林木胸径与材积的关系--Logistic衍生模型

基于著名的Logistic模型，以时间因子作媒介，推导出一个能较准确描述林木D-V关系的一元材积模型——Logistic衍生模型。这是一个既有理论依据。又有实用价值的新模型。实践证明，Logistic衍生模型具有较强的数据拟合能力和广泛的适用性，除林木D-V关系外，尚可用于林木D-H关系等项研究，具有理论和应用上的双重意义。     

气相色谱法测定沼液中的游离蛋白氨基酸

采用柱前衍生气相色谱法测定了7种沼液中的游离蛋白氨基酸。结果表明 ,沼液中含有多种游离蛋白氨基酸 ,且含有多种人体必需氨基酸。该测试方法简便、低耗 ,重现性较好     

柱前衍生-气相色谱法测定柑橘中2,4－D残留量研究初报

为了解决柑橘出口中2,4-Ｄ残留监测问题,研究了快速测定柑橘中2,4－D残留方法。样品经酸性乙腈提取,用酸性硅藻土净化,经三甲基氢氧化硫(TMSH)衍生后,用带电子捕获检测器的气相色谱仪进行测定。试验结果表明：2,4－D的最低检出量为5×10-13g,最低检出浓度为4×10-4mg/kg,在0.001、0.01、0.1mg/kg三种添加水平下,添加回收率范围为77.16%~97.72%,变异系数范围为3.30%~8.65%。该分析方法快速、准确、灵敏,重现性好,适用于柑橘中2,4-D残留量的检测。     

Conformity and genetic relatedness estimation in crop species having a narrow genetic base: the case of cucumber (Cucumis sativus L.)*

A set of 155 SSR (107) and SCAR (48) markers were used to evaluate 53 cucumber (Cucumis sativus L.) accessions of diverse origin to characterize genetic relationships and to define a standard marker array that was most effective in detecting genetic differences in this germplasm array. A multivariate marker‐based analysis of diverse germplasm using this standard marker array (17 SSR and 5 SCAR markers) was compared with results from a set of 70 previously reported RAPD markers, and then used to explore the potential value of these genetic markers for plant variety protection (PVP) and the establishment of essential derivation (ED) threshold values in this species using elite lines and hybrids and backcross progeny. Diversity analysis allowed identification of distinctly different lines that were used for the construction of three sets of backcross families (BC₁‐BC₃). While general genetic relationships among accessions were similar in SSR/SCAR analyses (r_s= 0.65) using two genetic distance (GD) estimators, differences in accession relationships were detected between RAPD and SSR/SCAR marker evaluations regardless of the estimator used. The GDs among elite germplasm with known pedigrees were relatively small (0.06‐0.23 for any pairwise comparison). GD values decreased and degree of fixation (at three to seven loci depending on the mating) increased with increased backcrossing such that recurrent parent allelic fixation occurred in least one family of each of the BC₃ families. In many instances the degree of fixation of loci was not uniformly achieved in the BC₃. Although the level of genetic polymorphisms will likely restrict the use of molecular markers for PVP and the establishment of ED values, the use of single nucleotide differences will likely provide opportunities to define specific functional distances that have potential for PVP in cucumber. Nevertheless, without an expanded, genetically robust standard marker array (e.g. 50 codominant markers), ED threshold values will be difficult to define in this species, and perhaps will require the appraisal of single nucleotide polymorphisms as discriminators of difference in this species.     

平地情况下允许压力差最优分配比的探讨

本文研究了田间管网优化设计中支、毛管允许压力偏差水头分配的问题。在平地上布置微灌系统时,得出了支、毛管的最优分配比不是一个定值,而是随支管上毛管的根数和支、毛管长度的变化而变化,改进了美国J·凯勒和D·喀麦林提出的只给一个固定常数的方法,对节约管网投资有一定的实际意义。     

DABS-Cl柱前衍生-HPLC测定稻米中γ-氨基丁酸方法优化

建立4-二甲胺基苯基偶氮苯磺酰氯柱前衍生-高效液相色谱测定稻米γ-氨基丁酸（GABA）含量的方法。样品采用80%的乙醇溶液提取后,1.0mL样液依次加入0.20mL碳酸氢钠和0.40mL DABS-Cl在70℃下衍生20min,利用C18色谱柱,乙腈-三水合乙酸钠溶液作为流动相在436nm波长下测定GABA含量。结果显示：GABA在糙米和精米的添加回收率大于87.60%,相对标准偏差小于9.07%;GABA在1.0~100.0mg/L内具有良好的线性关系,相关系数为r=0.9995（n=3）。用本方法测定了14种糙米和精米样品的GABA,其含量为6.38~108.7mg/kg,湖南精米和糙米中的GABA含量最高。     

白蜡虫多糖的提取及单糖组分分析

采用水提醇沉法对资源昆虫——白蜡虫中水溶性多糖组分进行提取,测定了提取物的多糖含量、蛋白含量和氨基酸含量;以1-苯基-3-甲基-5-吡唑啉酮(PMP)为柱前衍生化试剂,利用毛细管区带电泳(CZE)对其多糖的单糖组成及摩尔比率进行分析,对电泳缓冲液的浓度和pH值进行了优化。结果表明:白蜡虫水溶性多糖的提取率为2.1%,多糖含量为256 mg.g-1,蛋白含量为242 mg.g-1;白蜡虫多糖由葡萄糖、甘露糖及半乳糖3种单糖组成,其摩尔比为1∶0.85∶0.93。     

试论汉语语源分化下的汉字分化

中国传统思维是一种从整体出发,以经验为基础的直觉思维,汉语语源分化受到传统思维方式的影响,而汉语语源分化又制约和影响着汉字的分化,随着汉语语源的分化产生了一批新的汉字形体。     

非交换素环上导子为零导子的条件

设R是一个特征不为2的非交换素环,d与g是R的两个导子。如果对任意的x∈R都有xdx-xxg∈Z(R),那么d=g=0。设R是一个6!-扭自由的非交换素环,如果存在环R的一个Jordan导子d使得对任意的x∈R都有x[xx,x]x=0,那么d=0.     

柱后衍生高效液相色谱法测定水产品中河豚毒素含量

采用柱后衍生高效液相色谱法检测水产品中的河豚毒素含量，选用河豚Takifugu）和织纹螺（Nassarius）为主要研究对象，样品先由0.1%乙酸提取，经过C18固相萃取柱净化。以庚烷磺酸钠为离子对试剂，应用反相离子对液相色谱分离河豚毒素，采用在线柱后衍生系统，在110 ℃高温和4 mol·L^-1 NaOH强碱条件下，将河豚毒素衍生化成具有荧光特性的C9碱，荧光检测器定量检测。河豚毒素在5～1 600 ng范围内呈良好的线性相关，相关系数r=0.999 7；1、2、8 μg·g^-1，3个浓度水平添加样，日内和日间的回收率为80.9%～91.2%、相对标准偏差为1.93%～5.57%；方法定量限为1 μg·g^-1；从添加样色谱图上看，河豚毒素目标峰附近没有干扰峰，定性准确性好。采用柱后衍生高效液相色谱法与小鼠生物法检测同一阳性河豚样，检测结果一致性好。实验结果表明，柱后衍生高效液相色谱法适用于水产品中河豚毒素的检测。