对光周期敏感雄性核不育水稻的初步研究——修饰基因对光敏感雄性不育后代表现型值的影响

利用人工控制光周期程序(简称SPAC)处理或在北京自然长日下栽培,考察了15个群体的自交结实率和正常花粉率频率分布,得到了如下结果。 1.F_1的育性正常。F_1群体的表现型值呈双峰连续分布。分离出1个无法准确划分的“败育群”;2.在F_2的“败育群”或农垦58原种S群体内,雄性彻底败育的个体只是少数,其余多数个体败育不完全,表现型值各不相同,在低值端呈连续分布;3.由F_1选出的光敏感雄性不育单株繁衍来的F_4家系群体,其表现型值依然分离,在低值端呈连续分布。雄性完全败育个体的比例在各家系、株系、甚至同一株系内的植株间存在差别;4.仅F_4家系群体中的1个株系。农垦58S或鄂宜105S群体内表现型值基本一致,雄性彻底败育了。作者认为,连续分布是水稻光敏感雄性不育初级群体表现型值分布的普遍形式。它多半产生于修饰基因分离、重组造成的基因型值的连续变异。

Surface diurnal warming in the East China Sea derived from satellite remote sensing

Process of sea surface diurnal warming has drawn a lot of attention in recent years, but that occurs in shelf seas was rarely addressed. In the present work, surface diurnal warming strength in the East China Sea was calculated by the sea surface temperature(SST) data derived from the MODIS sensors carried by the satellites Aqua and Terra. Due to transit time difference, both the number of valid data and the surface diurnal warming strength computed by the MODIS-Aqua data are relatively larger than Terra. Therefore, the 10-year MODIS-Aqua data from 2005 to 2014 were used to analyze the monthly variability of the surface diurnal warming. Generally, the surface diurnal warming in the East China sea is stronger in summer and autumn but weaker in winter and spring, while it shows different peaks in different regions. Large events with ΔT≥5 K have also been discussed. They were found mainly in coastal area, especially near the Changjiang(Yangtze) River estuary. And there exists a high-incidence period from April to July. Furthermore, the relationship between surface diurnal warming and wind speed was discussed. Larger diurnal warming mainly lies in areas with low wind speed. And its possibility decreases with the increase of wind speed. Events with ΔT ≥2.5 K rarely occur when wind speed is over 12 m/s. Study on surface diurnal warming in the East China Sea may help to understand the daily scale air-sea interaction in the shelf seas. A potential application might be in the marine weather forecasts by numerical models. Its impact on the coastal eco-system and the activities of marine organisms can also be pursued.

Adsorption of lignite humic acid onto magnetite particle surface

Modified humic acid (MHA) binder based on lignite humic substances is a novel sort of promising organic binder for iron ore pellets.Humic acid (HA) is one of the main ingredients of MHA binder.Pure HA was firstly isolated from lignite and then adsorption of HA onto magnetite particle surface was investigated.The final results indicate that the adsorption of HA onto magnetite surface accords with Langmuir model well,and it is evidently influenced by the initial HA concentration and solution pH value.Adsorption depends on chemical interaction at pH values above the PZC (the pH where the Zeta potentials of minerals are zero) of magnetite,while electrostatic attraction and chemical interaction both contribute to the adsorption at pH values below the PZC.

Surface Roughness of Material Processing during Milling Process

To realize full automation in machining process, Computer Numerically Controlled （CNC） machine tools have been implemented during the past decades. The CNC machine tools require less operator input, provide greater improvements in productivity, and increase the quality of the machined part. End milling is the most common metal removal operation encountered. It is widely used to mate with other part in die, aerospace, automotive, and machinery design as well as in manufacturing industries. Surface roughness is an important measure of the technological quality of a product and a factor that greatly influences manufacturing cost. The quality of the surface plays a very important role in the performance of milling as a good-quality milled surface significantly improves fatigue strength, corrosion resistance, or creep life. Consequently, the desired surface roughness value is usually specified for an individual part, and specific processes are selected in order to achieve the specified finish. Purpose of the study is to develop a technique to predict a surface roughness of the part to be machined according to technological parameters. Such technique could be achieved by making mathematical model of machining. In this study as machining process the milling process is chosen, especially for end milling operation. Additionally to the study, one of the key factors, which differ from similar studies, is that as surface parameters the 2D, 3D surface parameters are used. In this study, all the surface parameters are expressed as 2D, 3D parameters. The 2D, 3D surface parameters give more precise figure of the surface; therefore it is possible to evaluate the surface parameters more precisely according to technological parameters. The result of the study, mathematical model of end-milling is achieved and qualitative analysis is maintained. Achieved model could help technologists to understand more completely the process of forming surface roughness.

Impact Dynamics on Granular Plate

In this paper, a theoretical and numerical study on the impact of a rubber solid on the free surface of a granular plate is presented, showing a simulation of an aircraft wheel on impact with a flexible landing surface. This physical action, when we use a theological approach, becomes a fundamental parameter to investigate wear and tear, and consequently strength to micro and macro pavements failure. The study has developed initially from a microscopic point of view and subsequently on macroscale. The effects are strictly linked with material degradation associated with damage evolution. The problem is developed by energetic approach on an elastic-plastic element using the functional energy containing two contributions, bulk and surface. The model simulates the behaviour of flexible runway pavements during the landing phase.

Incorporation of TOPMODEL into land surface model SSiB and numerically testing the effects of the corporation at basin scale

In order to examine and analyze the effects of integration of land surface models with TOPMODEL and different approaches for the integration on the model simulation of water and energy balances,the coupled models have been developed,which incorporate TOPMODEL into the Simplified Biosphere Model(SSiB) with different approaches(one divides a basin into a number of zones according to the distribution of topographic index,and the other only divides the basin into saturated and unsaturated zones).The coupled models are able to(but SSiB is not able to) take into account the impacts of topography variation and vertical heterogeneity of soil saturated hydraulic conductivity on horizontal distribution of soil moisture and in turn on water and energy balances within the basin(or a grid cell).By using the coupled models and SSiB model itself,the daily hydrological components such as runoffs are simulated and final results are analyzed carefully.Simulated daily results of hydrological components produced by both SSiB and coupled models show that(i) There is significant difference between results of soil wetness,its vertical distribution and seasonal variation,water and energy balance,and daily runoff in the basin predicted by SSiB and by the coupled models.The land surface model currently used such as SSiB is likely to misrepresent real feature of water and energy balances in the basin.(ii) Compared with the results for the basin predicted by SSiB,the coupled models predict more strong vertical and seasonal changes in soil wetness,higher evaporation and lower runoff,and improve the base flow simulation obviously.(iii) Comparing the results for the basin predicted by two coupled models with different integration approach and SSiB one by one,the results of daily runoffs and soil wetness predicted by the two coupled models are quite similar.It means,for the coupled models,the approach by dividing a region being considered into more subzones may have limited effects on improving runoff simulation results.The scheme only to divide the region into saturated and unsaturated zones may be a convenient and effective scheme.But then,if the results from the two coupled models for the basin are carefully compared,the simulated results by the coupled model with dividing the basin into more subzones will show higher evaporation and surface runoff but lower subsurface flow,lower total runoff,and lower ground water level averaged for five years.

Evaporation of liquid fuel droplet at supercritical conditions

A comprehensive analysis of liquid fuel droplet evaporation at supercritical conditions is performed.The numerical model is based on complete time-dependent conservation equations,with a full account of variable thermophysical properties and vapor-liquid interfacial thermodynamics.And the model employs the Peng-Robinson(PR)equation of state(EOS).As a specific example,problems involving n-heptane droplet in nitrogen gas are investigated.The results indicate that the increase of ambient pressure and temperature results in the increase of surface temperature rise rate and surface regression rate.The transition from subcritical state to supercritical state can occur at the droplet surface when the droplet evaporates in a strongly supercritical environment.

Numerical Investigation of a Refractive Index SPR D-Type Optical Fiber Sensor Using COMSOL Multiphysics

Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance （SPR） phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized.

Numerical simulation of powder transport behavior in laser cladding with coaxial powder feeding

Laser cladding with coaxial powder feeding is one of the new ponent to improve performance of its surface. In the process, processes applied to produce well bonding coating on the com- the clad material is transported by the carrying gas through the coaxial nozzle, generating gas-powder flow. The powder feeding process in the coaxial laser cladding has important influence on the clad qualities. A 3D numerical model was developed to study the powder stream structure of a coaxial feeding nozzle. The predicted powder stream structure was well agreed with the experimental one. The validated model was used to explore the collision behavior of particles in the coaxial nozzle, as well as powder concentration distribution. It was found that the par- ticle diameter and restitution coefficient greatly affect the velocity vector at outlet of nozzle due to the collisions, as well as the powder stream convergence characteristics below the nozzle. The results indicated a practical approach to optimize the powder stream for the coaxial laser cladding.