Comprehensive Performance Evaluation of Family Farms from the Perspective of Land Transfer——Taking Rudong County as an Example

With the reform of agriculture, family farms have become hot spots in the reform of agricultural management system. Taking Rudong County of Jiangsu Province for an example, the land transfer performance of family farms was evalu- ated using the first hand data from field investigation by building an index system for comprehensive performance evaluation of family farm land transfer covering three dimensions of economy, society and ecology. The results show that land transfer in family farm mode has realized the scale management of land, enhanced the agri- cultural level of science and technology, effectively promoted the structural adjust- ment of agriculture and income increase of farmers, advanced the development of eco-agriculture, and achieved good economic and social performances. However, in the development process of family farms, inputs of agro-chemicals, fertilizers and other agro-products have brought about the eco-environmental problems, which are still worth noting.

Tradeoff Analysis of Factors Affecting Longitudinal Carrier Landing Performance for Small UAV Based on Backstepping Controller

Tradeoff analysis of the factors,including external environment and unmanned aerial vehicle(UAV)aerodynamic attributes,which affect longitudinal carrier landing performance,is important for small UAV.First,small UAV longitudinal carrier landing system is established,as well as the nonlinear dynamics and kinematics model,and then the longitudinal flight control system using backstepping technology with minimum information about the aerodynamic is designed.To assess the landing performance,a variety of influencing factors are considered,resulting in the constraints of aerodynamic attributes of carrier UAV.The simulation results show that the severe sea condition has the greatest influence on landing dispersion,while air wake is the primary factor on impact velocity.Among the longitudinal aerodynamic parameters,the lift curve slope is the most important factor affecting the landing performance,and increasing lift curve slope can improve the landing performance significantly.A better system performance will be achieved when the lift curve slope is larger than 2per radian.

Statistical Analysis of Studies on Performance Appraisal of China's Land Consolidation

We take the papers,on performance appraisal of land consolidation ( including land consolidation benefits,etc. ) published in the core journals in the Chinese Journal Full-text Database,as the study samples; conduct analysis in terms of the number of papers,the paper source journals,the impact of papers,research methods,research topics,and foundation project for research,through literature search and statistical analysis. The results show that the related scholars pay more and more attention to the study on the performance appraisal of land consolidation, and the number of papers increases overall; the core journals on agriculture,land,environment,economy and other areas,put increasing emphasis on the publishing of papers concerning the performance appraisal of land consolidation; in terms of citation frequency of papers,the impact of papers is wide,but the depth is not enough; the research methods are increasingly diversifying,and the research topics are concentrated; the foundation support is yet to be strengthened for research.

Dynamic model and performance analysis of landing buffer for bionic locust mechanism

The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed.Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance,and it establishes a theoretical basis for studies and engineering applications.

A Study on Theoretical Model and Applied Evaluation of Land Use Performance of High-tech Zone in Urban Fringe: A Case Study in Haidian District, Beijing

High-tech industrial zone is an important carrier for constructing innovative cities. It also plays an important role in implementing the national independent innovative strategy. How-ever, most of the high-tech industrial zones have many problems in their development process, such as efficiency of land use, weakness of oriented function and lack of land intensive. To solve these problems, the authors of this paper introduced the concept of land use performance and established the theoretical model to assess the land use performance of high-tech industrial zones. The model consists of the following three-dimensional parts: land use benefit, land use efficiency and innovative function. Based on this theory model, an index system which was composed of three secondary indictors, eight tertiary indictors and 37 fourth-grade indictors was set up to evaluate the land use performance of high-tech zone. To avoid the defects of plus model and function model, the authors brought out a three-dimensional evaluation model to examine the index of the land use performance of the high-tech industrial parks, which equals to the evaluation indicator system of land use performance of high-tech zone based on the above research. The authors examined the land use performance of five different high-tech industrial parks in Haidian District, Beijing City. The results indicated that the indicator system per-forms better in the aspect of evaluating land use benefit, land use efficiency and function of the high-tech industrial zone compared with other models.

Production Performance of Different Varieties of Oat A vena sativa) in Winter Dry Land of Hunan

The phenological phase, plant height, filler number, nutritional composition, yield and stem/leaf ratio of three oat （Arena sativa） varieties （lines） in winter dry land of Hunan were studied. The result shows that the three oat varieties were greatly different in plant height, nutritional composition, yield and stem/leaf ratio. Baiyan 7 had the best performance, with the plant height, tiller number and fresh yield of 101.67cm, 7.6 tiller/plant and 70.15 t/hm2 respectively ; the crude protein content of dry matter of Baiyan 7 was 32.63% ; the leaf weight per tiller of Baiyan 7 accounted for 31.6% of single tiller weight, while those of Baiyan 8 and Baiyan 2 accounted for 31.3% and 29.2%, respectively. The single tiller weight of oat could be estimated/calculated by the model/formula Y = 0.043 7X - 2.89 （ R2 = 0.913 4, P 〈 0.01 ）, where Y is the single tiller weight （ g ） and X is the plant height （cm）. Comprehensive analysis showed that Baiyan 7 had higher yields and stem/leaf ratio. Thus, Baiyan 7 is more suitable for planting as a winter-spring forage in the winter dry land of Hunan.

Performance Evaluation of Land Use Regulation

This article makes a quantitative study on economic performance of arable land protection and land use regulation with dummy variable model.It is shown that land use regulation is favorable for economic growth and protection of arable land and that there are still some problems in the implementation of land use regulation.Thus,it puts forward corresponding suggestion.

Impacts of Changes in Structure of Rural Land Property Rights on Agricultural Performance

In the reform process of the rural land property rights system,the incentive mechanism of the rural land property rights system has a crucial impact on the production activities of rural economic entities.Due to the different rights structures of the property rights system in different social and economic development stages,the land rights and interests enjoyed by rural economic subjects are different,and the degree of incentives for farmers is also different.This difference in incentives affects farmers investment in agricultural production factors,which in turn affects agricultural performance.This paper analyzes the incentive impacts of the structure of rural land property rights on the changes of farmers land rights and agricultural performance since the founding of the People s Republic of China,in order to further deepen the reform of the land system,protect the rights and interests of farmers,promote the modernization of agriculture and rural areas,and explore the realization form and operation mechanism of the rural collective land system in the new era.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

Performance evaluation of ecological compensation policy for cultivated land in China

The paper evaluates the changes in the ecological environment of cultivated land in the major crop-producing areas major crop-producing areas in the past 20 years by constructing an ecological pollution index;and quantitatively analyzes the effects of the existing policies and their main influencing factors by applying the PSM-DID method based on the frequency of policy enactment.The results are as follows:first,the existing ecological compensation policies for cultivated land are effective but not significant in improving the ecological environment in the major crop-producing areas.The economic development level and grain cultivation area of the major crop-producing areas are significantly and positively correlated with the improvement of the arable land ecological environment,while the level of agricultural infrastructure construction is significantly and negatively correlated with the improvement of the arable land ecological environment.Second,the reason for the ineffectiveness of the current arable ecological land compensation policy in protecting the arable land ecological environment in the main grain-producing regions is that the existing arable ecological land compensation policy in China has its own institutional defects and needs to be further improved.At the same time,the level of environmental pollution of cultivated land in the main grain-producing regions is positively correlated with the level of income from cultivated land and cultivated area.

Performance Analysis of Techniques Used for Determining Land Mines

Today, remote sensing is used for different methods and different purposes. In all of the detection methods, some considerations such as low energy consumption, low cost, insensitivity to environmental changes, high accuracy, high reliability and robustness become important. Taking into account these facts, remote sensing methods are used in applications such as geological and archeological research, engineering areas, health services, preserving and controlling natural life, determination of underground sources, controlling air, sea and road traffic, military applications, etc. The method to be used is based on the object type to be detected, material to be made, and location to be found. The remote sensing methods from the past up to today can be listed as acoustic and seismic, ground penetration radar (GPR) detection, electromagnetic induction, infrared (IR) imaging, neutron quadrupole resonance (NQR), thermal neutron activation (TNA), neutron back scattering, X-ray back scattering, and magnetic anomaly detection. In these methods, detected raw images have to be processed, filtered and enhanced. In order to achieve these operations, some algorithms are needed to be developed. In this study, the methods used in detecting land mines remotely and their performance analysis have been given. In this way, the last situation on the advantages and disadvantages of methods used, application areas and detection accuracies are determined. Furthermore, the algorithms such as transmission line matrix (TLM), finite difference time-domain (FDTD), the method of moment (MoM), split step parabolic equation (SSPE) and image processing and intelligent algorithms are presented in detail.

Yield performance and optimal nitrogen and phosphorus application rates in wheat and faba bean intercropping

Yield performance in cereal and legume intercropping is related to nutrient management,however,the yield response of companion crops to nitrogen(N)input is inconclusive and only limited efforts have focused on rationed phosphorous(P)fertilization.In this study,two multi-year field experiments were implemented from 2014-2019 under identical conditions.Two factors in a randomized complete block design were adopted in both experiments.In field experiment 1,the two factors included three planting patterns(mono-cropped wheat(MW),mono-cropped faba bean(MF),and wheat and faba bean intercropping(W//F))and four N application rates(N0,0 kg N ha^(-1);N1,90 and 45 kg N ha^(-1) for wheat and faba beans,respectively;N2,180 and 90 kg N ha^(-1) for wheat and faba beans,respectively;and N3,270 and 135 kg N ha^(-1) for wheat and faba beans,respectively).In field experiment 2,the two factors included three P application rates(P0,0 kg P_(2)O_(5) ha^(-1);P1,45 kg P_(2)O_(5) ha^(-1);and P2,90 kg P_(2)O_(5) ha^(-1))and the same three planting patterns(MW,MF,and W//F).The yield performances of inter-and mono-cropped wheat and faba beans under different N and P application rates were analyzed and the optimal N and P rates for intercropped wheat(IW)and MW were estimated.The results revealed that intercropping favored wheat yield and was adverse to faba bean yield.Wheat yield increased by 18-26%,but faba bean yield decreased by 5-21% in W//F compared to MW and MF,respectively.The stimulated IW yield drove the yield advantage in W//F with an average land equivalent ratio(LER)of 1.12.N and P fertilization benefited IW yield,but reduced intercropped faba bean(IF)yield.Nevertheless,the partial LER of wheat(pLER_(wheat))decreased with increasing N application rates,and the partial LER of faba bean(pLER_(faba bean))decreased with increasing P application rates.Thus,LER decreased as N input increased and tended to decline as P rates increased.IW maintained a similar yield as MW,even under reduced 40-50% N fertilizer and 30-40% P fertilizer conditions.The estimated optimum N application rates for IW and MW were 150 and 168 kg ha^(-1),respectively,and 63 and 62 kg ha^(-1) for P_(2)O_(5),respectively.In conclusion,W//F exhibited yield advantages due to stimulated IW yield,but the intercropping yield benefit decreased as N and P inputs increased.Thus,it was concluded that modulated N and P rates could maximize the economic and ecological functions of intercropping.Based on the results,rates of 150 kg N ha^(-1) and 60 kg P_(2)O_(5) ha^(-1) are recommended for IW production in southwestern China and places with similar conditions.

The Performance of Atmospheric Component Model R42L9 of GOALS/LASG

This paper examines the performance of an atmospheric general circulation model (AGCM) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics (LASG/IAP). It is a spectral model truncated at R42(2.8125°long×1.66°lat) resolution and with nine vertical levels, and referred to as R42L9/LASG hereafter. It is also the new version of atmospheric component model R15L9 of the global ocean-atmosphere-land system (GOALS/LASG). A 40-year simulation in which the model is forced with the climatological monthly mean sea surface temperature is compared with the 40-year (1958-97) U.S. National Center for Environmental Prediction (NGEP) global reanalysis and the 22-year (1979-2000) Xie-Arkin monthly precipitation climatology. The mean DJF and JJA geographical distributions of precipitation, sea level pressure, 500-hPa geopotential height, 850-hPa and 200-hPa zonal wind, and other fields averaged for the last 30-year integration of the R42L9 model are analyzed. Results show that the model reproduces well the observed basic patterns, particularly precipitation over the East Asian region. Comparing the new model with R15L9/LASG, the old version with coarse resolution (nearly 7.5°long×4.5°lat), shows an obvious improvement in the simulation of regional climate, especially precipitation. The weaknesses in simulation and future improvements of the model are also discussed.

Government-oriented Land Circulation from the Perspective of Social Governance

This paper firstly summed up institutional change of land circulation after the foundation of new China,analyzed main characteristics and internal drawbacks of government-oriented land circulation,discussed the governance cost of local government-oriented land circulation,and evaluated the governance performance on the basis of the transaction cost theory. Results show that local government-oriented land circulation is a resource allocation mode for maximizing benefits of an organization,and its microscopic functions and values are mainly encouragement and restriction,while its macroscopic functions are comprehensive administration of results of state policies. Finally,it put forward policy suggestions for improving local government-oriented land circulation: cultivating diversified rural land circulation modes and regulating acts of local officials; stressing that building harmonious land circulation mechanism is the responsibility of central government; setting up recognition mechanism of the public to local government.

Evaluation of Four Geomembrane-Mounted PV Systems for Land Reclamation in Southern Arizona

Four different PV （photovoltaic） systems deployed around Tucson Arizona on geomembranes are used to test the feasibility of converting mine tailings and landfills into solar energy generating sites. Differences between these deployed systems include： two types of geomembrane materials, two different module anatomies and two different locations. Module mounting techniques unique to mine tailing sites are described. Several system failures observed during the first two years of operation are explained here in detail. Validated predictions for the operating temperature of these systems and their associated electrical performance are presented. It was determined that PV modules mounted on light-colored thermoplastic with shielded wiring operate at lower temperatures, are structurally stable, and experience fewer wiring failures.

宁夏盐碱地饲用小黑麦品种(系)生产性能及营养品质综合评价

【目的】筛选适合宁夏盐碱地种植的优质高产小黑麦(Triticosecale wittmack)品种(系)。【方法】2021年在宁夏石嘴山市惠农区开展晋饲草1号、冀饲草1号、鉴47、鉴46、优能、普瑞、冀饲3号、石大1号、中饲1048和甘农2号共10个品种(系)小黑麦的适应性研究,并利用主成分分析(PCA)对其农艺性状、生产性能及营养成分等指标进行综合评价。【结果】所有供试饲用小黑麦品种(系)均能在宁夏盐碱地安全越冬并完成生育期。晋饲草1号株高、分蘖数和干草产量最突出,分别达131.11 cm、4.40个和9.34 t/hm 2;冀饲3号和晋饲草1号粗蛋白含量较高,分别为9.95%和9.86%;冀饲3号的相对饲喂价值最高,为94.25。聚类分析结果表明,10个饲用小黑麦品种(系)可以分为3个类群,第Ⅰ类群为普瑞和优能,第Ⅱ类群为甘农2号、中饲1048和鉴47,第Ⅲ类群为晋饲草1号、冀饲3号、冀饲草1号、鉴46和石大1号。主成分分析结果显示,综合得分排名前三的小黑麦品种(系)为冀饲3号、晋饲草1号和石大1号。【结论】冀饲3号、晋饲草1号和石大1号均可在宁夏盐碱地大面积推广种植。

农地确权与农户政治信任:基于中央和基层组织的分析

农地确权的经济影响效应受到了学界的广泛关注,但鲜有研究关注农地确权政策的政治效应。基于3期农地确权追踪调查数据,利用广义DID模型评估农地确权对农户政治信任水平的影响。结果表明:农地确权使农户的中央级政治信任、村级政治信任分别提升0.142个单位和0.215个单位。上述结果在考虑平行趋势、样本随机性、控制潜在遗漏变量、替换被解释变量、更换计量模型后依然稳健。机制分析表明,农地确权通过降低地权权益的保护成本、提升盘活农地产权收益两条途径对农户政治信任产生影响。进一步分析显示:农地确权执行规范程度越高,不影响农户的中央级政治信任,但会显著提升农户的村级政治信任水平。由此认为,农地确权除产生经济影响外,也是政府投资农户政治信任的有效途径。

宅基地退出绩效:评价体系、实证分析与提升路径——基于东中西部典型试点区域的全景式考察

研究目的:明晰宅基地退出绩效目标,构建评价体系,对典型试点区域宅基地退出绩效进行实证分析,探寻宅基地退出绩效提升路径。研究方法:质性研究方法与政策绩效评价工具方法的综合运用。研究结果:宅基地退出绩效目标主要由中央政策目标和地方政府、村集体、退出农户的利益诉求构成;回应绩效目标,基于政府绩效管理理论,引入利益相关者理论,并嵌入乡村韧性理论,构建了从过程到结果、兼顾多维利益诉求、考虑长短期变化的宅基地退出绩效评价体系;通过实证考察和评价分析发现,义乌、余江、泸县的宅基地退出绩效总体表现良好,但主要在经济韧性上存在短板,面临着资金紧张、主体乏力、盘活再利用受限等困境。研究结论:全面提升宅基地退出绩效,关键要在宅基地“三权分置”改革统领下,通过优化退出资金运作模式、形成多主体共治局面、拓宽退出土地盘活路径等,健全宅基地退出长效激励机制与保障机制。

辣椒漂盘苗机械化移栽适应性研究

为了探索辣椒漂盘苗对机械化移栽的适应性,以贵州某辣椒基地所育适栽期辣椒漂盘苗和2ZB-2旱地吊杯鸭嘴式移栽机为测试对象,完成了辣椒苗形态特征参数测量、落苗基质损失及田间机械栽植的试验研究。结果表明:从辣椒苗的苗高、叶面展幅、基质情况来看,所育漂盘苗基质饱满,且适于膜上移栽常用的鸭嘴式栽植器;漂盘苗基质含水率在56.4%~63.5%时,利于机械移栽的基质保持;田间机械移栽的栽植深度合格率、漏栽率、伤苗率分别为76.7%、2.4%、3.2%,满足指标要求;直立度合格率为88.7%,低于93%的指标下限。总体来说,辣椒漂盘苗与移栽机适应性较好,基本能达到贵州辣椒机械化栽植作业要求。

舰载机前起落架缓冲性能参数敏感性研究

为了同时满足缓冲和突伸性能,舰载机前起落架常采用双腔缓冲器设计。以某型机前起落架为研究对象,建立前起落架缓冲性能分析动力学模型,并将仿真计算结果与试验结果进行验证对比,验证理论模型的有效性和正确性。对缓冲器高、低压腔初始压力以及体积占比进行参数敏感性分析。结果表明,高、低压腔初始充填压力和体积占比对起落架缓冲性能的影响有别于它们对突伸性能的影响,所以对舰载机前起落架缓冲器的设计需不断优化,同时兼顾缓冲和突伸性能。