Unconventional superconductivity in PuCoGa5

In the Bardeen-Cooper-Schrieffer theory of superconductivity, electrons form (Cooper) pairs through an interaction mediated by vibrations in the underlying crystal structure. Like lattice vibrations, antiferromagnetic fluctuations can also produce an attractive interaction creating Cooper pairs, though with spin and angular momentum properties different from those of conventional superconductors. Such interactions have been implicated for two disparate classes of materials--the copper oxides and a set of Ce- and U-based compounds. But because their transition temperatures differ by nearly two orders of magnitude, this raises the question of whether a common pairing mechanism applies. PuCoGa5 has a transition temperature intermediate between those classes and therefore may bridge these extremes. Here we report measurements of the nuclear spin-lattice relaxation rate and Knight shift in PuCoGa5, which demonstrate that it is an unconventional superconductor with properties as expected for antiferromagnetically mediated superconductivity. Scaling of the relaxation rates among all of these materials (a feature not exhibited by their Knight shifts) establishes antiferromagnetic fluctuations as a likely mechanism for their unconventional superconductivity and suggests that related classes of exotic superconductors may yet be discovered.     

Speciation by hybridization in Heliconius butterflies

Speciation is generally regarded to result from the splitting of a single lineage. An alternative is hybrid speciation, considered to be extremely rare, in which two distinct lineages contribute genes to a daughter species. Here we show that a hybrid trait in an animal species can directly cause reproductive isolation. The butterfly species Heliconius heurippa is known to have an intermediate morphology and a hybrid genome, and we have recreated its intermediate wing colour and pattern through laboratory crosses between H. melpomene, H. cydno and their F1 hybrids. We then used mate preference experiments to show that the phenotype of H. heurippa reproductively isolates it from both parental species. There is strong assortative mating between all three species, and in H. heurippa the wing pattern and colour elements derived from H. melpomene and H. cydno are both critical for mate recognition by males.     

长歌短哭总未宜--小论史湘云

史湘云是“金陵十二钗”中最爽朗真率、英气夺人的“异样女子”。她出身不幸,却乐观开朗;才情洋溢,却不矜不骄;出言爽利,却坦荡无私;喜爱男妆,颇有名士之风、英豪之气。然而,这一切都填不平命运给她预设的陷阱,难逃“万艳同悲”的结局。     

Unconventional critical behaviour in a quasi-two-dimensional organic conductor

Changing the interactions between particles in an ensemble--by varying the temperature or pressure, for example--can lead to phase transitions whose critical behaviour depends on the collective nature of the many-body system. Despite the diversity of ingredients, which include atoms, molecules, electrons and their spins, the collective behaviour can be grouped into several families (called 'universality classes') represented by canonical spin models. One kind of transition, the Mott transition, occurs when the repulsive Coulomb interaction between electrons is increased, causing wave-like electrons to behave as particles. In two dimensions, the attractive behaviour responsible for the superconductivity in high-transition temperature copper oxide and organic compounds appears near the Mott transition, but the universality class to which two-dimensional, repulsive electronic systems belongs remains unknown. Here we present an observation of the critical phenomena at the pressure-induced Mott transition in a quasi-two-dimensional organic conductor using conductance measurements as a probe. We find that the Mott transition in two dimensions is not consistent with known universality classes, as the observed collective behaviour has previously not been seen. This peculiarity must be involved in any emergent behaviour near the Mott transition in two dimensions.     

湖北应山自然保护区蝶类多样性及区系的研究

对湖北省应山自然保护区蝶类资源进行调查研究，共发现蝶类68种，隶属8科45属，其中的蛱蝶亚科的类为保护区蝶类中的优势种群，研究表明，该地区蝶类具有东洋界属性向古北界过渡的特征。     

信阳地区蝶类记录

记录河南信阳地区蝶类73种,隶属于47属8科.东洋种25种(占34.25%),古北种29种(占39.73%),东洋古北共有种7种(占9.59%),广布种5种(占6.85%),中国特产种7种(占9.59%),其中河南省新记录3种.     

论李白形象的非凡化

李白的一些生平事迹在他生前身后被非凡化了,这是一个很值得注意的文化现象。“长庚入梦”的神话化、“醉使力士”的英雄化以及“捉月骑鲸”的传说化这三个非凡化了的形象是人们向往“非凡”的心理的真实体现。     

一种非常规矩形薄板弯曲元

提出一种与非常规三角形薄板弯曲元（ＴＲＵＮＣ）元相配的非常规矩形薄板弯曲元．这种新单元虽然采用与常规ＡＣＭ元相同的位移模式，但其精度一般都比后者高，而且比ＡＣＭ元的结构更简单，计算量更少，编程更容易     

一个非常规高效数值积分方法

利用一个特殊非协调矩形元导出了一个新的使用节点少而代数精度高的非常规数值积分公式.利用有限元方法的分析技巧,在较弱的条件下(即在Sobolev空间模意义下)证明了由此公式导出的复化公式具有与复化Simpson公式和复化Gauss公式一样的收敛阶O(h4).而且在精细剖分下,该公式比后两种积分公式大致节约25%的计算量.最后,通过两个数值算例验证了理论分析的正确性.     

多糖的非常规提取研究

多糖提取方法的研究已成为近年来的热点。随着研究的深入,出现了一些新的提取分离方法,如酸碱提取法、微波法、超声波法、酶提取法、超滤分离法、超临界萃取法、双水相萃取法等。通过对这些非常规提取方法进行综合性的论述,分析了这些方法的优缺点,并对其发展进行了展望。     

Reinforcement of pre-zygotic isolation and karyotype evolution in Agrodiaetus butterflies

The reinforcement model of evolution argues that natural selection enhances pre-zygotic isolation between divergent populations or species by selecting against unfit hybrids or costly interspecific matings. Reinforcement is distinguished from other models that consider the formation of reproductive isolation to be a by-product of divergent evolution. Although theory has shown that reinforcement is a possible mechanism that can lead to speciation, empirical evidence has been sufficiently scarce to raise doubts about the importance of reinforcement in nature. Agrodiaetus butterflies (Lepidoptera: Lycaenidae) exhibit unusual variability in chromosome number. Whereas their genitalia and other morphological characteristics are largely uniform, different species vary considerably in male wing colour, and provide a model system to study the role of reinforcement in speciation. Using comparative phylogenetic methods, we show that the sympatric distribution of 15 relatively young sister taxa of Agrodiaetus strongly correlates with differences in male wing colour, and that this pattern is most likely the result of reinforcement. We find little evidence supporting sympatric speciation: rather, in Agrodiaetus, karyotypic changes accumulate gradually in allopatry, prompting reinforcement when karyotypically divergent races come into contact.     

Captivity masks inbreeding effects on male mating success in butterflies

Small isolated populations are frequently genetically less diverse than core populations, resulting in higher homozygosity that can hamper their long-term survival. The decrease in fitness of organisms owing to matings between relatives is well known from captive and laboratory animals. Such inbreeding can have strongly deleterious effects on life-history traits and survival, and can be critical to the success of population conservation. Because pedigrees are hard to follow in the wild, most field studies have used marker loci to establish that fitness declines with increasing homozygosity. Very few have experimentally explored the effects of inbreeding in the wild, or compared observations in the laboratory with field conditions. Here, using a technique involving the transfer of marker dusts during copulation, we show that a small decrease in mating success of captive inbred male butterflies in cages is greatly accentuated in conditions with unconstrained flight. Our results have important implications for conservation and for studies of sexual selection because they show that the behaviours underlying patterns of mating can be profoundly influenced by a history of inbreeding or by any restraining experimental conditions.     

关于实施河南省非常规能源开发的思考

河南不仅沉积盆地分布较广,而且时代分布较全,不仅是常规能源主要生产基地,而且是新能源资源较大的省份,同样也必将是非常规能源(含地热资源)开发利用的后起之秀。开发利用河南非常规能源对优化能源结构,坚持资源和环境可持续发展,推进中原经济区和丝绸之路经济带建设,实现河南跨越式发展意义重大。为此,建议以实施河南非常规能源开发行动计划为依托,以设立的专业机构和重大项目规划为指导,统筹协调非常规能源的勘查、示范和开发工作;以非常规能源协同创新中心为综合研发协作平台,汇聚国际国内非常规能源的人才和技术;以三大示范实验区为载体,实现在关键技术和工艺上的突破。最终实现河南非常规能源的商业化开采,建设美丽中原,为丝绸之路经济带的发展添油加气。     

能量正交非常规板元的多重网格方法

给出了一种用多重网格方法求解能量正交非常规板元离散的双调和方程方法，且证明了在能量模变量意义下仍然能够优质非协调有限元求解双调和方程的最佳收敛性。