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Effect of Low pH on Forming Process of Desulfurization Gypsum Composite Boards Strengthened by Melamine-formaldehyde Resin
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作者 CAO Lijiu ZHANG Jiyao +4 位作者 WANG Xinqi ZHANG Xinhe HUANG Jian CHEN Yufang JIN Tao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1223-1228,共6页
Through exploring the effects of low pH on the composite system of desulfurization gypsum(DG)enhanced by melamine-formaldehyde resin(MF),it is found that the inducing of sulfate-ion,in contrast to chloride and oxalate... Through exploring the effects of low pH on the composite system of desulfurization gypsum(DG)enhanced by melamine-formaldehyde resin(MF),it is found that the inducing of sulfate-ion,in contrast to chloride and oxalate ions,favors the longitudinal growth of the crystalline form of the hydration product,which was relatively simple and had the highest length to width(L/D)ratio.At the same time,MF can also improve L/D ratio of gypsum hydration products,which favors the formation of hydrated whiskers.Finally,in a composite system composed of hemihydrate gypsum,MF,and glass fibers,when dilute sulfuric acid was used to regulate pH=3-4,the tight binding formed among the components of the composite system compared to pH=5-6.The hydration product of gypsum adheres tightly to glass fiber surface and produces a good cross-linking and binding effect with MF.The flexural strength,compressive strength,elastic modulus,and water absorption of the desulphurized gypsum composite board is 22.7 MPa,39.8 MPa,5608 MPa,and 1.8%,respectively. 展开更多
关键词 MF-reinforced desulphurized gypsum board composite forming system low ph condition hydration process aspect ratio synergistic effect
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Construction of Value Models of Consumer Creation for Agricultural Products Based on the Analytic Hierarchy Process(AHP) 被引量:2
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作者 杨庆先 汤自英 《Agricultural Science & Technology》 CAS 2010年第4期180-183,共4页
With the increased competition of modern economy and globalization,consumer creation which based on the analysis of consumer behavior was more and more attentioned and respected by business.Based on the meaning and ch... With the increased competition of modern economy and globalization,consumer creation which based on the analysis of consumer behavior was more and more attentioned and respected by business.Based on the meaning and characteristics of agricultural product consumer creation,index system of value model of agricultural product consumer creation was put forward through analytical hierarchy process(AHP).The weights of the indicators and related indicators of impact on the value were analyzed,and value models of agricultural product consumer creation were constructed to provide ideas for development of agricultural product consumer market and research of consumer value.Consumer creation was constructed to provide ideas for development of agricultural product consumer market and research of consumer value. 展开更多
关键词 Agricultural Products Consumer Creation Analytic Hierarchy process(AHP) value Model
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A LIMIT THEOREM FOR INTERACTING MEASURE-VALUED BRANCHING PROCESSES
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作者 赵学雷 杨敏 《Acta Mathematica Scientia》 SCIE CSCD 1997年第3期241-249,共9页
It is well known that Fleming-Viot superprocesses can be obtained from the Dawson-Watanabe superprocesses by conditioning the latter to have constant total mass. The same question is investigated for measure-valued br... It is well known that Fleming-Viot superprocesses can be obtained from the Dawson-Watanabe superprocesses by conditioning the latter to have constant total mass. The same question is investigated for measure-valued branching processes with interacting intensity independent of the geographical position. It is showed that a sequence of conditioned probability laws of this kind of interacting measure-valued branching processes also approximates to the probability law of Fleming-Viot superprocesses. 展开更多
关键词 interacting measure-valued Branching processes DW-superprocesses FV-superprocesses conditioned probability law
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CROSSING TIME AND RENEWAL NUMBERS OF TWO PH-RENEWAL PROCESSES
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作者 SHI DINGHUA AND MIR G. H. TALPUR 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1995年第2期111-122,共12页
This paper considers how to find some joint distributions and their marginal distributions of crossing time and renewal numbers related to two PH-renewal processes by constructing an absorbing Markov process.
关键词 ph-distribution absorbing Markov process ph-renewal process.
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Influence of pH value and chelating reagent on performance of Li_3V_2(PO_4)3/C cathode material 被引量:2
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作者 向伟 唐艳 +4 位作者 王雁英 钟本和 方为茂 刘恒 郭孝东 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1395-1402,共8页
The Li3V2(PO4)3/C composite cathode material was synthesized via sol-gel method using three different chelating agents (citric acid, salicylic acid and polyacrylic acid) at pH value of 3 or 7. The crystal structur... The Li3V2(PO4)3/C composite cathode material was synthesized via sol-gel method using three different chelating agents (citric acid, salicylic acid and polyacrylic acid) at pH value of 3 or 7. The crystal structure, morphology, specific surface area and electrochemical performance of the prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge test. The results show that the effects of pH value on the performance of the prepared materials are greatly related to the chelating agents. With salicylic acid or polyacrylic acid as the chelating reagent, the structure, morphology and electrochemical performance of the samples are greatly influenced by the pH values. However, the structure of the materials with citric acid as the chelating agent does not change as pH value changes, and the materials own uniform particle size distribution and good electrochemical performance. It delivers an initial discharge capacity of 113.58 mA·h/g at 10C, remaining as high as 108.48 mA·h/g after 900 cycles, with a capacity retention of 95.51%. 展开更多
关键词 Li3V2(PO4)3 cathode material sol-gel method chelating agents ph value
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Influence of pH Value on Photocatalytic Activity of Bi4Ti3O12 Crystals Obtained by Hydrothermal Method 被引量:1
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作者 林雪 宫宇宁 +2 位作者 张耀丹 闫永胜 关庆丰 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第2期209-213,I0004,共6页
Bi4Ti3O12 (BIT) crystals were controllably synthesized via a facile hydrothermal process without adding any surfactant or template. The morphologies of BIT with nanosphere, nanoplate, nanobelt, and nanosheet can be ... Bi4Ti3O12 (BIT) crystals were controllably synthesized via a facile hydrothermal process without adding any surfactant or template. The morphologies of BIT with nanosphere, nanoplate, nanobelt, and nanosheet can be selectively obtained by adjusting the pH value of the reactant. The formation mechanisms of these distinctive morphologies were then discussed based on the structural analysis of samples obtained at different pH values. BIT sample prepared at pH=1 showed the highest photocatalytic activity under visible light irradiation. The photocatalytic activities difference for the BIT samples synthesized at different pH values was studied based on their shape, size, and the variation of local structure. 展开更多
关键词 phOTOCATALYSIS BI4TI3O12 ph value Local structure
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Hazard assessment of landslide disaster using information value method and analytical hierarchy process in highly tectonic Chamba region in bosom of Himalaya 被引量:14
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作者 Kanwarpreet SINGH Virender KUMAR 《Journal of Mountain Science》 SCIE CSCD 2018年第4期808-824,共17页
The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalay... The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalaya. During study, the information about the causative factors was generated and the landslide hazard zonation maps were delineated using Information Value Method(IV) and Analytical Hierarchy Process(AHP) using Arc GIS(ESRI). For this purpose, the study area was selected in a part of Ravi river catchment along one of the landslide prone Chamba to Bharmour road corridor of National Highway(NH^(-1)54 A) in Himachal Pradesh, India. A numeral landslide triggering geoenvironmental factors i.e. slope, aspect, relative relief, soil, curvature, land use and land cover(LULC), lithology, drainage density, and lineament density were selected for landslide hazard mapping based on landslide inventory. Landslide hazard zonation map was categorized namely "very high hazard, high hazard, medium hazard, low hazard, and very low hazard". The results from these two methods were validated using Area Under Curve(AUC) plots. It is found that hazard zonation map prepared using information value method and analytical hierarchy process methods possess the prediction rate of 78.87% and 75.42%, respectively. Hence, landslide hazardzonation map obtained using information value method is proposed to be more useful for the study area. These final hazard zonation maps can be used by various stakeholders like engineers and administrators for proper maintenance and smooth traffic flow between Chamba and Bharmour cities, which is the only route connecting these tourist places. 展开更多
关键词 Information value Analytical Hierarchy process Landslide hazard zonation GIS Remote sensing HIMALAYA
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Nonlinear Model Algorithmic Control of a pH Neutralization Process 被引量:11
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作者 邹志云 于蒙 +4 位作者 王志甄 刘兴红 郭宇晴 张风波 郭宁 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第4期395-400,共6页
Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinea... Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors. 展开更多
关键词 model algorithmic control nonlinear model predictive control Hammerstein model ph neutralization process control simulation
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Effect of Cu and Ni on Growth, Mineral Uptake,Photosynthesis and Enzyme Activities of Chlorella vulgaris at Different pH Values 被引量:3
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作者 P.K.RAI NirupamaMALLICK 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1994年第1期56-67,共12页
A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and i... A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment. 展开更多
关键词 Mineral Uptake photosynthesis and Enzyme Activities of Chlorella vulgaris at Different ph values Effect of Cu and Ni on Growth ph CU NI
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Effects of processing pH stimulation on cooperative bioleaching of chalcopyrite concentrate by free and attached cells 被引量:2
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作者 Tang-jian PENG Li-juan SHI +5 位作者 Run-lan YU Guo-hua GU Dan ZHOU Miao CHEN Guan-zhou QIU Wei-min ZENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第8期2220-2229,共10页
In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached ce... In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group. 展开更多
关键词 CHALCOPYRITE processing ph stimulation free cells attached cells microbial community real-time quantitative PCR
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Adaptive predictive functional control based on Takagi-Sugeno model and its application to pH process 被引量:5
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作者 苏成利 李平 《Journal of Central South University》 SCIE EI CAS 2010年第2期363-371,共9页
In order to obtain accurate prediction model and compensate for the influence of model mismatch on the control performance of the system and avoid solving nonlinear programming problem,an adaptive fuzzy predictive fun... In order to obtain accurate prediction model and compensate for the influence of model mismatch on the control performance of the system and avoid solving nonlinear programming problem,an adaptive fuzzy predictive functional control(AFPFC) scheme for multivariable nonlinear systems was proposed.Firstly,multivariable nonlinear systems were described based on Takagi-Sugeno(T-S) fuzzy models;assuming that the antecedent parameters of T-S models were kept,the consequent parameters were identified on-line by using the weighted recursive least square(WRLS) method.Secondly,the identified T-S models were linearized to be time-varying state space model at each sampling instant.Finally,by using linear predictive control technique the analysis solution of the optimal control law of AFPFC was established.The application results for pH neutralization process show that the absolute error between the identified T-S model output and the process output is smaller than 0.015;the tracking ability of the proposed AFPFC is superior to that of non-AFPFC(NAFPFC) for pH process without disturbances,the overshoot of the effluent pH value of AFPFC with disturbances is decreased by 50% compared with that of NAFPFC;when the process parameters of AFPFC vary with time the integrated absolute error(IAE) performance index still retains to be less than 200 compared with that of NAFPFC. 展开更多
关键词 Takagi-Sugeno (T-S) model adaptive fuzzy predictive functional control (AFPFC) weighted recursive least square (WRLS) ph process
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Effects of Straw and Biochar Returned to the Soil on Soil Physical Properties and pH Value in Cold Rice Region 被引量:1
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作者 Yuefeng CUI Hongru SHI +5 位作者 Aonan GUO Guocai SUN Guiyan WANG Jian WANG Wenjia HUANG Tiegang LU 《Asian Agricultural Research》 2021年第2期27-32,共6页
[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly ret... [Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly returned to the soil and charred straw(biochar)returned to the soil on soil bulk density,porosity,temperature and pH value of cold paddy soil were studied in this paper.[Results]The results showed that compared with conventional production,straw(6 t/ha),a small amount of biochar(2 t/ha)and a large amount of biochar(40 t/ha)returned to the soil reduced paddy soil bulk density at different growth stages by 6.02%-11.86%,2.69%-6.67%and 8.58%-11.32%,respectively,increased total porosity by 7.41%-14.93%,3.19%-8.38%and 9.81%-14.27%,respectively,and increased aeration porosity by 22.28%-192.11%,17.80%-92.11%and 52.44%-157.11%,respectively.Straw and a small amount of biochar returned to the soil had no significant effect on soil temperature and pH value of paddy field,but a large amount of biochar returned to the soil could significantly increase soil temperature by 5.13%-8.79%and pH value by 3.15%-5.96%in the later stage of rice growth.[Conclusions]The straw and biochar returned to the soil could reduce soil bulk density,increase total porosity and aeration porosity,and only a large amount of biochar returned to the soil could significantly increase soil temperature and pH value. 展开更多
关键词 STRAW BIOCHAR Cold rice region Soil physical properties Soil ph value
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Innovation Management Processes and Routines for Business Success and Value Creation 被引量:1
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作者 Luis Vala Renato Pereira Isabel Caetano 《Management Studies》 2017年第5期471-481,共11页
Innovation is managed through the development of processes and routines, considered as critical for business success and value creation. The identification of relevant routines as well as the understanding of which fa... Innovation is managed through the development of processes and routines, considered as critical for business success and value creation. The identification of relevant routines as well as the understanding of which factors affect business innovation is the main objective of this research, based on a survey applied in Portuguese companies and their experience shared in best practices guides. Conclusions highlighted 10 key innovation routines, reinforcing the idea that innovation must be supported through a systematic and sustained management process. Results also indicate that SMEs face greater difficulties in benefiting from the potential of innovation practices and collaboration may present opportunities to overcome their limited resources. Therefore, regardless of size, business activity, science and technology intensity or other factors influencing firms dynamic capabilities, innovation should be considered as a management imperative as it can influence not only the present but also the future of business success. 展开更多
关键词 innovation management innovation process innovation routines value creation SMES PORTUGAL
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Adsorption Kinetics of NH_4^+ by Purple Soils with Different pH Values
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作者 张迪男 蒋先军 《Agricultural Science & Technology》 CAS 2015年第7期1336-1339,1370,共5页
Ammonium adsorption and desorption properties by purple soils with dif- ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4+ by purple soils increased with the increase of NH4... Ammonium adsorption and desorption properties by purple soils with dif- ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4+ by purple soils increased with the increase of NH4+ concentration, regardless of soil pH values; the largest adsorption and desorption amounts of NH4+ by purple soil at pH 6.0 were 10.3 and 7.96 mg/g, respectively; the largest adsorp- tion and desorption amounts of NH4+ by purple soil at pH 7.2 were 12.8 and 4.62 mg/g, respectively; the largest adsorption and desorption amounts of NH4+ by purple soil at pH 8.0 were 13.5 and 2.23 mg/g, respectively. The isothermal adsorption ki- netics of NH4+ by purple soils fits the Freundlich equation best (R〉0.95). This study shows that the adsorption of NH4+ by purple soils with different pH values is multi- molecular layer uneven surface adsorption. 展开更多
关键词 NHZ ADSORPTION DESORPTION ph value Isothermal adsorption equation
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The Construction of a Class of Measure-valued Processes of Stochastic Flows
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作者 ZHANG Xiang-wei WANG Jian-ping 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第2期159-164,共6页
In this article, we give a description of measure-valued processes with interactive stochastic flows. It is a unified construction for superprocesses with dependent spatial motion constructed by Dawson, LI, Wang and s... In this article, we give a description of measure-valued processes with interactive stochastic flows. It is a unified construction for superprocesses with dependent spatial motion constructed by Dawson, LI, Wang and superprocesses of stochastic flows constructed by Ma and Xiang. 展开更多
关键词 stochastic flows infinitesimal generator measure valued processes martingale problem
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The Multiplicative Analytic Hierarchy Process (MIAHP) as a Quality Criterion Determining the Technological Value of the Egyptian Cotton Varieties
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作者 Khaled M. Hussein AbdElbaset A. Hassan Mostafa M. Kamal 《American Journal of Plant Sciences》 2010年第2期106-112,共7页
This study was undertaken to develop a numerical process that can be used as a quality criterion to determine the technological value of the Egyptian cotton varieties, which in turn would denote the end-use of their f... This study was undertaken to develop a numerical process that can be used as a quality criterion to determine the technological value of the Egyptian cotton varieties, which in turn would denote the end-use of their fibers. However the material used in the study comprised the 6 Egyptian cotton varieties Giza70, Giza80, Giza86, Giza88, Giza90 and Giza92. According to the local practice in Egypt, Giza70, Giza88 and Giza92 belong to the Extra-Long Staple (ELS) category, while Giza80, Giza86 and Giza90 are included under the Long Staple (LS) category. The regression analysis of the relationships between fiber properties and yarn skein strength (lea product) of the 2 carded ring counts 40 and 50 Ne, was employed to drive an equation for calculating the Multiplicative Analytic Hierarchy Process (MIAHP) values. The values of the MIAHP have been used as numerical determinations of the technological values of the Egyptian cotton varieties. Nevertheless, the findings of this study clarified that with respect to the criteria weights, the pair-wise comparisons denoted that fiber length properties of Egyptian cotton ranked first where they revealed the most dominant effect on yarn strength, while tensile properties ranked second with a relative weight close to that of fiber length. On the contrary, the relative weight of fiber fineness (micronaire reading) was found to be marginal. With regard to the relative weight of sub-criterion, the pair-wise comparisons indicated that the role of fiber tenacity as a determinant of yarn strength is much superior to that of fiber elongation. Further the global weights of the sub-criterion of fiber length pointed out that the UHML (upper half mean length) plays an important role in determining yarn strength of the Egyptian cotton comparing with either the UI (uniformity index) or the SFC (short fiber content). In conformity with the values of the MIAHP, it was found that in the order of descending rank, Giza88 ranked first, followed by Giza92, Giza70, Giza86, Giza80 and finally Giza90. 展开更多
关键词 ANALYTIC HIERARCHY process Cotton Fiber QUALITY Technological value
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Analyzing pH value, energy and phospholipid metabolism of various cerebral tumors and normal brain tissue with ^(31)P magnetic resonance spectroscopy
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作者 Wei Tan Guangyao Wu Junmo Sun 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第3期248-252,共5页
BACKGROUND: ^31p magnetic resonance spectroscopy (^31p MRS) can be used to non-injuredly and dynamicly detect vadous metabolites including phosphorus in organis and reflect changes of phospholipid metabolism and en... BACKGROUND: ^31p magnetic resonance spectroscopy (^31p MRS) can be used to non-injuredly and dynamicly detect vadous metabolites including phosphorus in organis and reflect changes of phospholipid metabolism and energy metabolism in tissue and pH value in cells. OBJECTIVE: To observe changes of pH value, phospholipid metabolism and energy metabolism of various cerebral tumors and normal brain tissue with sip MRS. DESIGN: Semi-quantitative contrast observation PARTICIPANTS : A total of 44 patients with cerebral tumor diagnosed with surgery operation were selected from the Department of Magnetic Resonance, Central South Hospital, Wuhan University from September 2004 to June 2006. All the subjects had complete sip MRS data before steroid and operation. Among them, 16 patients had glioma of grade Ⅱ-Ⅲ, 12 spongioblastoma and 16 meningioma. The mean age was (45±6) years. Another 36 subjects without focus on cerebral MRI were regarded as normal group, including 19 males and 18 females, and the mean age was (41±4) years. Included subjects were consent. METHODS: Eclipse1.5T MRS (Philips Company) was used to collect wave spectrum; jMRUI(1.3) was used to analyze expenmental data and calculate pH value in voxel and ratios of phosphocreatine (PCr)/inorganic phosphate (Pi), PCr/phosphodiesterase (PDE) and phosphomonoesterase (PME)/β-adenosine triphosphate (β-ATP) of vadous metabolites. ^31p MRS results were compared with t test between tumor patients and normal subjects. MAIN OUTCOME MEASURES: Changes of phospholipid metabolism (PME./PDE), energy metabolism (PCr/ATP) and pH value of various cerebral tumors and normal brain tissues. RESULTS : A total of 44 cases with cerebral tumor and 36 normal subjects were involved in the final analysis. pH value and semi-quantitative measurements of normal brain tissues and various cerebral tumors: ① pH value at top occipital region and temple occipital region of normal brain tissue was 7.04 ±0.02; PCr/β-ATP was 1.51 ±0.03; PCr/Pi was 2.85±0.20; PDE/β-ATP was 2.70±0.40; PME/β-ATP was 1.01 ±0.03. Giioma of grade Ⅱ - Ⅲ : Tumor tissue was alkalized. The pH value was 7.09±0.01, which was higher than that in normal group (t=-1.823, P 〈 0.05); PCr/β-ATP, PME/β-ATP and PCr/ Pi were 1.50±0.04, 1.04±0.07 and 2.49±0.21, respectively, which was close to that in normal group (P 〉 0.05); PDE/β-ATP was 1.73±0.20, which was lower than that in normal group (t=-2.168, P 〈 0.05). ③ Spongioblastoma: Tumor tissue was alkalized. The pH value was 7.12±0.02, which was higher than that in normal group (t=-2.170, P 〈 0.05); PCr/β-ATP and PCr/Pi were 1.48±0.05 and 2.39±0.23, respectively, which was lower than that in normal group, but the difference was not significant (P 〉 0.05); PDE/β-ATP was 1.61±0.25, which was lower than that in normal group (t=-3.582, P 〈 0.01); PME/β-ATP was 1.64±0.05, which was higher than that in normal group (t=-3.930, P 〈 0.01). ④ Meningioma: Tumor tissue was alkalized. The pH value was 7.16±0.03, which was higher than that in normal group (t=-2.978, P 〈 0.01); PCr/β-ATP, PCr/Pi and PDE/β-ATP were 0.46±0.04, 1.08±0.16 and 0.82±0.10, respectively, which was lower than that in normal group (t=-3.132, 3.983, 3.985, P 〉 0.01); PME/β-ATP was 2.05±0.03, which was higher than that in normal group (t=-3.007, P〈 0.01). CONCLUSION: ^31p MRS can provide informations about pH value of cerebral tumor, phospholipid metabolism and energy metabolism. Changes of pH value, PCr, PME and PDE can reflect metabolic characteristics of various cerebral tumors. 展开更多
关键词 P magnetic resonance spectroscopy Analyzing ph value PDE ph
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CONTINUITY OF l^2-VALUED TWO-PARAMETER ORNSTEIN UHLENBECK PROCESSES
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作者 Wen JiweiDept. of Math.,Zhejiang Univ.(Xixi Campus),Hangzhou 310028. 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第4期423-429,共7页
Let {Y (t);t= (t 1,t 2)≥0}={X k(t 1,t 2);t 1≥0,t 2≥0} ∞ k=1 be a sequence of two parameter Ornstein Uhlenbeck processes (OUP 2) with coefficients α k>0,β k>0 . A Fernique type in... Let {Y (t);t= (t 1,t 2)≥0}={X k(t 1,t 2);t 1≥0,t 2≥0} ∞ k=1 be a sequence of two parameter Ornstein Uhlenbeck processes (OUP 2) with coefficients α k>0,β k>0 . A Fernique type inequality is established and the sufficient condition for a.s. l 2 continuity of Y(·) is studied by means of the inequality. 展开更多
关键词 l 2 valued two parameter Ornstein Uhlenbeck processes Fernique type inequality continuity.
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Effect of pH values on extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans during chalcopyrite bioleaching 被引量:6
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作者 余肇璟 余润兰 +4 位作者 刘阿娟 刘晶 曾伟民 刘学端 邱冠周 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第2期406-412,共7页
The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleachi... The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleaching. The results indicate that the extracellular protein is always more than the extracellular polysaccharide secreted by attached cells on the chalcopyrite, on the contrary, and is always less than the extracellular polysaccharide secreted by free cells in the solution at bacterial adaptive phase, logarithmic phase and stationary phase whenever pH value is at 1.0, 1.5, 2.0 or 2.5; free cells are mainly through the secretion of extracellular polysaccharide rather than the extracellular protein to fight against disadvantageous solution environment, such as high concentration of metal ions and unsuitable pH solution; both amounts of polysaccharide and protein secreted by attached cells are mainly positively related to the solution acidity rather than the total concentration of soluble metal ions. The experimental results imply that bacteria are mainly through secreting more extracellular polysaccharide to fight against disadvantageous environment and the extracellular protein perhaps plays an important role in oxidation?reduction reactions in the bioleaching system. 展开更多
关键词 extracellular protein Acidithiobacillus ferrooxidans CHALCOPYRITE BIOLEACHING ph value
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Corrosion behaviour of die-cast AZ91D magnesium alloys in sodium sulphate solutions with different pH values 被引量:5
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作者 田赟 杨丽景 +4 位作者 李艳芳 卫英慧 侯利锋 李永刚 Ri-Ichi MURAKAMI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第4期912-920,共9页
The corrosion behaviours of die-cast AZ91D magnesium alloys were investigated in 0.1 mol/L sodium sulphate (Na 2 SO 4 ) solutions with different pH values. The corrosion rates, morphologies, and compositions of the ... The corrosion behaviours of die-cast AZ91D magnesium alloys were investigated in 0.1 mol/L sodium sulphate (Na 2 SO 4 ) solutions with different pH values. The corrosion rates, morphologies, and compositions of the corrosion products were studied by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffractometry (XRD). The results indicate that the order of corrosion rates in Na 2 SO 4 solutions with various pH values is pH 2pH 4pH 7pH 9pH 12. The corrosion rates in acidic solutions are higher than those in alkaline solutions, and the corrosion products are mainly magnesium hydroxide (Mg(OH) 2 ) and hydrated sulphate pickeringite (MgAl 2 (SO 4 ) 4 ·22H 2 O). The results also indicate that the solution pH can influence the corrosion rate and morphology of corrosion products. Chloride ions and sulphate ions have different pitting initiation time. 展开更多
关键词 magnesium alloy CORROSION sodium sulphate ph value
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