地下水脆弱性风险预警和评估的区间三角模糊多属性决策模型

应用基于逼近理想解排序法的区间三角模糊多属性决策模型,对三江平原六大分区地下水脆弱性进行了风险预警和评估.评估结果与前人吻合,可为有关决策部门采取相应降低环境风险的措施提供参考.实例验证表明,模型具有更高的计算精度和更好的评价效果,为有关环境风险决策部门对地下水风险预警和评估提供了新的思路和方法.     

Lattice Attacks on Digital Signature Schemes

We describe a lattice attack on the Digital Signature Algorithm (DSA) when used to sign many messages, m_i, under the assumption that a proportion of the bits of each of the associated ephemeral keys, y_i, can be recovered by alternative techniques.     

基于二进制转换的0—1规划隐枚举法

本针对常规隐枚举法,提出了一种基于二进制转换的快速有效枚举出所有可能解的方法,包括旨在加速优化过程的所有可能解的排列规则,并给出了一个算例。     

The apolar bilinear form in geometric modeling

Some recent methods of Computer Aided Geometric Design are related to the apolar bilinear form, an inner product on the space of homogeneous multivariate polynomials of a fixed degree, already known in 19th century invariant theory. Using a generalized version of this inner product, we derive in a straightforward way some of the recent results in CAGD, like Marsden's identity, the expression for the de Boor-Fix functionals, and recursion schemes for the computation of B-patches and their derivatives.

     

Reduction of fourth order ordinary differential equations to second and third order Lie linearizable forms

Meleshko presented a new method for reducing third order autonomous ordinary differential equations (ODEs) to Lie linearizable second order ODEs. We extended his work by reducing fourth order autonomous ODEs to second and third order linearizable ODEs and then applying the Ibragimov and Meleshko linearization test for the obtained ODEs. The application of the algorithm to several ODEs is also presented.     

Sobolev Stability of Plane Wave Solutions to the Nonlinear Schrödinger Equation

This article explores the questions of long time orbital stability in high order Sobolev norms of plane wave solutions to the NLSE in the defocusing case.     

Media pressures on Welsh language preservation

Despite compulsory school instruction in the Welsh language and strong cultural incentives to acquire the language, the most recent UK Census showed a downward trend in the number of speakers. The asymmetry in explicit language acquisition incentives is here considered to be offset by the media dominance of the English language. This dominance is modeled by the introduction of time-dependent connectivity and infectivity among English speakers into an adapted epidemiological model. Extrapolations up to 2050 are made, this being the announced date of a Welsh Assembly language-planning target of one million Welsh speakers.     

Extremal generalized centralizers in matrix algebras

We describe matrices with extremal generalized centralizers over algebraically closed fields.     

中西部地区人口就近城镇化意愿的受教育程度差异研究

基于对中西部地区15个省市农业转移人口就近城镇化意愿的问卷调查数据,以社会认同度为研究视角,构建多群组结构方程模型分析中西部地区人口就近城镇化的受教育程度差异及其影响因素。研究结果表明:个人特征差异性对中西部地区不同受教育程度的农业转移人口的就近城镇化意愿影响显著;中西部地区不同受教育程度的农业转移人口的社会认同度与其就近城镇化意愿显著正相关,且社会认同度对中西部地区小学及以下学历的农业转移人口就近城镇化意愿的影响最显著,大专及以上学历的农业转移人口的就近城镇化意愿受社会认同度的影响最小。     

Plasmon-Induced Radical-Radical Heterocoupling Boosts Photodriven Oxidative Esterification of Benzyl Alcohol over Nitrogen-Doped Carbon-Encapsulated Cobalt Nanoparticles

Selective oxidation of alcohols under mild conditions remains a long-standing challenge in the bulk and fine chemical industry, which usually requires environmentally unfriendly oxidants and bases that are difficult to separate. Here, a plasmonic catalyst of nitrogen-doped carbon-encapsulated metallic Co nanoparticles (Co@NC) with an excellent catalytic activity towards selective oxidation of alcohols is demonstrated. With light as only energy input, the plasmonic Co@NC catalyst effectively operates via combining action of the localized surface-plasmon resonance (LSPR) and the photothermal effects to achieve a factor of 7.8 times improvement compared with the activity of thermocatalysis. A high turnover frequency (TOF) of 15.6 h⁻¹ is obtained under base-free conditions, which surpasses all the reported catalytic performances of thermocatalytic analogues in the literature. Detailed characterization reveals that the d states of metallic Co gain the absorbed light energy, so the excitation of interband d-to-s transitions generates energetic electrons. LSPR-mediated charge injection to the Co@NC surface activates molecular oxygen and alcohol molecules adsorbed on its surface to generate the corresponding radical species (e.g., ⋅O₂⁻, CH₃O⋅ and R-⋅CH-OH). The formation of multi-type radical species creates a direct and forward pathway of oxidative esterification of benzyl alcohol to speed up the production of esters.