism to shuttle (i.e., the tapered shape). The tapering formation of ADP crystallites was structurally studied in a novel view....

        2020-11-22 17:58:37瀏覽:26 crystalstructurechemicalbondgrowthhabitADPhydrogentapering

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      • Verification of topological relationship in 2-D grain growth process by simulation

        Behaviors of the quasi-steady state grain size distribution and the corresponding topological relationship were investigated using the Ports Monte Carlo method to simulate the normal grain growth process. The observed quasi-steady state grain size distribution can be well fit by the Weibull function rather than the Hillert distribution. It is also found that the grain size and average number of grain sides are not linearly related. The reason that the quasi-steady state grain size distribution deviates from the Hillert distribution may contribute to the nonlinearity of the relation of the average number of grain sides with the grain size. The results also exhibit the reasonability of the relationship deduced by Mullins between the grain size distribution and the average number of grain sides....

        2020-11-22 17:58:37瀏覽:30 graingrowthsizedistributiontopologyMonteCarlosimulationHillert

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      • Sintering process and grain growth of Mn-Zn ferrite nanoparticles

        The density, microstructure and magnetic properties of non-doped Mn-Zn ferrite nanoparticles sintered compacts were investigated. The compacts of non-doped Mn-Zn ferrite nanoparticles were sintered by segmented-sintering process at lower sintering temperature. The density of sintered samples was measured by Archimedes method, and the phase composition and microstructure were examined by XRD and SEM. The sintered Mn-Zn ferrite magnetic measurements were carried out with Vibrating Sample. The results show that the density of sintered compacts increases with the rising of sintering temperature, achieving 4.8245 g·cm-3 when sintered at 900 ℃, which is the optimal density of Mn-Zn functional ferrite needed and from the fractured surface of sintered samples, it can be seen that the grain grows well with small grain size and homogeneous distribution....

        2020-11-11 22:33:38瀏覽:24 Mn-Znferritesinteringtemperaturegraingrowthdensitymagneticproperties

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      • OPTICAL DIAGNOSTIC AND MODELING SOLUTION GROWTH PROCESS OF SODIUM CHLORATE CRYSTALS

        Both a real time optical interferometric experiment and a numerical simulation of two-dimension non-steady state model were employed to study the growth process of aqueous sodium chlorate crystals. The parameters such as solution concentration distribution, crystal dimensions, growth rate and velocity field were obtained by both experiment and numerical simulation. The influence of earth gravity during crystal growth process was analyzed. A reasonable theory model corresponding to the present experiment is advanced. The thickness of concentration boundary layer was investigated especially. The results from the experiment and numerical simulation match well....

        2020-11-11 22:33:38瀏覽:25 crystalgrowthinterferometrynumericalsimulationconcentrationboundarylayer

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      • Experimental Study on Minimization of Sludge Production by Ozonation Process

        Based on the hypothesis of reducing sludge production under cryptic growth conditions, ozone was used as cell lysis agent to treat excess sludge,and then the ozonated supernatant was returned to the aeration tank. The results show that COD and NH+4-N removal efficiencies in ozonation process were 87.96% and 84.42%, respectively. Meanwhile, a low excess sludge yield coefficient of 0. 113 ( g SS/g COD removed) was obtained. Compared with that of the control test, the process configuration decreased the excess sludge production by 51.3%....

        2020-11-10 09:33:08瀏覽:21 ozonationsludgeminimizationcrypticgrowthexcessyield

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      • Influence of concentration of zinc ions on electrocrystallization process of zinc

        Cyclic voltammetry, chronoamperometry and scanning electron microscopy were employed to study the influence of Zn2+ ion concentration in electrolyte solutions on zinc electroplating process. The results show that, at high overpotentials, the nucleation of zinc is instantaneous, and nuclear density increases with the overpotentials increasing. While at low overpotentials, the zinc may be preferentially electrodeposited on surface inhomogeneities such as emergence points of edge, screw dislocations, atomic disorder, kink sites, or monoatomic steps, and no distinguished nucleation current can be observed. The major dissolution peak in cyclic voltammogram drifts positively due to the change of the rate-determining step of zinc electroplating processes from diffusion to the electrochemical reaction with the increase of Zn2+ ion concentration....

        2020-11-10 09:33:08瀏覽:27 zincelectroplatingnucleationgrowthmechanism

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      • 河南省人口紅利與經濟增長關系研究

        基于柯布道格拉斯生產函數的理論推導,建立人均收入、人均物質資本和總撫養比三者的計量模型,利用1987—2013年的時間序列數據,通過協整理論對計量模型進行檢驗,研究河南省人口紅利與經濟增長的關系。結果顯示:三者之間存在長期穩定關系,在長期,總撫養比對人均收入具有負向影響,人均物質資本對經濟增長具有正向影響,并且總撫養比變化對人均收入的影響比物質資本投入大;在短期,撫養比變化并未直接作用于經濟增長,物質資本的投入對經濟增長的影響具有滯后性。...

        2020-11-03 10:30:25瀏覽:22 人口紅利經濟增長總撫養比協整理論demographicdividendeconomicgrowthtotaldependencyratio

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      • 設計與自然

        通過描繪自然本色,旨在引導人們去發現自然之美;通過論述自然對人類的關照和啟示,說明了自然之美與人類文明之美是相容相通的,從而啟示人們如何去正確地處理人與自然的關系,如何去對環境進行有效地設計與改造。...

        2020-10-30 20:43:45瀏覽:20 生命自然生長文明之美平等lifenaturalgrowthbeautyofcivilizationequality

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      • Influence of furfural concentration on growth and ethanol yield of Saccharomyces kluyveri

        Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In order to find out the furfural concentration range in which furfural inhibits the fermentation process, we used one strain Saccharomyces kluyveri selected from soil and cultured in several different furfural content media under low glucose concentration condition. Experiment results show that microorganism growth was stimulated and dry cell weight decreased when furfural concentration in the medium was 0.25 mg/ml. Furfural had negative effect on cell growth when its concentration was above 1.00 mg/ml. At the same time, the strain growed better and had higher glucose consumption rate in 5% original glucose concentration condition than in 3% original glucose concentration condition. The results show that appropriate exaltation of original glucose concentration in stalk hydrolysates will increase the strain resistance to furfural....

        2020-10-22 17:35:41瀏覽:20 furfuralconcentrationSaccharomyceskluyverifermentationgrowthethanolyield

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      • Synthesis of carbon nanofibers by ethanol catalytic combustion technique

        A general, simple and economic synthetic method for synthesizing carbon nanofibers was presented. In the method, ethanol was employed as carbon source; metal salts such as nickel nitrate, ferric nitrate and ferric chloride were used as catalyst precursor respectively; copper plate was employed as the support material. A lot of products were obtained by catalytic combustion deposition of ethanol vapor. Then the as-prepared carbon nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, energy dispersion X-ray spectroscopy and selected-area electron diffractometry. By analyzing the results of characterization, the conclusions are as follows: 1) the large catalyst particles tend to formlarge-diameter CNFs, small catalyst particles are inclinable to form small-diameter CNFs; 2) the morphology of the catalyst can affect the final morphology of the CNFs. Moreover, the possible growth mechanisms were proposed and the degree of graphitization of samples was estimated by Raman spectroscopy characterization....

        2020-10-22 17:35:41瀏覽:26 synthesisethanolcatalyticcombustioncarbonnanofibersgrowthmechanismdegree

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      • Probe into Environmental Kuznets Characteristics and Causes of Wastewater,Waste Gas, and Solid Waste

        Environmental Kuznets characteristics and causes of waste water, waste gas, and solid wastes in Wuhan city was researched; By comparing the variation of "three wastes", i.e. waste water, waste gas, and solid wastes, the model between standardized per capita GDP and values of "three wastes" discharge was established and the causes were analyzed based on the theory of environmental economics. The results show that 1) the total amount is fluctuantly increasing, but the discharges of the three kinds are temporarily different, 2) the curve conforms to the three-power function, in which the curve descends from 1985 to 1994, and the curve preliminary shows the environmental Kuznets characteristics from 1995 to 2001, 3) the simulated calculation illustrates that the turning point of this environmental Kuznets curve would be over 25007.25 Yuan per caprta, and 4) the economic development, changing of industry structure, energy resource structure, and environmental policies are the main factors leading to the Environmental Kuznets Curve in Wuhan city....

        2020-09-15 12:28:59瀏覽:33 dischargeofeconomicgrowthEnvironmental

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      • Growth, Gas Exchange, Abscisic Acid, and Calmodulin Response to Salt Stress in Three Poplars

        In the present study, we investigated the effects of increasing salinity on growth, gas exchange, abscisic acid(ABA), calmodulin (CAM), and the relevance to salt tolerance in seedlings of Populus euphratica Oliv. and cuttings of P. "pupularis 35-44" (P. popularis) and P. x euramericana cv. 1-214 (P. cv. Italica). The relative growth rates of shoot height (RGRH) for P. cv. Italica and P. popularis were severely reduced by increasing salt stress,whereas the growth reduction was relatively less in P. euphratica. Similarly, P. euphratica maintained higher net photosynthetic rates (Pn) and unit transpiration rates (TRN) than P. cv. Italica and P. popularis under conditions of higher salinity. Salinity caused a significant increase in leaf ABA and CaM in the three genotypes after the onset of stress, but NaCl-induced ABA and CaM accumulation was more pronounced in P. euphratica,suggesting that P. euphratica plants are more sensitive in sensing soil salinity than the other two poplars.Furthermore, P. euphratica maintained relatively higher ABA and CaM concentrations under conditions of high salinity. The higher capacity to synthesize stress signals, namely ABA and CaM, in P. euphratica and the contribution of this to the salt resistance of P. euphratica are discussed....

        2020-09-15 12:28:59瀏覽:18 abscisicacidcalmodulingasexchangegrowthNaClPopuluseuphratica

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      • 重組人角質細胞生長因子-Ⅰ的聚乙二醇修飾及體外活性

        研究大腸桿菌表達的重組人角質細胞生長因子-Ⅰ型N端缺失突變體(△N23KGF-Ⅰ)的mPEG-馬來酰亞胺(mPEG-maleimide、mPEG-Mal)修飾工藝及修飾位點和初步體外生物活性。首先修飾得到聚乙二醇化的△N23KGF-Ⅰ,然后對△N23KGF-Ⅰ作還原和非還原質量肽圖,確定其各肽段,對△N23KGF-Ⅰ-m PEG-Mal-20K做還原質量肽圖,確定修飾位點。最后,通過BAF-3細胞對△N23KGF-Ⅰ國際標準品、△N23KGF-Ⅰ、△N23KGF-Ⅰ-m PEG-Mal-20K測活。結果表明,在尿素環境下,mPEG-MAl被均一修飾在△N23KGF-I的Cys40位。與國際活性標準品相比,△N23KGF-Ⅰ的活性保留了116%,△N23KGF-Ⅰ-m PEG-Mal-20K的活性保留了36%。...

        2020-07-10 14:39:05瀏覽:23 重組人角質細胞生長因子質量肽圖聚乙二醇修飾keratinoeytegrowthfactorpeptidemassmapping(PPM)

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      • A Study on the Effects of Carrier Gases on the Structure and Morphology of Carbon Nanotubes Prepared

        Carbon nanotubes (CNTs) were prepared using different carrier gases,with ferrocene as the catalyst precusor and acetylene as the carbon source. The effects of ammonia and nitrogen as carrier gases on the structure and morphology of CNTs were investigated. Transmission electron microscope (TEM),high-resolution electron microscope (HRTEM),scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the products and the catalyst. Experiment results show that the CNTs grown in N2 gas exhibited cylindrical and tubular structure,while a bamboo-like structure was observed for the CNTs grown in NH3 gas. Moreover,vertically aligned CNTs were obtained on an Al2O3 disk when NH3 was used as the carrier gas. The carrier gas also exerted influence on the shape of the catalyst. Based on the theory of active centers of catalysis and combined with the particle shape of the catalyst,a growth model for the vertically aligned CNTs on the substrate is given....

        2020-07-08 21:52:19瀏覽:26 carbonnanotubeferroceneverticallyalignedBamboo-likecarriergasgrowth

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      • EFFECT OF MAGNETIZATION OF WATER ON INDUCTION TIME AND GROWTH PERIOD OF NATURAL GAS HYDRATE

        The effect of diluted solution's magnetization on induction time and growth period of natural gas hydrate (NGH) has been investigated in quiescent reaction system at pressure of 4. 5 MPa and temperature of 274 K with SDS as surfactant, by using volume fixed and pressure falling method. Experimental results show that magnetization will have effect on the induction time of NGH. After magnetization with magnetic field intensity of 0.33 T, the induction time of NGH has been reduced to 47 min (average) from 99 min (average) in which there is no magnetization. On the other hand, the induction time has been prolonged after magnetization of the diluted solution with magnetic field intensity of 0.05 T, 0. 11 T, 0.22 T, 0.44T. Especially with magnetic field intensity of 0.11 T, the induction time had even been prolonged to 431min (average). The effect of magnetization on the growth period of NGH has not been found at the experimental condition....

        2020-07-08 21:52:19瀏覽:27 naturalgashydratemagnetizationgrowthinductiontime

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      • Influence of water logging time on the growth of candel seedlings

        Influence ofwaterlogging time on the growth ofKandeliacandel(L.) Druce seedlings grown for 70 d in the artificial-tidal tanks' simulated semidiumal tide under greenhouse is studied. Sand and soil act as the substrate and artificial sea-water with salinity of 15 is used in cultivation. Shorter waterlogging time (inundated for about 2 ~ 4 h) promotes thegrowth of K. candel seedlings, while longer time(inundated more than 8 h) or no waterlogging(0 h) inhibits theirgrowth. The number and length of aerating roots increase with the increase ofwaterlogging time. Under existing condi-tions, the optimalwaterlogging time for the growth of K. canoel seedlings is about 2 ~ 4 h in every tide cycle. Com-pared with other treatments, the 2 h sanded treatments obtain the highest biomass of seedlings, have the lowest massloss ofhypocotyl and broaden the photosynthetic area by increasing the area per leaf after 70-d cultivation. And the soiltreatments have the similar tendeney. However, waterlogging for 8 h in every tide cycle is critieal for normal develop-ment of seedlings. K. candel seedlings are highly tolerant to waterlogging and a proper waterlogging is beneficial to thegrowth ofK. candel seedlings....

        2020-07-08 08:49:41瀏覽:21 K.candelgrowthoptimalwaterloggingtimecritical

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      • Vegetation Growth Monitoring Under Coal Exploitation Stress by Remote Sensing in the Bulianta Coal M

        Coal exploitation inevitably damages the natural ecological environment through large scale underground exploitation which exhausts the surrounding areas and is the cause of surface subsidence and cracks.These types of damage seriously lower the underground water table.Deterioration of the environment has certainly an impact on and limits growth of vegetation, which is a very important indicator of a healthy ecological system.Dynamically monitoring vegetation growth under coal exploitation stress by remote sensing technology provides advantages such as large scale coverage, high accuracy and abundant information.A scatter plot was built by a TM (Thematic Mapper) infrared and red bands.A detailed analysis of the distributional characteristics of vegetation pixels has been carried out.Results show that vegetation pixels are affected by soil background pixels, while the distribution of soil pixels presents a linear pattern.Soil line equations were obtained mainly by linear regression.A new band, reflecting vegetation growth, has been obtained based on the elimination of the soil background.A grading of vegetation images was extracted by means of a density slice method.Our analysis indicates that before the exploitation of the Bulianta coal mining area, vegetation growth had gradually reduced; especially intermediate growth vegetation had been transformed into low vegetation.It may have been caused by the deterioration of the brittle environment in the western part of the mining area.All the same, after the start of coal production, vegetation growth has gradually improved, probably due to large scale aerial seeding.Remote sensing interpretation results proved to be consistent with the actual situation on the ground.From our research results we can not conclude that coal exploitation stress has no impact on the growth of vegetation.More detailed research on vegetation growth needs to be analyzed....

        2020-06-12 16:16:47瀏覽:1405 coalexploitationlinearregressiondensityslicevegetationgrowth

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      • 生物質炭在畜禽生產中的應用

        生物質炭是農林業廢棄的生物質在缺氧條件下熱解形成的富碳產物。近年來,隨著全球對生物質炭科學研究的加強,生物質炭在畜禽生產中改善動物腸道健康、促進生長性能、提高飼糧利用效率、減少糞尿污染環境等作用正在引起有關方面的廣泛關注。本文綜述了國內外學者在畜禽生產中應用生物質炭的最新研究成果。...

        2020-06-12 15:43:33瀏覽:1392 生物質炭農業廢棄物畜禽生長biocharagriculturalandforestryresidueslivestockgrowth

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