Plant Regeneration in vitro of Cuscuta chinensis Lam.

选取萌发3～5d、长度3～5cm的中国菟丝子(Cuscuta chinensis Lam.)幼苗,将其分为上、中、下3部分并作为外植体进行离体培养与植株再生研究。结果表明,其上、中部片段更适宜愈伤组织诱导;诱导培养基以添加1mgL-1NAA和1mgL-1BA的MMS培养基效果最好,此培养基也可用于愈伤组织的继代培养,愈伤组织在上述培养基中已生长一年之久。分化培养基为添加1mgL-1BA的MMS培养基,平均每块愈伤组织可以产生2.8株植株。An efficient method of callus induction and plant regeneration of Cuscuta chinensis was established.The seedlings germinated for 3~5 d and about 3~5 cm length were selected as explants,and then divided into three parts,upper,middle and lower.Callus were inducted from upper or middle parts of seedlings on a modified Murashige and Skoog(MMS)medium supplemented with 1 mg L-1 NAA and 1 mg L-1 BA.The calli have been subcultured on such medium for over a year.Shoot regeneration from callus was achieved on MMS medium containing 1 mg L-1 BA and could obtain 2.8 shoots per callus

第十八届美国理论与应用力学大会总结

1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

Y型聚乙二醇干扰素琢-2b注射液治疗HCV基因2/3型慢性丙型肝炎患者疗效和安全性的多中心随机对照试验研究

目的以标准剂量的聚乙二醇干扰素(Peg IFN)α-2a联合利巴韦林作为阳性对照,评价新型试验药物Y型Peg IFNα-2b注射液联合利巴韦林治疗2型/3型慢性丙型肝炎(CHC)患者的疗效和安全性。方法采用多中心、随机开放、阳性药对照的Ⅲ期临床试验,筛选符合要求的2型/3型CHC患者,按照2:1的比例随机分配到Y型Peg IFNα-2b组和Peg IFNα-2a组,同时口服利巴韦林,疗程24 w,停药随访24 w。采用Abbott Real Time HCV Genotype II检测HCV基因型,采用Cobas Taq Man实时定量PCR法检测血清HCV RNA水平。详细记录不良事件。主要疗效指标为持续病毒学应答(SVR),并进行非劣效检验。结果本试验实际入组2型/3型CHC患者255例,实际治疗241例。全分析集(FAS)数据显示,158例试验组和83例对照组患者SVR分别为85.4%(95%CI 79.94%~90.94%)和79.5%(95%CI 70.84%~88.20%,P=0.2402);对符合方案分析集(PPS)人群分析显示,试验组和对照组患者SVR分别为87.9%(95%CI 82.45%~93.27%)和85.9%(95%CI 77.82%~94.01%,P=0.7060),率差的95%可置信区间均符合非劣效标准;对PPS人群分析显示,85.8%受试者获得了早期病毒学应答(RVR),RVR的阳性预测值为90.1%;试验组和对照组不良事件发生率相似,分别为95.6%和95.2%,严重不良事件发生率分别为3.8%和3.6%。结论应用Peg IFNα联合利巴韦林治疗2型/3型CHC患者,新型试验药物Y型Peg IFNα-2b具有与对照药物Peg IFNα-2a相似的疗效和安全性。国家科技部“十二五”重大专项(编号:2012ZX10002-003)；“重大新药创制”十二五科技重大专项(编号:2012ZX09303019)

商业可重复使用火箭关键技术与创新

近8年来,美国太空探索技术(SpaceX)公司的“猎鹰” 9火箭凭借着超高的运载效率和可重复使用技术,在世界运载领域独树一帜。随着航天产业的发展,研制低成本、高可靠、使用方便灵活的可重复使用运载器是下一阶段航天技术发展的重要方向之一,而突破可重复使用关键技术是发展可重复使用火箭的前提条件。本文将对目前典型可重复使用火箭的概况进行介绍,并论述可回收火箭的关键技术

Underwater acoustic metamaterial based on double Dirac cone characteristics in rectangular phononic crystals

We theoretically construct a rectangular phononic crystal (PC) structure surrounded by water with C-2v symmetry, and then place a steel rectangular scatterer at each quarter position inside each cell. The final complex crystal has two forms: the vertical type, in which the distance s between the center of the scatterer and its right-angle point is greater than 0.5a, and the transverse type, in which s is smaller than 0.5a (where a is the crystal constant in the x direction). Each rectangular scatterer has three variables: length L, width D, and rotation angle theta around its centroid. We find that, when L and D change and theta is kept at zero, there is always a linear quadruply degenerate state at the corner of the irreducible Brillouin zone. Then, we vary theta and find that the quadruply degenerate point splits into two doubly-degenerate states with odd and even parities. At the same time, the band structure reverses and undergoes a phase change from topologically non-trivial to topologically trivial. Then we construct an acoustic system consisting of a trivial and a non-trivial PC with equal numbers of layers, and calculate the projected band structure. A helical one-way transmission edge state is found in the frequency range of the body band gap. Then, we use the finite-element software Comsol to simulate the unidirectional transmission of this edge state and the backscattering suppression of right-angle, disorder, and cavity defects. This acoustic wave system with rectangular phononic crystal form broadens the scope of acoustic wave topology and provides a platform for easy acoustic operation

基于非圆齿轮的机械臂重力补偿机构研究

目前大多数机器人工作过程中需要消耗大量能量来克服自身重力,为了降低能耗并提高机器人性能,提出一种用于转动关节机械臂的重力补偿装置,该装置采用非圆齿轮行星轮系扭转弹簧机构,可实现机械臂任意可达工作空间的重力补偿;建立机械臂静平衡力学模型,根据静平衡约束条件设计非圆齿轮行星轮系,对非圆齿轮行星轮系传动比分配进行讨论,得到满足力矩平衡的最简轮系;以2R平行四杆机构机械臂为例进行设计分析,并导入ADAMS中进行验证,仿真结果表明,重力补偿机构有效降低了驱动力矩