37 research outputs found

    台指選擇權波動率指數在期貨上的應用與發展

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    西元1993年時,現任Duke大學的Whaley教授提出新的市場參考指標「市場波動率指數」(Market Volatility Index,簡稱為VIX指數),為衡量未來股票市場價格波動程度的方法。同年,美國芝加哥選擇權交易所利用選擇權交易時波動率之變化,推出波動率指數提供市場參考。波動率指數發展至今,在美國股市中,已被法人當作判斷市場方向的交易及避險參考指標。 最新推出的波動率指數衍生性商品則是由芝加哥選擇權交易所推出上市的波動率指數選擇權契約商品,及道瓊工業平均指數的波動率指數期貨。在研究資料期間內,很明確地道瓊工業平均指數與S&P500指數正相關性非常密切,兩者的波動率指數正向關係也很高。而各自對應的波動率指數則呈現高度負相關性,其意義表示為波動率指數與其對應的市場指數呈現反向趨勢。 台灣選擇權市場發展至今,依研究資料顯示,成熟度已與國際選擇權市場相當,此刻討論台灣期貨市場編製波動率指數的可能性已較具有可行性。藉由設計波動率指數期貨與選擇權契約商品提供股票市場參與者規避波動率風險的有利工具。同時,創造台灣波動率衍生性商品交易的可能性

    An Empirical Study of the Disclosure Strategies of Management Earnings Forecasts by Acquiring Companies during Mergers and Acquisitions Events

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    本文对中国沪深两市A股上市公司2007-2011年并购前管理层业绩预告的披露策略进行研究。研究发现,并购前管理层会策略性地发布好消息业绩预告、高精度业绩预告和乐观业绩预告;并购前强制性披露公司与自愿性披露公司在管理层业绩预告披露策略上存在差异,自愿性披露较强制性披露发布更多好消息,但是披露精度较低,并且倾向于披露悲观业绩预告。研究结论有利于投资者理性评估管理层业绩预告,有利于证券市场监管者完善管理层业绩预告制度。This paper finds that the management would strategically disclose good, precise point and optimistic earnings forecasts before the mergers and acquisitions events.It also finds that there is difference between the management earnings forecasts disclosure strategies by the voluntary disclosure companies and that by the mandatory disclosure companies.In detail, the voluntary disclosure companies tend to disclose more good, imprecise and pessimistic earnings forecasts than the mandatory disclosure companies.These findings are valuable for the investors to rationally assess the management earnings forecasts, and for the financial market regulators to improve the management earnings forecasts policy.国家自然科学基金项目(G0206-71172050和G020102-71002039); 教育部人文社会科学规划项目(08JC630069)的研究资

    Robust H Fault Tolerant Control on Suspension System of Maglev Train with Delayed Input

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    Taking into account of the input time-delay, mathematical model of the suspension system was established for single suspension module of maglev train. Based on state feedback and LMI approaches, robust H fault tolerant controller was designed under the case of actuator failures, furthermore, the gap variation in case of different actuator failures was simulated. Simulation results showed that the designed fault tolerant controller could make the maglev train suspend and run steadily with actuator failures

    锰离子浓度对氧化亚铁硫杆菌生长动力学的影响

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    考察不同初始&rho;(Mn~(2+))条件下,氧化亚铁硫杆菌(A.ferrooxidans)培养体系中Fe~(2+)浓度的变化曲线和A.ferrooxidans菌的生长活性。结果表明:A.ferrooxidans菌对Mn~(2+)具有一定的耐受能力;当培养基中&rho;(Mn~(2+))&le;1 g/L时,Mn~(2+)对A.ferrooxidans菌生长活性影响很小;&rho;(Mn~(2+))为5~15 g/L时,A.ferrooxidans菌生长开始受到抑制;&rho;(Mn~(2+))=20 g/L时,A.ferrooxidans菌生长完全受到抑制。为了进一步描述Mn~(2+)对其生长活性的影响,利用[Fe~(2+)]...</p

    锰离子浓度对氧化亚铁硫杆菌生长动力学的影响

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    考察不同初始ρ(Mn2+)条件下,氧化亚铁硫杆菌(A.ferrooxidans)培养体系中Fe2+浓度的变化曲线和A.ferrooxidans菌的生长活性。结果表明:A.ferrooxidans菌对Mn2+具有一定的耐受能力;当培养基中ρ(Mn2+)≤1 g/L时,Mn2+对A.ferrooxidans菌生长活性影响很小;ρ(Mn2+)为5~15 g/L时,A.ferrooxidans菌生长开始受到抑制;ρ(Mn2+)=20 g/L时,A.ferrooxidans菌生长完全受到抑制。为了进一步描述Mn2+对其生长活性的影响,利用Fe2+/Fe3+的比值及A.ferrooxidans菌对Fe2+的得率系数对不同Mn2+浓度下细菌的比生长速率进行拟合,较好地描述Mn2+浓度对氧化亚铁硫杆菌生长的影响

    十二胺浮选分离菱锰矿与方解石及其机理

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    研究十二胺浮选分离菱锰矿与方解石的行为,考察调整剂水玻璃、六偏磷酸钠和柠檬酸对菱锰矿和方解石浮选的影响。单矿物浮选结果表明:pH 为7~8时,菱锰矿与方解石可浮性存在差异。人工混合矿浮选结果表明,菱锰矿与方解石可浮性相当,难以分离。红外分析结果显示,十二胺以物理吸附方式存在于菱锰矿与方解石表面。矿物晶格能、溶液化学计算和SEM-EDS表明,方解石的可浮性略大于菱锰矿的,混合矿中方解石表面向菱锰矿转化,导致两矿样表面性质相似而不可分离

    十二胺浮选分离菱锰矿与方解石及其机理

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    研究十二胺浮选分离菱锰矿与方解石的行为,考察调整剂水玻璃、六偏磷酸钠和柠檬酸对菱锰矿和方解石浮选的影响。单矿物浮选结果表明:pH 为7~8时,菱锰矿与方解石可浮性存在差异。人工混合矿浮选结果表明,菱锰矿与方解石可浮性相当,难以分离。红外分析结果显示,十二胺以物理吸附方式存在于菱锰矿与方解石表面。矿物晶格能、溶液化学计算和SEM-EDS表明,方解石的可浮性略大于菱锰矿的,混合矿中方解石表面向菱锰矿转化,导致两矿样表面性质相似而不可分离

    The Separation and Purification of E.coli Bacteriophage and Its Characteristics

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    通讯作者: msshen@ xmu. edu. cn[中文文摘]探讨了从生活污水中分离、纯化大肠杆菌噬菌体的方法.经富集,从厦门大学、厦门港的生活污水中获得3种噬菌体.一是:蝌蚪状不可收缩尾的噬菌体,其头部为二十面体,直径约110~120 nm,尾部长220~230 nm,尾宽13~15 nm,无尾鞘、基板、尾丁、尾丝等结构.二是蝌蚪状可收缩尾的噬菌体,其头部为三十面体,约70 nm×110 nm,尾部长约120~130 nm,尾宽约18~22 nm,有尾鞘、基板、尾丁、尾丝等结构,该类噬菌体在污水中占绝大多数.三是短尾噬菌体,其头部为二十面体,大小为20 nm,尾部长约2~3 nm,在污水中占有一定的比例.2种噬菌体在-18℃冰箱可存活56天.经噬菌体处理的污水,总菌数下降了30%左右,大肠杆菌总数下降90%以上.[英文文摘]How to separate and purify coliphage from the sewage drained from daily life was discussed.Three kinds of phage from the daily sewage of the Xiamen University and the Xiamen harbor were separated enrichedly.One was a pollywog shape phage,which had a head of icosahedrons with diameter about 110~120 nm,a un-contractive tail with length about 220~230 nm and width around 13~15 nm.This phage doesn′t have the structures of tail sheath,base-tube and tail fibers etc.The second was pollywog-like phage,which had a contractive.tail with length about 120~ 130 nm and width about 18~ 22 nm,and a triacon tahedron head with size about 70 nm nm×110 nm. It had the structure of tail sheath,tail tube and base-plate.This category was the overwhemlingm ajor ity of the daily-life sewage.The third is a short-tail phage with an icosahedron head abou t 20 nm,the length of the tail is only 2~ 3 nm.Th is phage covered considerable propor tion in the daily-life sew age. The phage obtained from the sewage could live abou t 56 days in the - 18 refrigerator. The total number of bacterial in the sew age was redu ced about 30% and theE. coli was reduced about 90% .国家基础科学人才培养基金(J0630649);2007年教育部大学生创新计划项目资

    海南蜡皮蜥保护行动野外考察记

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    蜡皮蜥,别名坡马,是一种穴居的蜥蜴类动物,在中国主要分布于广东、澳门、海南、广西的沿海地区,国外分布于越南。在海南主要分布于沿海木麻黄林一些相对开阔的生境中, 但由于近年来沿海地区人类的生产活动、人为的猎捕和旅游设施的开发, 蜡皮蜥的生境和种群数量正以惊人的速度递减,如果再不加以制止,相信不用多久,蜡皮蜥就可能在人们的视野中永远消失了。为了开展蜡皮蜥的保护工作,
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