远程教育中基于粗糙集的聚类算法

针对目前远程教育中个性化教学水平较低的问题,提出了一种基于粗糙集的Web学习者聚类算法,并应用粗糙集的约简方法解决了学习者特征数据中的属性冗余问题,提高了聚类算法的效率,从而提高了远程教学网站的个性化教学水平.     

基于索引表的专家系统知识库表示与推理应用

知识表示是构造专家系统重要的环节之一.现给出基于索引表的专家系统知识库模型及通用表示格式,同时介绍了满足这种表达方式的推理机制,并将其应用到辣椒营养诊断专家系统中,增强知识库的可维护性和扩展性.     

薄层扫描法测定夏桑菊颗粒中熊果酸的含量

采用薄层扫描法测定夏桑菊颗粒中熊果酸的含量.以环己烷—氯仿—醋酸乙酯—冰醋酸(20∶5∶8∶0.5)为展开剂,检测波长为520 nm,参比波长为700 nm,SX=3,标准曲线Y=1291.28X 34.12,R=0.998 2,熊果酸在1.017-2.373μg范围内与峰面积积分值呈良好的线性关系,平均回收率100.82%,RSD=1.94%.     

Ecdysteroids in the larvae of Opogona sacchari （Bojer）, a invasive alien pest

In order to understand the composition and quantitative variation of ecdysteriods in the larvae of Opogona sacchari (Bojer), a invasive alien pest, we analyzed the larval ecdysteroid composition and titers in this pest. The main component of ecdysteriods in the larvae of O. sacchari is 20-hydroxyecdysone, and also there is a little 26-hydroxyecdysone. The titer of ecdysteriods in the larvae from the 1st instar to the 7th instar was gotten higher gradually compared on ng ecdyster-oid/larva, but no regularity could be found about the titer if compared on ng ecdysteroid/g avoirdupois. There was only one peak of ecdysteroids (0.5475 ng/larva) showed at day 2 during the developmental time of the 6th instar larvae. However, there were two peaks appearing during the developmental time of the 7th instar larvae , one peak (0.29415 ng/larva) at day 3, another (0.214 ng/larva) at day 5.     

Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea

Clay minerals have played a significant role in the study of the East Asian monsoon evolution in the South China Sea by being able to track oceanic current variations and to reveal contemporaneous paleoclimaUc changes prevailing in continental source areas. As one of the most important rivers inputting terrigenous matters to the northern South China Sea, the Pearl River was not previously paid attention to from the viewpoint of clay mineralogy. This paper presents a detailed study on clay minerals in surface sediments collected from the Pearl River drainage basin （including all three main channels, various branches, and the Lingdingyang in the estuary） by using the X-ray diffraction （XRD） method. The results indicate that the clay mineral assemblage consists dominantly of kaolinite （35%-65%）, lesser abundance of chlorite （20%-35%） and illite （12%-42%）, and very scare smectite occurrences （generally 〈5%）. Their respective distribution does not present any obvious difference throughout the Pearl River drainage basin. However, downstream the Pearl River to the northern South China Sea, the clay mineral assemblage varies significantly： kaolinite decreases gradually, smecUte and illite increase gradually. Additionally, illite chemistry index steps down and illite crystallinity steps up. These variations indicate the contribution of major kaolinite, lesser illite and chlorite, and very scarce smecUte to the northern South China Sea from the Pearl River drainage basin. The maximum contribution of clay minerals from the Pearl River is 72% to the northern margin and only 15% to the northern slope of the South China Sea. In both glacials and interglacials, kaolinite indicates that the ability of mechanical erosion occurred in the Pearl River drainage basin.     

Authigenic sulfide minerals and their sulfur isotopes in sediments of the northern continental slope of the South China Sea and their implications for methane flux and gas hydrate formation

This is a report of the study of the authigenic sulfide minerals and their sulfur isotopes in a sediment core (NH-1) collected on the northern continental slope of the South China Sea, where other geo-physical and geochemical evidence seems to suggest gas hydrate formation in the sediments. The study has led to the findings: (1) the pyrite content in sediments was relatively high and its grain size relatively large compared with that in normal pelagic or hemipelagic sediments; (2) the shallowest depth of the acid volatile sulfide (AVS) content maximum was at 437.5 cm (>2 μmol/g), which was deeper than that of the authigenic pyrite content maximum (at 141.5-380.5 cm); (3) δ 34S of authigenic pyrite was positive (maximum: 15‰) at depth interval of 250-380 cm; (4) the positive δ 34S coincided with pyrite enrichment. Compared with the results obtained from the Black Sea sediments by Jorgen-sen and coworkers, these observations indicated that at the NH-1 site, the depth of the sulfate-methane interface (SMI) would be or once was at about 437.5-547.5 cm and the relatively shallow SMI depth suggested high upward methane fluxes. This was in good agreement with the results obtained from pore water sulfate gradients and core head-space methane concentrations in sediment cores collected in the area. All available evidence suggested that methane gas hydrate formation may exist or may have existed in the underlying sediments.     

绿色技术创新政策的国际经验对福建的借鉴与启示

绿色技术创新是福建可持续发展的重要途径。本文首先对美国、日本和欧盟的绿色技术创新的法律政策、财政税收支持政策、绿色采购政策和教育政策等四个方面进行深入分析,并与福建进行对比分析,找出目前福建在绿色技术创新政策的不足与发展方向,希望对福建省制订和完善绿色技术创新政府以及更好地推进资源节约型和环境最好型社会的建设具有借鉴意义。     

带相依利率结构风险模型的破产持续时间

在利率具有二阶自回归相依结构,同时考虑到保费、理赔支付时间的离散时间风险模型下,得到了在停时T,保险公司在初始准备金为u时,破产持续时间的分布的递推公式.     

烯烃气相色谱保留指数的预测

通过对部分烯烃在不同固定相不同柱温下的1031个样本集的气相色谱保留指数值(RI)与其部分参数关系的研究,发现RI与拓扑指数(mQ)、双键原子杂化状态指数(DHSI)、支链对双键的极化效应指数(PBD)、固定液极性值(CP)及柱温(T)的关系可表示为:^RI=-58.138 57.7460Q-8.2591Q 0.120T 0.807CP 36.460PBD 7.919DHSI(R=0.9989)继以留一法(Leave-one-out,LOO)进行交互检验,相关系数RCV=0.9977,说明所建模型具有良好的稳定性和预测能力,较好地揭示了烯烃类化合物气相色谱保留指数RI随固定相极性、柱温的改变而变化的规律.     

论金融控股公司风险监管法律制度

金融控股公司作为金融业多元化经营的一种载体蕴含着监管盲区、资本安全、内部交易及风险集中等诸多特殊的新风险。我国应从金融本土资源出发，参考国际上的先进经验，完善金融控股公司风险监管法律制度，具体包括：树立为创新而监管的理念，渐进式地改革金融监管模式，完善内控制度，适当限制内部交易等。