CoPt-Co hybrid supported on amino modified SiO_2 nanospheres as a high performance catalyst for hydrogen generation from ammonia borane

CoPt-Co hybrids were successfully supported on amino modified SiO_2 nanospheres by a chemical reduction method at a temperature of 278 K.The solid carrier i.e.amino modified SiO_2,provides numerous anchoring sites for the metal nanoparticles(NPs)to improve the dispersion while reducing the size of metal NPs.The supported NPs displayed a narrow particle size distribution on the SiO_2 surface with an average diameter of 12 nm.The XRD results alongside with the binary alloy phase diagram suggest that the resulted NPs are bimetallic,composed of CoPt and amorphous Co.Among the prepared materials,the solid with the specific composition of SiO_2@Pt_(0.1)Co_(0.9)was proved to be effective catalyst for ammonia borane(AB)hydrolysis in aqueous solution.The turnover frequency(TOF)value of the supported nanocatalyst was 25.59mol_(H_2)min~(-1)·mol_M~(-1),almost twice as that of unsupported Pt_(0.1)Co_(0.9)NPs while the activation energy was 37.05 kJ mol~(-1).Furthermore,the SiO_2@Pt_(0.1)Co_(0.9)composite manifested high catalytic activity even after five cycles of reuse.     

Test for Heteroscedasticity in Partially Linear Regression Models

Testing heteroscedasticity determines whether the regression model can predict the dependent variable consistently across all values of the explanatory variables. Since the proposed tests could not detect heteroscedasticity in all cases, more precisely in heavy-tailed distributions, the authors established new comprehensive test statistic based on Levene's test. The authors built the asymptotic normality of the test statistic under the null hypothesis of homoscedasticity based on the recent theory of analysis of variance for the infinite factors level. The proposed test uses the residuals from a regression model fit of the mean function with Levene's test to assess homogeneity of variance. Simulation studies show that our test yields better than other methods in almost all cases even if the variance is a nonlinear function. Finally, the proposed method is implemented through a real data-set.     

微波接力组网的节点再优化研究

为进一步完善常规方法构建的微波接力网组网拓扑,提出了一种基于最优链路集的网络节点再优化方法。该方法综合考虑节点吸引系数、链路衰落概率、节点通信冗余等因素,借助网络拓扑优化的思想,采用遗传算法构造了微波接力网的最优链路集;以节点在该集合中的度为依据,通过对节点的合理排序,以部分用户节点代替非必要的干线节点,完善了组网拓扑。在修改链路和节点价值集后,该方法还可解决其他网络干线、中继节点的选择问题。     

An empirical investigation on the risk-return relationship of carbon future market

This paper examines the risk-return relationship for the carbon future market during Phases I, II and III of the European Union Emission Trading Scheme (EU ETS). The risk factors derived from the newly developed LSW model, are embedded into a GARCH framework. This new specification is compared with several GARCH-M type models analyzing the risk-return relationship in the carbon market. The results show that the new specification consistently achieves a good fit and possesses superior explanatory power for the European Union Allowance (EUA) data. Some policy suggestions regarding market efficiency are also provided.     

休闲视角下哈大齐城市群体育社团发展研究

运用文献资料、问卷调查、访谈、数理统计和逻辑分析等调查方法,对哈大齐城市群体育社团的发展概况、形成时间、注册情况、体育社团负责人情况、办公场所及活动场地设施情况、组织活动、经费来源渠道等方面的现状进行了详细的调查研究.在此基础上分析哈大齐城市群体育社团发展的优势以及面临的困难和需要解决的问题,并借鉴国内外社团发展经验,提出相应的意见和建议,为体育社团在黑龙江省更好地发展提供理论参考依据.     

试论滇文化青铜贮贝器的“纪念碑性”

中国的青铜时代又可称为“礼制艺术时代”。这一时期的时代特点是用青铜材料铸造各种“礼器”，这些礼器具有逐渐丰富的以政治和宗教为核心的“纪念碑性”，也可视之为另一种意义上的“纪念碑”。青铜贮贝器是滇文化时期的重器，其纪念碑性来源于铜鼓、铜桶等礼器，最初体现了滇人对权力与财富的占有。在此基础上表达了滇人在军事、宗教与社会生活等诸多方面的观念。从贮贝器纪念碑性产生、发展到衰落的历程可看出，滇文化时期的滇池区域也具有中国青铜时代的一般特点。     

Graphene-based hybrid materials and their applications in energy storage and conversion

Graphene attracts more and more scientists and researchers owing to its superior electronic,thermal,and mechanical properties.For material scientists,graphene is a kind of versatile building blocks,and considerable progress has been made in recent years.Graphene-based hybrid materials have been prepared by incorporating inorganic species and/or cross-linking of organic species through covalent and/or noncovalent interactions.The graphene-based hybrid materials show improved or excellent performance in various fields.In this review,we summarize the synthesis of graphene and graphene-based hybrid materials,and their applications in energy storage and conversion.     

浅谈水泥稳定碎石基层的质量控制

通过对基层的设计、试验、施工等各个环节的控制，提高水泥稳定碎石基层的强度，控制其裂缝的产生，从而保证工程质量。     

瞬变电磁法在一四井煤矿采空区探测中的应用

采用瞬变电磁法(TEM)在河南省新密市境内探查一四井煤矿采空区积水分布情况、断层等构造的含导水性情况及二1煤底板的富水性情况,为矿井防治水工作的合理实施提供依据.     

劳动、价值与生产方式:重估马克思政治经济学的若干重要概念

鲍德里亚的政治经济学批判企图瓦解马克思政治经济学的劳动二重性,使得符号价值成为一个抽象的支配者,从而使得传统的价值结构被瓦解为一个非真实的符号游戏,最终鲍德里亚的矛头指向生产方式概念,指认它使得马克思在深层逻辑上成为一个生产主义者,从而成为资产阶级劳动意识形态的沉默的捍卫者。对劳动、价值和生产方式概念的挑战及回应一方面证明马克思政治经济学的基地仍然是稳固的,但是另一方面马克思主义应当适时提出迫切的自我要求,即在当代它必须更新自己的政治经济学理论。