Overview of Ecological Agriculture with High Efficiency

From the presentation, connotation, characteristics, principles, pattern, and technologies of ecological agriculture with high efficiency, we conduct comprehensive and systematic analysis and discussion of the theoretical and practical progress of ecological agriculture with high efficiency. (i) Ecological agriculture with high efficiency was first advanced in China in 1991. (ii) Ecological agriculture with high efficiency highlights "high efficiency", "ecology", and "combination". (iii) Ecological agriculture with high efficiency is characterized by diverse organisms, good environment, good structure, powerful function, good quality, high benefit, low emission, sustainability. (iv) The yield increase and efficiency increase principle of ecological agriculture with high efficiency lies in full land use, three-dimensional light use, sufficient use of season, multi-layer water consumption, efficient fertilizer consumption, symbiosis and mutual supplement, ecological disaster reduction, recycling. (v) The typical pattern of ecological agriculture with high efficiency includes three-dimensional use pattern, biological symbiosis pattern, multi-industry combination pattern, industrial extension pattern, technology-driven pattern, environmental renovation pattern, resource recycling pattern, leisure and sight-seeing pattern. (vi) The key technologies of ecological agriculture with high efficiency include resource-saving technology, water and fertilizer regulation technology, biological technology for increasing soil fertility, disaster prevention and mitigation technology, comprehensive utilization technology, water conservation technology, structural adjustment technology, energy development technology, watershed control technology, and modern high-tech technology.

Calculation of Agricultural Production Efficiency Based on a Three-stage Data Envelopment Analysis Model and Analysis of the Spatial-temporal Characteristics: A Case Study of the Yangtze River Economic Belt

In response to the strategic call for the " Great Protection" of the Yangtze River Economic Belt and to fulfill the important historical tasks assigned by the state to the provinces and cities of the area,the Yangtze River Economic Belt is adjusting the agricultural industry structure,optimizing the input-output ratio,and ensuring stable and sustainable agricultural production. Based on the combination of the three-stage Data Envelopment Analysis( DEA) model and cluster analysis,this study examined the Yangtze River Economic Belt from 2008 to 2018 to measure its agricultural production efficiency and to analyze its temporal and spatial characteristics. Studies showed that exogenous environmental factors significantly( P < 5%) impacted agricultural production efficiency in the Yangtze River Economic Zone,and there were temporal and spatial differences. These included:(1) after excluding environmental factors,the overall agricultural production efficiency of the Yangtze River Economic Zone had improved. Sichuan Province and Jiangsu Province were at the forefront of efficiency,whereas the agricultural production efficiency of Shanghai had declined obviously.(2) The agricultural production efficiency of the Yangtze River Economic Belt varied year by year,with fluctuating development. The middle reaches of the Yangtze River had advanced agricultural production efficiency more than the upstream and downstream regions,and the agricultural production efficiency of the individual provinces did not match their economic and social development.(3) Increases in labor,land,irrigation,and other input factors increased agriculture production efficiency,and there was no correlation between fiscal investment,per capita gross domestic product( GDP) and agricultural production efficiency,while the disaster-affected area had a significantly negative impact on agricultural production efficiency.

Study on High-efficiency Ecological Agricultural Development Based on Science and Technology in the Yellow River Delta

Based on the analysis of the status, characteristics and technological functions of high-efficiency ecological agricultural development in the Yellow river delta, the paper pointed out technological bottlenecks of the high-efficiency ecological agricultural development in the Yellow river delta. Some suggestions were proposed including changing the development concept, implementing nine projects, increasing capital investment, focusing on demonstration, and strengthening human resources.

Dust removal efficiency of high pressure atomization in underground coal mine

To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.

Flow-rate Characteristics Measurement of Regulators Based on the Pressure Response in an Isothermal Tank

Regulators are important components in pneumatic system, and their flow-rate characteristics are the key parameters for designers. According to the correlatively international standard and national standard of China, which describe the flow-rate characteristics measurement method of pneumatic regulators, the pressure and the flow are measured point by point, and then the flow-rate characteristics curve is plotted point to point. This method has some disadvantages, such as equipment complexity, much air consumption, and low efficiency. To settle the problems presented above, this paper puts forward a new high efficient and energy saving flow-rate characteristics measurement method of regulators, which is based on the pressure response when charging and discharging to an isothermal tank without any flow meters. The measurement principle, the system and the steps are introduced. And the tracking differentiator is used for the data processing of the pressure difference. Two typical kinds of regulators were experimentally investigated, and their flow-rate characteristics curves were obtained with the new and the conventional method, respectively. Comparatively, it＇s proved that this new method is feasible because it is not only able to meet the demand of the measurement precision, but also to save energy and improve efficiency. Compared to the conventional method, the new method takes only about 1/10 amount of time and consumes about only 1/30 amount of air. Hopefully it will be able to serve as an international standard of flow-rate characteristics measurement method of regulators.

Highly-Efficient Aerodynamic Optimal Design of Rotor Airfoil Using Viscous Adjoint Method

In order to overcome the efficiency problem of the conventional gradient-based optimal design method,a highly-efficient viscous adjoint-based RANS equations method is applied to the aerodynamic optimal design of hovering rotor airfoil.The C-shaped body-fitted mesh is firstly automatically generated around the airfoil by solving the Poisson equations,and the Navier-Stokes(N-S)equations combined with Spalart-Allmaras(S-A)one-equation turbulence model are used as the governing equations to acquire the reliable flowfield variables.Then,according to multi-constrained characteristics of the optimization of high lift/drag ratio for hovering rotor airfoil,its corresponding adjoint equations,boundary conditions and gradient expressions are newly derived.On these bases,two representative rotor airfoils,NACA0012 airfoil and SC1095 airfoil,are selected as numerical examples to optimize their synthesized aerodynamic characteristics about lift/drag ratio in hover,and better aerodynamic performance of optimal airfoils are obtained compared with the baseline.Furthermore,the new designed rotor with the optimized rotor airfoil has better hover aerodynamic characteristics compared with the baseline rotor.In contrast to the baseline airfoils optimized by the finite difference method,it is demonstrated that the adjoint optimal algorithm itself is practical and highly-efficient for the aerodynamic optimization of hover rotor airfoil.

高质量发展目标下脱贫县农业产业化与农地利用生态效率耦合协调分析:以江西省为例

探究脱贫县农业产业化与农地利用生态效率耦合协调关系,对促进农业高质量发展具有重要意义。基于新发展理念,以江西省25个脱贫县为研究对象,构建农业产业化与农地利用生态效率耦合评价体系,借助耦合协调模型和泰尔指数模型测度两者的耦合协调水平及其区域差异。结果表明:(1)2011—2020年,江西省脱贫县农地利用生态效率总体水平较高,年均值为0.738,赣南地区高于赣中和赣北地区;(2)2011—2020年,江西省脱贫县农业产业化发展指数总体水平较低,年均值为0.414,赣北地区最高,其次为赣中,赣南最低;(3)2011—2020年,脱贫县农业产业化与农地利用生态效率耦合协调指数由期初的0.321升至期末的0.342,总体处于中度失调和轻度失调阶段;(4)脱贫县地区内差异对泰尔指数总体贡献最大,县域农业发展协调性较弱。进一步分析可以发现,市场与政府的作用差异是导致农业产业化水平与农地利用生态效率存在差异的主要原因,综合运用行政和市场手段推动农业产业化发展是提高两者耦合协调水平的关键。

农业生态效率的演变特征与空间收敛——基于黄河流域47个城市的实证

基于2000—2020年黄河流域47个地级市的面板数据,构建黄河流域农业生态效率的投入产出指标体系,运用非期望产出的超效率SBM模型测算各市的农业生态效率,结合GIS空间分析、Moran’s I指数、ML指数等方法分析农业生态效率的演变特征,并进行空间收敛性分析。结果表明:黄河流域农业生态效率水平整体偏低,但正处于由低水平迈向高水平的“爬坡”阶段,其中下游地区的效率增长最快;效率增长的主要来源为技术进步,流域内农业规模化水平仍有较大提升空间;在空间关联格局上,效率的空间依赖性不固定,但空间聚集性总体增强;黄河流域农业生态效率呈现显著的空间收敛特征,且工业化水平、农业经济发展水平、农业机械化密度、财政支农力度、农业市场化程度会促进效率的空间收敛。

数字科技促进海南热带特色高效农业发展实践与探索

随着物联网、大数据等现代信息技术的快速发展,数字技术应用已成为传统农业转型升级的重要手段。热带特色高效农业是海南省的主要支柱产业,同时也是高质量推进自贸港建设的重要支撑。通过数字技术赋能热带特色高效农业高质量发展具有重要的意义。总结当前海南省在热带特色高效农业数字化转型方面取得的重大进展,剖析数字农业发展统筹力度不强、农业数字化基础设施和装备水平仍较落后、农业农村数据资源整合不足、主导产业的数字化水平不高、关键核心技术研发滞后等主要问题,从强化顶层设计、夯实数字化基础支撑、构建数字农业基础数据资源体系、推动重点产业数字化转型、培育扶持数字农业市场主体等方面,探索助推海南省热带特色高效农业数字化发展的有效路径。

民勤县特色农产品加工业高质量发展研究

民勤县立足优质肉羊、蜜瓜、茴香、特色果蔬以及肉苁蓉、锁阳、枸杞、甘草等食药两用沙生中药材资源禀赋优势,用工业化的思维和理念谋划特色农产品加工业,在全面推动加工业高质量发展方面取得了显著成效。针对目前存在农产品加工业层次较低、规模较小、链条较短,运营模式比较传统、管理技术人才匮乏、企业经营成本较高等问题,我们通过全面系统研究,用工业化的思维和理念精心谋划民勤县特色农产品加工业高质量发展,提出了以“锻长板、扬优势、强弱项、补短板”为关键措施,通过“建链、延链、补链、强链”培育竞争优势,做优做强果蔬产业、聚力发展羊肉加工产业、培育壮大沙生中药材产业、稳步提升“土特产”食品加工业,通过打造绿色农产品加工产业集群、改造提升传统农产品加工产业、强化农产品加工链主企业培育、增强企业自主创新能力、完善产业支撑服务体系等一系列措施,构建民勤县特色农产品加工业高质量发展新格局。

习近平特色农业发展理念的科学内涵与时代价值

习近平特色农业发展理念萌芽于其七年知青时的乡村农业生产实践,形成于地方从政时的区域农业发展探索,升华于治国理政时的大国农业体系构建。随着社会主要矛盾转变,习近平认为新时代特色农业发展应着力解决发展不平衡不充分问题,构建现代产业体系、绿色生产体系和新型经营体系,营造良好的农业发展环境。习近平特色农业发展理念继承和丰富了马克思主义农业理论,是引领“大国小农”高质高效发展特色农业的行动指南,是推进实现全体人民共同富裕的根本遵循,为世界提供了推进实现农村农民共同富裕的中国方案。

川渝地区农业绿色高效用水科技攻关方向与对策建议

川渝地区农业种植面积大、从业人员多、产业份额大、战略意义强,但该地区长期面临严重的季节性干旱和工程性缺水,且农业绿色高效用水发展水平与经济发展、区域地位并不匹配,需提高农业节水抗旱减灾保产能力和水资源利用效率,推动川渝现代节水农业高质量发展。总结了川渝地区农业用水现状和高水效农业发展面临的问题,分析了该地区农业绿色高效用水的实际需求,在此基础上提出开展川渝农业绿色高效用水关键科技项目攻关、构建农业绿色高效用水专家智库、构建西南季节性干旱区农业绿色高效用水技术体系、建设特色水果产业节水科技创新中心、建立川渝农业绿色高效用水产业联盟等一系列对策建议。

乡村振兴背景下海南热带特色高效农业发展研究

基于乡村振兴的视角,从南繁种业、冬季瓜菜、热带水果、特色热带经济作物、现代渔业、特色畜禽等产业层面,分析海南实施乡村振兴战略以来热带特色高效农业产业发展的现状,指出了影响海南热带特色高效农业产业发展的因素,提出振兴海南热带特色高效农业产业的新思路,即构建新型生产体系、新型供给体系、新型经营体系。最后提出乡村振兴背景下海南热带特色高效农业产业发展,应着力构建粮食安全保障体系、着力打造科技创新支撑体系、着力打造秀美生态田园景观、着力打造数字农业应用典范、着力推动产业融合价值提升、着力提升产品市场竞争能力、着力推进全球热带农业高质量发展等对策建议。

兆瓦级高效紧凑型核动力系统运行特性研究

为研究兆瓦级高效紧凑型核动力系统的运行特性,使用自主开发的热管堆瞬态分析程序TAPIRS(Transient Analysis code for heat Pipe and AMTEC power conversion space Reactor power System)和超临界二氧化碳布雷顿循环的瞬态分析程序SCTRAN/CO_(2)(Super Critical reactors Transient Analysis code/Carbon Dioxide)的耦合程序对其反应性、负荷、冷却水温度和流量等扰动进行了开环动态响应分析,并据此进行了控制系统设计。在此基础上,对线性变负荷、阶梯式变负荷以及甩负荷这三种变负荷运行工况进行了计算分析。结果表明:该核动力系统的转速对扰动的变化较为敏感,需要加以控制;低负荷下旁通会使压缩机流量上升,需对压缩机流量加以控制;系统在控制方案下能以6%FP(Full Power)·min^(−1)的速度实现0%~100%的负荷变动,且可以在任意负荷水平下运行;甩负荷下系统的波动时间变长,但是仍可达到新的稳态进行工作,且各参数处于安全范围内。本研究可为新型核动力系统的概念设计提供参考。

数字经济发展水平对碳排放约束下农业生产效率的影响

提高碳排放约束下农业生产效率是推动我国现代农业高质量发展的重要动力。数字经济发展通过优化农业资源配置,促进农业绿色发展,提高农业生产效率。本研究利用2011—2021年我国30个省(直辖市、自治区,不包括香港地区、澳门地区、台湾地区和西藏)的面板数据测度区域数字经济发展水平与碳排放约束下农业生产效率。从产业结构视角出发,研究数字经济发展通过促进农村三产融合进而影响碳排放约束下农业生产效率的作用机制。将农村人力资本和农业科技创新作为调节变量,分析在其调节作用下,数字经济发展水平对碳排放约束下农业生产效率的影响。实证结果表明:1)总体而言,数字经济发展提高了我国碳排放约束下的农业生产效率,在一系列稳健性检验和内生性讨论后结论依然显著。2)中介效应分析表明,数字经济发展能够通过促进农村三产融合提高碳排放约束下的农业生产效率,其中数字经济发展水平对农业产业链延伸和农业多功能拓展具有显著促进作用。3)农业科技创新进步和农村人力资本水平提高强化了数字经济发展水平对碳约束下农业生产效率的促进作用。4)在我国农村三产融合非试点区、东部地区和粮食主产区,数字经济发展水平对碳排放约束下农业生产效率的提升效果更为显著。本研究从数字经济视角为提高我国碳排放约束下农业生产效率和助力现代农业高质量发展提供了政策启示。

新疆灌区农业节水发展现状与对策建议

水是新疆可持续发展的生命线,也是新疆农业发展的瓶颈。农业是新疆用水大户,占经济社会总用水量的90%以上,南疆农业用水占比更高。新疆节水潜力重点在农业,农业节水是新疆经济社会可持续发展的根本出路。为提高新疆农业水资源利用效率,促进农业高质量发展,本文梳理回顾了新疆灌区农业节水发展历程,分析了农业节水发展现状及存在问题,结合新时期国家对新疆农业发展的新定位、新要求,提出了大力发展适水型现代农业、加大高效节水工程建设、持续推进降盐节水、加强数字化灌区建设、加强农业节水宣传培训、健全农业节水服务体系等对策建议,以期为新疆现代农业可持续发展和保障国家粮棉油安全提供有力支撑。

“双碳”目标下黄河流域农业生态效率的动态演进与收敛特征

“双碳”目标下推进黄河流域农业生态效率提升,是推动实施黄河流域生态保护和高质量发展战略的重要途径。在农业减排固碳的发展要求下,以落实农业“双碳”目标为着力点,运用超效率SBM模型、Dagum基尼系数和收敛检验方法,测度2006-2021年黄河流域农业生态效率的时序演进、空间差异和收敛特征。结果表明:黄河流域农业生态效率整体呈波动上升趋势,但整体农业生态效率水平偏低,形成了“下游领跑、中游追赶、上游落后”的空间格局;黄河流域内农业生态效率差异逐渐扩大,差异主要源自超变密度,区域内差异由低到高依次为上游、下游和中游;黄河流域整体及上、中、下游的农业生态效率不存在σ收敛现象,但都存在显著的β绝对收敛和β条件收敛,种植业产值、机械化水平、农业产业集聚度、产业结构高级化水平等因素对β条件收敛的影响具有异质性。

铝熔炼炉排烟罩捕集性能分析及优化数值模拟

铝加工厂房熔炼工艺中高温烟尘散发强度大、浓度高,对建筑室内外环境和人员健康危害大。为提高铝熔炼炉局部排烟罩捕集效率,本文研究了排烟罩捕集效率与量纲一排风量(排烟罩排风量/烟尘散发量)的关系;基于消涡原理及气流卷吸特性,提出了排烟罩捕集性能优化方法。研究表明,当量纲一排风量小于3.2时,增大排风量会显著提升排烟罩的捕集效率,为风量经济区。排烟罩几何特征优化后,在风量经济区内烟尘逃逸率降低了20%左右,系统排风量降低了6.1%~44.1%。

中国农业农村高质量发展的时空特征、区域差异及影响因素

农业农村高质量发展是新时代中国经济社会高质量发展的基础支撑。采用核密度估计、莫兰指数和Dagum基尼系数分析2006-2020年30个省农业农村高质量发展水平、时空特征及区域差异,并运用地理探测器模型分析影响因素。研究发现:(1)中国农业农村发展质量稳步提升但区域差异显著,东部整体水平最高,西部增长速度最快。(2)空间上正相关性显著,多数省份处于HH区和LL区且无跃迁现象,时间上核密度估计曲线逐渐右移,西部地区省际差异趋于收敛,其余地区内部差异逐渐扩大。(3)基尼系数呈“U”型变化趋势,区域间差异为首要来源,分地区看,东-西部地区间发展差异最大,分维度看,创新及开放发展区域间差异最大。(4)农业农村高质量发展受科技创新、产业结构和金融支农水平等多因素共同影响。

中国农业低碳转型及驱动因素:基于空间面板模型的实证检验

低碳化是农业高质量发展的本质要求,如何测算农业低碳转型绩效并探测其主要驱动因素,对于加快推动中国农业高质量发展具有重要的理论意义.有鉴于此,基于1999-2021年中国269个城市的平衡面板数据,采用Meta-frontier DEA方法测度农业低碳转型绩效(碳排放效率),并在此基础上构建空间面板模型探究促进农业低碳转型的驱动因素.结果表明:中国农业全局碳排放效率远低于当期和跨期碳排放效率,主要是因为各省内部和各省间的碳排放效率差异较大.分区域来看,农业碳排放效率呈现东部、中部、西部和东北递减的特征.基准回归及稳健性检验结果表明,扩大土地经营规模、促进经济增长、加大财政支农力度和提高森林覆盖率均能够显著促进农业碳排放效率提升,其中扩大土地经营规模是主要驱动因子,而城镇化和农业科技投入尚未对农业低碳转型发挥正向支撑作用.