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1.
烟叶是烟草行业发展的基础,其稳定发展是行业上下宏观调控的基本目标。作为专卖体制下特殊的农产品,烟叶生产的稳定发展和粮食等主要农产品的稳定发展有相同之处,又各有侧重。笔者以粮食安全对烟叶安全的启示为切入点,对烟叶生产稳定发展的国内外研究动态进行评述,归纳出国外烟叶生产的特点,提出中国烟叶生产稳定发展不同主体,尤其是烟叶产区烟草部门和烟农需要进一步研究的课题,旨在为实现烟叶生产的平稳发展和持续满足卷烟工业企业优势品牌优质原料需求提供参考。  相似文献   

2.
In binary phase diagram there are many stable compounds. Hereby a new method for calculating activities of compounds from binary phase diagram involved stable compounds is presented. Based on the available formula for calculating activities in binary phase diagram, the activities of the two pure components are gained. And the balance constant K~0 can be obtained from mass action law. Thereby, the activities of stable compounds are obtained from the activities of the two pure components. By using this method, the activities of stable compounds in In-Sb system are obtained. It proves that this method is feasible.  相似文献   

3.
This paper discusses a calculation method which can be used to increase the measuring speed of weihging system for products. The usual measuring method can only get exact value after the value has been stable, whereas the method discussed in this paper uses a limited number of transient value obtained during measuring time to calculate the stable value. Simulation result shows that the measuring time can be reduce to about one third.  相似文献   

4.
The exponential dynamic neural network proposed.by T.D.Chiuch and R.M.Goodman in 1988 is investigated. A concise sufficient condition for the given standard patterns to bestable is presented. A one-step conversence radius of such a stable state is obtained. It is also shownthat there do not exist sporious stable states in the probabilistic sense.  相似文献   

5.
PAM对潮土水稳性团聚体的影响   总被引:2,自引:1,他引:1  
通过室内土柱培养,研究四种不同浓度PAM对潮土水稳性团聚体的改良效果。结果表明,加入不同浓度PAM均可促使>0.25mm水稳性团聚体的形成,并有效降低团聚体分形维数,改善土壤结构。随着PAM浓度的增加,改良效果逐渐增强。在加入浓度为1g/kg时达到最好的效果,较对照,>0.25mm水稳性团聚体增加了42.69%,分形维数降低了10.11%。关键词:聚丙烯酰胺(PAM);水稳性团聚体;分形维数  相似文献   

6.
用高稳系数法分析大豆新品种高产稳产性   总被引:5,自引:0,他引:5  
应用高稳系数法分析了1991-1992年河南省区试10个大豆参试品种的高产稳产性,并与常用的统计分析法的几种稳定性参数进行了比较和分析。结果表明,高稳系数法是分析大豆新品种高产稳产性的准确、简便的方法。  相似文献   

7.
Summary We report here, for the first time, the stable expression and Mendelian segregation of transgenes in a tree species. So far we have evidence for a 1 : 1 segregation of thenos gene in the R1 of transgenic apple progeny. In addition we present evidence for stable gene expression of bothnos and the co-transferred genenptII in the fruit flesh of the apple fruit some 7 years after the initial transformations.  相似文献   

8.
为了更好地鉴定广东省甜玉米新品种的丰产性以及稳定性,本研究采用高稳系数和稳定性参数等分析方法,对2017年春植甜玉米区域试验15个甜玉米新组合区域试验数据的高产性和稳产性进行分析比较。结果表明,高稳系数最高的前五位是‘华美甜9号’>‘优群甜1号’>‘金百甜15’>‘金百甜28’>‘新美甜818’;变异系数最小的前五位为‘优群甜1号’<‘江甜019’<‘微风甜6号’<‘天丰甜618’<‘新美甜818’;结合稳定性系数,表现出高产稳产的有两个组合分别为‘优群甜1号’和‘新美甜818’,综合表明15个区试中‘优群甜1号’和‘新美甜818’的高产稳产性最好。本试验为筛选高产稳产性甜玉米品种提供参考依据。  相似文献   

9.
It is difficult to obtain the globe optimum solution by applying conventional sizing and geometrical optimization methods. Evolutionary topology optimization is conducted for the lower stable of a hydraulic press using a bi directional evolutionary structure optimization (BESO) method based on ratio of stress changes, and the evolutionary history and index are analyzed. The presented algorithm obtains the simultaneous optimization on both geometry and topology, and a new topology of the lower stable of the press is evolved which possesses a reasonable topological structure. The results of finite element analysis show that the new structure has decreased maximum stress, uniform stress distribution and good material usage.  相似文献   

10.
稳定碳同位素测量法不受时间、空间限制,测定过程简便准确,为了消除常规传统测定水分利用效率(WUE)方法中的缺陷,可将稳定碳同位素示踪技术引用于指示作物的WUE中。本研究综述了稳定碳同位素分馏的基本原理,从植物器官组织、气候因子和水分条件分析了稳定碳同位素分馏特征与WUE的关系和在植物抗旱节水育种上的应用。通过分析不同光合型植物稳定碳同位素分馏特征得出,WUE与碳同位素比值(δ13C)及碳同位素分辨率(Δ13C)具有相关性,植物不同部位器官的δ13C值均有差异,降雨量、光照强度和时长以及土壤水分都对植物δ13C值和WUE产生显著影响。因此,利用δ13C和Δ13C这两个稳定碳同位素指标能够更好地指示植物高WUE和抗旱性,可为提高植物WUE和选育抗旱性品种提供理论依据。  相似文献   

11.
稳定性氢氧同位素在植物用水策略中的研究进展   总被引:1,自引:1,他引:0  
作为一种新的分析方法和示踪手段,稳定同位素技术近20多年来在植物生态研究中得以快速发展。文章系统介绍了稳定性氢氧同位素在植物用水策略研究中的最新进展,着重对该技术在确定不同生境下植物用水策略、区分不同功能群植物水分来源、植物水分再分配及指示环境气候信息等研究中的应用及前景作了阐述。  相似文献   

12.
The connections of frame structure elements at a node are ofen an elastic connection between hinged and rigid.In this paper,the stiffness matrix and the loading transfer matrix of frame element with turn elastic connections is deduced,the cross shear effect has been taken into consideration simultaneously.The stiffness matrices of some bar elements,such as both ends of the bar are hinged or rigid and one end is hinged but the other is rigid,are special cases of the stiffness matrices presented in this paper.After pointing out that the elastic coefficient at a node of a bar element with elastic joint is really a fuzzy quantity,the fuzzy stiffness matrix of the bar element is obtained,and a solution to structural fuzzy finite element equilibrium equations is presented.The fuzzy solution obtained from above is not only containing the solution of ordinary finite element method but also providing some additional informations with practical value.[WT5HZ]  相似文献   

13.
河南夏大豆区试新品种丰产稳产性评价分析   总被引:3,自引:0,他引:3  
为了客观、科学、公平、公正评价河南省夏大豆区域试验参试品种的丰产性、遗传稳定性及适应性,应用作物品种区域试验统计分析系统(RCTAS)对2013年河南省夏大豆区域试验汇总资料进行品种在不同生态条件下的丰产稳产性分析和比较,为河南大豆新品种在生产及育种中的有效利用提供理论依据。结果表明,‘秋乐1205’、‘安豆5156’和‘驻豆02-19’等9个大豆新品种丰产性好,比对照‘豫豆22号’均增产5%以上;‘农丰18’、‘驻豆03-56’和‘周豆22’丰产稳产性均好;对照‘豫豆22号’稳产性好;‘泛09C6’丰产性差,但稳产性好。试验结果结合大豆区试新品种的田间实际表现佐证了RCTAS是一款理论与实践紧密结合、系统设计优良、应用方便快捷的作物品种区域试验的统计分析软件,同时也为河南省夏大豆新品种的鉴定、筛选、审定和推广提供了准确可靠的科学依据。  相似文献   

14.
《保鲜与加工》2000,(6):1-4
For the boundary element method of elastodynamics, some properties of matrices are discussed in case of similar boundary elements and the similar boundary element method is presented. In a series of similar boundary elements, when the corresponding matrices of a boundary element are obtained, the ones of other boundary elements in the series can be obtained by proportion. Then the coefficient matrix of the last system of linear algebraic equations can be obtained by the method of superposition. Compared with the general boundary element method, the computing speed can be raised by the similar boundary element method given in this paper.  相似文献   

15.
品种稳定性参数和高稳系数在小麦区试中的应用及其分析   总被引:51,自引:0,他引:51  
经过试验,用高稳系数法分析品种的高产稳定性,计算简便且分析容易,但比较粗放。回归系数座标分析法较为详细准确,缺点是比较繁琐。所以在对区试结果不需详细分析时,用高稳系数法较简便容易;如需详细分析时,则用回归系数座标分析法较准确可靠。同时对几种品种稳定性参数的准确性进行了比较分析,结果表明品种间回归系数的大小能较准确地反映出品种间稳定性差异程度的大小,其对稳定性的代表性要准确于其他稳定性参数。  相似文献   

16.
In this paper we prove existence theorem of upper bound constant of multiplier for ELSP and propose an easily programmable algorithm for solving the problem of determining lot size for n items to be produced on a single machine based on the existence theorem. We give some interesting examples to show the bound constant is useful. In some cases we can find optimal solution immediately with the bound constant and it is difficult to find a feasible solution without this bound constant.  相似文献   

17.
河北省不同生态区夏玉米丰产、稳产性品种筛选研究   总被引:5,自引:1,他引:4  
针对河北省各地区生态条件差异大,适应不同生态条件的丰产、稳产玉米品种较少的突出问题,以当前推广的紧凑型、半紧凑型和松散型玉米为材料,采用高稳系数法对近几年河北省主要推广的夏播玉米品种在不同生态区的丰产、稳产性能进行研究和探讨。结果表明,不同生态区最适宜推广的品种如下:山前平原区为郑单958、雅玉12和浚单22,高稳系数(HSC)分别为0.85、0.87、0.86;冀东平原区为豫玉23、唐玉15和浚单20,HSC分别为1.02、0.97、0.96;黑龙港地区为蠡玉16、矮秆225,HSC分别为0.95、0.83。本研究为筛选适宜河北省不同生态区种植的丰产、稳产玉米新品种提供了依据。  相似文献   

18.
分析高产优质多抗国审小麦新品种‘瑞华麦520’的产量表现和构成因素,旨在为品种的推广提供科学依据。利用国家、省中间试验及大面积应用多点数据,对‘瑞华麦520’的高产稳产性进行分析。结果表明:‘瑞华麦520’在江苏省3年中间试验增产点率达100%,国家区试两年增产点率均为88.2%,均值变异系数分别为7.16%和12.2%,位居参试品种最小值的第1和7位,品种离优度值分别为494.97和618.97,位居参试品种最小值的第2和3位,平均穗数633.0±64.5万穗/hm2、穗粒数31.1±4.5粒、千粒重40.2±3.0 g,产量三要素协调稳定,均值变异系数和品种离优度值均较低。多年多点试验表明,‘瑞华麦520’产量潜力高、稳产性好,对黄淮南片麦区主要病害、灾害具有良好的抗(耐)性,有较高的推广价值。  相似文献   

19.
The matrlx basic theorem in normed linear spaces is extended to topological vec-tor spaces,by using it we also proved some important results of funcational analysis.  相似文献   

20.
黑粒小麦色素稳定性的研究   总被引:2,自引:1,他引:1  
黑粒小麦是中国近几年育成的一类新品种,其富含丰富的天然黑色素和营养价值。为了从黑粒小麦中提取天然色素并研究其理化性质,以黑粒小麦为材料,对它进行天然色素的提取及色素稳定性质进行研究。结果表明,天然黑色素易溶于水、乙醇等极性溶剂,为水溶性色素;在酸性条件下呈现红色,碱性条件下为绿色;黑粒小麦色素较耐热(<80℃);Ca2+、Ba2+、K+、Fe3+、Al3+、Cu2+、Mg2+这些金属离子对该色素都有一定的增色作用,但Ba2+、Al3+、Fe3+使其有沉淀出现;Vc、H2O2使色素色泽变浅,Na2HSO4对色素有较强的褪色作用;食盐、蔗糖、柠檬酸对黑粒小麦色素有增色的作用。由此得出,黑粒小麦色素的理化性质比较稳定,是较理想的天然色素添加剂。  相似文献   

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