A potent attractant of zoospores ofAphanomyces cochlioides isolated from its host,Spinacia oleracea

A highly potent attractant of zoospores ofAphanomyces cochlioides, a causal fungus of the root rot disease of spinach (Spinacia oleracea), was isolated from spinach roots, and its structure was determined by spectroscopic evidence and chemical synthesis as cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone,1). A chromosorb particle prepared by soaking in solution of1 showed a potent attracting activity toward the zoospores using concentrations of1 above 10^–9 or 10^–10 M.     

人工神经网络的硬件实现——A/D转换电路

本文阐述4位A/D转换器的基本原理及其在硬件实现中的主要技术问题.给出了从Hopfield的原理电路逐步演化成实际电子电路的设计过程,讨论了如何保证各个神经元在最佳状态下进行翻转,从而获得可靠、准确的输入-输出特性.同时指出了在计算机仿真中人们难以发现的极限环现象及其消除方法.     

2,3,16,17-四羧基酞菁钴对氧还原的电催化作用

用循环伏安法及旋转圆盘-环电极研究了2,3,16,17-四羧基酞菁钴(CoTCPc)在溶液中及CoTCPc/GC修饰电极上对O_2还原的电催化作用。实验结果表明,CoTCPc对O_2电还原有明显的催化作用。在Co(Ⅱ)TCPc还原为Co(Ⅰ)TCPc的第一个峰电势附近,O_2在CoTCPc/GC修饰电极上定量地还原为H_2O_2,在稍负的第二个峰电势附近,有H_2O_2还原产生H_2O的过程发生。本文并对CoTCPc对O_2还原电催化过程的机理进行了讨论。     

应用Intel 8279芯片实现多路D／A转换

一种多路D/A转换器,它主要由Intel 8279芯片、一路基本D/A转换电路、一个模拟开关和相应的采样保持器组成,与其它的多路D/A电路相比,其不同之处在于它用8279中的显示RAM和扫描线实现转换数据的存放和对各路D/A的循环扫描,从而减轻了CPU的负担,而且电路简单,成本低.经过研究表明,这种电路不仅能实现8路8位的D/A转换,而且还能实现16路8位和8路16位的多路D/A转换。     

声参量混合定则预测生物组织组分的研究

从理想混合液模型出发，将生物组织看作是主要由水、脂肪、蛋白质所构成的三元理想系统．测量了蛋白、蛋黄及其混合物的声速、密度和非线性声参量Ｂ／Ａ，并根据修正后的Ａｐｆｅｌ混合定则，对该混合物进行水分、脂肪和蛋白质体积含量预测．结果表明，实测体积含量与Ａｐｆｅｌ混合定则预测值吻合较好     

Early circulating erythroid progenitors (BFU-E) in sickle cell anemia

Sickle cell anemia (SS) patients can be divided into two sub-populations according to peripheral HbF levels. Patients with low (<9%) HbF levels (LFSS) are characterized by an increased number of circulating BFU-E in active DNA synthesis, and release of burst promoting activity (BPA) by unstimulated low density (LD) adherent cells. In contrast, circulating BFU-E from SS patients with high (>9%) HbF levels (HFSS) are normal in number, largely in resting phase, and their LD cells do not release BPA-like activity.More recently further heterogeneity has been found among these two groups. In LFSS patients GM-CSF is constitutively produced by unstimulated monocytes. In contrast, HFSS patients' adherent cell depletion increases cycling of BFU-E in culture. CM from HFSS patients inhibits BFU-E expression in culture. Hence, LD adherent cells from HFSS patients may release an inhibitory factor(s). The nature of this factor has to be determined.In addition, there are distinct subpopulations of BFU-E responsiveness to growth factor (GM-CSF, IL-3): a) LFSS patients have a homogeneous BFU-E population, equally responsive to GM-CSF and IL-3; b) HFSS patients, in addition to this subpopulation, have a subset of BFU-E dependent exclusively on IL-3 which is 20 to 40% of the total number of circulating BFU-E. This is similar to BFU-E from normal individuals. Hence, LFSS BFU-E represent an actively proliferating population, equally responsive to GM-CSF and IL-3, controlled by at least constitutively produced GM-CSF and possibly other factors.These observations suggest a significant modification in BFU-E behavior in the subset of SS patients with low HbF levels and high hemopoietic stress. The heterogenous regulation of BFU-E in SS disease seems to be an epiphenomenon of HbF levels, and not vice-versa.     

关于测度的弱收敛

如对任意有界连续实函数g,都有lim∫_Qgdμ_n=∫_Qgdμ,称测度序列{μ_n}弱收敛于μ,记作μ_n??μ.文〔2〕在取值于Banach空间中函数的Bochner积分意义下推广该极限.该文则在取值于(F)-空间中抽象函数的Bochner积分意义下作进一步推广.     

拟正则映射和变分关系

研究了ｐ－调和方程在拟正则映射作用下的一种不变性,并对得到的Ａ型调和方程建立了局部梯度Ｌｐ可积性及解的Ｈｌｄｅｒ连续性     

企业并购目标选择的模糊决策

针对企业并购过程中的现实问题,分析了企业并购摧在动因,运用模糊数学工具,建立并购目标选择的模糊决策方法,并通过案例分析阐述该方法的具体应用,有助于提高最优并购目标选择的科学性。