弱L-余拓扑空间的可数紧性

紧性是模糊拓扑学中的重要概念.给出了弱L-余拓扑空间中紧性,可数紧性的定义,讨论了可数紧集在L-值Zadeh型函数下的逆不变性,证明了可数紧集与紧集的乘积是可数紧的. 另外, 通过引入具有有限交性质的弱闭集族给出了可数紧空间的一个新特征.     

局部仿紧空间

在仿紧基础上定义了三种局部仿紧性，给出了三者等价的充分条件，分别讨论了它们的一些性质．结果表明局部紧空间中某些好的性质在相应的局部仿紧空间中仍成立，将紧性进一步推广，使紧理论更加丰富．     

紧性的非标准定义及其性质

在非标准扩大模型和拓扑的非标准定义基础之上, 对拓扑空间中紧性的概念及相关结论进行了描述和刻画.一方面, 这种新的定义与一般的紧性定义是一致的;另一方面, 这种新的定义方法简化了原有的概念和结论, 使它们的本质特性更为清晰, 因而在一定程度上发展了拓扑空间中原有的紧性理论.     

L-fuzzy拓扑空间中的几乎可数层仿紧性

仿紧性是模糊拓扑学中的重要概念.在可数层仿紧性的基础上,介绍了几乎可数层仿紧性,并刻画了其基本特征.研究了L-fuzzy拓扑空间中几乎可数层仿紧性的性质.对闭子集遗传,与几乎可数强F紧集的乘积是几乎可数层仿紧集,是"L-好的推广",具有LF拓扑不变性.     

Hilbert空间中框架的若干性质

应用算子论方法研究了Hilbert空间H中框架的若干性质，包括框架的特征、对偶性、紧性等问题。建立了框架序列与H到l^2(Z)中的相应算子之间的对应关系与构造框架的统一方法。     

双参数C_0半群的紧性性质

首先引入双参数C_0半群和无穷小生成元的定义,并给出双参数C_0半群紧的定义.进而利用C_0半群的紧性,研究双参数C_0半群的紧性性质.得到双参数C_0半群紧的一些性质,并推广了双参数C_0半群的相关结果.     

LF闭包空间中的几乎可数仿紧性

在LF闭包空间中的紧性研究基础上,定义几乎可数仿紧集,对其进行特征刻画,证明了几乎可数仿紧集对于Cech闭包算子的像集是可遗传的.在由F诱导出连续的L-Zadeh型函数的映射下保持性质不变,且具有弱同胚不变性质.进一步证明若(Lx,ωL(～))具有几乎可数仿紧性,当且仅当分明闭包空间(X,～)具有几乎可数仿紧性,即LF闭包空间中的几乎可数仿紧性是“L-好的推广”.     

推理闭包空间中的紧集

用闭集定义了推理闭包空间中的紧集并用开覆盖和非标准分析方法刻画了推理闭包空间中的紧集,具体地描述了2个推理闭包空间中的紧集.在此基础上给出了推理闭包空间中一个子集成为紧集的一些充分条件,证明了推理闭包空间中的紧集被连续映射保持.     

框架小波的可扩展性

规范紧框架小波的可扩展性是超小波理论的一个重要方面.阐述了规范紧框架小波的维数函数的定义和相关性质.作为维数函数的应用,更进一步地研究了框架小波的可扩展性,得到了一个规范紧框架小波可扩展成任何长度超小的充分条件.另外,给出一个例子和两个推论.     

带有临界项的薛定谔-泊松系统的基态解

研究带有双临界项的薛定谔-泊松系统基态解的存在性,其中位势函数和非线性项是渐近周期函数。根据介值定理获得了Nehari流形的一些性质,并利用分析技巧估计了Nehari流形上的极小值。运用球面映射得到了极小化序列为相应泛函的(PS)序列。同时结合逼近和集中紧性原理证明系统基态解的存在性。     

钢丝绳麻类纤维芯紧密度系数计算与分析

钢丝绳麻类纤维芯已被列为钢丝绳生产的主要材料。比较剑麻钢丝绳芯新旧2个标准对绳芯线密度的不同要求。经计算核实,不涂油状态下除了Ф7.30,7.60,7.90 mm 3种规格的剑麻钢丝绳芯紧密度系数为0.70外,其他均为0.66;涂油状态下剑麻钢丝绳芯紧密度系数基本稳定在0.80,不足10%的数值为0.79,Ф7.30,7.60,7.90mm 3种规格的剑麻钢丝绳芯紧密度系数为0.84。GB/T 15030—2009应补充剑麻钢丝绳芯有关线密度公称值的相应数据。黄麻钢丝绳芯的紧密度系数为0.65或0.66,明显低于剑麻钢丝绳芯的。实践证明剑麻钢丝绳芯使用性能明显高于黄麻,剑麻钢丝绳芯及其复合材料绳芯在应用领域和使用数量上不断增加。     

燃烧模型粘性解的收敛性

利用补偿紧致方法得到了燃烧模型方程组的粘性解的有界逼近序列在Ｌ２空间的收敛性。     

具耗散项弹性力学方程组弱解存在性

利用粘性消失法和补偿紧致理论证明具耗散项弹性力学方程组弱解的存在性．     

精梳纯毛针织绒线的SR整理技术

精梳纯毛针织绒线SR整理技术是集丝光、超柔、防缩、防蛀等功能一体的一种新技术,可运用普通液流式绞纱染色机进行多功能整理,成本较低,适于当今的小批量、多品种、多花色、短交期的市场需求。     

利用紧密纺技术加工半精纺纱线

根据生产实践经验,分析了半精纺纱线的主要特点,指出传统环锭纺纱过程中因纺纱三角区的存在,使半精纺纱线的毛羽多且长,条干水平不理想,影响织物质量。介绍了紧密纺纱技术以及运用紧密纺技术生产半精纺纱线的优点：强力高、纱疵少、毛羽少,条干均匀等,探讨了紧密纺生产半精纺纱线应注意的事项,及需探讨和摸索的若干问题。     

常压室温等离子体诱变选育DHA高产菌株

以野生型裂殖壶菌(Schizochytrium limacinum SR21)为出发菌株,经过常压室温等离子体(ARTP)诱变,碘乙酸、丙二酸及丙二酸-碘乙酸复合平板筛选,摇瓶发酵及GC定量分析选育DHA高产菌株。结果表明:在功率100 W、气流量10 L/min下,经ARTP诱变15 s,以1. 2 g/L丙二酸作为筛选平板,获得一株诱变菌NA2。摇瓶发酵120 h后,其生物量、油脂总量、DHA产量与原始菌株相比分别提高了18. 11%、14. 87%、46. 12%,DHA产量为6. 59 g/L。经5次传代,性状稳定。     

Short communication: Effect of stocking rate on the economics of pasture-based dairy farms

Data from a multiyear farm systems study evaluating the effect of stocking rate (SR) on pasture production and utilization, milk production per cow and per hectare, reproduction, and cow health were used to determine the economic implications of altering SR. The effect of SR was also evaluated relative to cow size and total feed available (comparative stocking rate; CSR), to account for differences in cow size and feed supplement availability. Milk production, gross revenue, operating expenses, and operating profit per cow all declined with increasing SR and CSR. In comparison, milk production, gross revenue, and operating expenses per hectare increased with increasing SR and CSR. These effects were irrespective of milk price. The effect of SR on operating profit and return on assets, however, was dependent on milk payment system. When payment was based on the economic value of milk fat and protein, operating profit and return on assets were quadratically associated with both SR and CSR, declining at an SR greater or less than 3.3 cows/ha and a CSR greater or less than 77 kg of body weight/t of feed dry matter available. In comparison, when milk payment was based on a fluid milk pricing system, profit per hectare increased linearly with increasing SR and CSR, but return on assets was not affected by SR or CSR.     

What do we know about grapevine bunch compactness? A state‐of‐the‐art review

Bunch compactness (or density) is a grapevine specific trait that affects the commercial quality and sanitary status of wine and tablegrapes. Compact bunches are more susceptible to diverse pests and diseases such as Botrytis bunch rot and their berries ripen more heterogeneously, causing important economic losses through a reduction in crop yield and grape and wine quality. Bunch compactness is determined by the fraction of the morphological volume of the bunch that is filled by berries, but this simple definition contrasts sharply with the difficulty to measure it. While there are several objective and quantitative methods available to measure bunch compactness, the lack of a consistent approach between researchers makes comparing measurements difficult. The complexity of bunch compactness initially arises from the several bunch and berry traits that influence it, and from the distinct effects that these traits may cause in different cultivars. In addition to this genetic effect, diverse environmental signals impact on bunch compactness by affecting those primary factors that contribute to the solid component of the bunch (berry number, berry size) or to its spatial arrangement (rachis architecture). Last, several viticultural approaches, including agronomic techniques and growth regulators, have also proven to affect bunch compactness in different ways. This review aims to discuss present knowledge about this relevant grapevine trait.