Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi_(1-y)/2Fe_yMg_(1-y)/2O₃–(x)CaTiO₃ (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μ_B/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10⁻⁷ s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.     

2000—2015年中国铜废碎料贸易及效益风险分析

铜是具有重要战略意义的关键金属。中国长期以来进口“六类废杂铜”和“七类废杂铜”两种废碎料来冶炼再生铜。本文基于海关贸易和有色金属工业统计数据,利用物质流分析和生命周期评价方法研究了铜废碎料贸易的资源、环境和经济效益以及环境与健康风险。结果显示：①2000—2015年,中国累计进口铜废碎料实物量6680万t,其中含金属铜约2000万t,占同期国内再生铜累计产量的56%;②相比利用铜矿石生产精炼铜,利用进口铜废碎料生产再生铜在非生物性资源消耗、温室效应和人体毒性等方面减少了一系列环境影响,同时累计节约铜矿山投资成本约580亿美元。然而,进口的“七类废杂铜”在带来资源效益的同时也造成严重的区域性环境与健康风险：一是进口低品位铜废碎料中夹杂大量有机物,在拆解和熔炼过程中容易产生二恶英等有毒有害物质;二是部分工业园区和小企业在工艺、技术、空间布局和生产管理等方面的落后引发了局部地区较为严重的环境和健康危害。因此,建议辩证和全面地认识铜废碎料进口带来的效益和风险,在坚决禁止进口“以回收铜为主的废电机、电线、电缆和五金电器”这些“七类废杂铜”的同时,继续利用进口“六类废杂铜”作为重要的铜资源,以降低中国对原生铜矿石的依赖以及造成的采矿和原矿冶炼阶段的环境影响。     

学位论文馆际互借的知识产权风险及其规避

依据学位论文的著作权状态,分析了馆际互借学位论文的知识产权风险,提出了防范和规避风险的操作模式及方案。     

小波变换在信号奇异性检测中的应用

小波变换突破了传统傅里叶变换等信号处理方法的限制,在时域和频域上可同时对信号实现局部化处理,这更符合信号非平稳的变频带结构特征,因而在信号检测奇异性等方面具有广泛的应用价值。本文简要地介绍了小波应用在信号奇异性检测方面变换的基本原理,并通过仿真实验进行了验证。     

在华跨国公司的社会责任实践与强化问题探析

跨国公司的社会责任对自身的可持续发展及全球经济与贸易的增长都具有重要的意义。可部分进入中国市场的跨国公司却做出了忽略甚至缺失社会责任的事情。本文分析了这种现象的原因,并提出了若干促进在华跨国公司承担社会责任的措施。     

具有动态学习能力的分层进化粒子群优化算法

针对粒子群算法(PSO)在优化高维多极值问题时容易陷入局部极值的问题,结合分层进化与动态学习策略,提出一种具有动态学习能力的分层进化粒子群优化算法(DHEPSO).该算法首先根据粒子适应度值将粒子划分为不同层级,对不同层级粒子采取不同的进化策略,避免迭代后期种群多样性快速消失;然后根据粒子所属层级的不同动态调整粒子学习...     

收益分配公平目标下的教育结构调整

以社会经济地位指数(SEI)作为衡量收益分配是否公平的一个替代性指标,利用课题组的调查数据将不同类型教育形式对收益分配的影响进行实证分析的结果表明,我国社会成员收益的两极分化情况较为严重。解决这一问题需要调整我国现行的教育结构,即完善就业前培训制度,实行普通高中后职业教育;加强专科层次的职业教育;大力发展本科层次的职业教育,试点更高层次的职业教育。     

中美高校兼职教师聘用机制的比较与探析

文章对中美两国高校兼职教师的聘用程序、比例结构、来源及管理等方面进行了比较分析,指出我国应借鉴美国高校兼职教师管理的成功经验,加快兼职教师社会资源的开发与利用,加强高校师资队伍的建设。     

计算机软件课程立体化教学模式的探索

文章从分析高校计算机专业的教学实际与高校计算机专业的教育目标的矛盾入手,用计算机教育学的理念、核心、方法,分析和探索计算机软件课程的立体化教学模式。从教学理念、教学内容、教材选用、教学方法、教学手段和考核评定等几个方面,建立立体化教学模式。     

Genomic diversity and post-admixture adaptation in the Uyghurs

Population admixture results in genome-wide combinations of genetic variants derived from different ancestral populations of distinct ancestry, thus providing a unique opportunity for understanding the genetic determinants of phenotypic variation in humans. Here, we used whole-genome sequencing of 92 individuals with high coverage (30–60×) to systematically investigate genomic diversity in the Uyghurs living in Xinjiang, China (XJU), an admixed population of both European-like and East-Asian-like ancestry. The XJU population shows greater genetic diversity, especially a higher proportion of rare variants, compared with their ancestral source populations, corresponding to greater phenotypic diversity of XJU. Admixture-induced functional variants in EDAR were associated with the diversity of facial morphology in XJU. Interestingly, the interaction of functional variants between SLC24A5 and OCA2 likely influences the diversity of skin pigmentation. Notably, selection has seemingly been relaxed or canceled in several genes with significantly biased ancestry, such as HERC2–OCA2. Moreover, signatures of post-admixture adaptation in XJU were identified, including genes related to metabolism (e.g. CYP2D6), digestion (e.g. COL11A1), olfactory perception (e.g. ANO2) and immunity (e.g. HLA). Our results demonstrated population admixture as a driving force, locally or globally, in shaping human genetic and phenotypic diversity as well as in adaptive evolution.