52 research outputs found

    金融衍生产品:风险、市场失灵与公共政策

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    金融衍生产品的引入在中国已是大势所趋,然而至今为止,我们尚未对其真实的特殊风险进行深入的分析和探讨,而且在理论和实务界对衍生产品风险还存在认识误区。衍生产品可能导致额外风险,但这些风险对市场个体的影响并不重要,重要的是,金融衍生市场本身存在的市场失灵,从而可能 导致风险的放大。然而,这些风险是可以管理和控制的。基于此,相应的公共政策与监管原则应针对风险进行控制和管理,并且注重于预防系统性风险和提供公平竞争的市场环境

    Electrochemical Construction and Biological Performance of Micropatterned CaP Films

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    基于表面分子自组装和光催化转印技术,在TIO2膜层表面获得超亲/超疏水阵列微图案模板,结合电化学沉积技术,成功制备了微图案化钙磷盐膜(CAP)层.扫描电子显微镜(SEM)和电子探针分析(EPMA)结果表明,通过超亲/超疏水阵列微图案模板可构筑高空间分辨的微图案化钙磷盐膜层.微图案化钙磷盐膜层的体外Mg-63细胞培养证实,细胞对钙磷盐膜层微单元有强烈的选择性粘附作用,从而可望控制细胞在微单元中的贴壁生长,实现高通量评价细胞行为.Based on surface molecule self-assembly and photocatalytic lithography techniques, superhydrophilic/ superhydrophobic micropatterns were fabricated on TiO2 films.Micropatterned calcium phosphate (CaP) films were successfully fabricated by the as-prepared superhydrophilic/superhydrophobic template combined with the electrochemical deposition method.Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) indicated that micropatterned CaP films with a high spatial resolution could be constructed using the superhydrophilic/ superhydrophobic micropatterns as templates.In vitro MG-63 cell tests of the micropatterned CaP films showed that the cells selectively adhered to the tiny CaP film units, which is promising for the control of the adherent growth of the cells on the tiny units and to achieve a high throughput evaluation of the cell behavior.国家自然科学基金-重大国际合作研究项目(20620130427);国家自然科学基金项目(20773100);国家重点基础研究发展规划项目(973)(2007CB935603);国家科技部国际合作重大项目(2007DFC40440)资助---

    Global Climate Change and Adaptive Management of Forest Ecosystem

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    人类活动所引起的温室效应及由此造成的全球气候变化对全球生态环境的影响正越来越引起人们的关注。森林作为全球陆地生态系统的一个重要组分,对全球气候变化的响应较为敏感。文中系统总结了全球气候变化对物种和森林类型分布、森林生态系统结构和物种组成、森林生产力、森林土壤碳氮循环和森林灾害等几个方面的影响,以及森林生态系统管理面临的挑战,在此基础上提出了适应未来气候变化的森林生态系统管理策略。Human-induced greenhouse effects and their impacts on global climate change and eco-environments,especially the responses of forests to global climate change,have increasingly aroused the concerns worldwide.The forest,as an important component of global terrestrial ecosystem,is more sensitive to the response of global climate change.This paper systematically summarized the existing impact of global climate change on the distribution of species and forest types,forest ecosystem structure and species composition,forest productivity,forest soil carbon and nitrogen cycle and forest disasters,and concluded the challenges which the forest ecosystem management is facing.Based on the review,the forest ecosystems management strategies adaptable to the future climate change were proposed.国家自然科学基金项目海陆交界带的土地利用变化对典型植被碳吸存影响的宏微观尺度研究(41176092); “十一五”国家科技支撑项目南亚热带防台风防护林体系研究与示范(2009BADB2B0302); 国家林业局南方山地用材林培育重点实验室; 福建省森林培育与林产品加工利用重点实验室资助项

    Preparation of Co-YSZ/HAp Nano-composite Coating on Ti Substrate by Electrochemical Method

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    采用复合电沉积和电泳沉积两步法在钛基体上制备了Co-YSZ/HAp纳米复合涂层,与只采用电泳沉积法在钛基体上制备纳米HAp单一涂层进行了比较研究.采用场发射扫描电镜、X射线衍射和能量散射谱对复合涂层的微观形貌,纳米HAp外层表面形貌,晶相,复合涂层的断面形貌及元素组成分布进行分析研究.通过粘结-拉伸实验测定了涂层与基体的结合强度,结果表明,Co-YSZ/HAp纳米复合涂层与钛基体的结合强度明显高于纳米HAp单一涂层与钛基体的结合强度,说明复合涂层具有更好的力学性能.Co-YSZ/HAp nano-composite coating and nano-HAp single coating were deposited on Ti substrate using the combination of electrocodeposition and electrophoretic deposition, and electrophoretic depositions, respectively. Surface and cross section morphologies of the coatings were observed by scanning electron microscope. Element distribution and crystal phase of the coatings were analyzed by energy dispersive spectrum and X-ray diffraction. The adhesive strength of the coating and Ti substrate was determined by shear strength testing. The results indicate that the adhesive strength of Co-YSZ/HAp nano-composite coating and Ti substrate is higher than that of nano-HAp single coating and Ti substrate. It shows that Co-YSZ as an interlayer reduces the mismatch of the thermal expansion coefficients between HAp and titanium and Co-YSZ/HAp nano-composite coating has better mechanical properties.国家自然科学基金(20573086,200273055);; 福建省自然科学基金(E0210004)资助项

    Monthly changes in the caloric values of the leaves of four shrubby and four tree-dwelling palmae species

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    对 4种灌木状棕榈植物 (香棕、袖珍椰子、棕竹、江边刺葵 )与 4种乔木状棕榈植物 (假槟榔、董棕、国王椰子、大王椰子 )叶的热值和灰分含量的月变化进行了研究。结果表明 :( 1 ) 8种植物叶的灰分含量存在差异且具有不同的月变化 ;从灰分含量的比较看 ,乔木类的 4种植物叶平均灰分含量分别为 :假槟榔 1 3.64%± 2 .94%、董棕 9.74%± 1 .90 %、国王椰子 9.1 2 %± 1 .1 8%、大王椰子 8.69%± 3.5 5 % ;灌木类的 4种植物叶平均灰分含量分别为 :棕竹 8.73%± 2 .5 2 %、袖珍椰子 8.67%± 1 .1 9%、香棕 8.63%± 1 .2 0 %、江边刺葵 7.60 %± 0 .98% ,乔木类植物 (除大王椰子外 )叶平均灰分含量高于灌木类的植物 ;( 2 )从干重热值的月变化来看 ,分 3种类型 :江边刺葵与棕竹有相反的变化趋势 ;假槟榔、董棕、袖珍椰子的月变化趋势相同 ;国王椰子、香棕、大王椰子具有各自的变化趋势 ;在 8种棕榈植物中 ,除香棕外 ,灌木类的植物平均干重热值大于乔木类 ;灌木类中 ,茎单生的江边刺葵干重热值高于茎丛生的棕竹、香棕和袖珍椰子 ;( 3)假槟榔、袖珍椰子、大王椰子的干重热值与灰分含量具有极显著的线性相关 ( P<0 .0 1 ) ,棕竹的干重热值与灰分含量有显著的线性相关 ( P<0 .0 5 ) ;而香棕、董棕、江边刺葵、国王椰Monthly changes in the ash contents and caloric values of the leaves of 8 Palmae species(four shrubby species: Arenga engleri, Chamaedorea elegans, Rhapis excelsa and Phoenix roebelenii; four tree dwelling species: Archontophoenix alexandrae, Caryota urens, Ravenea rivularis and Roystonea regia) were discussed in this paper, and the results showed as follows: (1) The ash contents of the 8 Palmae species were different and varied with season; the annual average ash contents of the four tree dwelling species were 13 64%±2 94% for Archontophoenix alexandrae, 9 74%±1 90% for Caryota urens, 9 12%±1 18% for Ravenea rivularis, and 8 69%±3 55% for Roystonea regia; those of the four shrubby species were 8 73%±2 52% for Rhapis excelsa, 8 67%±1 19% for Chamaedorea elegans, 8 63%±1 20% for Arenga engleri, and 7 60%±0 98% for Phoenix roebelenii, respectively; the average ash contents of the four tree dwelling species (except for Roystonea regia ) were higher than those of the four shrubby species; (2) The 8 species had three types of monthly gross caloric value change trends: Archontophoenix alexandrae, Caryota urens and Chamaedorea elegans had similar monthly change trend, while Phoenix roebelenii and Rhapis excelsa had the opposite trends of monthly changes; the other three species ( Ravenea rivularis, Arenga engleri and Roystonea regia ) each had its own changing trend. The shrubby species had higher gross caloric value than the tree dwelling species except for Arenga engleri, of the shrubby species, Phoenix roebelenii (monaxial stem) had the highest gross caloric value (than Arenga engleri, Chamaedorea elegans and Rhapis excelsa (clumpy stem)); Seasonal changes in gross caloric values varied with various species; (3) Gross caloric values were correlated remarkably with ash contents for Archontophoenix alexandrae, Chamaedorea elegans and Roystonea regia (P <0 01), they were correlated for Rhapis excelsa (P <0 05), too, whereas there was no significant correlation between gross caloric values and ash contents for other species; (4) the average ash free caloric values of the shrubby species were 22 65±0 59 kJ/g for Phoenix roebelenii, 22 19±0 48 kJ/g for Chamaedorea elegans, 21 94±0 76 kJ/g for Rhapis excelsa and 21 35±0 75kJ/g for Arenga engleri, respectively; those of the tree dwelling species were 21 76±0 55kJ/g for Ravenea rivularis, 21 20±0 72kJ/g for Caryota urens, 21 12±0 52kJ/g for Archontophoenix alexandrae and 20 98±0 55 kJ/g for Roystonea regia respectively; the shrubby species had higher ash free caloric value than the tree dwelling species except for Arenga engleri. The seasonal changes in ash free caloric values were different from those in gross caloric values due to various ash contents in the leaves of the 8 Palmae species.国家建设部资助项目;; 厦门市园林局资助项目~

    Effect of Refractive Index of Substrate on Fabrication and Optical Properties of Hybrid Au-Ag Triangular Nanoparticle Arrays

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    以石英和不同型号的玻片为基底,系统研究了基底折射率对周期性金银复合纳米阵列的制备及其光学性能的影响。采用离散偶极子近似(ddA)数值方法研究了复合阵列的局部表面等离子共振(lSPr)光谱特性,计算结果表明,当基底折射率为1.43和1.68时,纳米阵列的折射率灵敏度(rIS)和品质因子(fOM)比较优异。利用纳米球刻蚀法(nSl)制备了二维周期性复合纳米点阵结构,实验结果表明,当基底折射率为1.43和1.68时,基底与贵金属纳米颗粒有较好的粘合度,纳米阵列结构形貌比较规则清晰。Based on the substrate of silica and different types of slides, the effect of refractive index of substrate on fabrication and optical properties of hybrid Au- Ag triangular periodic nanoparticle arrays is systematically investigated.The optical spectrum of localized surface plasmon resonance(LSPR) simulated by discrete dipole approximation(DDA) numerical method shows that the nanoparticle arrays can obtain better refractive index sensitivity(RIS) and figure of merit(FOM), when refractive index of substrate is 1.43 and 1.68, respectively.The nanosphere lithography(NSL) is used to fabricate the periodic nanostructure arrays.The experimental results demonstrate that when refractive index of substrate is 1.43 and 1.68, nanoparticles and substrate have better adhesive ability.Meanwhile, the nanoparticles both form a large-scale monolayer array with the hexagonally close-packed structure.国家自然科学基金(11074207); 厦门科技项目(3502Z20143020;2012S0484); 福建省教育厅科技项目(JA11157;12200); 集美大学潘金龙基金(C512038

    Preparation of Co-YSZ/HAp nano-composite coating on Ti substrate by electrochemical method

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    Co-YSZ/HAp nano-composite coating and nano-HAp single coating were deposited on Ti substrate using the combination of electrocodeposition and electrophoretic deposition, and electrophoretic depositions, respectively. Surface and cross section morphologies of the coatings were observed by scanning electron microscope. Element distribution and crystal phase of the coatings were analyzed by energy dispersive spectrum and X-ray diffraction. The adhesive strength of the coating and Ti substrate was determined by shear strength testing. The results indicate that the adhesive strength of Co-YSZ/HAp nano-composite coating and Ti substrate is higher than that of nano-HAp single coating and Ti substrate. It shows that Co-YSZ as an interlayer reduces the mismatch of the thermal expansion coefficients between HAp and titanium and Co-YSZ/HAp nano-composite coating has better mechanical properties

    低温胁迫对长苞铁杉幼苗的生理影响

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    经模拟低温(-12、-8、-4、0、4℃)胁迫处理后,长苞铁杉幼苗叶片和根系相关生理指标均发生明显变化.随着温度降低,叶片光合色素含量增加,但反映光合活性强弱的Chla/Chlb降低;叶片中渗透调节物质脯氨酸和可溶性糖含量增加,呈极显著正相关(r=0.804,p<0.01),根系中可溶性糖含量的减少说明根对低温胁迫的渗透调节更依赖于脯氨酸的累积.幼苗在-4℃及更低温度胁迫下受到严重的冻害使SOD活性持续下降,叶片中POD活性与SOD活性变化呈极显著负相关(r=-0.908,p<0.01),但根系中POD活性与SOD活性没有相关性,说明长苞铁杉幼苗对抗外界胁迫机理的复杂性.叶片MDA含量比根系低可能与叶片中Car能缓解1O2对细胞的伤害有关

    中国物理海洋学研究70年:发展历程、学术成就概览

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    本文概略评述新中国成立70年来物理海洋学各分支研究领域的发展历程和若干学术成就。中国物理海洋学研究起步于海浪、潮汐、近海环流与水团,以及以风暴潮为主的海洋气象灾害的研究。随着国力的增强,研究领域不断拓展,涌现了大量具有广泛影响力的研究成果,其中包括:提出了被国际广泛采用的"普遍风浪谱"和"涌浪谱",发展了第三代海浪数值模式;提出了"准调和分析方法"和"潮汐潮流永久预报"等潮汐潮流的分析和预报方法;发现并命名了"棉兰老潜流",揭示了东海黑潮的多核结构及其多尺度变异机理等,系统描述了太平洋西边界流系;提出了印度尼西亚贯穿流的南海分支(或称南海贯穿流);不断完善了中国近海陆架环流系统,在南海环流、黑潮及其分支、台湾暖流、闽浙沿岸流、黄海冷水团环流、黄海暖流、渤海环流,以及陆架波方面均取得了深刻的认识;从大气桥和海洋桥两个方面对太平洋–印度洋–大西洋洋际相互作用进行了系统的总结;发展了浅海水团的研究方法,基本摸清了中国近海水团的分布和消长特征与机制,在大洋和极地水团分布及运动研究方面也做出了重要贡献;阐明了南海中尺度涡的宏观特征和生成机制,揭示了中尺度涡的三维结构,定量评估了其全球物质与能量输运能力;基本摸清了中国近海海洋锋的空间分布和季节变化特征,提出了地形、正压不稳定和斜压不稳定等锋面动力学机制;构建了"南海内波潜标观测网",实现了对内波生成–演变–消亡全过程机理的系统认识;发展了湍流的剪切不稳定理论,提出了海流"边缘不稳定"的概念,开发了海洋湍流模式,提出了湍流混合参数化的新方法等;在海洋内部混合机制和能量来源方面取得了新的认识,并阐述了混合对海洋深层环流、营养物质输运等过程的影响;研发了全球浪–潮–流耦合模式,推出一系列海洋与气候模式;发展了可同化主要海洋观测数据的海洋数据同化系统和用于ENSO预报的耦合同化系统;建立了达到国际水准的非地转(水槽/水池)和地转(旋转平台)物理模型实验平台;发展了ENSO预报的误差分析方法,建立了海洋和气候系统年代际变化的理论体系,揭示了中深层海洋对全球气候变化的响应;初步建成了中国近海海洋观测网;持续开展南北极调查研究;建立了台风、风暴潮、巨浪和海啸的业务化预报系统,为中国气象减灾提供保障;突破了国外的海洋技术封锁,研发了万米水深的深水水听器和海洋光学特性系列测量仪器;建立了溢油、危险化学品漂移扩散等预测模型,为伴随海洋资源开发所带来的风险事故的应急处理和预警预报提供科学支撑。文中引用的大量学术成果文献(每位第一作者优选不超过3篇)显示,经过70年的发展,中国物理海洋学研究培养了一支实力雄厚的科研队伍,这是最宝贵的成果。这支队伍必将成为中国物理海洋学研究攀登新高峰的主力军

    Study on mission reachability problem for multiple AUVs Based on Object-oriented Petri Net

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    To cope with the difficulty for the development, upgrade and maintenance of control systems for Autonomous Underwater Vehicles (AUVs), this paper focuses on the architecture of AUVs. Firstly, the design of a generalized architecture is presented. And then, according to its characteristic of modular packaging and hierarchical organization, the Object-oriented Petri Net (OPN) method is adopted to model this architecture. Based upon this, to the problem of mission reachability, a sufficient criterion is proposed, thus, the correctness of the timing and logic relationship of this architecture is thoroughly demonstrated. Finally, experiments, in which different types of AUVs cooperate to detect objects, are carried out to validate the effectiveness of this architecture
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