基于接触的捞雷具夹紧爪接触面形状优化

介绍了在捞雷具夹紧爪设计过程中引入的基于接触的有限元形状优化设计方法．传统的机械设计方法仅考虑了零件的几何尺寸，而对其形状的设计却考虑不够，导致设计结果不理想．文中将基于接触的有限元形状优化方法应用于传统的机械设计过程．对捞雷具夹紧爪建立基于有限元分析的优化设计模型，使夹紧爪既能满足打捞鱼雷的要求，又得到了优化的形状．结构的特性与受力状况均得到改善．     

计算机图象检测在生丝检验中应用的研究

本文讨论了计算机图象检测用于生丝检验的新方法，介绍了测量的算法和异常情况的处理，并提出了实用测试系统的设计要点     

水土保持治理对河道系统影响研究的若干基础理论问题

依据流域环境系统的观点，认为开不土保持治理应考虑对下游河道系统的影响，并通过近期初步研究，论述了河道系统对流域治理的反馈响应问题。经，提出了建议开展水土保持治理对河道系统影响的若干基础理论问题。     

Hydrolytic cleavage of epoxy ring during the epoxidation of alkenes over boron modified titanium silicalites of MFI topology

Boron incorporated bifunctional microporous titanium silicalites of MFI topology, which contained both oxidizing and acidic sites, can effectively catalyse the selective epoxidation of α-olefins, followed by ring opening of the epoxide through hydrolysis reactions. Data are presented that correlate the oxidative and acidic functions of these catalysts. The rate of hydrolysis is seen to depend on the phases generated by incorporation of the boron atoms. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effective design of barrier enclosure to contain aerosol emissions from COVID-19 patients

Facing shortages of personal protective equipment, some clinicians have advocated the use of barrier enclosures (typically mounted over the head, with and without suction) to contain aerosol emissions from coronavirus disease 2019 (COVID-19) patients. There is, however, little evidence for its usefulness. To test the effectiveness of such a device, we built a manikin that can expire micron-sized aerosols at flow rates close to physiological conditions. We then placed the manikin inside the enclosure and used a laser sheet to visualize the aerosol leaking out. We show that with sufficient suction, it is possible to effectively contain aerosol from the manikin, reducing aerosol exposure outside the enclosure by 99%. In contrast, a passive barrier without suction only reduces aerosol exposure by 60%.     

Gold(I)/Copper(II)‐Cocatalyzed Tandem Cyclization/Semipinacol Reaction: Construction of 6‐Aza/Oxa‐Spiro[4.5]decane Skeletons and Formal Synthesis of (±)‐Halichlorine

A simple and efficient strategy for the construction of 6‐aza/oxa‐spiro[4.5]decane skeletons under the cocatalysis of gold(I)/copper(II) was developed, and its potential utility was demonstrated by a formal synthesis of the biologically active marine alkaloid (±)‐halichlorine.

     

Loss processes affecting submicrometer particles in a house heavily affected by road traffic emissions

The fraction of outdoor aerosol that penetrates into indoor environments plays an important role in determining the contribution of outdoor particles to the total lung dose of particles in human exposure. The objective of this study was to investigate the physical processes affecting migration of outdoor traffic particles into indoor environments. Particle number size distributions were measured by a fast mobility particle sizer system in both indoor and outdoor environments of a house located in close proximity to a busy street in Bologna (Italy) in the period February–April 2012. Indoor to outdoor (I/O) ratios for submicron particle number concentrations showed strong dependence on particle size and meteorological conditions. The loss rates of particles due to deposition, coagulation, and evaporation were determined using dynamic mass balance and coagulation models. Higher loss rates were found for small particles (nucleation and Aitken mode) indoors than for larger particles (accumulation mode). The coagulation and evaporation processes made a significant contribution to the loss of traffic nanoparticles indoors, especially during the day time. Application of positive matrix factorization to the indoor and outdoor particle size distributions showed a substantial loss of traffic-generated nucleation mode particles in the indoor environment, with evaporation playing a major role.

Copyright © 2017 American Association for Aerosol Research     

Ultrasensitive detection of endocrine disruptors via superfine plasmonic spectral combs

The apparent increase in hormone-induced cancers and disorders of the reproductive tract has led to a growing demand for new technologies capable of detecting e...     

A DFT Study of Structural,Elastic, Thermodynamic,Magneto-optical,and Electrical Properties of Double-Perovskite Bi2CrMO6 (M = Zn,Ni) Using GGA and TB-mBj Functionals

Journal of Superconductivity and Novel Magnetism - The electrical, optical, and transport properties of double-ordered Bi2CrMO6 (M?=?Zn, Ni) perovskites were studied in detail in this...