天气衍生品的运作机制与精算定价

天气衍生品是为了规避天气风险给天气敏感行业带来收入的不稳定性而兴起的创新型风险管理工具，其实质是通过衍生合约对天气风险进行分割、重组和交易的证券化产品。不同于传统金融衍生品，天气衍生品的价值取决于温度、湿度或降雨量等天气指数。本文在分析天气衍生品市场发展的基础上，重点探讨了最常见的天气期货和天气期权的运作机制及其精算定价。     

祁连山南麓高寒灌丛GPP变化特征及对生长季积温的响应

全球气候变化背景下气温逐渐升高,将会对陆地生态系统碳循环产生重要影响。研究利用2003?2016年的涡度相关系统观测资料,研究了祁连山南麓高寒灌丛生长季(5月?9月)总初级生产力(gross primary productivity,GPP)在不同时间尺度上对生长季有效积温(growing season degree days,GDD)的响应,对于研究气候变暖对高寒生态系统碳循环的影响有重要意义。结果表明:高寒灌丛生态系统在生长季的月GPP、GDD都表现为先增大后减小的单峰变化趋势,都在7月或8月达到峰值,在5月达到最小值。在整个生长季尺度上,GPP与GDD具有较高变异性,但整体上表现为逐渐增加的趋势(P<0.05)。2003?2016年整个生长季GPP与GDD的均值分别为507.11 g·m^?2和975.93℃。在月尺度和生长季尺度上,GPP与GDD都呈显著正相关关系(P<0.05)。但是,通过比较生长季每个月GPP与GDD的关系发现,5、9月的GPP与GDD没有显著相关性(P>0.05),而在7月相关性最为显著(P<0.01)。整体上看,高寒灌丛生态系统植被的总初级生产力与热量条件表现为正相关关系,由此说明在全球气候变暖的背景下,青藏高原高寒灌丛生态系统植被的光合生产能力将会提高。     

盐胁迫对5份无芒雀麦苗期生长和生理生化的影响及综合性评价

为了明确不同无芒雀麦苗期耐盐能力的强弱,本研究选择5份不同株型的无芒雀麦作为供试材料。根据新疆土壤盐碱成分设置中性盐(M盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶4∶0和碱性盐(A盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶1∶8两种处理,于三叶期每盆一次性浇灌2 L电导率(EC)为20 ms·cm^-1的盐处理液,CK浇灌等量自来水。处理30 d后测定生长指标、叶绿素荧光特性参数、丙二醛(MDA)和渗透调节物质含量,并通过相关性分析、主成分分析、隶属函数分析对13个指标进行分析评价。结果表明：除F_v/F_m和F_v/F_o外,盐胁迫显著影响其余11个指标,且5份材料间差异显著(P<0.05);5份无芒雀麦的株高、茎粗、分蘖数、地上生物量、根冠比、MDA和脯氨酸含量在不同盐胁迫下表现出不同的适应变...     

小麦新陈快速鉴别方法的研究

对小麦的新陈快速鉴别方法进行了研究。研究结果表明,愈创木酚法在小麦收获后的前两个月用于现场收购当年产的新麦,有较高的准确度;酸度指示法在一定程度上可以快速判断小麦的新鲜程度,适用于异地调运新麦。     

Effect of the Silicic Acid Polymerization Degree on the Coagulating Property of Polyalumium Silicate Chloride

Polyaluminum silicate is a new type of inorganic macromolecular flocculants, which is developed as a complex product in recent years on the base of polyalumium flocculant and polysilicic acid flocculant. Sodium silicate is diluted to the concentration of 3.0% SiO 2 with distilled water. The solution was adjusted to pH 4.5 with sulphate acid and kept at quiescency for different time to get polysilicic acid with different polymerization degrees. Using polysilicic acid prepared and aluminium chloride as materials, a series of polyaluminium silicate chlorides(PASC) with different basicities(B), Al/Si molar ratios and polymerization degree of silicic acid are prepared by copolymerization technique. The Al-Ferron timed complex colorimetric method is applied to characterize species distribution of PASC and to study its influence factors. The interaction between hydrolyzed aluminum species and polysilicic acid with different polymerization degrees in PASC is discussed.The flocculant prepared is applied to the treatment of commercial concrete wastewater. The turbidity removal of commercial concrete wastewater is up to 97% when a PASC, prepared with polysilicic acid of 145 min polymerization degree.     

Reasoning Method Based on Motorcycle Design

According to the needs of setting up a professional system based on motorcycle design,the CBR(case based reasoning) and RBR(rule based reasoning) methods are introduced.After discussing the difference between the two kinds of reasoning,a method of integrating them into the motorcycle design flow is put forward to realize the design reusable technology and improve the design efficiency,by using the CBR in the step of selecting the similar motorcycle and the RBR in project's modification according to correlative rules.     

Using BP Neural Network to Determine the Membership Function of the Input of Fuzzy Control System

While design the fuzzy controller, it is very important to determine the membership function of fuzzy variables.The data can be broadly classified as fuzzy sets by using the classification property of the BP neural network. The author selects a BP neural network with one hide layer and uses S function to the input and hide layer, and linear function to the output layer.Advanced BP algorithm isused to train the BP neural network in the environment of MATLAB . The nearer to the target values is the better the last output is.With the trained BP network , the membership values of the inputs can be got ten. This method has high rate and low error.     

Weighting Coefficient Optimization Unification of Lexicographic Method in Fuzzy Multi -objective Optimization Design

The Lexicographic method has subjective and empirical character,so a weighting coefficient is introduced by considering the importance and proportion of each individual object,the preferable result of every individual object can be confirmed by comparing the degree of similarity between the perfect one and the ecumenic one and the Fuzzy optimization will be perfect.The effectiveness of these methods is illustrated by a fuzzy optimal design of the three-bar truss.     

Application of Matter Element Analysis in Assessment of Ambient Air Quality

A new method for assessment of ambient air quality is proposed by using matter element analysis.This model is simple and reasonable in assessment.The practical example is given,and compared with other methods.     

The Method of Diagnosing Brain-dysfunction Based on Membership Function and BP Neural Network

Membership functions.formed with the characteristic values obtained by applying the continuous reaction time (CRT) theory from controls and heptic encephalopthy and proposedin this paper.whith these membership functions,the CRT data to be diagnosed are calculated in advance,and then discriminated by BP meural network to differentiate patients with or without braindysfunction.The troubles of low accuracy and efficiency,encountered in training BP network withfuzzy samples.scattered data and extended samples,are solved.