Planar Thermoelectric Microgenerators Based on Silicon Nanowires

Silicon nanowires have been implemented in microfabricated structures to develop planar thermoelectric microgenerators (??TEGs) monolithically integrated in silicon to convert heat flow from thermal gradients naturally present in the environment into electrical energy. The compatibility of typical microfabrication technologies and the vapor?Cliquid?Csolid (VLS) mechanism employed for silicon nanowire growth has been evaluated. Low-thermal-mass suspended structures have been designed, simulated, and microfabricated on silicon-on-insulator substrates to passively generate thermal gradients and operate as microgenerators using silicon nanowires as thermoelectric material. Both electrical measurements to evaluate the connectivity of the nanowires and thermoreflectance imaging to determine the heat transfer along the device have been employed.     

Second-order statistics of maximal-ratio and equal-gain combining in Weibull fading

Exact expressions for the level crossing rate and average fade duration of M-branch equal-gain and maximal-ratio combining systems in a Weibull fading environment are presented. The expressions apply to unbalanced, nonidentical, independent diversity channels. In addition, new closed-form solutions for some special cases are obtained.     

用于平板显示器的RGB LED

LED背光变得比CCFL还常用。带有RGB LED背光的LCD显示器而板可以实现出色的色彩还原,加强了观看体验。跟一般的CCFL不同,RGB LED扩展了可视色彩的范围。CCFL背光显示器的色域(频谱)有限,并且色彩鲜艳度不足,见图1。CCFL覆盖NTSC色域约为80％,而RGB可     

Disclosing the Role of Defect-Engineered Metal–Organic Frameworks in Mixed Matrix Membranes for Efficient CO2 Separation: A Joint Experimental-Computational Exploration

Incorporation of defects in metal–organic frameworks (MOFs) offers new opportunities for manipulating their microporosity and functionalities. The so-called “defect engineering” has great potential to tailor the mass transport properties in MOF/polymer mixed matrix membranes (MMMs) for challenging separation applications, for example, CO₂ capture. This study first investigates the impact of MOF defects on the membrane properties of the resultant MOF/polymer MMMs for CO₂ separation. Highly porous defect-engineered UiO-66 nanoparticles are successfully synthesized and incorporated into a CO₂-philic crosslinked poly(ethylene glycol) diacrylate (PEGDA) matrix. A thorough joint experimental/simulation characterization reveals that defect-engineered UiO-66/PEGDA MMMs exhibit nearly identical filler–matrix interfacial properties regardless of the defect concentrations of their parental UiO-66 filler. In addition, non-equilibrium molecular dynamics simulations in tandem with gas transport studies disclose that the defects in MOFs provide the MMMs with ultrafast transport pathways mainly governed by diffusivity selectivity. Ultimately, MMMs containing the most defective UiO-66 show the most enhanced CO₂/N₂ separation performance—CO₂ permeability = 470 Barrer (four times higher than pure PEGDA) and maintains CO₂/N₂ selectivity = 41—which overcomes the trade-off limitation in pure polymers. The results emphasize that defect engineering in MOFs would mark a new milestone for the future development of optimized MMMs.     

Light-Controlled Nanosystem with Size-Flexibility Improves Targeted Retention for Tumor Suppression

Although great promise has been achieved with nanomedicines in cancer therapy, limitations are still encountered, such as short retention time in the tumor. Herein, a nanosystem that can modulate the particle size in situ by near-infrared (NIR) light is self-assembled by cross-linking the surface-modified poly(lactic-co-glycolic acid) from the up-conversion nanoparticle with indocyanine green and doxorubicin–nitrobenezene–polyethylene glycol (DOX–NB–PEG). The nanosystem with its small size (≈100 nm) achieves better tumor targeting, while the PEG on the surface of the nanosystem can effectively shield the adsorption of proteins during blood circulation, maintaining a stable nanostructure and achieving good tumor targeting. Moreover, the nanosystem at the tumor realizes the rapid shedding of PEG on its surface by NIR irradiation, and the enhanced cellular uptake. At the same time, aggregation occurs inside the nanosystem to form bigger particles (≈600 nm) in situ, prolonging the retention time at the tumor and producing enhanced targeted therapeutic effects. In vitro data show higher cellular uptake and a higher rate of apoptosis after irradiation, and the in vivo data prove that the nanosystem have a longer residence time at the tumor site after NIR irradiation. This nanosystem demonstrates an effective therapeutic strategy in targeted synergistic tumors.     

Design and Test of a Certifiable ASIC for a Safety-Critical Gas Burner Control System

The purpose of this paper is to present a methodology and tools for the design and test of an EN298 compliant ASIC chip for a safety-critical gas burner control system. Safe operation, as far as the critical variable is concerned, is guaranteed in the presence of two simultaneous faults. Emphasis is put on circumventing methodology, EDA (Electronic Design Automation) and foundry limitations and on product certification requirements.     

Elimination of Fresnel Reflection Boundary Effects and Beam Steering in Pulsed Terahertz Computed Tomography

For the past few decades there has been tremendous innovation and development of Terahertz (THz) science and imaging. In particular, the technique of 3-D computed tomography has been adapted from the X-Ray to the THz range. However, the finite refractive index of materials in the THz range can severally refract probing THz beams during the acquisition of tomography data. Due to Fresnel reflection power losses at the boundaries as well as steering of the THz beam through the sample, refractive effects lead to anomalously high local attenuation coefficients near the material boundaries of a reconstructed image. These boundary phenomena can dominate the reconstructed THz-CT images making it difficult to distinguish structural defect(s) inside the material. In this paper an algorithm has been developed to remove the effects of refraction in THz-CT reconstructed images. The algorithm is successfully implemented on cylindrical shaped objects.     

In vitro and in vivo determinations of sun protection factors of sunscreen lotions with octylmethoxycinnamate

The aim of this work was to evaluate the correlation between in vitro and in vivo determinations of sun protection factors (SPF) of sunscreen lotions containing the synthetic sunscreen octyl methoxycinnamate. Three sunscreen lotions containing either 2, 4.5 or 7.5% octyl methoxycinnamate were prepared. The in vitro SPFs of these sunscreen lotions were determined according to the spectrophotometric method of Mansur et al. The in vivo SPF values were determined according to the Food and Drug Administration (FDA) method. The results indicate that there was a good correlation between the in vitro and in vivo determinations for the sunscreen lotions examined.     

Electrospun Fibrous Architectures for Drug Delivery,Tissue Engineering and Cancer Therapy

The versatile electrospinning technique is recognized as an efficient strategy to deliver active pharmaceutical ingredients and has gained tremendous progress in drug delivery, tissue engineering, cancer therapy, and disease diagnosis. Numerous drug delivery systems fabricated through electrospinning regarding the carrier compositions, drug incorporation techniques, release kinetics, and the subsequent therapeutic efficacy are presented herein. Targeting for distinct applications, the composition of drug carriers vary from natural/synthetic polymers/blends, inorganic materials, and even hybrids. Various drug incorporation approaches through electrospinning are thoroughly discussed with respect to the principles, benefits, and limitations. To meet the various requirements in actual sophisticated in vivo environments and to overcome the limitations of a single carrier system, feasible combinations of multiple drug‐inclusion processes via electrospinning could be employed to achieve programmed, multi‐staged, or stimuli‐triggered release of multiple drugs. The therapeutic efficacy of the designed electrospun drug‐eluting systems is further verified in multiple biomedical applications and is comprehensively overviewed, demonstrating promising potential to address a variety of clinical challenges.     

Correlation study between VAD preform deposition surface and Germanium doping profiles

The refractive index profile of germanium doped preforms for optical fibers is determined by the radial distribution of germanium concentration. Knowing that there is a correlation between the germanium doping profile and the deposition surface profile of vapor-phase axial deposition (VAD) preforms, the study of this correlation has been carried out in order to estimate, indirectly, the refractive index profile of VAD preforms for optical fibers during the deposition stage. This correlation was studied through the parameterization of the preform deposition surface using two parameters: the power law index profile that best fits the preform bottom profile (/spl alpha/) and the axial distance from the bottom tip to a reference height (h). A range of values of these parameters to produce VAD preforms with standard and special doping profiles has been presented. Preforms with triangular index profile can be fabricated with /spl alpha/ and h values of about 2.0 and 5.0 mm, respectively, and preforms with parabolic index profiles can be produced with /spl alpha/ and h values of about 2.0 and 4.0 mm, respectively.