H_3BO_3掺杂Li_2ZnTi_3O_8陶瓷的微波介电性能

采用传统的固相烧结工艺制备了H3BO3掺杂的Li2ZnTi3O8陶瓷。研究了H3BO3掺杂量对所制Li2ZnTi3O8陶瓷的烧结特性、相成分、微观结构以及微波介电性能的影响。结果表明:H3BO3对于所制陶瓷相成分没有影响,仅为单一的Li2ZnTi3O8相;H3BO3能够将Li2ZnTi3O8陶瓷的烧结温度降低200℃左右,同时没有显著损害该陶瓷的微波介电性能;当H3BO3掺杂量为质量分数2.0%时,950℃烧结的Li2ZnTi3O8陶瓷微波具有良好的介电性能:εr=25.99,Q.f=54 926GHz,τf=-12.17×10–6/℃。     

复合助烧剂对CaO-BaO-Li2O-Sm2O3-TiO2陶瓷低温烧结和性能的影响

采用传统固相反应法制备了CaO-BaO-Li_2O-Sm_2O_3-TiO_2(CBLST)陶瓷。研究了复合添加BaCu(B_2O_5)(BCB)和Li_2O-B_2O_3-SiO_2(LBS)对CBLST陶瓷的烧结特性、微观组织、相组成及介电性能的影响。结果表明:添加质量分数w(BCB)=60%和w(LBS)=0.5%～5.0%的CBLST陶瓷的相组成未改变,仍为正交钙钛矿相和BaSm_2Ti_4o_(12)(BST)相。通过添加w(BCB)=6.0%和w(LBS)=0.5%,可以使CBLST陶瓷的烧结温度从1325℃降到1050℃,并且在1050℃烧结2h的CBLST陶瓷介电性能优良:ε_r=81.9,tanδ=0.0062,τ_f=–3.75×10~(–6)/℃,其tanδ比纯CBLST陶瓷的tanδ(0.016)明显降低。     

掺杂Li_2CO_3低温烧结ZnO-TiO_2系介质陶瓷的研究

用传统工艺合成了Li2CO3掺杂的ZnO-TiO2系微波介质陶瓷,系统研究了其烧结行为、显微结构和介电性能。结果表明:掺杂质量分数1%的Li2CO3可使ZnO-TiO2陶瓷的烧结温度从1100℃降到980℃;掺杂3%Li2CO3时,在950℃保温2h烧结,于6～8GHz测试试样的介电性能为:εr约为20,Q·f约为40000GHz,τf约为–14×10–6℃–1。     

高温合金-不锈钢异种金属光纤激光焊接试验研究

采用光纤激光对GH3128与304不锈钢进行对接焊,研究了焊接速度、激光作用位置等工艺参数对焊缝成形及接头力学性能的影响规律。结果表明:通过工艺参数优化,可以获得无气孔、裂纹等缺陷的焊接接头。焊接速度较低时,焊缝上下部的熔宽较大,随焊接速度的提高,焊缝下部的熔宽减小到与中部相当,随激光作用位置向不锈钢侧靠近,接头强度和延伸率降低。当激光作用于GH3128侧,在焊接速度小于2m/min时,焊接接头拉伸试验时断于304不锈钢母材:当焊接速度为3m/min时,焊缝存在未熔合,接头强度仅为母材的37%。     

一种锂电池电量监测电路设计方法

针对常见锂电池过压过流保护、电池电量监测问题,提出一种实用的解决方案,该方案采用DS2762芯片作为核心器件,配合必须的外围器件完成对锂电池的监测,通过数据线与主控制器交换信息,为主控制器提供电池的各种状态信息。该电路方案性能优良,扩展性强,可以广泛应用于各类电子设备,完成对电池的全面监控和管理。     

Furnishing Continuous Efficient Bidirectional Polysulfide Conversion for Long-Life and High-Loading Lithium–Sulfur Batteries via the Built-In Electric Field

Most catalysts cannot accelerate uninterrupted conversion of polysulfides, resulting in poor long-cycle and high-loading performance of lithium–sulfur (Li–S) batteries. Herein, rich p-n junction CoS₂/ZnS heterostructures embedded on N-doped carbon nanosheets are fabricated by ion-etching and vulcanization as a continuous and efficient bidirectional catalyst. The p-n junction built-in electric field in the CoS₂/ZnS heterostructure not only accelerates the transformation of lithium polysulfides (LiPSs), but also promotes the diffusion and decomposition for Li₂S the from CoS₂ to ZnS avoiding the aggregation of lithium sulfide (Li₂S). Meanwhile, the heterostructure possesses a strong chemisorption ability to anchor LiPSs and superior affinity to induce homogeneous Li deposition. The assembled cell with a CoS₂/ZnS@PP separator delivers a cycling stability with a capacity decay of 0.058% per cycle at 1.0 C after 1000 cycles, and a decent areal capacity of 8.97 mA h cm⁻² at an ultrahigh sulfur mass loading of 6 mg cm⁻². This work reveals that the catalyst continuously and efficiently converts polysulfides via abundant built-in electric fields to promote Li–S chemistry.     

Quantum Phases of 7Li Atoms in an Optical Lattice

We study the quantum phases that may arise when ⁷Li atoms that possess an attractive two-body interaction are loaded into an optical lattice. The phase diagram that we have obtained for ⁷Li atoms within a mean-field approximation is composed of the superfluid and Mott-insulator phases as for bosonic atoms with a repulsive two-body interaction. We have found that the repulsive three-body interaction plays a vital role in stabilizing the quantum phases of ⁷Li atoms in an optical lattice. The ground-state energy and the average atom number per lattice site in the quantum phases have been calculated and found to be consistent with the nature of these quantum phases. The excitation spectra of quasi-particles and quasi-holes in the Mott-insulator phase have also been calculated. In our general investigation of the effects of the three-body interaction that is allowed to vary, we have found that the energies of quasi-particles are substantially increased as the strength of the repulsive three-body interaction is raised, whereas the energies of quasi-holes are slightly decreased at low-filling factors of atoms and substantially decreased at large filling factors.     

牙鲆生长激素基因的克隆及其在大肠杆菌中的融合表达

采用逆转录聚合酶链式反应(RT-PCR)方法,从牙鲆(Paralichthys olivaceus)脑垂体总RNA中扩增出编码牙鲆生长素(GH)成熟肽基因序列。重组至融合表达载体pGEX-4T-3中,构建成牙鲆GH基因融合表达载体pGEX-gh,转化大肠杆菌BL21(DF3),筛选阳性克隆,IVIG诱导表达。经SDS-PAGE电泳显示在45kD处有特异的蛋白条带出现,该蛋白的表达量随诱导时间的延长而增加,3h达最高值,达到细胞总蛋白的18．3％。该融合蛋白在胞内主要以包涵体状态存在,经优化表达条件,成功地获得了可溶性的融合蛋白,经Glutathione Sepharase 4B凝胶纯化后用Western-blotting检测表明其为牙鲆生长激素,并通过酶联免疫吸附受体法证实其具有生物学活性。