Macroscopic and Microscopic Coupling Mathematical Model for Solidification Process of Twin-roll Thin Strip

A macroscopic and microscopic coupling mathematical model for solidification process of twin-roll thin strip is developed. In the model, the latent heat is treated by the enthalpy method, and the grid and node are divided by assumed streamline boundary. The heterogeneous nucleation and the columnar-equiaxed transform(CET)model are introduced, together with the revison of the dendrite growth dynamic model of KGT. With the help of solid fraction, the coupling of the macro/micro aspects is realized by using different grid-sizes and time-steps, macro and micro, together with the columnar dendrite front tracing. The columnar dendrite arm spacing and deflection angle calculated by proposed model are in agreement with the experimental ones. Therefore, the model is proved to be reliable, and it can be used to predict the effects of the processing parameters on the solidification structure of twin-roll thin strips.     

Micromodel of Computer Emulational Simulation on Twin-roll Casting Strip Solidification Structure

Based on the research on the solidifiation of twin-roll casting strip,the analytical model and emulational model of nucleation,the growth of dendrity tip and colunar dendrity transformation to equiaxis dendrity (CET)of twin-roll casting strip solidification are established by means of the principle of metal solidification and modern computer emulational technology.The foundation for the emulational simulation of twin-roll casting strip solidification structure is laid.     

Growth of Potassium Perchlorate Single Crystals in Gels

Gel growth is the best method for growth of potassium perchlorate single crystals.The effect of concentration of reactants,concentration of gel,temperature,pH value of gel on crystal nucleation density,size,form and quality has been studied by experiments.The best growth parameters for growth of large size,well defined and transparent potassium perchlorate single crystals are obtained.The crystal morphology and the relative importance of crystal faces of potassium perchlorate single crystals are quantitatively analyzed for the first time,and the results are in satisfactory agreement with experimental observations.The theory of periodic bond chain(PBC) is verified in the experiment.     

安徽省粮食生产波动分析及政策建议

为了系统分析安徽省粮食生产情况,为政府制定粮食生产政策提供参考,保障安徽省和我国粮食安全,以1978-2012年为研究时段,对安徽省粮食总产量、稻谷、玉米、小麦变化总体态势进行分析,并采用剩余法对安徽省1978—2012年粮食生产波动态势进行系统分析和深入探讨。研究表明,安徽省粮食总产量、稻谷、小麦和玉米产量都呈现不同程度的增加,随着人们饮食结构的变化,稻谷产量占粮食总产量的比重有所下降,小麦和玉米产量占粮食总产量的比重有所增加;安徽省粮食总量及稻谷、玉米、小麦三大粮食作物的波动情况存在的共同特征,即波动频繁,周期短,波幅大,都属于古典型波动,但在波动周期、波动幅度方面还是有所差异。波动周期相比较而言,安徽省粮食总产量的波动周期最为频繁,平均周期长度为2.81;在三大粮食作物中安徽省小麦产量的波动周期最为频繁,平均周期长度为2.88,稻谷的波动周期最短,为3.77。波动幅度相比较而言,在平均波动古都中玉米产量的波动幅度最大,为61.89%,小麦产量的平均波动幅度次之,为40.24%,稻谷产量的平均幅度第3,为23.56%,粮食总量产波动幅度最小,仅为19.77%。古典型波动相比较而言,粮食总产量波谷环比增长率均为负的有9个,占到了周期总数的82%;稻谷产量波谷环比增长率均为负的有9个,占到了周期总数的100%;小麦产量波谷环比增长率均为负的有8个,占到了周期总数的77.78%;玉米产量波谷环比增长率均为负的有10个,占到了周期总数的100%。结合粮食生产波动情况,提出了从耕地资源、水资源、科技、政策、劳动力等方面保持安徽省粮食生产稳产增长,减少粮食生产波动的针对性政策建议。     

A rapid real-time PCR assay for detecting columnar growth in apples (Malus × domestica)

Columnar growth in apples can have considerable positive consequences for orchard maintenance, but the lack of columnar cultivars producing fruits with desired market quality prevents their broader utilization in orchards. New crossings focused on their breeding are therefore conducted throughout the world every year. Unfortunately, the reliable discrimination between columnar growth and normal phenotype is difficult until seedlings are 2–3 years of age. However, molecular marker–assisted selection (MAS) can be used in seedlings several weeks old providing immense help in breeding programmes focused on columnar apple production. Here, we describe a rapid and reliable method for the detection of both wild-type (WT) and columnar (Co) alleles originating from ‘McIntosh Wijcik’ in a single reaction using a real-time PCR allelic discrimination approach. Our assay was tested in 130 genotypes (80 normal and 50 columnar habit) from various crossings and their parents, and in all cases, genotype corresponded to phenotype. The assay is thus suitable for laboratories interested in high-throughput MAS for columnar tree habit breeding.     

Mechanism and Progress About Protein Crystal Growth by Atomic Force Microscopy

Atomic Force Microscopy(AFM) plays a very important role in researching crystal growth mechanism, especially protein crystals. The principle of AFM for protein crystal examination is briefly described as well as the importance of research on protein crystal growth, known growth mechanisms including 2-D steps nucleation, spiral dislocation, normal growth, 3-D nucleation and anisotropic development, and latest progress about eucommia antifungal protein(EAFP) and Trichosanthin(TCS) protein crystal growth mechanism, respectively. Finally, protein growth under microgravity environment is also expounded here and their development tendency and practical prospect.     

长江中游地区粮食生产的战略研究

长江中游地区(湖南、江西和湖北)是我国粮食生产主产区之一,该区的粮食安全与否直接影响到我国的粮食安全。本文首先从绝对和相对的角度分析了该区粮食生产的现状。结果表明：近10年来,一方面,区内的粮食生产总量一直在以增加种植面积而获得了稳步增长,其增长难以持续。同时区内的种植结构也在逐渐发生变化,主粮(水稻)的种植面积增幅要远大于杂粮小麦和薯类的增幅,尤其是大于豆类的增长幅度。另一方面,从全国范围来看,长江中游地区的主粮(水稻)的生产占全国比重呈下降趋势,而杂粮生产占全国比重反而有较大幅度的提高。其次,深层剖析了该区粮食生产发展所面临的困境,认为主要有农民(户)种粮积极性不高、农田水利基础设施薄弱、耕地质量退化严重、产业化水平不高、农业科技整体水平较低和粮食生产的结构性弊端初现等六大方面问题。最后,针对该区域所面临的困境依次提出了粮食生产发展的战略对策,为确保该区粮食安全提供参考。     

Analysis on Refining the ZLD11 Nuclear

The ZLD11 alloys containing Sr have been prepared by adding AlSr master alloy and the refinement effect of Sr on the microstructure are investigated with different contents of Sr in the finish alloys such as 0.04%,0.06%,0.08%and 0.10% Sr to change the grain size of ZLD11 alloy in mass, both microstouctve observation and gain size statistical analysis have been used to discover the proper additions of Sr. The effects of the main alloying elements on properties of ZLD11 alloy, as well as the smelting process are introduced. The results indicate that AlSr master alloy as a crystal refiner with X metal mold casting process has an effective grain refinement for ZLD11 alloy, the best refinement effect were obtained with addition of 0.08% Sr.     

气候变化对中国粮食生产的影响

气候变化对中国粮食生产的影响已得到高度关注,并形成了诸多研究成果,但影响的评估结果存在一定的争议。笔者对21世纪以来百篇国内外相关高质量文献进行整合梳理,总结讨论了气候变化对中国粮食生产的影响。研究表明：（1）1961年以来气候变化主要通过影响作物生长发育、引起种植结构改变、导致农业病虫害和气象灾害加剧的方式影响了中国的粮食生产,影响结果正负共存,总体上呈负效应,且气温升高的负效应最为显著。（2）气候变化对粮食生产的影响存在地域差异,在东北、西北绿洲等高纬度地区,气温升高改善了区域热量条件,粮食产量有增加趋势;在华北平原、南方稻区、西南地区和西北旱作区,气温升高缩短了作物生育期,加上降水变化,导致区域的粮食产量下降。（3）不考虑CO₂肥效作用,未来气候变化很可能造成粮食产量下降,且小麦的减产幅度可能高于水稻和玉米;考虑CO₂肥效作用,负面影响将会减弱,并可能对东北地区的水稻和华北平原的小麦产生正面影响。     

Computational Simulation on Temperature Field of Slab Continuous Casting Mold

On the core concepts that the distributing of temperature and solidified slab shell in mold are a stable process, a new method to calculate the temperature field in mold has been promoted. Consequently, a coupling model on fluid filed and temperature field in stable state has also been established. The concept of effective heat capacity is introduced to deal with the latent heat source term from phase transformation. During the programming for computation, the dynamic updating method is also applied to simulate the influence of solidification on physical properties. The resolution results of this model are analyzed and compared with the tested thickness of solidified shell from casting broke out slab, which demonstrates the correctness and applicability of this model to the practical continuous casting process. Additionally, the thickness distribution of solidified shell in slab mold are also studied in detail.     

中国粮食“十一连增”的主要因素分析与政策建议

为了找到确保中国粮食稳定发展的方法和途径,在对中国粮食生产特点分析的基础上,对推动粮食“十一连增”的具体动因及制约因素进行了深入分析。研究认为：在中国支持粮食产业财政投入不断加大、农业科技实力不断增强、种植业结构的高产替代模式等因素的推动下,中国粮食连续十一年增产。但是,中国粮食安全并非高枕无忧,粮食生产面临着资源约束加剧、比较效益降低、国际竞争力减弱、生态和环境持续恶化等挑战。因此,本研究提出要从财政、科技、环境、经营主体以及粮价视角出发,建立粮食稳定发展的长效机制。     

冀鲁豫夏玉米区玉米杂交种群体生育型演变──Ⅱ．第Ⅳ演化阶段群体生育型特征及演进趋向

运用群体生育型特征与演化的观点，分析了冀、鲁、豫夏玉米区玉米杂交种群体生育型演化进程至端的第Ⅳ演化阶段群体生育型基本特征与演化特征及其演进趋向，结果表明，第Ⅳ演化阶段群体生育型基本特征表现为株型紧凑或半紧凑，穗位叶适中，雄穗分枝较少，抗倒性和抗斑性优良，籽粒长，出籽率高；其演化特征主要由穗粒结构与第一叶面积、生育日数决定，其穗长演化将趋于稳态，穗行数、穗粗、百粒重、行粒数与第一叶面积、株高将呈现较明显的持续演进态势，其中生育日数、行粒数和株高将分别向早熟、多粒和高棵方向回归。第Ⅳ演化阶段群体生育型演进临近转型期。     

冬小麦不同粒型品种茎叶组织结构与籽粒形成关系的研究

本研究观察了冬小麦不同粒型４个品种茎秆，旗叶结构以及籽粒的形成过程。结果发现：穗下节的机械组织，输和同化组织随粒型不同而有显著差异，其中以大粒型兰考８６－７９维管组织最发达，而中大粒型豫麦２５茎壁及其内同化组织最大；旗叶则随粒型增大其，叶催厚度增加，维管束数目增多及主脉结构发达。不同粒型品种灌浆强度的差异在籽粒进入灌浆盛期最为     

植物生长物质对大豆叶片形态解剖结构及光合特性的影响

2006年度在黑龙江八一农垦大学实验农场大田栽培条件下,以大豆垦农4号为试材,选用植物生长物质为2-N,N-二乙氨基乙基己酸酯(DTA)、氯化胆碱(CC)和SOD模拟物(SOD_M),于开花始期叶面喷施,对大豆叶片形态解剖结构和光合指标进行了研究。结果表明,各处理的叶片栅栏组织厚度及栅海比增加,栅栏组织细胞排列的紧密程度为SOD_M＞DTA ＞CC＞CK;各处理不同程度地增加了单个细胞的叶绿体数、单个叶绿体中的基粒片层数和淀粉粒数,降低了叶绿体中的嗜锇体数;SOD_M、DTA分别显著、极显著增加了叶绿体的基粒数;各处理普遍提高了生育后期叶片Chl a、Chl b和Chl(a+b)含量,增加了Chl b/a比值;在较干旱条件下,与对照相比,各处理能使叶面积指数和光合势达到最大值时间提前,增加了籽粒干物质积累时期的总光合势,提高了净光合速率。     

A Method of Modeling with Structural Stochastic Parameters

In order to reflect the stochastic characteristic of a structure more completely and accurately,this paper presents a theory and method of modeling with structural stochastic parameters using probabilistic finite element method and perturbant finite element method,on the basis of modeling with deterministic parameters.It is applied to double decker space frame,good results are gained.     

利用SPSS实现玉米杂交种主要农艺性状与产量的相关和通径分析

以黑龙江省农业科学院玉米研究所自育的74个玉米杂交材料为研究对象,运用SPSS 18.0对玉米杂交种产量与主要农艺性状中的生育期、株高、穗位、穗长、穗粗、秃尖长、穗行数、行粒数、粒宽、粒厚、百粒重、容重、出子率关系进行逐步回归分析和通径分析,计算主要农艺性状对杂交种产量的决策系数。结果表明,出子率、百粒重、生育期、穗长和穗行数是影响玉米产量的主要正因素。     

北京市粮食直接补贴政策的效率分析

作为重要的农业支持政策,粮食直接补贴一直是中国各界关注的焦点问题;为了研究北京市粮食直接补贴政策实施的效率,依据相关政策和数据,通过采用Cobb-Douglas生产函数的回归分析,DEA方法以及Malmquist指数对北京市粮食直补及其效率进行了研究。结果表明,粮食直补变量在Cobb-Douglas生产函数的回归系数为正,并通过了显著性检验,粮食直接补贴在一定程度上促进了北京市粮食产量的增长;DEA结果显示,2009—2011年3年间北京市粮食直接补贴的综合效率平均值分别为0.909,0.837和0.901,北京市各区县的粮食补贴相对不同,表明北京市各区县的粮食直补效率各有不同的特点。     

Evaluation of One-dimension Electron Density Correlation Function in Three-phase Structure

The crystal polymer's correlation function of threephase structure with linear electron density interphase layers is calculated.The corresponding relation about invariant,interphase layers' thickness and scatter figure are found.The conclusions are compared with that G.R.Strobl got in the extension from two-phase model to three-phase model.Strobl's errors are pointed out and corrected the errors in the extension.The authors get long period,lamellar thickness,invariant and interphase layers' thickness from the correlation function figure of three-phase model,but the conclusion is that the definitions of lamellar thickness and invariant are not the same as those in the two-phase structure.     

The Mathematical Model of Cooling and Heat Transfer for the Solidification of Thin Slab during Continuous Casting Process

In the established model, the cooling differences are considered between the surface of inner radius and that of outer radius, and in the transverse direction of thin slab. And the conception for the effective coefficient of spraying water in continuous casting is firstly put forward. According to different casting speeds and different cooling zones, different time step lengths are adopted. In this model the heat transfer differences are thought over among vertical and curved zones, wide and narrow surfaces an well as angular zone of mould. The method of the corrected equivalent specific heat is used to deal with latent heat. The influence of forced convection is considered on heat transfer. Therefore, the model has higher accuracy and is consistent with the practice.