期刊文献+
共找到16,150篇文章
< 1 2 250 >
每页显示 20 50 100
Historical biogeography and evolutionary diversification of Lilium(Liliaceae): New insights from plastome phylogenomics 被引量:1
1
作者 Nian Zhou Ke Miao +4 位作者 Changkun Liu Linbo Jia Jinjin Hu Yongjiang Huang Yunheng Ji 《Plant Diversity》 SCIE CAS CSCD 2024年第2期219-228,共10页
Here, we infer the historical biogeography and evolutionary diversification of the genus Lilium. For this purpose, we used the complete plastomes of 64 currently accepted species in the genus Lilium(14plastomes were n... Here, we infer the historical biogeography and evolutionary diversification of the genus Lilium. For this purpose, we used the complete plastomes of 64 currently accepted species in the genus Lilium(14plastomes were newly sequenced) to recover the phylogenetic backbone of the genus and a timecalibrated phylogenetic framework to estimate biogeographical history scenarios and evolutionary diversification rates of Lilium. Our results suggest that ancient climatic changes and geological tectonic activities jointly shaped the distribution range and drove evolutionary radiation of Lilium, including the Middle Miocene Climate Optimum(MMCO), the late Miocene global cooling, as well as the successive uplift of the Qinghai-Tibet Plateau(QTP) and the strengthening of the monsoon climate in East Asia during the late Miocene and the Pliocene. This case study suggests that the unique geological and climatic events in the Neogene of East Asia, in particular the uplift of QTP and the enhancement of monsoonal climate, may have played an essential role in formation of uneven distribution of plant diversity in the Northern Hemisphere. 展开更多
关键词 Asian monsoon Climatic changes Distribution range Evolutionary complexity Radiative diversification Species diversity Qinghai-Tibet Plateau(QTP)
下载PDF
Parental Psychological Control and Internet Gaming Disorder Tendency:A Moderated Mediation Model of Core Self-Evaluation and Intentional Self-Regulation
2
作者 Zhiqiao Ji Shuhua Wei Hejuan Ding 《International Journal of Mental Health Promotion》 2024年第7期547-558,共12页
Internet gaming disorder(IGD)among junior high school students is an increasingly prominent mental health concern.It is important to look for influences behind internet gaming disorder tendency(IGDT)in the junior high... Internet gaming disorder(IGD)among junior high school students is an increasingly prominent mental health concern.It is important to look for influences behind internet gaming disorder tendency(IGDT)in the junior high school student population.The present study aimed to reveal the explanatory mechanisms underlying the association between parental psychological control(PPC)and internet gaming disorder tendency among junior high school students by testing the mediating role of core self-evaluation(CSE)and the moderating role of intentional self-regulation(ISR).Participants in present study were 735 Chinese junior high school students who completed offline self-report questionnaires on parental psychological control,core self-evaluation,intentional self-regulation,and Internet gaming disorder tendency.Analyses were conducted via mediation and moderated mediation.The results showed that:(1)Parental psychological control was positively related to junior high school students’Internet gaming disorder tendency.Core self-evaluation,and intentional self-regulation were negatively related to junior high school students’Internet gaming disorder tendency,respectively.(2)Core self-evaluation partially mediated the relationship between parental psychological control and junior high school students’Internet gaming disorder tendency.(3)Intentional self-regulation moderated the association between parental psychological control and Internet gaming disorder tendency,as well as the relationships between parental psychological control and core self-evaluation and core self-evaluation and Internet gaming disorder tendency in the mediated model.Based on these findings,we believe that there is a need to weaken parental psychological control,strengthen junior high school students’core self-evaluation and intentional self-regulation,and to recognize the important role of parents as well as their children’s personal positive traits in the healthy development of junior high school students. 展开更多
关键词 Internet gaming disorder tendency parental psychological control core self-evaluation intentional self-regulation moderated mediation model junior high school students
下载PDF
Analysis of Influencing Factors of Moderate to Severe Malnutrition in Elderly Patients with Lung Cancer during Chemotherapy
3
作者 Ying Li Jiaying Qin +1 位作者 Ying Gao Junying Nie 《Proceedings of Anticancer Research》 2024年第5期1-6,共6页
Objective:This study aims to identify the factors influencing moderate to severe malnutrition in elderly lung cancer patients undergoing chemotherapy and to provide a basis for developing clinical prevention and inter... Objective:This study aims to identify the factors influencing moderate to severe malnutrition in elderly lung cancer patients undergoing chemotherapy and to provide a basis for developing clinical prevention and intervention strategies.Methods:The clinical data of 150 elderly lung cancer patients who received chemotherapy were retrospectively analyzed.Demographic data,clinical characteristics,laboratory indicators,treatment plans,and other relevant information were collected.Independent risk factors for moderate to severe malnutrition during chemotherapy were identified.Results:During chemotherapy,50 patients(33.33%)developed moderate to severe malnutrition.The BMI of patients with moderate to severe malnutrition was significantly lower than that of patients with no or mild malnutrition(21.20±1.60 vs.26.14±2.31,P<0.001),and the proportion of patients with stage IV tumors was significantly higher(60.00%vs.27.00%,P<0.001).Serum pre-albumin(pre-ALB)and hemoglobin(Hb)levels in patients with moderate to severe malnutrition were significantly lower than those in patients with no or mild malnutrition(152.67±30.41 g/L vs.252.47±51.24 g/L and 102.44±10.09 g/L vs.154.21±15.18 g/L,respectively,P<0.001 for all).Conclusion:Low BMI,decreased serum pre-ALB levels,and decreased serum Hb levels before chemotherapy are independent risk factors for moderate to severe malnutrition in elderly lung cancer patients during chemotherapy.Close clinical attention should be given to these patients,with early intervention measures such as nutritional support to reduce the incidence of malnutrition and improve patients’quality of life and prognosis. 展开更多
关键词 Lung cancer CHEMOTHERAPY moderate to severe malnutrition Influencing factors
下载PDF
Moderately concentrated electrolyte enabling high-performance lithium metal batteries with a wide working temperature range 被引量:1
4
作者 Sisi Wang Zhichen Xue +3 位作者 Fulu Chu Zengqiang Guan Jie Lei Feixiang Wu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期201-210,共10页
The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability,which strongly influence the performances of high-energy lithium metal batteries.Here,we repor... The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability,which strongly influence the performances of high-energy lithium metal batteries.Here,we report a new electrolyte recipe viz.a moderately concentrated electrolyte comprising of 2.4 M lithium bis(fluorosulfonyl)imide(LiFSI)in a cosolvent mixture of fluorinated ethylene carbonate(FEC)and dimethyl carbonate(DMC)with relatively high ion conductivity.Owing to the preferential decomposition of LiFSI and FEC,an inorganic-rich interphase with abundant Li_(2)O and LiF nanocrystals is formed on lithium metal with improved robustness and ion transfer kinetics,enabling lithium plating/stripping with an extremely low overpotential of~8 mV and the average CE of 97%.When tested in Li||LiFePO_(4) cell,this electrolyte provides long-term cycling with a capacity retention of 98.3%after 1000 cycles at 1 C and an excellent rate performance of 20 C,as well as an areal capacity of 1.35 mA h cm^(-2)at the cathode areal loading of 9 mg cm^(-2).Moreover,the Li||LiFePO_(4) cell exhibits excellent wide-temperature performances(-40~60℃),including long-term cycling stability over 2600 cycles without visible capacity fading at 0℃,as well as extremely high average CEs of 99.6%and 99.8% over 400 cycles under-20℃ and 45℃. 展开更多
关键词 moderately concentrated electrolyte Wide temperature range LiFePO_(4)cathode Lithium metal battery Solid electrolyte interphase
下载PDF
Diversification evidence of bitcoin and gold from wavelet analysis
5
作者 Rubaiyat Ahsan Bhuiyan Afzol Husain Changyong Zhang 《Financial Innovation》 2023年第1期2584-2619,共36页
To measure the diversification capability of Bitcoin,this study employs wavelet analysis to investigate the coherence of Bitcoin price with the equity markets of both the emerging and developed economies,considering t... To measure the diversification capability of Bitcoin,this study employs wavelet analysis to investigate the coherence of Bitcoin price with the equity markets of both the emerging and developed economies,considering the COVID-19 pandemic and the recent Russia-Ukraine war.The results based on the data from January 9,2014 to May 31,2022 reveal that compared with gold,Bitcoin consistently provides diversification opportunities with all six representative market indices examined,specifically under the normal market condition.In particular,for short-term horizons,Bitcoin shows favorably low correlation with each index for all years,whereas exception is observed for gold.In addition,diversification between Bitcoin and gold is demonstrated as well,mainly for short-term investments.However,the diversification benefit is conditional for both Bitcoin and gold under the recent pandemic and war crises.The findings remind investors and portfolio managers planning to incorporate Bitcoin into their portfolios as a diversification tool to be aware of the global geopolitical conditions and other uncertainty in considering their investment tools and durations. 展开更多
关键词 Bitcoin GOLD WAVELET COHERENCE diversification
下载PDF
Why is the beautyberry so colourful? Evolution,biogeography,and diversification of fruit colours in Callicarpa(Lamiaceae)
6
作者 Xing Liu Hui-Min Cai +3 位作者 Wen-Qiao Wang Wei Lin Zhi-Wei Su Zhong-Hui Ma 《Plant Diversity》 SCIE CAS CSCD 2023年第1期6-19,共14页
Fruit colour is essential to seed dispersal,speciation,and biological diversity in global ecosystems.The relationship between fruit-colour variation and species diversification has long been of interest in evolutionar... Fruit colour is essential to seed dispersal,speciation,and biological diversity in global ecosystems.The relationship between fruit-colour variation and species diversification has long been of interest in evolutionary biology,but remains poorly understood at the genus level.Here,we used Callicarpa,a typical representative of pantropical angiosperm,to analyse whether fruit colours are correlated with biogeographic distribution,dispersal events,and diversification rate.We estimated a time-calibrated phylogeny for Callicarpa and reconstructed ancestral fruit colour.Utilizing phylogenetic methods,we estimated the major dispersal events across the phylogenetic tree and the most likely fruit colours related to each dispersal event,and tested whether the dispersal frequencies and distances of the four fruit colours between major biogeographical areas were equal.We then tested whether fruit colours are correlated with latitude,elevation,and diversification rate.Biogeographical reconstructions showed that Callicarpa originated in the East Asia and Southeast Asia during the Eocene(-35.53 Ma) and diverse species diverged mainly in the Miocene and lasted into the Pleistocene.Large-scale dispersal events were significantly associated with violet-fruited lineages.Furthermore,different fruit colours were markedly correlated with different latitudes and elevations(e.g.,violet fruits were correlated with higher latitudes and elevations;red fruits and black fruits with lower latitudes;white fruits with higher elevations).Notably,violet fruits were statistically associated with highest diversification rates,driving fruit colour variation among different regions globally.Our results contribute to further understanding why fruit colour is so variable at the genus level of angiosperms in different areas around the world. 展开更多
关键词 CALLICARPA Fruit colour PHYLOGENY BIOGEOGRAPHY Dispersal diversification
下载PDF
Determinants of Household Choice of Livelihood Diversification Strategies in Selected Drought Prone Areas of the Southern Nations Nationalities and Peoples’ Region, Ethiopia
7
作者 Aschalew Aweke Tewodros Tefera +1 位作者 Muluken Gezahegn Million Sileshi 《Agricultural Sciences》 2023年第10期1375-1392,共18页
The study aimed at identifying the determinants of household’s choice of livelihood diversification strategies. The result of the study based on a total of 384 sample respondents selected using multistage sampling pr... The study aimed at identifying the determinants of household’s choice of livelihood diversification strategies. The result of the study based on a total of 384 sample respondents selected using multistage sampling procedures. Furthermore the study employed bivariate Probit econometric model to identify factors affecting household’s choice of livelihood diversification strategies. The result of the descriptive statistics showed that households in the study area were engaged in four types of combination of livelihood diversification strategies: on-farm only, on-farm plus off-farm, on-farm plus non-farm, and on-farm plus off-farm plus non-farm with their respective share of 34.9, 11.5, 47.9 and 5.7 percent respectively. The econometric model result showed that wealth, sex, education level, livestok holding, and training were negatively and significantly determined households choice of off-farm livelihood strategies;whereas past erosion hazard and distance to market were positively and significantly determined their choice of off-farm livelihood strategies. On the other hand, wealth, dependency ratio, past erosion hazard, market availability, yield loss/reduction due to drought, distance to credit source, distance to market, frequency of extension contact, and ICT ownership (Radio, TV and/or Mobile phone) positively determine household’s choice of non-farm livelihood strategies whereas access to irrigation and distance to credit negatively determined their choice of non-farm livelihood strategies. 展开更多
关键词 Determinants DROUGHT Livelihood diversification Non-Farm Off-Farm ON-FARM
下载PDF
Cover Enhancement Method for Audio Steganography Based on Universal Adversarial Perturbations with Sample Diversification
8
作者 Jiangchuan Li Peisong He +2 位作者 Jiayong Liu Jie Luo Qiang Xia 《Computers, Materials & Continua》 SCIE EI 2023年第6期4893-4915,共23页
Steganography techniques,such as audio steganography,have been widely used in covert communication.However,the deep neural network,especially the convolutional neural network(CNN),has greatly threatened the security o... Steganography techniques,such as audio steganography,have been widely used in covert communication.However,the deep neural network,especially the convolutional neural network(CNN),has greatly threatened the security of audio steganography.Besides,existing adversarial attacks-based countermeasures cannot provide general perturbation,and the trans-ferability against unknown steganography detection methods is weak.This paper proposes a cover enhancement method for audio steganography based on universal adversarial perturbations with sample diversification to address these issues.Universal adversarial perturbation is constructed by iteratively optimizing adversarial perturbation,which applies adversarial attack tech-niques,such as Deepfool.Moreover,the sample diversification strategy is designed to improve the transferability of adversarial perturbations in black-box attack scenarios,where two types of common audio-processing operations are considered,including noise addition and moving picture experts group audio layer III(MP3)compression.Furthermore,the perturbation ensemble method is applied to further improve the attacks’transferability by integrating perturbations of different detection networks with heterogeneous architec-tures.Consequently,the single universal adversarial perturbation can enhance different cover audios against a CNN-based detection network.Extensive experiments have been conducted,and the results demonstrate that the average missed-detection probabilities of the proposed method are higher than those of the state-of-the-art methods by 7.3%and 16.6%for known and unknown detection networks,respectively.It verifies the efficiency and transferability of the proposed methods for the cover enhancement of audio steganography. 展开更多
关键词 Audio steganography cover enhancement adversarial perturbations sample diversification
下载PDF
Effectiveness of Enriched Flour in the Recovery of Children Aged 6 to 59 Months with Moderate Acute Malnutrition
9
作者 Oumalkher Youssouf Adam Imar Djibrine Soudy +2 位作者 Abdoullahi Hissein Ousman Mablahi Amina Kanika Mahamat Garba 《Food and Nutrition Sciences》 2023年第7期687-697,共11页
Introduction: In Chad, malnutrition is a silent emergency. Yet the use of local products in the fight against malnutrition is essential. The purpose of this study was to compare the efficacy of locally sourced enriche... Introduction: In Chad, malnutrition is a silent emergency. Yet the use of local products in the fight against malnutrition is essential. The purpose of this study was to compare the efficacy of locally sourced enriched flour in the recovery of children 6 to 59 months of moderate acute malnourishment compared to Ready-to-Use Therapeutic Foods (Plumpy’ Sup) in the city of Abéché-Chad. Methodology: This study took place from 1 October 2021 to 31 January 2022 in the city of Abéché, capital of the province of Ouaddaï. It was conducted in eight (8) urban health centers in the city of Abéché and concerned eighty (80) children with moderate acute malnutrition. It was based on a consumption assessment of two complementary foods by two groups of children. The assessment of nutritional status was made through anthropometric data such as weight, height and brachial perimeter. Results: All 80 children were tested for moderate acute malnutrition. Two complementary foods have been used which are locally produced flour and the Ready-to-Use Therapeutic Food. The study showed that the group 1 who consumed the locally produced flour had an average weight gain of 1100 g and the group 2 who consumed the Plumpy sup had an average weight gain of 400 g. Conclusion: The present study carried out in Abéché allowed us to compare the effectiveness of locally produced weaning flours with Ready-to-Use Therapeutic Foods on moderate malnourished child weight growth in the nutritional units of the town of Abéché. 展开更多
关键词 moderate Acute Malnutrition Local Food Ready-to-Use Therapeutic Foods (Plumpy’ Sup)
下载PDF
Mathematical Insight into Moderate Inversion Gate Delay Variability for Ultradeep Submicron Digital Circuit Design
10
作者 Shruti Kalra 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第4期68-75,共8页
Voltage scaling has been extensively used in industry for decades to reduce power consumption.In recent years,exploring digital circuit operation in moderate inversion has created an interest among researchers due to ... Voltage scaling has been extensively used in industry for decades to reduce power consumption.In recent years,exploring digital circuit operation in moderate inversion has created an interest among researchers due to its immense capability to provide a perfect tradeoff between high performance and low energy operation.But circuits operating in moderate inversion are susceptible to process variations and variability.To compute variability,statistical parameters such as the probability density function(PDF)and cumulative distribution function(CDF)are required.This paper presents an analytical model framework for delay calculations utilizing log skew normal distribution for ultradeep submicron technology nodes up to 22 nm.The CDF of the proposed model is utilized to calculate minimum and maximum delays with 3σ-accuracy providing better accuracy than the conventional methods.The obtained results are also compared with Monte Carlo simulations with errors lying within the acceptable range of 2%-4%. 展开更多
关键词 moderate inversion ultradeep submicron predictive technology model VARIABILITY log skew normal distribution
下载PDF
Moderate scale and realization potential of new citrus-planting business entities in hilly and mountainous areas in China
11
作者 ZHANG Xuan-yun ZHANG Shi-chao +3 位作者 LIU Jing-yu RAN Na ZHANG Xiang NING Qi-wen 《Journal of Mountain Science》 SCIE CSCD 2023年第8期2315-2343,共29页
The natural and economic conditions of agricultural resources vary greatly in China,especially in hilly and mountainous areas.The phenomenon of land fragmentation has become increasingly prominent,so that large-scale ... The natural and economic conditions of agricultural resources vary greatly in China,especially in hilly and mountainous areas.The phenomenon of land fragmentation has become increasingly prominent,so that large-scale operations cannot be fully achieved in a short period of time,and the centralized and continuous scale of operations cannot be realized in China.In addition,with increasingly strict farmland protection and agricultural land use control systems,the issues of nongrain production and nonagricultural cultivated land use have become increasingly restricted.Thus,it is quite necessary to determine the appropriate scale of operations and the means to achieve moderately scaled operations for the new business entities.On the basis of microsurvey data for 108 new citrus-planting business entities in the modern agricultural park in the Chongqing's Jiangjin District,an area with long citrus-planting history,we measured the moderate scale of new citrus-planting business entities to maximize profit using a translog growth model.According to the projection pursuit model,we evaluated the suitability conditions of citrus planting in garden land,woodland,grassland,and general cultivated land in the study area.We then explored the potential for new moderate-scale business entities within different farming radii.The results showed that large-scale planting conditions of citrus in garden land,forest land,grassland,and general cultivated land in the study area were suitable,and the proportion of high-suitable and mediumsuitable land was 73.42%.Under the existing social and economic conditions,the moderate scale of new citrus-planting business entities in the study area was 1.8–2.7 hm^(2).In particular,its rankings from large to small were agricultural enterprises(17.19–25.78 hm^(2)),farmer cooperatives(16.88–25.33 hm^(2)),big growers and breeders(6.39–9.59 hm^(2)),and family farms(5.02–7.53 hm^(2)).In the sample of 108 households,only 47.22%of the entities achieved moderate-scale operation,of which 25%of the entities achieved a scale greater than moderate operation.However,52.78%of the entities achieved a scale of less than moderate operation.These entities would have to transfer the surrounding adjacent garden land,forest land,grassland,or general cultivated land to achieve largescale land management.The land area of the adjacent gardens in a 1000 m farming radius could meet the moderate-scale operation demand of the vast majority of new business entities.For the vast majority of new business entities,the land area of the adjacent woodland,grassland,and general cultivated land could supplement the garden land to achieve moderate-scale operation in a 500 m farming radius.If the land area with moderate suitability and high suitability is prioritized,the land area in the adjacent gardens in the 1000 m farming radius could meet the moderate-scale operation demand for the vast majority of new business entities.Within the 500 m farming radius,the vast majority of new business entities have achieved moderate-scale operations if the land area adjacent to forest land,grassland,and general arable land was supplemented by gardens;however,a few entities could not achieve moderate-scale operations.From the village perspective,gardens were prioritized.Sixteen villages had planting areas and planting suitability that exceeded the average level of the study area,accounting for 23.53%.If combined with the reserve potential of the garden land,eight villages could improve their potential,accounting for 11.76%.Therefore,the conditions of large-scale citrus planting in the study area should be further improved,and the scale expansion of new citrus-planting business entities should receive additional scientific guidance. 展开更多
关键词 Land management Hilly and mountainous areas Agricultural business entities moderate operation scale Agricultural land resources Realizing potential
下载PDF
The Moderating Effect of Organizational Identification on Occupational Stress and Insomnia Among Nurses
12
作者 Jing Wang Haiyun Gai +3 位作者 Chunping Ni Juan Du Shanshan Li Huihui Yu 《Journal of Clinical and Nursing Research》 2024年第1期36-44,共9页
Objective:To explore the relationship between organizational identification,occupational stress,and insomnia among nurses and to analyze the moderating role of organizational identification between occupational stress... Objective:To explore the relationship between organizational identification,occupational stress,and insomnia among nurses and to analyze the moderating role of organizational identification between occupational stress and insomnia.Methods:Through stratified sampling,720 nurses working in a tertiary A-level hospital in Shandong Province from March to May 2021 were surveyed using an effort-reward imbalance questionnaire,an organizational identification questionnaire,and the Athens Insomnia scale.Results:Organizational identification was negatively correlated with occupational stress and insomnia(r_(1)=-0.121,P_(1)<0.01;r_(2)=-0.144,P_(2)<0.01).Occupational stress was positively correlated with insomnia(r=0.379,P<0.01).Organizational identity significantly moderated nurses’occupational stress and insomnia(β=-0.192,t=-2.558,P<0.05).Conclusion:Occupational stress and organizational identification can predict insomnia.Organizational identification could negatively mediate the relationship between occupational stress and insomnia.Improving organizational identification may help alleviate insomnia symptoms by relieving occupational stress. 展开更多
关键词 NURSE Occupational stress INSOMNIA Organizational identification moderating effect
下载PDF
The Impact of The Three-Dimensional Cultivation Model on the Development of the Suzhou Tea Industry:Estimating Value of Output Per Acre and Diversified Sales Models
13
作者 Shan Hao 《Proceedings of Business and Economic Studies》 2024年第3期126-132,共7页
This article explores the impact of the three-dimensional cultivation mode on the development of the Suzhou tea industry,focusing on the diversified estimation of the value of output per acre and sales mode.It introdu... This article explores the impact of the three-dimensional cultivation mode on the development of the Suzhou tea industry,focusing on the diversified estimation of the value of output per acre and sales mode.It introduces the history and traditional cultivation practices of tea in Suzhou,as well as the current challenges and problems faced by the industry.An in-depth analysis was conducted on the overview and improvement plans of the three-dimensional cultivation mode,covering relevant technical methods.Based on this analysis,the impact of the three-dimensional cultivation on the value of output per acre was studied and predicted.Its potential and advantages were explored and compared with the effectiveness of traditional cultivation models.Additionally,the impact of the three-dimensional cultivation mode on sales was analyzed,examining its market adaptability and competitiveness,as well as its advantages in expanding sales channels and market coverage.The study also focused on the promoting effect of diversified sales models on the Suzhou tea industry,including direct consumption market development,tea processing product development and promotion,and the integration of tea culture and the tourism industry.To ensure sustainable development,the article evaluates the environmental impact,economic feasibility,social benefits,and farmer benefits of the three-dimensional cultivation model.Finally,the prospects for the development of the Suzhou tea industry were discussed,and the positioning and response strategies of the threedimensional cultivation model were proposed. 展开更多
关键词 Suzhou tea industry Stereoscopic cultivation mode Value of output per acre Sales model diversification
下载PDF
Optimization of copper extraction for bioleaching of complex Cu-polymetallic concentrate by moderate thermophiles 被引量:4
14
作者 王玉光 苏丽君 +4 位作者 曾伟民 邱冠周 万利利 陈新华 周洪波 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1161-1170,共10页
Effects of initial pH, temperature, liquid volume, rotation speed, galvanic interaction (pyrite ratio) and pulp density on bioleaching of complex Cu-polymetallic concentrate were investigated. The results indicated ... Effects of initial pH, temperature, liquid volume, rotation speed, galvanic interaction (pyrite ratio) and pulp density on bioleaching of complex Cu-polymetallic concentrate were investigated. The results indicated that the copper extraction at pH 1.5 was 1.5 and 1.4 times that at pH 1.0 and pH 2.0 respectively. The copper extraction obtained at 45 ℃ was 1236.8%higher than that at 50 ℃. With the increase of rotation speed or the decrease of liquid volume, copper extraction was improved obviously. Copper extraction was improved gradually with the increase of pyrite ratio. However, when the ratio was higher than 20.0%, no further increase in copper extraction was observed. And the statistically significant interactive effects on copper extraction were found between temperature and pH, and temperature and pyrite ratio. 展开更多
关键词 moderate thermophiles BIOLEACHING complex Cu-polymetallic concentrate copper extraction optimization
下载PDF
Surface species of chalcopyrite during bioleaching by moderately thermophilic bacteria 被引量:3
15
作者 赵红波 王军 +4 位作者 覃文庆 郑细华 陶浪 甘晓文 邱冠周 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第8期2725-2733,共9页
X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses were carried out to investigate the surface species and interfacial reactions during bioleaching of chalcopyrite by different strains of ... X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses were carried out to investigate the surface species and interfacial reactions during bioleaching of chalcopyrite by different strains of moderately thermophilic bacteria (45 °C). Results show that monosulfide (CuS), disulfide (S22?), polysulfide (Sn2?), elemental sulfur (S0) and sulfate (SO42?) are the main intermediate species on the surface of chalcopyrite during bioleaching byA. caldus,S. thermosulfidooxidans andL. ferriphilum. The low kinetics of dissolution of chalcopyrite inA. caldus can be mainly attributed to the incomplete dissolution of chalcopyrite and the passivation layer of polysulfide. Polysulfide and jarosite should be mainly responsible for the passivation of chalcopyrite in bioleaching byL. ferriphilumorS. thermosulfidooxidans. However, elemental sulfur should not be the main composition of passivation layer of chalcopyrite during bioleaching. 展开更多
关键词 CHALCOPYRITE surface species BIOLEACHING PASSIVATION moderately thermophilic bacteria
下载PDF
FINITE ELEMENT MODELING OF MODERATELY THICK COMPOSITE PLATE WITH PIEZOELECTRIC SENSORS AND ACTUATORS 被引量:2
16
作者 周勇 王鑫伟 谈梅兰 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第2期205-210,共6页
A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The elemen... A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The element has four-node, 20-degrees-of-freedom with one potential degree of freedom for each piezoelectric layer to represent the piezoelectric behavior. The higher order derivation of deflection is obtained by using the normal rotation expressions to take the effects of transverse shear deformation into considerations. The finite element can accurately simulate the deformation of both thin and moderately thick plates. A Fortran program is written and a number of benchmark tests are exercised to verify its effectiveness. Results are compared well with the existing data. The unbalanced composite with piezoelectric layers is then analyzed by using the model. Results show that the changes of the ratio between the thickness of positive angle layers and the negative angle layers have an effect on the deformation of the structure under the same electric loading. 展开更多
关键词 finite element COMPOSITE moderately thick plate PIEZOELECTRIC ACTUATOR SENSOR
下载PDF
Source mechanism of small-moderate earth- quakes and tectonic stress field in Yunnan Province 被引量:73
17
作者 吴建平 明跃红 王椿镛 《地震学报》 CSCD 北大核心 2004年第5期457-465,共9页
In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred... In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred within or near the Chuandian rhombic block have strike-slip mechanism. The orientations of maximum compressive stresses obtained from source mechanism are changed from NNW-SSN to NS in the areas from north to south of the block, and tensile stresses are mainly in ENE-WSW or NE-SE. In the eastern Tibetan Plateau, the orientations of maximum compressive stress radiate toward outside from the plateau, and the tensile stress orientations mostly parallel to arc structures. Near 28N the orientations of both maximum compressive stress and tensile stress changed greatly, and the boundary seems to correspond to the southwestern extended line of Longmenshan fault. Outside of the Chuandian rhombic block, the orientations of P and T axes are some different from those within the block. The comparison shows that the source mechanism of small-moderate events presented in the paper is consistence with that of moderate-strong earthquakes determined by Harvard University, which means the source mechanism of small-moderate events can be used to study the tectonic stress field in this region. 展开更多
关键词 震源机制 中小地震 应力场 云南
下载PDF
中度嗜盐菌(moderate halophile)B5盐敏感和盐依赖突变菌株的筛选 被引量:1
18
作者 王海洪 樊振川 杨苏声 《山西农业大学学报》 CAS 2000年第1期64-67,共4页
B5是一株从新疆盐湖分离到的中度嗜盐球菌 ,可在 0~ 30 %的NaCl条件下生长。用固体亚硝基胍诱变该菌株 ,在选择培养基上筛选到盐敏感突变株和盐依赖突变株。
关键词 固体亚硝基胍 中度嗜盐菌 盐敏感突变株
下载PDF
Diversification of Autonomous Reading Materials for English Major
19
作者 刘佳 《海外英语》 2015年第12期253-253,256,共2页
Autonomous learning and its importance has attracted more and more attention,on the basis of which,independent read-ing activities should emphasizes the student as the center in the activity.So the choice of independe... Autonomous learning and its importance has attracted more and more attention,on the basis of which,independent read-ing activities should emphasizes the student as the center in the activity.So the choice of independent reading materials should bebased on their requirement.The materials should have the features of interesting and informative,varied style,content suitable forteaching materials,etc.At last how English teacher guide and conduct the students’activities of self-monitoring and self-assess-ment. 展开更多
关键词 AUTONOMOUS LEARNING ABILITY AUTONOMOUS READING diversification CHOICE
下载PDF
Livelihood diversification and cropland use pattern in agro-pastoral mountainous region of eastern Tibetan Plateau 被引量:25
20
作者 ZHANG Liping ZHANG Yili +1 位作者 YAN dianzhong WU Yingying 《Journal of Geographical Sciences》 SCIE CSCD 2008年第4期499-509,共11页
This study examined livelihood diversification and cropland use pattern in Keerma village, located in Jinchuan County, eastern Tibetan Plateau. Through stratified random sampling survey, participatory rural appraisal,... This study examined livelihood diversification and cropland use pattern in Keerma village, located in Jinchuan County, eastern Tibetan Plateau. Through stratified random sampling survey, participatory rural appraisal, investigation of households' plots and statistical methods, 63 households and 272 cropland plots were systemically investigated and sampled. The results show: (1) Different types of household have variety livelihood strategies, portfolio and income. Livelihood diversification and introducing and expanding off-farm activities can be the future trend, whereas, adverse natural environment, socio-economic conditions and peasants' capabilities together affect sustainable livelihood and land use. (2) Each livelihood strategy has its own impact on land use, mainly affecting land use type and land use intensi- fication level. (3) Diversification into off-farm activities could be the key of building sustainable livelihood and the essential approach of realizing sustainable land use in the region. 展开更多
关键词 HOUSEHOLD livelihood diversification off-farm employment land use Tibetan Plateau
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部