昆虫病原线虫生物防控草地贪夜蛾的室内及田间效果和影响因素

联合国粮食及农业组织2018年向全球发布草地贪夜蛾Spodoptera frugiperda是重要的预警害虫。据报道,2019年我国已有26个省（区、市）的作物受到草地贪夜蛾为害。目前已经发现草地贪夜蛾幼虫对某些化学农药产生抗性的现象,为缓解其抗药性产生,具有主动寻找寄主害虫的昆虫病原线虫为草地贪夜蛾的生物防治提供了应用潜能。该文从昆虫病原线虫高效侵染种（品系）及其浓度、共生菌、草地贪夜蛾幼虫易感龄期、田间致死力及影响防控效果的因素等方面进行综述,以期为田间有效利用昆虫病原线虫防治草地贪夜蛾提供参考。     

耕作方式对豫西旱地麦-豆轮作田土壤理化特性和酶活性的影响

为探明耕作方式对豫西旱地麦-豆轮作田不同土层土壤理化特性和土壤酶活性的影响,设置免耕(NT)、旋耕(RT)和翻耕(PT)3种耕作方式,分析了定位试验9 a(2009—2019年)后小麦收获期的土壤容重、孔隙度和有机质、全氮、有效磷和速效钾含量,以及土壤脲酶、蛋白酶、转化酶和碱性磷酸酶活性,并运用相关分析和通径分析研究了土壤理化性质与土壤酶活性的关系。结果表明：不同耕作方式对土壤理化特性和酶活性具有显著的调控作用,其调控效应与其作业深度相关。RT较PT有利于降低0～15 cm土层但增加15～35 cm土层容重,NT较RT和PT显著降低了0～5、15～35、35～60 cm土层的土壤容重,土壤孔隙度变化规律与容重相反。各处理间土壤有机质、全氮、有效磷含量以及土壤脲酶、蛋白酶、转化酶和碱性磷酸酶活性在0～5 cm土层和15～35 cm土层规律一致,0～5 cm土层均以NT最优,分别较最低值处理(PT)显著提高16.7%、53.2%、15.9%、23.6%、18.0%、34.7%和29.0%;15～35 cm土层均以PT最优,分别较最低值处理(NT)显著提高18.3%、23.4%、53.4%、...     

干旱区小麦多功能高分子植物生长调节剂增产和品质改善试验研究

以观测记录和拍照方式研究多功能高分子植物生长调节剂对小麦生长和繁殖、品质的影响,分别用土壤含水量为试剂保水指标,小麦生长、结实和产量指标、小麦品质指标以及经济效益指标与对照比较以评定试验效果。结果显示,施用试剂能够提高土壤保水率,有利于小麦的营养和结实生长,使小麦产量提高12.30%。小麦粗蛋白、赖氨酸和湿面筋含量均有显著提升,不利于人体健康的灰分和粗脂肪含量显著降低;经济效益有所提高,仅仅考虑增产就净增产值734.25￣794.85元/hm2。     

VISAR Data Reducing Method and Its Application to Impact Experiment

Identification and adjustment on the disfigurements of original data of VISAR are probed by developing software for VISAR data reducing based on measure theory. Then the software is applied to plate impact experiment of ceramics. The disfigurements of light intensity data are identified and adjusted through Lissajou~ figures. The results indicate that VISAR data are reduced quickly and effectively by the software, and the exact free surface velocity history is obtained.     

Physical simulation of fluid field and structure optimization in two-strand tundish

The influence of the structure and location of dam and weir on fluid flow state in a two-strand tundish is studied, and a set of optimal structure, combining with the average residence time calculated from RTD curve, is obtained. The result indicates that the fluid flow state can be changed and the path of the fluid flow can be prolonged as well as the average residence time is improved after using dam and weir. But there are some dead zones after fluid passed through the dam and weir. Combination scheme of No. one dam and weir is better than the others. Its average residence time is 299 s and the volume fraction of dead zone is 31.0%. After the optimization of flowing control parameters in tundish, the best case is that the distance between dam and weir is 290 mm and the distance between weir and the long nozzle is 383 mm. The longest average residence time is 351 s and the minimum volume fraction of dead zone is 19.0% under the above situation. Compared with that of no dam and weir, the average residence time increases by 65 s and the dead zone volume fraction decreases by 15.0%. Based on Newton formula, the calculated results show that the inclusions with diameter larger than 17.5 μm can float up within 351 s under this optimization situation.     

Experiment for Condensing Heat Transfer Performance in a New Type of Horizontal Three Dimensional Inner Microfin Tubes

A new type of three dimenstional inner microfin tube is devoloped. Under four different pressures and in the range of condensing mass velocities from 33 to 153 kg/m2 . s,and by the experimental study of the three kinds of tubes with different microfin parameters, the performances of the condensation heat transfer for R11 in the horizontal microfin tubes and obtained. The experiments show that the inner microfin tube is a hopeful and nighty effective condensing heat transfer enhancement tube.     

Solution the Polarization Field Strength inside Ellipsoid in a Homogeneous Dielectric

The solution of polarization field strength in ellipsoid and a homogeneous dielectric in condition of a constant external field is obtained with strict derivation and ellipsoidal coordinate. The conclusion that some textbooks given: the direction of polarization field strength with the direction of external field holds strict anti-parallel must be supplemented with additive certain conditions, otherwise it will not be correct. By means of the latticework and the step change calculation, the angle value of polarization vector with the external field is calculated and the changing situation about the angle value with the change of three half axes of ellipsoid is analysied.     

A Receiving Surface of Perturbative Photon Fluxes in Interaction Between Gravitational Waves and EM Fields

According to Electrodynamics in curved spacetime, the interaction between gravitational waves (GW) and electromagnetic (EM) fields will produce perturbative electromagnetic fields. In a special EM system, namely, a Gaussian beam (Gb) propagating through a static magnetic field, the photon flux along the direction of the electric field of the Gb will be only a pure perturbative photon flux,when a GW propagates along the symmetric axis of a Gaussian beam. Detailed alanysis and calculation of the photon flux along several typical surfaces are performed, and a possible optimum plane which can receive perturbative photons up to 10~4s~(-1) is proposed. It is possible to provide an important method to detection of GW.     

THREE CRITICAL POINTS THEOREM AND ITS APPLICATIONS

In this paper, by use of the pseudo-gradient vector field, the three critical points theorem in [2] is extended to the C1 function in the Ba-nach space, and therefore the three critical, points theorem in [5] is strengthened and the existence of the saddle point of the C2 function is discussed.