Intergeneric hybrid between Brassica napus and Diplotaxis harra through ovary culture and the cytogenetic analysis of their progenies

Brassica napus (2n = 38) and Diplotaxis harra (2n = 26) were used to investigate gene transfer from D. harra to B. napus. Intergeneric F₁ hybrids (dihaploid 2n = 32 chromosomes) were obtained through ovary culture. The chromosome associations in the first meiotic division was (0–2)_III + (2–10)_II + (12–28)_I. Many seeds were harvested in the F₁ hybrid after backcrossing with B. napus, and from open pollination of the F₁ hybrid. Somatic chromosome numbers of BC₁ and hybrid plants varied from 2n = 26 to 52. In the first meiotic division, high frequencies of bivalent association and relatively low pollen fertility were observed. BC₂ plants generated from the BC₁ plants with 2n = 38 chromosomes, 69.6% showed 2n = 38 chromosomes. Many aneuploids with addition and deletion of chromosomes were also obtained. A bridge plant between B. napus and D. harra with 2n = 32 chromosomes should be valuable material for the breeding of brassica crops.     

辐照技术在储粮害虫防治中的应用

辐照杀虫是利用电离辐射与害虫的相互作用所产生的物理、化学和生物效应,导致害虫不育或死亡的一种物理防虫技术.用于辐照杀虫处理的射线主要是γ射线(60Co或137Cs)、10 MeV以下电子束以及5 MeV以下的X射线,其中钴源辐照杀虫产业化发展迅速,电子束和X射线辐照发展相对滞后,随着近年来加速器技术的进步,电子束辐照杀虫显示出独特的优势,并受到越来越广泛的重视.辐照对不同储粮害虫、同一种储粮害虫的不同发育时期和性别有着不同的生物学效应,总体来看储粮害虫对辐照较为敏感:不同害虫的辐射敏感性顺序为:鞘翅目＞蜱螨目＞鳞翅目;同种害虫不同虫态的敏感性顺序为:卵、幼虫＞蛹＞成虫;雌性害虫的敏感性大于雄性害虫.粮食辐照杀虫工艺流程一般包括:辐照前处理、虫情调查、剂量决策、辐照处理、辐照后管理和重复辐照等几个部分.在辐照杀虫的工艺剂量(0.3～0.5 kGy)条件下,辐照对粮食的食用品质和功能特性没有影响,辐照后的粮食也不存在卫生安全性问题.因此,辐照杀虫技术作为一种安全有效的储粮害虫防治手段,是储粮化学药剂的一种重要补充和替代,在储粮害虫防治领域有着巨大的市场前景.     

Analysis of Heat Transfer and Optimal Parameters of Multi-louvered Fin Condenser

The authors conduct the experimental study and optimal computing for the condenser of automobile air conditioner. The especially the properties of heat transfer and flow at the side of air when using shutter fin. The authors the influence of several combinations of fin's geometry parameter to heat transfer and flow resistance. The maximal heat transfer is used as a criterion relation to select the fin's geometry parameters in the same facing air area of condenser. Furthermore, a program is designed to conduct optimal computing, and the computing results are basically consistent with experimental results. It shows that the optimal method is reasonable and the results can be applied to engineering practice.     

Dropwise Condensation Heat Transfer Coefficient on the Horizontal Circular Surface with Radial Gradient Surface Energy

A theoretical model is developed for the dropwise condensation heat transfer on the horizontal circular surface with radial gradient surface energy based on the heat transfer model of individual condensate drop and the size distribution model of condensate drop on homogeneous condensation surface.The effect of variation of contact angle on the gradient surface on condensation heat transfer and condensate drop size distribution is taken account of in this model.The theoretical calculation method was obtained to predict the dropwise condensation heat transfer coefficient on the horizontal circular surface with radial gradient surface energy under various wall subcooled temperature,contact angle profile on wall surface,and working fluid.The effects of surface energy gradient,wall subcooled temperature,and thermophysical properties of condensate on the condensation heat transfer are discussed respectively.The calculation results show that the condensation heat transfer coefficient increases slightly with the increase of wall subcooled temperature.As latent heat and surface tension increasing,the condensation heat transfer coefficient increases.A larger surface energy gradient induces a larger condensation heat transfer coefficient.     

Performance Simulation of EHE for 300MW CFB

With the development of circulating fluidized bed boiler(CFB),the study field of external heat exchanger(EHE) is greater in extent and degree.In order to research the working process of EHE,the model which deals with flow and heat transfer of EHE for 300MW CFB of Dong Fang Boiler Grou PCo.Ltd.is presented.Based on the cell modeling theory,the EHE is divided into several chamber by heating surfaces.The mass and energy conservation equations of each cell have been developed according to some reasonable assumption.The complete mathematical model has been compiled by Fortran and solved by classical Algorithm of Runge-Kutta.The static test and perturbation experiment of simulating model has been performed.The simulation results show that the model has been reached the steady state rapidly,the dynamic responses are reasonable and the modeling presented in the paper is reliable and appropriate.     

The Staged Simulation Method for Power Electronics Circuits

This paper in troduces a staged simulation method fur power electronics circuits,presents an exampleued the method for the CSI/IM drive system.