Improved thermoelectric performance in p-type Bi_(0.48)Sb_(1.52)Te_3 bulk material by adding MnSb_2Se_4

Bismuth telluride(Bi_2Te_3) based alloys, such as p-type Bi_(0.5)Sb_(1.5)Te_3, have been leading candidates for near room temperature thermoelectric applications. In this study, Bi_(0.48)Sb_(1.52)Te_3 bulk materials with MnSb_2Se_4 were prepared using high-energy ball milling and spark plasma sintering(SPS) process. The addition of MnSb_2Se_4 to Bi_(0.48)Sb_(1.52)Te_3 increased the hole concentration while slightly decreasing the Seebeck coefficient, thus optimising the electrical transport properties of the bulk material. In addition, the second phases of MnSb_2Se_4 and Bi_(0.48)Sb_(1.52)Te_3 were observed in the Bi_(0.48)Sb_(1.52)Te_3 matrix. The nanoparticles in the semi-coherent second phase of MnSb_2Se_4 behaved as scattering centres for phonons,yielding a reduction in the lattice thermal conductivity. Substantial enhancement of the figure of merit, ZT, has been achieved for Bi_(0.48)Sb_(1.52)Te_3 by adding an Mn_(0.8)Cu_(0.2)Sb_2Se_4(2mol%) sample, for a wide range of temperatures, with a peak value of 1.43 at 375 K, corresponding to ~40% improvement over its Bi_(0.48)Sb_(1.52)Te_3 counterpart. Such enhancement of the thermoelectric(TE) performance of p-type Bi_2Te_3 based materials is believed to be advantageous for practical applications.     

新型设备故障分析及排查思路

交流电驱动转盘是由电机驱动,变频器控制实现转盘的精确调速,达到钻井作业的目的。在正常工作时,由司钻在司钻台通过调速手轮发出给定命令,通过变频器控制,精确调节输出电流至交流电机,电机连接转盘联动箱从而驱动转盘。许多故障情况下不仅仅是电气控制故障,也不是单纯的机械原因,而是两种因素共同存在所引发的故障,所以维修人员不能单一从电气或者机械角度去排查。     

较宽压力范围内甲烷水合物的分子动力学模拟

利用GROMACS程序对0.1 MPa至30 MPa较宽压力范围内甲烷水合物体系进行分子动力学模拟.观察不同时刻甲烷水合物体系的分子分布状况,统计氢键数、径向分布函数、配位数等结构性质以及甲烷、水分子的扩散系数.结果表明甲烷水合物中水分子之间形成强大的氢键网络将甲烷包围并挤压,出现明显分相现象,导致压力对甲烷水合物中甲烷和水的局部结构和扩散系数的影响不同,并且甲烷水合物中甲烷的局部结构和扩散系数与纯甲烷体系差异很大.     

Recent advances in non-Pb-based group-Ⅳ chalcogenides for environmentally-friendly thermoelectric materials

Pb-based group-IV chalcogenides including Pb Te and Pb Se have been extensively studied as high performance thermoelectric materials during the past few decades.However,the toxicity of Pb inhibits their applications in vast fields due to the serious harm to the environment.Recently the Pb-free group-IV chalcogenides have become an extensive research subject as promising thermoelectric materials because of their unique thermal and electronic transport properties as well as the enviromentally friendly advantage.This paper briefly summarizes the recent research advances in Sn-,Ge-,and Sichalcogenides thermoelectrics,showing the unexceptionally high thermoelectric performance in Sn Se single crystal,and the significant improvement in thermoelectric performance for those polycrystalline materials by successfully modulating the electronic and thermal transport through using some well-developed strategies including band engineering,nanostructuring and defect engineering.In addition,some important issues for future device applications,including N-type doping and mechanical and chemical stabilities of the new thermoelectrics,are also discussed.     

关于高铁调度属地化施工的几点心得

高铁施工是铁路施工中等级最高的安全风险源,本文分析了高铁调度属地化施工的特点,然后从技术、安全、联锁管理等方面总结施工组织技术管理及高安全风险源,对今后的高铁施工有着比较重要的指导意义。     

白蚁头部纤维素酶基因的克隆与表达

对中国广泛分布的黑翅土白蚁(Odontotermes formosanus)头部内切β-1,4葡聚糖酶(endo-beta-1,4-glucanase)基因进行克隆,并在原核生物大肠杆菌体内进行了表达.根据Genbank上已报道的endo-beta-1,4-glu-canase基因设计引物,通过RT-PCR获得1个完整的内切β-1,4葡聚糖酶基因.通过基因测序以及基因比对发现与Genbank上发表的内切β-1,4葡聚糖酶同源性高达96.40%.将获得的基因导入大肠杆菌体内进行诱导表达,表达出的蛋白经Western-blot检测,为该基因所表达的目的蛋白.实验为进一步对内切β-1,4葡聚糖酶的实际应用奠定一定的实验基础.     

四个基于酰腙配体的双核苄基锡配合物的合成、晶体结构及体外抗癌活性

通过微波"一锅法"合成了4个双核苄基锡配合物:{[C_4H_3S(O)C=N-N=C(Me)COO](PhCH_2)_2Sn(MeOH)}_2(C1)、{[C_4H_3S(O)C=NN=C (Me)COO](p-Cl-C_6H_4CH_2)_2Sn (MeOH)}_2(C2)、{[C_4H_3S (O)C=N-N=C (PhCH_2)COO](PhCH_2)_2Sn (MeOH)}_2(C3)、{[C_4H_3S (O)C=N-N=C(PhCH_2)COO](p-Cl-C_6H_4CH_2)_2Sn(MeOH)}_2(C4),利用元素分析、IR、~1H NMR、~(13)C NMR、~(119)Sn NMR、HRMS以及X射线单晶衍射等表征了配合物结构。4个配合物分子均为双锡核分子,以Sn_2O_2四元环为中心对称,且中心锡原子与配位原子形成七配位畸变五角双锥构型。测试了配合物C1～C4的热稳定性以及配合物对癌细胞H460、HepG2、MCF7的体外抑制活性,结果表明:配合物C2是4个新合成的配合物中抑制癌细胞效果最好的化合物。