以小麦再生苗叶片为外植体的愈伤组织诱导再生培养体系建立

以小麦幼胚愈伤组织为外植体,研究继代培养时间、外源激素及叶片大小对小麦试管苗叶片愈伤组织诱导和再生的影响。结果表明：继代培养1～6个月的胚性愈伤组织,有较高的再生苗频率;当生长素浓度为2,4-D2mg／L＋NAA1mg／L、叶片高度为4cm时,小麦试管苗叶片愈伤组织的诱导率最高,从而建立了小麦试管苗叶片愈伤组织诱导和再生的培养体系。     

《广绝交论》作意新探——兼论梁初荆州雍州两大集团的矛盾斗争

刘峻《广绝交论》明指到洽兄弟,实指梁武帝萧衍。萧衍齐末在雍州起兵,与荆州萧颖胄集团结成联盟,取得灭齐之战的胜利。然而荆雍两大集团间始终存在矛盾。天监三年,曹景宗等坐视原属荆州集团的司州刺史蔡道恭被围而不救,致使蔡于城中病死、司州陷落,便是这一矛盾的表现。刘峻因为得罪萧衍而仕途受阻,对萧衍衔怨很深,于是作此文暗讽。     

Surface superconductivity in the type II Weyl semimetal TaIrTe4

The search for unconventional superconductivity in Weyl semimetal materials is currently an exciting pursuit, since such superconducting phases could potentially be topologically non-trivial and host exotic Majorana modes. The layered material TaIrTe₄ is a newly predicted time-reversal invariant type II Weyl semimetal with the minimum number of Weyl points. Here, we report the discovery of surface superconductivity in Weyl semimetal TaIrTe₄. Our scanning tunneling microscopy/spectroscopy (STM/STS) visualizes Fermi arc surface states of TaIrTe₄ that are consistent with the previous angle-resolved photoemission spectroscopy results. By a systematic study based on STS at ultralow temperature, we observe uniform superconducting gaps on the sample surface. The superconductivity is further confirmed by electrical transport measurements at ultralow temperature, with an onset transition temperature (T_c) up to 1.54 K being observed. The normalized upper critical field h*(T/T_c) behavior and the stability of the superconductivity against the ferromagnet indicate that the discovered superconductivity is unconventional with the p-wave pairing. The systematic STS, and thickness- and angular-dependent transport measurements reveal that the detected superconductivity is quasi-1D and occurs in the surface states. The discovery of the surface superconductivity in TaIrTe₄ provides a new novel platform to explore topological superconductivity and Majorana modes.     

Superconductivity in chromium nitrides Pr3Cr10-xN11 with strong electron correlations

Exploration of superconductivity in Cr-based compounds has attracted considerable interest because only a few Cr-based superconductors (CrAs, A₂Cr₃As₃ and ACr₃As₃ (A = K, Rb, Cs, Na)) have been discovered so far and they show an unconventional pairing mechanism. We report the discovery of bulk superconductivity at 5.25 K in chromium nitride in Pr₃Cr_10-xN₁₁ with a cubic lattice structure. A relatively large upper critical field of H_c2(0) ∼ 12.6 T is determined, which is larger than the estimated Pauli-paramagnetic pair-breaking magnetic field. The material has a large electronic specific-heat coefficient of 170 mJ K⁻² mol⁻¹—about 10 times larger than that estimated by the electronic structure calculation, which suggests that correlations between 3d electrons are very strong in Pr₃Cr_10-xN₁₁, and thus quantum fluctuations might be involved. Electronic structure calculations show that the density of states at the Fermi energy are contributed predominantly by Cr 3d electrons, implying that the superconductivity results mainly from the condensation of Cr 3d electrons. Pr₃Cr_10-xN₁₁ represents a rare example of possible unconventional superconductivity emerging in a 3D system with strong electron correlations. Nevertheless, clarification of the specific pairing symmetry needs more investigation.     

Supply Hub在现代供应链中的应用与发展

在企业竞争越来越激烈的今天,供应链中的供需不确定性对企业运行以及盈利造成了越来越大的影响,而供应链整体协同合作对供应链利润的作用也日益显著,在这种环境下越来越多的企业发展出了基于Supply Hub的供应体系.本文通过国内外制造业对Supply Hub的应用,阐述在现代企业中Supply Hub对JIT生产模式的重要作用,并对Supply Hub的研究现状进行了总结与分析.     

对中学语文审美教学的几点思考

在中学语文教学中进行审美教育,不但有利于提高语文教学的质量和效率,深化语文教育的效果,促进学生学习语文的主动性和积极性,同时还有利于培养学生的审美想像力。于是,探索语文审美教学便成为中学语文教学改革的一个重要课题。一、语文教学与审美教育的关系在语文教学中实现美育,是语文教学应有之义。一方面,语文教学内容所具有的审美属性,决定了语文教学与美育有着必然的联系。即二者相互依存、互为条件,语文教学的过程必须贯穿美育,美育通过语文教学得以实现。现行的中学语文教材,80%的课文是中外文学名作佳篇。文学作品中优美的语言,不…     

中国B2C电子商务中消费者信任前因的实证研究

网上信任危机限制了消费者进行在线交易,提高消费者对在线公司的信任度是促进中国B2C电子商务发展的重要途径。论文对影响中国消费者对在线公司信任的因素进行了实证研究。研究发现,网站隐私保护与安全控制措施及政策、公司的规模与品牌是最重要的因素,消费者个体特征和公司网站的易用性等品质因素对信任没有显著影响。公司应该在安全技术及政策、规模以及知名度等方面采取措施来提高消费者对在线公司的信任度。     

服务商道德风险与资金限制下的研发外包契约选择:奖励还是惩罚

针对研发外包中服务商道德风险防范与激励问题,在考虑服务商自有资金限制下,设计了奖励成功、惩罚失败、奖—惩混合的研发外包契约,并对三种契约的可行性与有效性进行了比较,得到各类契约的选择条件。研究表明,奖-惩混合契约完全等价奖励契约或者惩罚契约,而服务商资金实力是影响契约可行性与有效性的关键因素。具体而言,当服务商资金实力很差,具有较大负债时,奖励与惩罚契约均不可行,客户不应该把研发项目外包给此类企业;而随着服务商资金实力的增加,负债减少到一定程度时,首先是惩罚契约可行,此后当服务商资金实力继续增加到一定程度,奖励契约才可行,并且惩罚契约优于奖励契约;当服务资金实力强到一定程度后,奖励契约与惩罚契约均可行,且二者等价。     

Interleukin-6 polymorphisms modify the risk of periodontitis： a systematic review and meta-analysis

Objective  

To clarify the association of IL-6 polymorphisms and periodontitis, a meta-analysis of case-control studies and a systemic review were conducted.     

实用主义教育思想对 二十世纪二三十年代中国师生关系思想的影响

实用主义教育思想对二十世纪二三十年代中国师生关系思想有着极大的影响。当时我国教育理论界的大多数人都主张批判师道尊严,强调要以学生为中心,向学生学习,尊重学生个性,充分发挥学生的自动力,建立民主、平等、合作的师生关系。这些思想颠覆了我国传统师生关系理念,促使中国师生关系思想从传统走向现代。但也存在着盲目照搬,对我国传统师生关系思想否定太过,片面强调儿童中心,对教师的地位和作用估计太低,把以学生为本与儿童绝对中心相等同等缺点。