基于双曲线截断混沌多项式展开的地磁感应电流敏感度分析

地磁感应电流(GIC) 可能会引起变压器直流偏磁从而威胁电力设备和电网的安全。鉴于GIC计算所需的很多输入参数是不确定变量, 全面评估电网GIC水平及对电网的威胁有必要研究GIC的不确定度及GIC对输入变量的敏感度。基于混沌多项式展开(PCE) 提出了一种GIC的不确定度量化方法, 利用双曲线截断技术进一步提高了计算效率, 计算了GIC对输入参数的敏感度指标。以新疆750kV规划电网为例, 利用提出的方法对GIC进行了不确定度量化, 得到了GIC的均值和标准差等统计量。根据混沌多项式系数计算了Sobol敏感度指标, 得到了GIC对电场幅值和电网直流电阻等输入参数的敏感度。与蒙特卡罗法(MC) 相比, 此方法在保证精度的前提下大大提高了计算效率。     

Stereoselective Copper-Catalyzed Direct Aldol Reaction of β, γ-Unsaturated α-Ketoesters with Coumaran-3-Ones

An efficient direct aldol reaction between coumaran-3-ones and β, γ-unsaturated α-ketoesters by virtue of a chiral copper complex is developed. A series of coumaran-3-one derivatives containing chiral tertiary alcohol structures are obtained in excellent yields and stereoselectivities.     

Characterization and toxicological effects of three-dimensional graphene foams in rats in vivo

Current studies have demonstrated the advantage of graphene-based materials, which suggests their potential usage for biomedical applications. However, the in vivo toxicity and performance of three-dimensional (3D) graphene foams (GFs) remain largely unclear. In the present study, we identified the short-term and long-term tissue responses to GFs or graphene oxide foams (GOFs) in a rat model of subcutaneous implantation. Results from blood biochemistry, hematological analysis, histological examination, and behavioral test all indicated nearly no noticeable in vivo toxicity in either GF- or GOF-implanted rats during the first 2 weeks post-implantation. In addition, hematoxylin and eosin (H and E) stained images showed GFs or GOFs remained in the subcutaneous implantation site for at least 7 months without significant degradation after implantation. Our study demonstrates the non-biodegradable feature of GFs and GOFs as implanted scaffolds, while they exhibit good biocompatibility in vivo. It adds new evidence for the in vivo toxicological study of GFs and GOFs, which may provide reference for their biomedical applications.     

Copper-catalyzed 1,1-difunctionalization of terminal alkynes: a three-component reaction for the construction of vinyl sulfones

A copper-catalyzed 1,1-difunctionalization of terminal alkynes was achieved via a three-component reaction, providing a variety of vinyl sulfones with good yields and excellent chemo-and stereoselectivity. Preliminary mechanistic studies indicated that the reaction probably underwent a Cu-catalyzed formal C–H insertion to produce an allene intermediate, which was then trapped by a sulfonyl anion to give the corresponding product.     

Diketopiperazine Alkaloids from Penicillium spp. HS‐3, an Endophytic Fungus in Huperzia serrata

Cultivation of the fungus Penicillium spp. HS‐3, an endophytic fungus from the stems of Huperzia serrata, led to the isolation of a new diketopiperazine alkaloid, named as tryhistatin ( 1 ), together with three known ones, 2 – 4 , all of which share a similar backbone. The structure of 1 was established by detailed interpretation of the 1D‐ and 2D‐NMR spectra, and HR‐ESI‐MS data. Furthermore, 1D‐ and 2D‐NMR experiments were employed to elucidate the structure of 2 which was deduced previously only on the basis of the LC/MS method. In this article, we confirmed the correctness of the previously reported structure and made a complete assignment of the NMR signals of 2 for the first time.     

Two schemes of teleportation one-particle state by a three-particle GHZ state

In accordance with transformation operator, we give two schemes for teleporting an unknown one-particle state via a general GHZ state, Two Von Neumann type measurements are given for teleporting an unknown one-particle state. The first Von Neumann type measurement use four orthogonal states and the second Von Neumann type measurement is eight orthogonal states. For maximally entangled GHZ state, the successful probability and fidelity of two schemes both reach 1.     

荧光光谱法研究碳纳米管与牛血清白蛋白间相互作用

作为一类新型的纳米材料,碳纳米管(CNTs)所具有的独特结构、强细胞穿透能力和低免疫原性等特性引发了生物医学领域的广泛关注,并有望作为一类新型的药物和基因转运载体。因此,研究碳纳米管与生物大分子间的相互作用对其在体内的进一步应用具有极其重要的意义。本文运用荧光猝灭法、同步荧光法以及红边激发荧光位移法(REES法)研究了生理条件下碳纳米管与牛血清白蛋白(BSA)间的相互作用。结果表明,碳纳米管可引起BSA内源性荧光的静态猝灭,但同步荧光和REES的研究结果表明碳纳米管对BSA的构象基本没有影响。同时,通过对碳纳米管与BSA相互作用的机制的探讨,我们推测碳纳米管主要通过非特异性吸附的方式与BSA相互作用。