The long-term demographic role of community-based family planning in rural Bangladesh

Experimental studies demonstrating the effectiveness of nonclinical distribution of contraceptives are typically conducted in settings where contraceptive use is low and unmet need is extensive. Determining the long-term role of active outreach programs after initial demand is met represents an increasingly important policy issue in Asia, where contraceptive prevalence is high and fixed service points are conveniently available. This article examines the long-term rationale for household family planning in Bangladesh-where growing use of contraceptives, rapid fertility decline, and normative change in reproductive preferences are in progress, bringing into question the rationale for large-scale deployment of paid outreach workers. Longitudinal data are analyzed that record outreach encounters and contraceptive use dynamics in a large rural population. Findings demonstrate that outreach has a continuing impact on program effectiveness, even after a decade of household visitation. The policy implications of this finding are reviewed.     

Local magnetic properties of a monolayer of Mn12 single molecule magnets

The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12.     

Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow.     

Crystallographic phase induced electro-optic properties of nanorod blend nematic liquid crystal

Ultrasmall ZnS or PbS nanorods encapsulated in fluid-like soft organic surfactants show excellent miscibility in the nematic liquid crystal (LC ZLI-4792) host resulting in a novel soft matter type blend with enhanced electro-optic properties. The ultranarrow ZnS rods are of wurtzite phase and possess a chemical bipolarity and a net dipole moment. The centrosymmetric ultranarrow PbS rods possess a finite size and shape dependent inherent dipole moment despite their cubic rock-salt structure. When an electric field is applied, the blend aligns along the direction of the field producing a local unidirectional orientation of the rods and LC directors, and defining a unique axis for the system. The local ordering significantly affects the global ordering of the blend allowing a more rapid response of the electro-optic properties. The degree and switching speed of the blends depend upon the magnitude of dipole moments present in the dopant nanorods. We show how a non-mesogenic element designed with preferential crystallographic phase can be introduced within a LC for improvement of the switching properties of the LC blend. These types of unique blends are a model for fundamental conceptual advances in general understanding of interaction behaviour leading consequently to a significant technological advancement for superior device fabrication.     

Quantitative modeling of scratch-induced deformation in amorphous polymers

In order to predict scratch performance of polymers, the present study focuses on quantitative assessment of various scratch-induced deformation mechanisms based on a set of model amorphous polymers via numerical modeling. A modification of Ree-Eyring theory is used to account for the rate dependent behavior of the model polymers at high strain rates using the experimental data obtained at low strain rates. By incorporating the rate and pressure dependent constitutive and frictional behaviors in the finite element methods (FEM) model, good agreement has been found between FEM simulation and experimental observations. The results suggest that, by including appropriate constitutive relationship and frictional model in the numerical analysis, the scratch behavior of polymers can be quantitatively predicted with reasonable success. Usefulness of the present numerical modeling for designing scratch resistant polymers is discussed.     

Thermal fingerprint of silica encapsulated phase change nanoparticles

This paper describes a new type of silica microspheres that contain a panel of phase change nanoparticles (Field's alloy, indium, tin or lead-tin eutectic alloy). The thermophysical properties of solid-liquid phase change nanoparticles, i.e., composition-dependent melting temperatures, sharp melting peaks, and large thermal scan range, allow construction of a large number of silica microspheres that have thermally distinguishable patterns of melting temperatures.     

A cost-effective approach for fast voltage recovery of power distribution networks with renewable energy

This paper presents a cost-effective reactive power planning for active distribution networks based on a new index called reactive power loadability (Q-loadability). The impact of high renewable energy penetration on the static voltage stability of the system is analysed. The effect of load models in distributed generation planning is also demonstrated through nonlinear simulations. In order to ensure fast voltage recovery after a sudden disturbance, compensating devices are located using Q-loadability to increase the system voltage stability limit. Both static and dynamic analyses are carried out to determine the size of distribution static synchronous compensator (D-STATCOM). The parameters of the controller are also tuned to reduce the rating of D-STATCOM. Simulation results show that the proposed approach can reduce the sizes of compensating devices required which, in turn, reduces costs. The effectiveness of the proposed algorithm is verified through several case studies.     

典型绿色建筑评价体系室内环境指标对比分析

对典型绿色建筑评价体系的室内环境评价指标进行对比分析,包括对LEED、BREEAM和中国绿色建筑评价体系中室内环境部分的指标内容、权重体系、达标要求的对比。通过对比分析发现,室内空气品质、光环境、热湿环境、声环境是室内环境质量的主要组成部分,其中,室内空气品质在LEED体系的室内环境部分占大部分内容和分值比重,而在中国绿建体系和BREEAM体系中,四类组成部分的指标数量和分值的分布则相对均匀。虽然中国绿建体系不具有LEED的分值体系和BREEAM的一级权重体系,但其相对众多的控制项以及对应不同绿建等级的室内环境达标项数要求却独具特色。此外,通过对比分析出了三类指标体系所共同关注的室内环境评价的重要内容。