A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields

The geomagnetic fields, which play important roles in the ionospheric dynamo, can greatly affect the global distribution of ionospheric electric fields, currents and other ionospheric electrodynamics phenomena. In the study of ionospheric electrodynamics phenomena, such as the longitudinal variations of ionospheric electric fields, the non-dipolar component of the geomagnetic fields must be taken into account. In this paper, we deduce a theoretical electric field model for ionospheric dynamo at mid- and low-latitude which adopt a modified magnetic apex coordinates system. In the new electric field model, the geomagnetic fields can be calculated from either the IGRF model or the dipole field model, and the neutral winds and conductivities are calculated based on empirical models. Then the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method, and the ionospheric electric fields and currents are derived from the calculated potential. Our model can reproduce the main features of the ionospheric electrodynamics processes, so it will be a useful tool for the investigation of the upper atmosphere and ionosphere.     

高山松花菜栽培技术

松花菜又称散花菜。是十字花科甘蓝属花椰菜中的一个类型，因其蕾枝较长，花层较薄，花球充分膨大时形态不紧实，相对于普通花菜呈松散状，故此得名。与一般紧实型花菜品种相比，松花菜具有两个显著特点：一是耐煮性好，食味鲜美，很受消费者欢迎。二是早中熟品种耐热性强，适应性更广，近郊可“春延后”和“秋提前”栽培。高山栽培可在夏秋投产。     

小麦品种产量性状演变与预测的灰色系统分析

本文用灰色关联度分析的方法，对山东省及黄淮麦区不同时期种植的小麦品种产量性状的演变进行了分析，探讨了性状之间的变化态势的异同及相互影响的程度。用ＧＭ（１，１）模型对９０年代小麦产量及相关性状的发展趋势进行了预测。在此基础上，对制定科学合理的育种目标，明确育种的主攻方向，提高育种效率等问题进行了讨论了为小麦的遗传育种工作提供一定的参考信息。     

辣椒新品种——郑椒先锋辣椒

郑椒先锋辣椒是郑州市蔬菜研究所最新选育的中熟辣椒杂交新品种，是生产红、绿鲜椒的优良品种。     

剃齿时齿形中凹现象的形成机理

本文综合啮合原理、微分几何和弹性力学的基础理论,对剃齿过程中刀具齿面和被剃齿轮齿面间的失配进行了分析。最后利用径向力求出了齿面间的压切量,从而解释并验证了剃齿过程中产生的齿形中凹现象。这对提高剃齿精度、降低噪音有着重要意义。