On the solution of a rational matrix equation arising in G-networks

We consider the problem of solving a rational matrix equation arising in the solution of G-networks. We propose and analyze two numerical methods: a fixed point iteration and the Newton–Raphson method. The fixed point iteration is shown to be globally convergent with linear convergence rate, while the Newton method is shown to have a local convergence, with quadratic convergence rate. Numerical experiments show the effectiveness of the proposed methods.     

SiC纤维增强钛基复合材料界面强度研究进展

综述SiC纤维增强钛基复合材料界面强度的影响因素、微观实验测试技术以及数值模拟技术。在此基础上着重分析了微观实验测试技术与数值模拟技术存在的问题，指出了界面强度定量研究的发展方向。     

Modulation on C‐ and N‐Terminal Moieties of a Series of Potent and Selective Linear Tachykinin NK2 Receptor Antagonists

Herein we describe the synthesis of a series of new potent tachykinin NK₂ receptor antagonists by the modulation of the C‐ and N‐terminal moieties of ibodutant (MEN 15596, 1 ). The N‐terminal benzo[b]thiophene ring was replaced by different substituted naphthalenes and benzofurans, while further modifications were evaluated at the C‐terminal tetrahydropyran moiety. Most compounds demonstrated a high affinity for the human NK₂ receptor and high in vitro antagonist potency, indicating that a wide range of substituents at both termini can be incorporated in the molecule without detrimental effects on the interactions with the NK₂ receptor. Selected compounds were tested in vivo confirming their activity as NK₂ antagonists. In particular, after both iv and id administration to guinea pig, compound 61 b was able to antagonize NK₂‐induced colonic contractions with a potency and duration‐of‐action fully comparable to the reference compound 1 (MEN 15596, ibodutant).     

石墨烯的制备方法与工艺研究进展

石墨烯的理论基础及实际应用研究已经成为该领域的前沿和热点课题之一。综述制备石墨烯的6种主要方法及工艺,重点介绍碳化硅外延生长法、化学气相沉积法及氧化石墨还原法的原理和工艺过程,比较几种相似方法的异同,并指出其相应优缺点及今后发展方向。     

铜基复合材料的研究现状

综述了目前SiC颗粒、碳纤维和SCS-6 SiC连续纤维增强铜基复合材料的研究现状,介绍了其制备技术及存在的问题,并指出了今后的研究重点和发展方向.     

裂解C9资源研究进展

文章就裂解C9资源综合利用技术的国内外发展进行了概括,从而体现了裂解C9资源发展的趋势以及展望。     

评定钛基复合材料界面强度的新方法

从微区角度建立了评定界面剪切强度的理论公式,用有限元方法验证该公式的准确性.此外,分析了钛基复合材料底部脱粘现象的原因以及热残余应力对纤维顶出最大载荷的影响.     

金属基复合材料界面残余应力的研究进展

综述了金属基复合材料界面残余应力的各种影响因素、残余应力的实验测试方法和理论分析方法及残余应力对复合材料宏观力学性能的影响,分析讨论了目前研究中存在的问题和不足之处,并指出了今后工作的重点与方向.     

贝壳珍珠母增韧机理研究进展

基于国内外对贝壳材料微结构研究的实验照片与力学性能的研究成果,描述了贝壳珍珠母独特的微观结构,包括无机层与有机基质层"砖-泥"式交错层叠结构、文石层波纹表面和文石表面纳米凸起与矿物桥结构等,同时也揭示了贝壳珍珠母微结构对其韧性的增强机理。对国内力学家近年来提出的微观结构"缺陷不敏感"增韧理论进行了理论阐述。     

The laryngeal mask in pediatric anesthesia

We carried out a perspective study in order to assess the ease of insertion, the type and the incidence of perioperative complications connected with the use of the Laryngeal Mask Airway (LMA). We examined 300 consecutive patients, M/F 261/39, average age 4.2 yrs. (range 0.1-16), ASA I-II, who underwent surgical operations of short or average length not involving the pleural, the oropharyngeal or the peritoneum cavity. The choice about anesthesia was left to the discretion of the anesthesiologist. In 27 cases the position of the LM was controlled through a flexible fiberoptics. In 269 patients (89.6%) the LMA was correctly positioned during the first attempt. In 27 patients (9%), 2 or more attempts were necessary, and in 4 patients (1.4%) it was not possible to set the LMA. No differences of statistical significance were noticed between the different size of LMA, with regards to the facility of insertion. The control through fiberoptics showed a correct position, from an anatomical point of view, in 11 patients (41%), whereas in 13 patients (48%) some signs of partial obstruction were noticed (epiglottis interposing between the opening of LMA and larynx) and in 3 patients (11%) vocal cords are not visible. The following complications took place: laryngeal spasm on induction (2.3%), cough or movements on positioning (2.3%), hypoxia (4.3%), obstruction (1%), laryngeal spasm on awakening (1.7%), trauma (5%) and vomiting (0.3%). No connections were found between the size of LMA and total complications. Nevertheless, cough or movement during positioning and laryngeal spasm on awakening were significantly more frequent with LMA n. 3. In our experience, the LMA proved to be effectual and safe in the control of the airway during elective operations in pediatric surgery.