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Effect of Particle Phase Volume, Shape and Liquid Phase Concentrations on Rheological Properties of Large Particulate-Liquid Model Food Systems by Using Ball Measuring System
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作者 Chlharu Inoue Peter Versluis Pablo Coronel Johanna Maria Martina Elberse 《Journal of Chemistry and Chemical Engineering》 2013年第7期643-652,共10页
Rheological properties of large particulate-liquid model food systems were studied by using the BMS (ball measuring system). The model food systems were composed of alginate gel particles (-10mm) and a gelatinised... Rheological properties of large particulate-liquid model food systems were studied by using the BMS (ball measuring system). The model food systems were composed of alginate gel particles (-10mm) and a gelatinised starch solution with 1% w/w sodium chloride as a liquid phase. The effects of particle phase volume (Ф, 0-0.60), particle shapes (cube, sphere, rod and disc) and starch concentrations (3% and 5% w/w starch) were investigated. The power law model was successfully applied to characterize the flow properties of each system and the consistency K and power law index n were obtained. The K increased and n decreased with increasing # for samples at all particle shapes at 3% w/w starch in the liquid phase. The particle effect on the viscosity is further analysed by means of the Krieger-Dougherty model and the maximum packing fraction #,, and the intrinsic viscosity [η] were obtained in each system. The Фm, depended on the particle shape, as expected. The [7] value depended on particle shape and was largely in the order of 4.04 (cube), 3.28 (disc), 2.56 (sphere) and 2.32 (rod) at 3% w/w starch. The [η] also depended on starch concentration and was 1.1 at 5%,6 w/w starch in the liquid phase with spherical particles. The present results show successful application of BMS to study the rheological properties of large particulate liquid food systems at relatively small scale experiment (-0.5 L) and also that existing models for suspension rheology are applicable for such food systems to a great extend. 展开更多
关键词 Large particulate-liquid model food flow property ball measuring system power law model krieger-dougherty model.
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Assessing the Water-Energy-Food-Ecosystems Nexus in Smart Irrigation: A Potato Farming Case Study in Lebanon
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作者 Ali Karnib Hammou Laamrani Jauad El Kharraz 《Journal of Geoscience and Environment Protection》 2024年第8期80-96,共17页
This study examines the Water-Energy-Food-Ecosystems (WEFE) nexus in Lebanese agriculture, with a focus on the shift from conventional surface irrigation techniques to advanced smart irrigation systems in the Bekaa re... This study examines the Water-Energy-Food-Ecosystems (WEFE) nexus in Lebanese agriculture, with a focus on the shift from conventional surface irrigation techniques to advanced smart irrigation systems in the Bekaa region, specifically targeting potato cultivation. The study quantitatively analyzes the interaction among water, energy, and agricultural outputs at the farm scale using the WEFE Nexus framework for scenario analysis. It evaluates variations in water productivity, environmental effects, and economic outcomes, offering a detailed view of existing practices and their sustainable improvement potential. The WEFE Nexus assessment demonstrates that smart irrigation integration significantly decreased resource usage: water consumption was reduced by 58%, diesel fuel use for irrigation dropped by 57%, and the demand for labor and fertilizers decreased by 47% and 49%, respectively. This change led to enhanced crop yields and increased resource efficiency, demonstrating the potential of smart irrigation as a transformative strategy for sustainable agriculture in Lebanon and other arid areas. Economic analysis showed that farmers could recover the costs of installing the smart irrigation system within 3 months. The findings highlight the need for further research on integrating smart irrigation with renewable energy, showing potential for sustainable agricultural development. . 展开更多
关键词 Water-Energy-food-Ecosystems Nexus Sustainable Agriculture Smart Irrigation Q-Nexus model
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Stability and Neimark-Sacker bifurcation analysis of a food-limited population model with a time delay 被引量:2
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作者 姜晓伟 关治洪 +2 位作者 张先鹤 张顶学 刘峰 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期67-71,共5页
In this paper,a kind of discrete delay food-limited model obtained by the Euler method is investigated,where the discrete delay τ is regarded as a parameter.By analyzing the associated characteristic equation,the lin... In this paper,a kind of discrete delay food-limited model obtained by the Euler method is investigated,where the discrete delay τ is regarded as a parameter.By analyzing the associated characteristic equation,the linear stability of this model is studied.It is shown that Neimark-Sacker bifurcation occurs when τ crosses certain critical values.The explicit formulae which determine the stability,direction,and other properties of bifurcating periodic solution are derived by means of the theory of center manifold and normal form.Finally,numerical simulations are performed to verify the analytical results. 展开更多
关键词 food-limited model time delay Neimark-Sacker bifurcation periodic solution
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A dynamic food-chain model and program for predicting the consequences of nuclear accident 被引量:1
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作者 Hu Er bang, Gao Zhan rong, Zhang He yuan, Wei Wei qiang Institute of Environmental Science, CIRP, Taiyuan 030006, China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1998年第2期96-103,共8页
A dynamic food chain model and program, DYFOM 95, for predicting the radiological consequences of nuclear accident has been developed, which is not only suitable to the West food chain but also to Chinese food chain. ... A dynamic food chain model and program, DYFOM 95, for predicting the radiological consequences of nuclear accident has been developed, which is not only suitable to the West food chain but also to Chinese food chain. The following processes, caused by accident release which will make an impact on radionuclide concentration in the edible parts of vegetable were considered: dry and wet deposition interception and initial retention, translocation, percolation, root uptake and tillage. Activity intake rate of animals, effects of processing and activity intake of human through ingestion pathway ware also considered in calculations. The effects of leaf area index LAI of vegetable were considered in dry deposition model. A method for calculating the contribution of rain with different period and different intensity to total wet deposition was established. The program contains 1 main code and 5 sub codes to calculate dry and wet deposition on surface of vegetable and soil, translocation of nuclides in vegetable, nuclide concentration in the edible parts of vegetable and in animal products and activity intake of human and so on. 展开更多
关键词 dynamic food chain model and program consequences of nuclear accident.
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Deterministic and Stochastic Fractional-Order Hastings-Powell Food Chain Model
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作者 Moustafa El-Shahed Asmaa M.Al-Dububan 《Computers, Materials & Continua》 SCIE EI 2022年第2期2277-2296,共20页
In this paper,a deterministic and stochastic fractional-order model of the tri-trophic food chain model incorporating harvesting is proposed and analysed.The interaction between prey,middle predator and top predator p... In this paper,a deterministic and stochastic fractional-order model of the tri-trophic food chain model incorporating harvesting is proposed and analysed.The interaction between prey,middle predator and top predator population is investigated.In order to clarify the characteristics of the proposed model,the analysis of existence,uniqueness,non-negativity and boundedness of the solutions of the proposed model are examined.Some sufficient conditions that ensure the local and global stability of equilibrium points are obtained.By using stability analysis of the fractional-order system,it is proved that if the basic reproduction number R_(0)<1,the predator free equilibrium point E_(1) is globally asymptotically stable.The occurrence of local bifurcation near the equilibrium points is investigated with the help of Sotomayor’s theorem.Some numerical examples are given to illustrate the theoretical findings.The impact of harvesting on prey and themiddle predator is studied.We conclude that harvesting parameters can control the dynamics of the middle predator.A numerical approximation method is developed for the proposed stochastic fractional-order model. 展开更多
关键词 food chain model global dynamics stability STOCHASTIC Hastings-Powell model HARVESTING
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A DYNAMIC FOOD CHAIN MODEL FOR HONG KONG BASED ON RADFOOD MODEL AND BIRCHALL-JAMES ALGORITHM
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作者 余君岳 吴国斌 +1 位作者 张增 杨健明 《Nuclear Science and Techniques》 SCIE CAS CSCD 1995年第1期37-46,共10页
In this paper a dynamic food chain model for Hong Kong which simulates the transfer of radioactive substances from a fallout deposition via the food chain into the human bodies is built. The model is based on the RADF... In this paper a dynamic food chain model for Hong Kong which simulates the transfer of radioactive substances from a fallout deposition via the food chain into the human bodies is built. The model is based on the RADFOOD model and the BirchallJames algorithm. The radionuclides 13if and 90Sr representing the short-term and long-term risk situations have been studied as sample cases. Various types of crops,and the dietary pattern of the public have been collsidered. The resulting internal radiation doses have been calculated. The results are obtained for food consumption starting at various time after the fallout deposition and for different consumption durations. 展开更多
关键词 Dynamic food chain model Fallout deposition 131I 90Sr
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Ecological controls on biogeochemical fluxes in the western Antarctic Peninsula studied with an inverse foodweb model
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作者 Hugh W.Ducklow S.C.Doney S.F.Sailley 《Advances in Polar Science》 2015年第2期122-139,共18页
Sea ice in the western Antarctic Peninsula (WAP) region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affec... Sea ice in the western Antarctic Peninsula (WAP) region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affect ocean stratification and freshwater balance and in turn impact every component of the polar marine ecosystem. Long-term observations from the WAP nearshore and offshore regions show a pattern of chlorophyll (Chl) variability with three to five years of negative Chl anomalies interrupted by one or two years of positive anomalies (high and low Chl regimes). Both field observations and results from an inverse food-web model show that these high and low Chl regimes differed significantly from each other, with high primary productivity and net community production (NCP) and other rates associated with the high Chl years and low rates with low Chl years. Gross primary production rates (GPP) averaged 30 mmolC.m^-2.d^-1 in the low Chl years and 100 mmolC.m-2.d1 in the high Chl years. Both large and small phytoplankton were more abundant and more productive in high Chl years than in low Chl years. Similarly, krill were more important as grazers in high Chl years, but did not differ from microzooplankton in high or low Chl years. Microzooplankton did not differ between high and low Chl years. Net community production differed significantly between high and low Chl years, but mobilized a similar proportion of GPP in both high and low Chl years. The composition of the NCP was uniform in high and low Chl years. These results emphasize the importance of microbial components in the WAP plankton system and suggest that food webs dominated by small phytoplankton can have pathways that funnel production into NCP, and likely, export. 展开更多
关键词 ecological controls BIOGEOCHEMICAL food-web model
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Mathematical Modeling of a Metabolic Network to Study the Impact of Food Contaminants on Genomic Methylation and DNA Instability
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作者 Etienne Z. Gnimpieba Souad Bousserouel Abalo Chango 《Journal of Biosciences and Medicines》 2014年第10期1-7,共7页
Environmental contamination of food is a worldwide public health problem. Folate mediated one- carbon metabolism plays an important role in epigenetic regulation of gene expression and mutagenesis. Many contaminants i... Environmental contamination of food is a worldwide public health problem. Folate mediated one- carbon metabolism plays an important role in epigenetic regulation of gene expression and mutagenesis. Many contaminants in food cause cancer through epigenetic mechanisms and/or DNA instability i.e. default methylation of uracil to thymine, subsequent to the decrease of 5-methylte- trahydrofolate (5 mTHF) pool in the one-carbon metabolism network. Evaluating consequences of an exposure to food contaminants based on systems biology approaches is a promising alternative field of investigation. This report presents a dynamic mathematical modeling for the study of the alteration in the one-carbon metabolism network by environmental factors. It provides a model for predicting “the impact of arbitrary contaminants that can induce the 5 mTHF deficiency. The model allows for a given experimental condition, the analysis of DNA methylation activity and dumping methylation in the de novo pathway of DNA synthesis. 展开更多
关键词 DNA-METHYLATION DNA INSTABILITY MATHEMATICAL modeling Logic Programming Metabolic Network food CONTAMINANT
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Relevance of a standard food model in combination with electronic jaw movement recording on human mastication pattern analysis
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作者 Gregor Slavicek Mikhael Soykher +2 位作者 Marina Soykher Haymo Gruber Peter Siegl 《Advances in Bioscience and Biotechnology》 2010年第2期68-78,共11页
The aim of this paper is to describe the possibilities of analyzing human mastication. The development of a standardized food model is presented. Based on the findings of a systematic literature search an elastic food... The aim of this paper is to describe the possibilities of analyzing human mastication. The development of a standardized food model is presented. Based on the findings of a systematic literature search an elastic food model was created with the aim of standardizing size and elastic properties. Three different eatable jellied products were chosen, created by a changing of the amount of gelatin (260 Blooms) related to the total mass of the standard jellied food. The different hardness were classified in soft, medium and hard, flavored identically, but stained with different colors: soft-green, medium-yellow, hard-red. A cylindrical form was chosen with a height of 1 cm and a diameter of 2 cm. A standard protocol for analyzing chewing patterns in men was created. The condylographic data off several patients are described in details to demonstrate the possible clinical implementation. The newly developed standard food model (SFM) showed the capability to serve in experimental settings to analyze human mastication, although only a few patients have been examined. In addition, strength and size of the newly developed SFM load the masticatory system in an extent;it should be possible to disclose subclinical symptoms of patients within a short time of examination. The diagnostic procedure of temporo-mandibular disorder (TMD) should be endorsed by this new method. The condylographic data created by a standardized protocol should have the ability to enhance the clinical functional analysis of patients previous to restorative dental procedures. 展开更多
关键词 HUMAN MASTICATION STANDARD food model MANDIBULAR Movement EMG Condylography Biomechanics Temporo-Mandibular Joint SWALLOWING CHEWING CHEWING Muscle Activity Craniomandibular System Nutrition Tooth Loss
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安徽省农业碳排放效率与粮食安全耦合协调研究
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作者 梅莹 戴理政 吴梦瑶 《安全与环境学报》 CAS CSCD 北大核心 2024年第11期4506-4517,共12页
选取安徽省2011—2020年16市的农业相关数据,采用超效率SBM(Slacks-Based Measure)模型和熵值法对安徽省农业碳排放效率和粮食安全水平进行评估,并通过耦合协调度模型探讨两者之间的协调发展程度。研究结果显示:(1)安徽省农业碳排放效... 选取安徽省2011—2020年16市的农业相关数据,采用超效率SBM(Slacks-Based Measure)模型和熵值法对安徽省农业碳排放效率和粮食安全水平进行评估,并通过耦合协调度模型探讨两者之间的协调发展程度。研究结果显示:(1)安徽省农业碳排放效率均值在2011—2020年处于波动上升趋势,从0.801增至1.018,增幅为27.09%。在2011年,以淮南和黄山为中心的周边地区效率较高,在2020年,除安庆、铜陵外全省达到了高效率水平。(2)粮食安全水平在2011—2020年呈现“上升—下降—上升”的趋势,粮食安全水平整体从0.241增至0.763。在空间分布上,皖北粮食安全水平高于皖南地区。(3)农业碳排放效率与粮食安全耦合协调度情况在2011—2020年处于波动上升的过程,农业减排和保障粮食安全朝着高质量协调方向发展,皖北和皖中地区协调等级优于皖南地区。因此,未来安徽省应加快提高农业防灾减灾能力,建立空间关联网络并根据区域特点制定差异化策略,实现安徽省农业减排与保障粮食安全的优质协调发展。 展开更多
关键词 环境学 农业碳排放效率 超效率SBM模型 粮食安全 耦合协调
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生鲜电商平台消费者购菜意愿多元提升路径及适配组态研究 被引量:4
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作者 李连英 闵欣 傅青 《农林经济管理学报》 CSSCI 北大核心 2024年第1期60-69,共10页
基于南昌市519份调查数据,运用技术接受模型3和期望确认理论模型,采用fsQCA方法对生鲜电商平台消费者购菜意愿进行组态分析,探讨消费者购菜意愿适配组态的要素构成条件及提升策略。结果表明:单一条件变量均不是生鲜电商平台消费者购菜... 基于南昌市519份调查数据,运用技术接受模型3和期望确认理论模型,采用fsQCA方法对生鲜电商平台消费者购菜意愿进行组态分析,探讨消费者购菜意愿适配组态的要素构成条件及提升策略。结果表明:单一条件变量均不是生鲜电商平台消费者购菜意愿的必要条件,说明变量间可能存在替代作用;存在乐趣性与顾客认可型路径、适应性与情感导向型路径、体验感与顾客评价型路径、个性化与挑战导向型路径、影响力与便利导向型路径等5条产生高购菜意愿的路径;其中,高主观规范和高满意度作为核心条件存在于4条路径中,对生鲜电商平台消费者产生购菜意愿发挥着更普适的作用。基于此,建议整合多元路径,根据组态效应调整购菜意愿提升策略;确保产品质量,提升售后服务,重视满意度的普适性作用;建立良好口碑,发挥社交圈的积极作用,以实现平台发展的良性循环。 展开更多
关键词 生鲜电商平台 购菜意愿 技术接受模型3 期望确认理论 fsQCA
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Finding Food Security through Changing the Agricultural Model to Sustain Insect Biodiversity
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作者 Astrid Jankielsohn 《Advances in Entomology》 2021年第3期122-130,共9页
Worldwide biodiversity is being threatened by human activities to a greater level wherein the natural ecosystems are reaching the verge of collapsing. We are faced with four major interrelated challenges namely a chan... Worldwide biodiversity is being threatened by human activities to a greater level wherein the natural ecosystems are reaching the verge of collapsing. We are faced with four major interrelated challenges namely a changing climate, biodiversity loss, human population growth and food production for this growing population. Agricultural intensification contributes significantly to biodiversity loss. The agricultural model for our current food production systems is mainly based on the Green Revolution, which promoted the cultivation of crops in extensive monoculture fields and intensified external inputs of agrochemicals. This model resulted in biodiversity loss, particularly in insect populations. A model based on ecological intensification as an alternative to agricultural intensification with minimized use of agro-inputs may slow the rate of biodiversity loss resulting in more sustainable agricultural ecosystems. 展开更多
关键词 food Security Agricultural model Biodiversity Loss Climate Change Ecological Intensification INSECTS Ecosystem Functioning Human Population Increase
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2000-2020年黄河流域水-能源-粮食系统耦合协调时空演变特征 被引量:2
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作者 王锐 祝笑笑 +2 位作者 彭艳艳 赵素霞 肖东洋 《水土保持研究》 CSCD 北大核心 2024年第1期354-362,共9页
[目的]探讨黄河流域水—能源—粮食系统的耦合协调时空演化特征,可为定量评估流域高质量发展和区域可持续发展提供科学依据。[方法]通过耦合协调度模型分析水—能源—粮食系统的综合发展水平和耦合协调特征,并利用灰色关联度对各子系统... [目的]探讨黄河流域水—能源—粮食系统的耦合协调时空演化特征,可为定量评估流域高质量发展和区域可持续发展提供科学依据。[方法]通过耦合协调度模型分析水—能源—粮食系统的综合发展水平和耦合协调特征,并利用灰色关联度对各子系统内部指标进行排序,进而判断对水—能源—粮食系统耦合协调度的影响程度。[结果](1)黄河流域水—能源—粮食系统的综合发展指数呈上升趋势,水资源子系统波动幅度最大。(2) 2000—2020年黄河流域水—能源—粮食系统耦合协调度从初级协调向良好协调阶段发展;不同省区间的系统耦合协调发展水平差异较为明显,整体上可表现为上游地区>中下游地区。(3)各子系统与系统耦合协调度的影响程度排名可表示为水资源子系统>粮食子系统>能源子系统,其中水资源子系统内部指标与系统耦合协调度关联度均在85%以上,水资源子系统相对其他子系统的严格管理尤为重要。[结论]水—能源—粮食系统的耦合协调发展水平有待提高,为促进系统协调发展和流域高质量发展应综合考虑各子系统的相互作用关系。 展开更多
关键词 黄河流域 水—能源—粮食系统 耦合协调度模型 灰色关联度分析
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新工科背景下食品工艺学课程教学创新研究 被引量:1
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作者 李书红 陈桂芸 陈野 《中国轻工教育》 2024年第2期1-7,共7页
针对食品工艺复杂问题与学科思维单一之间的矛盾、跨学科知识组合与深度融合及灵活运用之间的矛盾、认知层面责任担当与实践层面行动不力之间的矛盾,课程团队基于“建构主义”学习理论,建立了“食艺世界,思想舞台”的教学理念,开展了“... 针对食品工艺复杂问题与学科思维单一之间的矛盾、跨学科知识组合与深度融合及灵活运用之间的矛盾、认知层面责任担当与实践层面行动不力之间的矛盾,课程团队基于“建构主义”学习理论,建立了“食艺世界,思想舞台”的教学理念,开展了“核心概念重构,核心任务引领,学—研—创—探—践—悟”教学模式的创新与实践,构建了“赋情、赋律、塑形”两赋一塑的思政育人模式,建立线上、线下相结合的立体化教学环境,融合产学情境,引入前沿科技,实施“三课”渐进,提升育人实效,旨在打造高质量的食品工艺学课堂,培养“新工科”背景下的新型食品人才。 展开更多
关键词 食品工艺学 教学模式 创新与实践 教学理念
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基于投影寻踪模型的水-能源-粮食-人口系统安全评价
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作者 何立新 周帅宇 +1 位作者 张峥 李志会 《人民黄河》 CAS 北大核心 2024年第4期73-78,共6页
河北省作为京津冀城市圈中不可或缺的一部分,其水、能源、粮食、人口等资源安全稳定对于整个区域经济和社会的发展尤为重要。为了深入了解河北省水-能源-粮食-人口系统的安全状况,将人口因素纳入水-能源-粮食系统进行分析,构建水-能源-... 河北省作为京津冀城市圈中不可或缺的一部分,其水、能源、粮食、人口等资源安全稳定对于整个区域经济和社会的发展尤为重要。为了深入了解河北省水-能源-粮食-人口系统的安全状况,将人口因素纳入水-能源-粮食系统进行分析,构建水-能源-粮食-人口系统的安全评价指标体系,运用基于麻雀算法改进的投影寻踪模型对河北省2010—2019年水-能源-粮食-人口系统安全进行时空演变综合评价。结果表明:在研究期,河北省水-能源-粮食-人口系统安全等级逐渐升高,各市的水-能源-粮食-人口系统安全差异性降低;河北省各市水-能源-粮食-人口系统安全等级值在1.32~3.95之间,说明该系统安全处于不安全、亚安全、安全3个等级。建议河北省根据自身资源优势,合理分配资源,实现水、能源、粮食和人口的协调发展。 展开更多
关键词 人口因素 安全评价 水-能源-粮食 投影寻踪模型 河北省
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粮食供应链韧性影响因素及提升策略研究
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作者 韩光鹤 潘鑫 +1 位作者 张欣 孙伟仁 《粮油食品科技》 CAS CSCD 北大核心 2024年第6期19-27,共9页
粮食供应链韧性关乎粮食安全,探究粮食供应链韧性的影响因素具有现实意义。基于文献研究法和专家访谈法,从预测能力、抵抗能力、恢复能力、成长能力4个维度确定影响粮食供应链韧性的20个重要因素,构建DEMATEL-ISM综合模型并绘制ISM层级... 粮食供应链韧性关乎粮食安全,探究粮食供应链韧性的影响因素具有现实意义。基于文献研究法和专家访谈法,从预测能力、抵抗能力、恢复能力、成长能力4个维度确定影响粮食供应链韧性的20个重要因素,构建DEMATEL-ISM综合模型并绘制ISM层级结构图。在探究各因素对粮食供应链韧性的重要程度和影响力大小的基础上,识别其关键影响因素,并利用ISM将各因素划分层级,明晰各要素之间的相互作用关系。结果表明:政策支持、政策与市场变动、信息共享能力、数字技术应用与创新4个因素是粮食供应链韧性的关键影响因素,也是最深层的根本因素。预测能力和成长能力会对粮食供应链韧性的抵抗能力和恢复能力产生影响,是韧性能力的基础,对粮食供应链韧性起直接作用。该研究结论为我国粮食供应链韧性提升提供了针对性建议。 展开更多
关键词 粮食供应链 韧性 粮食安全 DEMATEL-ISM模型
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基于SIPS理论模型的美食短视频传播城市形象策略研究
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作者 胡志超 《鞍山师范学院学报》 2024年第1期100-104,共5页
智能媒体时代,短视频为大众主动参与城市形象的建构与传播提供了新的视角和实践。美食因其独特魅力,成为城市独有的特殊符号和城市形象传播的重要载体。以短视频垂直细分领域下的美食短视频作为切入点,解析美食短视频在城市形象传播上... 智能媒体时代,短视频为大众主动参与城市形象的建构与传播提供了新的视角和实践。美食因其独特魅力,成为城市独有的特殊符号和城市形象传播的重要载体。以短视频垂直细分领域下的美食短视频作为切入点,解析美食短视频在城市形象传播上的重要性,厘清其在传播城市形象过程中存在的问题,结合SIPS模式,分别从共鸣、确认、参与、共享四个阶段,提出优化美食短视频传播城市形象的策略。 展开更多
关键词 SIPS模式 美食 短视频 城市形象
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基于WOFOST模型与遥感数据同化的县级尺度玉米估产研究
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作者 钱凤魁 王化军 +3 位作者 王祥国 于远俊 辛家佶 顾汉龙 《沈阳农业大学学报》 CAS CSCD 北大核心 2024年第2期138-152,共15页
区域尺度的作物生长动态监测和产量预测对于保障粮食安全和农业政策的制定具有重要参考依据。遥感数据同化应用极大提高了作物估产的时效性和精度。为及时、准确地实现县级尺度粮食产量的估测,以及提升产量估测的精度,以辽宁省铁岭县为... 区域尺度的作物生长动态监测和产量预测对于保障粮食安全和农业政策的制定具有重要参考依据。遥感数据同化应用极大提高了作物估产的时效性和精度。为及时、准确地实现县级尺度粮食产量的估测,以及提升产量估测的精度,以辽宁省铁岭县为研究区,采用WOFOST(world food studies)模型与遥感同化相结合的方法对铁岭县玉米进行估产研究。通过采用扩展傅里叶幅度敏感性检验算法(extened Fourier amplitude sensitivity test,EFAST)敏感性分析方法实现玉米估产敏感性参数的分析,以及本地化;通过采用参数自动率定程序PEST(parameter estimation)实现参数的优化,验证结果为采样点产量的平均误差为852.39 kg·hm^(-2),模型模拟的精度达到92.82%。为进一步提高和优化模型估产精度,将遥感反演得到的叶面积指数采用集合卡尔曼滤波算法与模型模拟的叶面积指数进行数据同化,平均误差从同化前的852.39 kg·hm^(-2)降低为435.01 kg·hm^(-2),估产精度从92.82%提高到96.33%,有效提高了WOFOST模型估产的精度。结果表明:水分对玉米的生长发育限制并不大,其产量形成主要受光温影响,对温度、光能利用效率和最大同化速率有关的参数具有较高的敏感性;优化后的模型能够较好模拟铁岭县玉米生长发育情况,产量验证表明优化后的模型模拟的效果较好,但仍存在一定的误差;比值植被指数与叶面积指数的相关性最高,反演模型精度较好,反演结果表明叶面积指数在抽雄吐丝期差距较大,而在成熟期的差距不大;经过作物模型与遥感数据同化之后,估产的精度得到明显提高,说明遥感与作物模型同化是一种有效地提高作物估产和产量预测精度的方法。 展开更多
关键词 world food studies模型 遥感 数据同化 玉米估产 铁岭县
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水体富营养化及物种入侵对星云湖食物网的影响 被引量:1
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作者 邓素炎 郭雯 +5 位作者 温雯雯 王明果 黄林培 陈子栋 陈光杰 赵帅营 《中国环境科学》 EI CAS CSCD 北大核心 2024年第2期932-943,共12页
以云南浅水富营养化湖泊星云湖为研究区域,于2019~2020年对星云湖水质样品、初级生产者浮游植物(浮游碳源)、沉水植物(底栖碳源)、流域有机质(陆源)以及消费者浮游动物、底栖动物、鱼类等生物样品进行系统采集,甄别了星云湖初级生产者... 以云南浅水富营养化湖泊星云湖为研究区域,于2019~2020年对星云湖水质样品、初级生产者浮游植物(浮游碳源)、沉水植物(底栖碳源)、流域有机质(陆源)以及消费者浮游动物、底栖动物、鱼类等生物样品进行系统采集,甄别了星云湖初级生产者和消费者的碳、氮稳定同位素组成特征,并使用MixSIAR模型对消费者食物来源进行量化,对比分析以初级生产者(模式A)、以碳源贡献权重(模式B)和以初级消费者(模式C)3种不同氮稳定同位素基准计算的消费者营养级结果,进而构建适用于浅水富营养化湖泊的食物网结构,探讨富营养化以及外来入侵物种可能对星云湖食物网产生的影响.结果表明,MixSIAR模型结果显示浮游碳源、底栖碳源、陆源对消费者的贡献分别为77.3%、12.2%、10.5%,且沿岸带、敞水区不同生境鱼类的碳同位素信号不存在显著性差异,与浮游碳源的相近,指示浮游碳源是富营养湖泊消费者最主要的食物来源,其能量传输以浮游路径为主.对于不同食性的鱼类,杂食性鱼类的基础食物源(CR)跨度大,而肉食性鱼类营养长度(NR)更高,两者的核心生态位分离,且杂食性鱼类的核心生态位面积(3.79)高于肉食性鱼类(2.46),表明杂食性鱼类具有更高的适应性.模式B计算的营养级结果与消费者的食性较一致,可应用于星云湖消费者营养级计算.模式B结果显示,星云湖食物链长度为3.73,顶级掠食者为抚仙鲇,入侵物种太湖新银鱼营养级(3.37)次之,且与星云白鱼(3.01)在食物和生存空间上存在竞争.研究认为,富营养化导致的物源和能流的改变以及外来物种的入侵是造成星云湖土著鱼类资源衰退、食物网结构中生物多样性减少及生态系统功能弱化的主要原因. 展开更多
关键词 富营养化 物种入侵 碳氮稳定同位素 MixSIAR模型 营养级 湖泊食物网 星云湖
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多国粮食限制出口背景下中国食物安全潜在风险与策略——基于大食物观视角
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作者 刘华楠 陈伟洁 《中国渔业经济》 2024年第4期10-21,共12页
近年来,全球公共卫生事件和地缘冲突事件频发。面对重大突发事件的冲击,许多国家为保障本国粮食安全限制对外出口,这将对中国食物进口造成不利影响。文章对多国粮食限制出口前后中国食物进口变动进行分析,并用时间序列ARIMAX模型分析中... 近年来,全球公共卫生事件和地缘冲突事件频发。面对重大突发事件的冲击,许多国家为保障本国粮食安全限制对外出口,这将对中国食物进口造成不利影响。文章对多国粮食限制出口前后中国食物进口变动进行分析,并用时间序列ARIMAX模型分析中国食物大类、谷物类、畜肉类和水产品类安全水平的主要影响因素,设定的主要因素有国际各类食物贸易动荡程度和中国食物受害风险,分析出当前中国食物安全水平主要受蛋白质类食物供给的影响,多国粮食限制出口对中国谷物类食物和水产品类食物供给影响不大,对畜肉类食物长期供给的影响需警惕。最后,本文基于多国粮食限制出口前后中国食物进口变动分析和实证结果提出未来在大食物观视角下保障中国食物安全的政策建议。 展开更多
关键词 粮食限制出口 重大突发事件 食物安全 大食物观 ARIMAX模型
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