鲐鱼灯光围网渔船合适作业间距的初步研究

使用点光源海面照度计算方法,对一组鲐鱼（Scomber japonicus）灯光围网渔船（主灯船、副灯船网、网船的集鱼灯总功率分别为180 kW、120 kW和40 kW）的有效光诱距离和合适作业间距进行计算。结果表明,适宜照度为0.01 lx时围网渔船的有效光诱距离为872.0 m,主灯船与副灯船之间的最小作业距离为1 650.4 m,副灯船与网船之间的最小作业距离为1 585.7 m,主灯船与网船之间的最小作业距离为1 669.7 m,2个灯光围网渔船船组间的合适作业距离为1 744.0 m;适宜照度为14.00 lx时围网渔船的有效光诱距离为138.3 m,主灯船与副灯船之间的最小作业距离为262.9 m,副灯船与网船之间的最小作业距离为249.4 m,主灯船与网船之间的最小作业距离为263.1 m,2个灯光围网渔船船组间的合适作业距离为276.6 m。     

基于改进Huffman编码的农机作业数据传输压缩方法

为解决通讯环境较差的农业机械作业状态数据的传输难题,该文提出了基于改进Huffman编码技术的数据压缩方法实现数据的压缩、传输、解析与解压。数据压缩与解压测试的结果表明,数据采集周期为5 s、数据长度为918.38 kb时,基于改进Huffman算法压缩的数据长度为412.56 kb,同样条件下对比传统Huffman算法压缩的数据长度498.56 kb小86 kb,压缩率从传统Huffman算法的45.71%提升至改进Huffman算法的55.08%;传统Huffman算法中数据传输出错率和数据传输丢包率为2.47%和4.18%,而在同样传输要求下的筛选压缩传输中数据传输出错率和数据传输丢包率降至2.06%和0.78%。该方法能满足农业机械作业状态数据压缩传输要求,在单个数据包数据较少、传输时间短的压缩传输方式下能够获得较低的传输出错率和丢包率,且该方法具有计算量少、压缩效率较高特点,适合在农业机械作业区域进行数据传输。     

管道不满流对装船计量的影响

南输成品油管道(抚顺至鲅鱼圈新港)末站油库装船管道经过翻越点后出现不满流管段,影响了末站装船计量的准确性。根据装船管道管路特征及运行工况,结合实际生产数据,对不满流管段运行状态进行了描述,分析了不满流管段对装船差量影响的原因,提出了解决差量问题的具体措施。     

Performance of small harvester head in a thinning operation

Medium to large size harvester heads mounted on large machines are popular in Japan. These machines encounter some problems during thinning operations,e.g. damage to residual stand and the compaction of soil. The performance of these large harvesters was compared with that of smaller ones operating simultaneously in the same line thinning operation of the same stand. The results of a time study showed that mean cycle times for the smaller and larger harvesters were not significantly different. This means that the work efficiency of the smaller harvester can be at the same level as the larger harvester on sites similar to those of this study. The mean values “Feed” element of the cycle time, however, were significantly different. Although this time difference appears to provide an advantage to the larger harvester, simulation results show that the advantage is not great enough to significantly shorten the total cycle times. That is to say, the work efficiency remains essentially the same even if the feeding performance of the small size harvester becomes as high as that of larger ones. The small harvester performs adequately in thinning operations, and is not inferior to the larger ones. This result indicates that there is economic potential for small base machines that can be mounted with small harvester heads, resulting in less damage to residual trees and site soils during thinning operation. A part of this paper was orally presented at the 109th Annual Meeting of the Japanese Forestry Society (1998). The time study research presented in this paper was supported by the National Federation of Logging Contractors Cooperative Associations.     

白云山水库调度管理系统设计与开发

根据水电站的运行特点,以白云山水库为对象,设计开发了水库调度管理系统。系统总体结构由基本数据库、原始数据库、中间数据库、结果数据库等四部分组成。可完成水库兴利调度、洪水预报调度、数据常规处理、数据资料管理等功能。对以上结构和功能做了详细介绍。     

宅基地退出加剧了农村劳动力非农转移吗?——来自安徽省金寨县农户的证据

基于宅基地退出试点区安徽省金寨县626户农户的微观调研数据,系统考察宅基地退出是否加剧了农村劳动力非农转移?结果表明:宅基地退出对农村劳动力非农转移有显著正向影响,在利用倾向得分匹配法和处理效应模型纠正选择性偏误后,所得结果依然稳健;基于中介效应模型的分析表明,宅基地退出通过提高农业经营成本、增加家庭负债和提升外出务工...     

收储制度改革提高粮食加工企业经营效益了吗?——基于全国17省176家粮食加工企业的调查数据

为探究粮食收储制度对粮食加工企业经营效益的影响,基于2013-2016年全国17省176家粮食加工企业的调查数据,从产权属性和规模两个维度对比分析不同类型粮食加工企业在经营效益上的差异.结果 表明:多元市场主体对粮食加工企业的生产经营效益产生了显著影响,通过价格传导机制抬高原料粮价格,最终导致粮食加工企业收益减少;面对...     

Construction of Transgenic Crop Germplasm Effective Function and Characteristic Analysis

Germplasm effect reflects the quantitative relation between production ability of germplasm elements and yield （quality） of a certain crop, which can be shown by mathematic function, namely, germplasm effect function. Germplasm effect of a crop variety is an aggregation of many effective factors, and is restrained by different effective factors; constant increase of any one effect of germplasm elements would lead to law of effect decline, therefore, possible modes of transgenic crops effect function were deduced according to the law of effect decline. The possible modes of single transgenic germplasm effect function and multi-transgenic germplasm effect regression equation were discussed, and the characteristics of germplasm effect regression equation were analyzed in this paper.     

新型低压高效精米机组研发

针对当前精米加工普遍采用强力碾削的现状,指出“过碾”是导致“出米率”低和电耗高的原因。新型低压高效精米机组,采用全程低压碾米技术,符合现代精米加工“多机轻碾”工艺要求,实现真正内因致导型低温升碾米。在核心主机铁辊米机设计中,采用独特的大长径比榄形铁辊和锥台型碾白室构造,将碾白室内部压力分段设定为摩擦碾白、擦离抛光和擦离刷亮所对应的压力范围,以实现碾、抛、刷综合精碾功能。新型低压精米机组具有增碎率低、糙出白率高、动力消耗低和制得精米表面质量好等特点,尤其适合于南方稻产区的籼稻与杂交稻加工。     

单轨制与多元化农业科技成果转化运行机制利弊分析

随着经济体制的变革,农业科技成果转化运行机制发生了从单轨制农业科技成果转化运行机制向政府主导的多元化农业成果转化运行机制的转变。文章从不同方面对两种农业科技成果转化运行机制的利弊进行了分析。