一类拟线性椭圆系统的多重解

利用上下解方法和强极大值原理研究了一类拟线性椭圆系统正解的存在性问题.用山路引理研究了该椭圆系统在次临界增长条件下解的多重性问题.

Abstract：

Using upper-lower solution method and strong maximum principle,the existence of positive solutions is considered for a class of quasilinear elliptic systems.By means of mountain pass lemma,the multiplicity of solutions is considered for the related systems with subcritical growth condition.     

一类具有非线性记忆的退化奇异抛物方程解的爆破

运用上下解方法讨论具有非线性记忆和齐次Dirichlet边界条件的退化奇异抛物方程x~mu_t-(x~ru_x)_x=∫_0u~pds正解的爆破性质,得到方程解在有限时间爆破和全局存在的条件.

Abstract：

This paper deals with the blow-up properties of the solution to the degenerate and singular para-bolic equationx~mu_t-(x~ru_x)_x=∫_0u~pds with non-local memory and homogeneous Dirichlet boundary condi-tions. The existence of a unique classical nonnegative solution is established and the sufficient conditions for the solution to exist globally or blow up in finite time are obtained.     

环境因子对巢湖沉积物中NH4+释放的影响（英文）

[Objective] The aim of the research was to reveal the influence mechanism of sediment-water exchange of nutrients in Chaohu Lake. [Method] The effects of environmental factors （overlying water, temperature, pH and dissolved oxygen concentration） on NH₄⁺ release in sediment from Chaohu Lake were studied under controlled laboratory conditions. [Results] With the rising of temperature and the decrease of NH₄⁺ concentration in overlying water, NH₄⁺ released from sediment increased significantly. pH had a great effect on NH₄⁺ release with a complicated mechanism. The largest release amount of NH₄⁺ under anaerobic condition was about 6 times as much as that under aerobic condition. [Conclusion] This research would provide theoretical support for environmental management of Chaohu Lake in the project of leading water from the Yangtze River to Chaohu Lake.     

关于预不变拟凸函数的一些特征

给出了预不变拟凸函数的必要条件,并利用该必要务件证明了严格预不变拟凸函数的等价条件,最后给出了中间点预不变拟凸函数的充分必要条件.

Abstract：

Some characterizations about prequasiinvex functions are obtained.Firstly,a necessary condition about prequasiinvex functions is established.Secondly,a necessary and sufficient condition of strictly prequasiinvex func-tions is provided by making use of the necessary condition.Finally,a necessary and sufficient condition is estab-lished about intermediate-point prequasiinvex functions.     

非轻质多弹簧串联系统的有效质量和劲度系数计算

通过引入弹簧的形状函数,导出了非均匀拉伸条件下多根非轻质弹簧串联系统的劲度系数和有效质量表达式,以此为基础讨论了均匀拉伸时串联弹簧系统的劲度系数和有效质量,具体计算了2根弹簧和3根弹簧串联时的劲度系数和有效质量,所得结果与相关文献完全一致.

Abstract：

By using shape function, the elastic constant and effective mass of massive springs in series under the condition of non-uniform stretch were derived. Based on this expression, the elastic constant and effective mass of massive springs in series under the condition of uniform stretch were discussed and the elastic constant and effective mass of two or three massive springs in series were calculated. The results thus obtained were in complete agreement with the related literature.     

Stability of QTL Across Environments and QTL-by-Environment Interactions for Plant and Ear Height in Maize

Better understanding of genotype-by-environment interaction （GEI） is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments. To elucidate the genetic basis of the plant and ear height, 2 F2：3 populations were derived from the crosses of Qi 319 × Huangzaosi （Q/H） and Ye 478 × Huangzaosi （Y/H） with 230 and 235 families, respectively, and their parents were evaluated under 3 diverse environments in Henan, Beijing, and Xinjiang, China during the year of 2007 and 2008, and all the lines were also evaluated under water stress environment. The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population, respectively, and 24 and 13 QTLs for ear height, respectively. About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction （QE1） in the normal joint analyses for Q/H and Y/H population, respectively, and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H. Most of the detected major QTLs exhibited high stability across different environments. Besides, several major QTLs were detected with large and consistent effect under normal condition （Chr. 6 and 7 in Q/H; Chr. 1, 3 and 9 in Y/H）, or across 2 water regimes （Chr. 1, 8 and 10 for in Q/H）. There were several constitutive QTLs （3 for Q/H and 1 for Y/H） with no or minor QTL-by-environment for the 2 populations. Finally, we found several genomic regions （Chr. 1, 10, etc.） to be co-located across the populations, which could provide useful reference for genetic improvement of these traits in maize breeding programs. Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr. 1, 6, and 8, respectively.     

带约束的增长曲线模型中线性预测的泛容许性

在二次损失下研究了带不完全椭球约束的增长曲线模型中未来观察值线性预测的泛容许性.根据线性可预测变量泛容许预测的定义和Φ函数的合理条件,得到了齐次和非齐次线性预测在对应的线性预测类中是泛容许预测的充要条件.

Abstract：

This article considers the general admissibility of the linear predictor of future observations in a growth curve model subject to an incomplete ellipsoidal restriction under quadratic loss function.According to the definition for general admissible predictor of a linear predictable variable and the reasonable conditions of function,the necessary and sufficient conditions for a linear predictable variable to be general admissible in classes of the homogeneous or inhomogeneous linear predictors are obtained.     

美伐他汀产生菌橘青霉原生质体的制备与再生

确定美伐他汀产生菌橘青霉(Penicillium citrinum)的原生质体的制备及再生的最佳条件.通过正交实验设计的方法,确定了接种量约10~8个孢子时,于85 mL YPL-20液体培养基中25℃,210 rpm,培养60 h,0.5%纤维素酶和蜗牛酶等比例混合酶液,在30℃酶解2 h,以蔗糖为高渗稳定剂的PGA培养基,原生质体再生形成率可达42.45%.本结果为深入研究橘青霉菌株的原生质体诱变、构建基因工程菌和提高美伐他汀产量奠定基础.

Abstract：

This study was aimed at exploring an optimal condition for the process of formation and regeneration of protoplasts from the mevastatin-producing fungus Penicillium citrinum. The results of an orthogonal design experiment identified that the maximum formation rate (42.45%) was achieved when approximately 10~8 spores were incubated in 85ml YPL-20 liquid medium for 60 hours at 25 ℃, and then a 0.5% mixture of cellulose and snailase was added and digested at 30 ℃ for 2 hours in sucrose-PGA medium. This work has laid a foundation for the further research on protoplast mutagenesis, genetic engineering strain construction and output increase of mevastatin.     

一类参数不确定广义时滞系统的H∞保性能鲁棒控制

针对一类状态时滞的参数不确定性广义系统,讨论了它的保性能控制问题.目的是对状态时滞的参数不确定广义系统,提出它的时滞无关保性能鲁棒控制器的一个设计方法.首先给出了广义时滞系统正则、脉冲自由且稳定的严格线性矩阵不等式表示的时滞无关充分条件;然后采用线性矩阵不等式方法,给出参数不确定性广义时滞系统的时滞无关保性能控制问题可解的一个严格线性矩阵不等式表示的充分条件,在此条件可解时,给出了时滞无关保性能鲁棒控制器表达式,以及相应的可保性能指标.最后给出了所提出方法的应用.

Abstract：

The guaranteed cost control problem is studied for singular systems with time-delay and parameter uncertainty in order to design a delay-independent guaranteed cost controller for singular systems with time-delay and parameter uncertainty. First, a delay-independent sufficient condition is derived, which is expressed by strict linear matrix in-equality (LMI) for singular systems with time-delay to be regular, impulse free and stable. Then, the delay-independent sufficient condition for the existence of guaranteed cost controller is given in terms of strict linear matrix inequalities via LMI approach. When these LMI are feasible, an explicit expression of delay-independent robust guaranteed cost controllers and the corresponding guaranteed cost of the systems are obtained. Finally, a numerical example is provided to demonstrate the application of the proposed method.     

浅谈饲料中有效能的测定技术

饲料中有效能是供动物生长发育的基础.不同动物所用的有效能体系不同,目前大多数动物采用消化能、代谢能体系,但随着研究的发展与深入,发现最能反映饲料有效能的是净能体系.无论哪种体系,采用合理的测定技术准确测定饲料中的有效能值显得尤其重要,通过对饲料有效能值的准确测定可以实现动物所需能量的精确供给,减少养殖成本,使经济效益最大化.文章综述了几种有效能评价体系的测定技术.     

《河北农业大学学报》创刊年代考

清光绪二十八年(1902)河北农业大学前身—直隶农务学堂诞生,经几易其名,于1958年更名为河北农业大学至今。清光绪三十一年(1905)直隶高等农业学堂时期创办了《北直农话报》,清光绪三十四年(1908)更名为《直隶农务官报》,中华民国七年(1918)改出《农学月刊》,中华民国十七年(1928)易名为《河大农刊》,中华民国二十三年(1934)更名为《河北通俗农刊》,中华民国二十四年(1935)易名为《河北农林学刊》,1948年更名为《河北农学院研究专刊》,1959年更名为《河北农业大学学报》至今。《河北农业大学学报》前身诸刊都与现时的《河北农业大学学报》有着一脉相承的历史渊源,各刊之间联系紧密,连续性、继承性强。因此,《河北农业大学学报》的创刊时间应追溯至1905年创办的《北直农话报》。     

高校贫困生认定工作面面观

国家贫困生资助政策实施以来,对贫困生帮助很大,同时在实际运行中还存在着一些问题。本文提出贫困生认定工作仍需要进一步采取各种相关配套措施,以推动和保障贫困生资助工作更好地开展。     

生态旅游潜在客源市场特征的调查研究--以湖南永州金洞森林旅游开发为例

为探明客源市场生态旅游消费的潜在特征,采用问卷调查的形式,就长沙市居民对湖南金洞生态旅游开发的意向等问题进行抽样调查．结果显示,生态旅游符合人们“回归自然”的旅游新时尚,有着极大的开发空间,指出生态旅游的开发要注重环境保护和可持续发展．开发的产品要以休闲度假类的大众产品为主,开发生态旅游都市客源市场还要多种渠道并用,尤其是要注重媒体的宣传．     

探究板栗的科学贮藏方法

板栗属壳斗科栗属(Castanea mollisima Blume),其种子属于顽拗型种子,不耐贮藏。基于近年来板栗贮藏保鲜技术研究成果,从合理采收、贮前处理、贮藏方法等方面进行论述。     

动物疫苗接种异常反应的处理

动物疫病是畜牧业生产的大敌,要发展畜牧业生产就要防治动物疫病。但在疫苗接种时,经常出现正常反应外的其他不利于机体的反应,如废食、皮疹、休克、死亡等,正确处理或避开这些问题,对推行动物疫病的计划免疫,实施强制免疫,保护人畜安全具有十分重要的现实意义和作用。     

厚胶合板弹性模量预测模型

为了预测厚胶合板弹性模量,通过简化层合板理论,该文建立了胶合板弹性模量预测模型,并以单板条、经过涂胶热压处理的单板条和相同工艺条件下的单板层积材的弹性模量,采用4种不同铺层方式的19层桉树胶合板对模型进行了验证。结果表明:3种预测值与实测值的趋势一致,相关系数R2顺纹在0.86以上,横纹在0.88以上,但是精度不同。采用单板条弹性模量预测的胶合板弹性模量比实测值偏低;采用经过涂胶热压处理后的单板条弹性模量预测的胶合板弹性模量比实测值偏高;采用相同工艺条件下的单板层积材弹性模量预测的胶合板弹性模量与实测值偏差较小,顺纹平均误差为4.64%,横纹平均误差10.94%。因此,采用相同工艺条件下的单板层积材的弹性模量来预测胶合板的弹性模量是可行的。      

增强我国水果业出口竞争力的思考

分析了入世4年来,我国水果出口在量上实现了突破,但并没有实现质变的主要原因,指出我国水果业存在的问题。论述了引进外资对发展我国水果业的意义,并提出了具体可行的对策与建议。     

山茱萸多糖提取工艺优化及马钱苷含量测定

采用L（934）正交设计试验,对山茱萸浸提液中山茱萸多糖的酶水解法提取工艺进行了优化研究,并对浸提液的中有效成分马钱苷含量进行了HPLC法分析。结果表明,山茱萸多糖浸提的最佳工艺为：液料比1∶5,浸提时间4 h,浸提温度80℃,果胶酶添加量0.55 g/L。用HPLC法测定出的山茱萸浸提液中马钱苷平均含量为0.512 ...     

黑豆不同部分馏油的体外抗氧化性比较

[目的]通过体外抗氧化体系比较黑豆不同部分馏油抗氧化性活性。[方法]通过正交试验优化索氏提取黑豆馏油的最佳工艺,提取黑豆不同部分馏油;研究黑豆不同部分馏油对羟基自由基(·OH)、DPPH自由基(DPPH·)的清除能力。[结果]在样品浓度为1.0 mg/mL时,黑豆不同部分馏油对·OH的清除率分别为全豆馏油83.9%、豆黄(黑豆去皮部分)馏油64.8%、豆皮馏油17.3%,对DPPH·的清除率分别为全豆馏油41.3%、豆黄馏油33.2%、豆皮馏油77.9%。[结论]黑豆不同部分馏油均具有较好的抗氧化性,是良好的天然抗氧化剂。黑豆不同部分馏油对·OH的清除能力从大到小依次为全豆馏油、豆黄馏油、豆皮馏油,对DPPH·的清除能力从大到小依次为豆皮馏油、全豆馏油、豆黄馏油。