检索结果-南通市图书馆

Forest Ecosystems 2022年第4期9卷 439-448页

作者： Anthony Amoah Adusei Jumah Kofi Korle School of Sustainable Development University of Environment and Sustainable DevelopmentSomanyaGhana&Africa Centre for Economics and Policy Research(ACAEP)Ghana Department of Economics Central UniversityAccraGhana

In recent years, debates on the alarming rate of forest depletion emanating from growth in urban settlement and changed urban land-use patterns have gained prominence across the globe. The present study adopts a demandside management approach to investigate household’s willingness-to-pay for the restoration and maintenance of protected forest reserves in three municipalities in Ghana. Using survey data of 733 households from the Greater Accra Region of Ghana, we model the demand for forest restoration and maintenance, respectively, by means of the contingent valuation technique. As part of the findings, the study shows evidence that a household is willing to pay Gh￠50.99($8.67) and Gh￠31.12($5.29) per annum to restore and maintain the protected forests,respectively. These amounts constitute less than one percent of the average household income per month.Consequently, critical validity tests are conducted to validate the robustness of the results. This study provides willingness-to-pay estimates for forest and forest resources, and its associated determinants. These estimates seek to bridge the information gap and inform policy decisions toward the overarching aim of ensuring sustainable forest management in Ghana.

关键词： Reserved forest Restoration maintenance Tobit model Willingness-to-pay CVM

Activity maintenance of the excised branches and a case study of NO_2 exchange between the atmosphere and P.nigra branches

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2019年第6期31卷 316-326页

作者： Chun Chen Yuzheng Wang Yuanyuan Zhang Xiaoxiu Lun Chengtang Liu Yujing Mu Chenglong Zhang Pengfei Liu Chaoyang Xue Min Song Can Ye Junfeng Liu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Excellence in Urban Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences College of Environmental Science & Engineering Beijing Forest University

The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.

关键词： Excised branches Activity maintenance NO2 exchange flux Hydroponics Dynamic chamber

Epigenomic profiling identifies the role of Nr5a2 and CYP1B1 in hepatocellular carcinoma stemness maintenance

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2019年第16期64卷 1132-1135页

作者： Jun Cao Hong Jiang Ran Zhang Amr.R.Ghanam Honghai Xia Yuting Zhu Zhen Yang Xiaoyuan Song Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Brain Function and DiseaseNeurodegenerative Disorder Research CenterSchool of Life SciencesDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230026China Department of Emergency Surgery The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001China Core Facility Center for Life Sciences School of Life SciencesUniversity of Science and Technology of ChinaHefei 230026China

Cancer stem cells (CSCs) are largely responsible for the formation of tumor heterogeneity and tumor’s resistance to traditional treatments such as chemotherapy due to its self-renew capability and multi-lineage differentiation potential (1)However, it remains elusive how the CSCs maintain their stemness, thus restricting the development of therapeutic treatments specifically targeting the CSCs.

关键词： HCC Epigenomic profiling identifies the role of Nr5a2 and CYP1B1 in hepatocellular carcinoma stemness maintenance CYP

maintenance Awareness of Student Group about College Historical Buildings

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2019年第3期36卷 293-299页

作者：李亮周晓健 School of Art Design Shanghai University of Engineering ScienceShanghai 201620China China Center for Special Economic Zone Research Shenzhen UniversityShenzhen 518060China

In order to investigate the maintenance awareness of student group on historical buildings in colleges,this paper employs fuzzy comprehensive evaluation method and determines the evaluation system of maintenance awareness.Through sampling survey,it s found that maintenance awareness of college students belongs to medium level,and emotional identity level is high.However,protection behavior is little,which is due to the lack of protection knowledge and college propaganda.What s more,the usage of historical buildings also affects the maintenance awareness level.

关键词： maintenance awareness fuzzy comprehensive evaluation college campus historical buildings

Initiation and maintenance of plant stem cells in root and shoot apical meristems

在线全文

学校读者我要写书评

暂无评论

aBIOTECH 2020年第3期1卷 194-204页

作者： Junxia Wang Yinghua Su Xiangpei Kong Zhaojun Ding Xian Sheng Zhang The Key Laboratory of Plant Development and Environmental Adaptation Biology Ministry of EducationCollege of Life SciencesShandong UniversityQingdao 266237ShandongChina State Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTai’an 271018ShandongChina

Plant stem cells are a small group of cells with a self-renewal capacity and serve as a steady supply of precursor cells to form new differentiated tissues and organs in plants.Root stem cells and shoot stem cells,which are located in the root apical meristem and in the shoot apical meristem,respectively,play a critical role in plant longitudinal growth.These stem cells in shoot and root apical meristems remain as pluripotent state throughout the lifespan of the plant and control the growth and development of plants.The molecular mechanisms of initiation and maintenance of plant stem cells have been extensively investigated.In this review,we mainly discuss how the plant phytohormones,such as auxin and cytokinin,coordinate with the key transcription factors to regulate plant stem cell initiation and maintenance in root and shoot apical meristems.In addition,we highlight the common regulatory mechanisms of both root and shoot apical meristems.

关键词： Stem cell Initiation maintenance Auxin Cytokinin Transcription factors

Joint optimization of inspection, maintenance, and spare ordering policy considering defective products loss

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2021年第5期32卷 1167-1179页

作者： HAN Mengying YANG Jianhua ZHAO Xiao School of Economics and Management University of Science and Technology BeijingBeijing 100083China Beijing Enter-prise Low-Carbon Operation Strategy Research Base University of Science and Technology BeijingBeijing 100083China School of Business Hebei University of Economics and BusinessShijiazhuang 050061China

This paper proposes a joint inspection-based maintenance and spare ordering optimization policy that considers the problem of integrated inspection,preventive maintenance,spare ordering,and quality control for a four-state single-unit manufacturing system.When an inspection detects a minor defect,a second phase inspection is initiated and a regular order is placed.Product quality begins to deteriorate when the system undergoes a severe defect.To counter this,an advanced replacement of the minor defective system is carried out at the Jth second phase inspection.If a severe defect is recognized prior to the Jth inspection,or if system failure occurs,preventive or corrective replacement is executed.The timeliness of replacement depends on the availability of spare.We adopt two modes of ordering:a regular order and an emergency order.Meanwhile,a threshold level is introduced to determine whether an emergency order is preferred even when the regular order is already ordered but has not yet arrived.The optimal joint inspection-based maintenance and spare ordering policy is formulated by minimizing the expected cost per unit time.A simulation algorithm is proposed to obtain the optimal two-phase inspection interval,threshold level and advanced replacement interval.Results from several numerical examples demonstrate that,in terms of the expected cost per unit time,our proposed model is superior to some existing models.

关键词： maintenance two-phase inspection spare ordering three-stage failure process delay-time model

Parents' participation in physical activity predicts maintenance of some,but not all, types of physical activity in offspring during early adolescence:A prospective longitudinal study

在线全文

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2019年第3期8卷 273-279页

作者： Jennifer Brunei Jeffrey Gaudet Erin K.Wing Mathieu Bélanger School of Human Kinetics University of Ottawa Institut du Savoir Montfort (ISM) H?pital Montfort Cancer Therapeutic Program Ottawa Hospital Research Institute (OHRI) Centre de formation medicale du Nouveau-Brunswick Universite de Moncton Centre de formation médicale du Nouveau-Brunswick Université de Moncton

Purpose: We aimed to examine the longitudinal associations between parents' and youth's participation in physical activity(PA).Methods-: One hundred and ninety youth cuompleted self-admitiistered questionnaires 3 times per year from 2011 to 2015, and their parents completed an interviewer-administered questionnaire during a telephone interview once in2011-2012. Data on youth's and parents' activities were classified as interdependent or coactive/imdependent.Results: Youth with one or both parents who participated in interdependent activities were more likely to maintain participation in interdependent activities(hazard ratio(HR) = 3.63: 95% confidence interval(CI) = 1.30-10.17). Youth's sustained participation in coactive/independent activities was not associated with parents' participation in coactive/independent activities(HR= 0.97; 95%CI=0.46-2.06).Conclusion: Longitudinal associations between parents' and youth's participation in PA differed across type of PA. Encouraging parents' participation in interdependent activities may promote sustained participation in interdependent activities in youth.

关键词： Longitudinal maintenance Parental behavior Physical activity Sports Youth

maintenance OF MULTI-STATE PRODUCTION SYSTEMS DETERIORATED BY RANDOM SHOCKS AND PRODUCTION

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2011年第1期20卷 110-118页

作者： Won Seok YANG Dae E.LIM Kyung C.CHAE Department of Business Administration Hannam University Department of Industrial and Systems Engineering

We consider the preventive maintenance of a production system that is deteriorated by random shocks and the production process itself. The degree of deterioration is modeled by discrete and finite states. Shocks arrive according to a Poisson process and deteriorate the system by random amounts. The system may deteriorate whenever it produces an item. The system is continuously monitored and repaired if the system state is at or above a predetermined level for maintenance. We analyze the lifetime, product quantity, average cost, and average profit considering revenue from the product and cost due to setup, operation, and repair. Assuming a structure of system parameters and costs, using numerical examples, we investigate the impact of production and shock arrivals on the average profit and the optimal maintenance level that maximizes the average profit. The proposed model is applicable to manufacturing tasks in which machines wear due to production, for example, press processes, milling, turning, punching, and drilling.

关键词： Multi-state deterioration random shock maintenance cost-benefit analysis

Novel Taguchi scheme-based DEMATEL methods and DEMATEL method for the principal performance indicators of maintenance in a food processing industry

在线全文

学校读者我要写书评

暂无评论

International Journal of Intelligent Computing and Cybernetics 2021年第3期14卷 363-397页

作者： Victor Chidiebere Maduekwe Sunday Ayoola Oke Department of Mechanical Engineering Faculty of EngineeringUniversity of LagosAkoka YabaNigeria

Purpose-Key performance indicators(KPIs)of maintenance systems serve as benchmarks to workers and organizations to compare their goals for decision-making purposes.Unfortunately,the effects of one KPI on the other are least known,restraining decisions on prioritization of KPIs.This article examines and prioritizes the KPIs of the maintenance system in a food processing industry using the novel Taguchi(T)scheme-decisionmaking trial and evaluation laboratory(DEMATEL)method,Taguchi-Pareto(TP)scheme-DEMATEL method and the DEMATEL method.Design/methodology/approach-The causal association of maintenance process parameters(frequency of failure,downtime,MTTR,MTBF,availability and MTTF)was studied.Besides,the optimized maintenance parameters were infused into the DEMATEL method that translates the optimized values into cause and effect responses and keeping in view the result of analysis.Data collection was done from a food processing plant in Nigeria.Findings-The results indicated that downtime and availability have the most causal effects on other criteria when DEMATEL and T-DEMATEL methods were respectively applied to the problem.Furthermore,the frequency of failure is mostly affected by other criteria in the key performance indication selection using the two methods.The combined Taguchi scheme and DEMATEL method is appropriate to optimize and establish the causal relationships of factors.Originality/value-Hardly any studies have reported the joint optimization and causal relationship of maintenance system parameters.However,the current study achieves this goal using the T-DEMATEL,TP-DEMATEL and DEMATEL methods for the first time.The applied methods effectively ease decisions on prioritization of KPIs for enhancement.

关键词： maintenance Performance DEMATEL Food processing Indicators

Posture maintenance Control of 2-Link Object By Nonprehensile Two-Cooperative-Arm Robot Without Compensating Friction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1397-1403页

作者： Changan Jiang Satoshi Ueno Department of Mechanical Engineering Ritsumeikan University1-1-1 Noji-higashiKusatsuShiga 525-8577Japan

In this paper, a method to posture maintenance control of 2-link object by nonprehensile two-cooperative-arm robot without compensating friction is proposed. In details, a mathematical model of the 2-link object is firstly built. Based on the model, stable regions for holding motion of nonprehensile two-cooperative-arm robot are obtained while the 2-link object is kept stable on the robot arms with static friction. Among the obtained stable regions, the robust pairs of orientation angles of the 2-link object are found. Under the robust orientation angles, a feedback control system is designed to control the arms to maintain the 2-link object's posture while it is being held or lifted up. Finally, experimental results are shown to verify the effectiveness of the proposed method.

关键词： Nursing care nonprehensile robot posture maintenance static friction two-cooperative-arm robot