Study of incident angle dependence for dual-band double negative-index material using elliptical nanohole arrays

This work demonstrates the angular dependence of dual-band negative-index materials implemented by elliptical nanohole arrays (ENAs) consisting of an Al2O3 dielectric layer between two Au films. This article, it is believed for the first time, analyzes the scattering coefficients and displacement current of the ENA at different angles of plane-wave incidence to show that the ENA is double negative (showing both a negative effective permeability μ(eff) and a negative effective permittivity ε(eff) at multiple wavelengths (1095 and 1680 nm) for p polarization over a broad range of incident angles.     

地毯的抗静电性能与工艺设计

利用导电纤维等抗静电材料,以不同质量分数和不同方法加入地毯,探讨地毯的电阻与静电压的关系。     

FROM DATABASE TO OPERATION DESIGN USING A MULTIPLE MODEL APPROACH

We address the problem of estimating the input conditions (mixture compositions, operating temperature, pressure, etc.) that will result in manufacturing a product with the required properties using a data-based approach. A single-model type paradigm is shown to be unsuitable for all data sets or even for all output variables in a particular data set. A multiple-model type paradigm is therefore advocated. The input-output map is first obtained using one or more of the several modeling approaches. These models are then inverted to suggest operational strategies that will meet production goals. Several examples are presented to demonstrate the efficacy of the proposed methodology.     

The Synthesis of Boron Carbide Ceramic via Electrospinning Technique

In this study, polyvinyl alcohol (PVA) and boric acid (BA) were mixed in an aqueous medium by heating in order to prepare a PVA/BA hybrid material. The viscosity and pH values of the PVA/BA hybrid material mixed in various proportions were determined. Then the hybrid polymer was electrospun to give dimensions to fibers. The FT-IR spectra of these fibers revealed that BA chemically reacted with PVA and formed B–O–C bonds. The fibers were first calcified at 500 °C and then the calcified products were pelleted and exposed to the sintering process at 1300 °C. The XRD peaks of the sintered product were seen at 2θ = 34.7 and 37.7° verified the formation of boron carbide. The study proved that it was possible to use sub-micron fibers for the production of sub-micron boron carbide material.     

流沙地质顶管穿越的设计与施工

油气管道穿越省道、国道、高速公路、铁路等交通频繁或不能阻断交通的地方时,无法采取大开挖穿越方式,设计上一般采用顶管或者定向钻的穿越方式,如果穿越点地质条件为流沙,无论是顶管还是定向钻,都会因流沙的地质特点产生各种意外问题,造成穿越失败。文章着重对流沙地质顶管穿越从设计和施工的角度进行分析,针对问题提出相应的设计措施,以达到成功顶管的目的。     

Abatement of Organic Pollutant Concentrations in Residual Treatment Sludges: A Review of Selected Treatment Technologies Including Drying

As a result of increasing population, industrialization, and effluent quality, sludge production has increased worldwide. Organic micropollutants in sludge have become a more critical environmental health concern compared to heavy metals. New sludge disposal regulations limit persistent organic pollutants (POPs) in addition to conventional organic indicators like total and dissolved organic carbon. This study aims at providing a brief review on POP concentration in the sludge in different regions of the world, sludge regulations, assessment of conventional biological sludge stabilization methods according to their ability to remove POPs, and discussions on alternative sludge treatment methods. The impact of sludge treatment unit operations including conditioning, thickening, mechanical and thermal dewatering, and biological and thermal stabilization on sludge management is also discussed in the context of organics. The occurrence and removal of micropollutants such as absorbable organic halogen compounds (AOX), nonylphenol and nonylphenol ethoxylates (NPE), di-2-(ethyl-hexyl)-phthalate (DEHP), dibenzo-p-dioxins and furans (PCDD/F), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) are also evaluated specifically for sludge treatment unit operations. A concise discussion is also included on different drying technologies suitable for drying of sludge.     

Polystyrene Suspension Polymerization: The Effect of Polymerization Parameters on Particle Size and Distribution

Effects of polymerization parameters are studied to better understand interactions between parameters in stirred-tank polymerization reactors and to derive a regression model correlating polymer particle size and particle-size distribution with agitator speed, agitator diameter, tricalcium phosphate, dodecyl benzene sodium sulfonate concentrations, and mass cycle period. The derived equations give way to prediction of the polymerization conditions in order to obtain desired particle size and particle-size distributions which covers particle sizes between 0.3 and 5 mm. The roles of some other parameters and limiting agitation parameters are also investigated.     

Improved cure optimization in pultrusion with pre-heating and die-cooler temperature

Optimization studies are performed on the pultrusion of a thermosetting composite. The three-dimensional finite element/nodal control volume procedure developed for simulation and optimization of the process is employed for this purpose. The aim of optimization is to achieve the desired degree of cure with minimum local variations across the pultrudate cross-section. The die-heating environment is optimized for a few cases with different initial temperatures for a glass/epoxy wet preform and for the cooler installed within the pultrusion die near its entrance. The role of these temperature parameters in moderating the optimization constraints is examined. Simultaneous optimization of die-heater temperatures and pull-speed is also considered. It is observed that the temperature overshoot within the composite pultrudate can be reduced and better optimization results can be achieved by a proper choice of a pre-die temperature for the composite and the die-cooler temperature.     

溶剂萃取在无机盐工业中的应用和研究

溶剂萃取是一种高效的分离方法,投资少,无污染,应用萃取富集、分离、提纯,可以由矿石直接生产金属无机盐,纯度高、成本低。将萃取用于无机盐制备开创出许多新型高效流程,利用谇取技术开发、改进的许多碱土金属无机盐生产流程可提高回收率和产品纯度、降低生产成本。     

Aging, hearing acuity, and the attentional costs of effortful listening.

A dual-task interference paradigm was used to investigate the effect of perceptual effort on recall of spoken word lists by young and older adults with good hearing and with mild-to-moderate hearing loss. In addition to poorer recall accuracy, listeners with hearing loss, especially older adults, showed larger secondary task costs while recalling the word lists even though the stimuli were presented at a sound intensity that allowed correct word identification. Findings support the hypothesis that extra effort at the sensory–perceptual level attendant to hearing loss has negative consequences to downstream recall, an effect that may be further magnified with increased age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)