Solid-state dye-sensitized solar cells based on ZnO nanoparticle and nanorod array hybrid photoanodes

The effect of ZnO photoanode morphology on the performance of solid-state dye-sensitized solar cells (DSSCs) is reported. Four different structures of dye-loaded ZnO layers have been fabricated in conjunction with poly(3-hexylthiophene). A significant improvement in device efficiency with ZnO nanorod arrays as photoanodes has been achieved by filling the interstitial voids of the nanorod arrays with ZnO nanoparticles. The overall power conversion efficiency increases from 0.13% for a nanorod-only device to 0.34% for a device with combined nanoparticles and nanorod arrays. The higher device efficiency in solid-state DSSCs with hybrid nanorod/nanoparticle photoanodes is originated from both large surface area provided by nanoparticles for dye adsorption and efficient charge transport provided by the nanorod arrays to reduce the recombinations of photogenerated carriers

Progress on Silicone Packaging Materials for Power LED

AbstractEncapsulation materials are very vital to the power light emitting diode packaging and become a hot topic for worldwide researchers because the devices packaging and assembly yield, and the devices reliability and lifespan are determined by the quality of packaging and assembly materials as well as their processing. In this paper, the functions requirements and properties of power LED packaging materials were introduced. In addition, the research progress on traditional LED packaging materials, especially high refractive index silicone encapsulants were discussed in detail. Meanwhile, the direction of further development of encapsulation materials was pointed out

Support Vector Selection for Regression Machines

In this paper, we propose a method to select support vectors to improve the performance of support vector regression machines. First, the orthogonal least-squares method is adopted to evaluate the support vectors based on their error reduction ratios. By selecting the representative support vectors, we can obtain a simpler model which helps avoid the over-fitting problem. Second, the simplified model is further refined by applying the gradient descent method to tune the parameters of the kernel functions. Learning rules for minimizing the regularized risk functional are derived. Experimental results have shown that our approach can improve effectively the generalization capability of support vector regressors

Stable smectic phase in suspensions of polydisperse colloidal platelets with identical thickness

6 pages, 6 figures.-- PACS nrs.: 61.30.Eb, 64.70.M−, 81.16.Dn, 82.70.Dd.-- ArXiv pre-print available at: http://arxiv.org/abs/0909.2625We report the nematic and smectic ordering in an aqueous suspension of monolayer α-Zirconium phosphate platelets possessing a high polydispersity in diameter but uniform thickness. We observe an isotropic-nematic transition as the platelet volume fraction increases, followed by the formation of a smectic, an elusive phase that has been rarely seen in discotic liquid crystals. The smectic phase is characterized by x-ray diffraction high-resolution transmission electron microscopy, and optical microscopy. The phase equilibria in this highly polydisperse suspension are rationalized in terms of a theoretical approach based on density-functional theory.Acknowledgment is made to the donors of ACS Petroleum Research Fund (Grant No. 45303-G7) and to the Dow Chemical Co. This work has been partly financed by start-up funds from Texas Engineering Experimental Station and Texas A&M University, by Grants No. NANOFLUID, No. MOSAICO, and No. S-0505/ESP-0299 from Comunidad Autónoma de Madrid (Spain), and Grants No. FIS2005-05243-C02-01, No. FIS2007-65869-C03-01, No. FIS2008-05865-C02-02, and No. FIS2007-65869-C03-C01 from Ministerio de Educación y Ciencia (Spain).Publicad

Study on thermal health and its safety management mode for the working environment

Thermal health concerns have gained significant attention due to the heightened health risks faced by workers who are exposed to extreme thermal environments for prolonged periods. To ensure the occupational health and safety of such workers, and to enhance work efficiency, it is imperative to examine the characteristics of thermal health in the working environment. This study proposes three key elements of thermal health in the working environment, namely thermal health states, absence of heat-related illnesses, and heat adaptability, which can be used to develop a safety management framework for thermal health. By exploring the interconnections between these elements, the study summarizes their features and outlines the necessary precautions to safeguard them. The PDCA (plan/do/check/action) cycle management mode is utilized as a framework, with the three components of thermal health forming the core, to establish a safety management mode for thermal health. To ensure that employees work in a safe, healthy, comfortable, and productive environment, the assessment and control objectives of the thermal environment are regularly revised through the use of labor protection technology and thermal environment control technology. This paper presents a PDCA cycle safety management mode based on the characteristics of thermal health, which offers novel insights and approaches for assessing and managing workers’ thermal health

Enabling 5G on the Ocean: A Hybrid Satellite-UAV-Terrestrial Network Solution

Current fifth generation (5G) cellular networks mainly focus on the terrestrial scenario. Due to the difficulty of deploying communications infrastructure on the ocean, the performance of existing maritime communication networks (MCNs) is far behind 5G. This problem can be solved by using unmanned aerial vehicles (UAVs) as agile aerial platforms to enable on-demand maritime coverage, as a supplement to marine satellites and shore-based terrestrial based stations (TBSs). In this paper, we study the integration of UAVs with existing MCNs, and investigate the potential gains of hybrid satellite-UAV-terrestrial networks for maritime coverage. Unlike the terrestrial scenario, vessels on the ocean keep to sea lanes and are sparsely distributed. This provides new opportunities to ease the scheduling of UAVs. Also, new challenges arise due to the more complicated maritime prorogation environment, as well as the mutual interference between UAVs and existing satellites/TBSs. We discuss these issues and show possible solutions considering practical constraints

9-(Dimethoxy­meth­yl)anthracene

In the title compound, C17H16O2, a dimethyl acetal of 9-anthraldehyde, the anthracene skeleton is planar and the two meth­oxy groups attached to the C atom at position 9 of the aromatic ring system are located above and below the ring system

Revisiting the Temporal Modeling in Spatio-Temporal Predictive Learning under A Unified View

Spatio-temporal predictive learning plays a crucial role in self-supervised learning, with wide-ranging applications across a diverse range of fields. Previous approaches for temporal modeling fall into two categories: recurrent-based and recurrent-free methods. The former, while meticulously processing frames one by one, neglect short-term spatio-temporal information redundancies, leading to inefficiencies. The latter naively stack frames sequentially, overlooking the inherent temporal dependencies. In this paper, we re-examine the two dominant temporal modeling approaches within the realm of spatio-temporal predictive learning, offering a unified perspective. Building upon this analysis, we introduce USTEP (Unified Spatio-TEmporal Predictive learning), an innovative framework that reconciles the recurrent-based and recurrent-free methods by integrating both micro-temporal and macro-temporal scales. Extensive experiments on a wide range of spatio-temporal predictive learning demonstrate that USTEP achieves significant improvements over existing temporal modeling approaches, thereby establishing it as a robust solution for a wide range of spatio-temporal applications.Comment: Under revie

A Novel k-out-of-n Oblivious Transfer Protocol from Bilinear Pairing

As traditional oblivious transfer protocols are treated as cryptographic primitives in most cases, they are usually executed without the consideration of possible attacks, e.g., impersonation, replaying, and man-in-the-middle attacks. Therefore, when these protocols are applied in certain applications, such as mental poker game playing and fairly contracts signing, some extra mechanisms must be combined to ensure its security. However, after the combination, we found that almost all of the resulting schemes are not efficient enough in communicational cost, which is a significant concern for all commercial transactions. Inspired by this observation, we propose a novel secure oblivious transfer protocol based on bilinear pairing which not only can provide mutual authentication to resist malicious attacks but also is efficient in communicational cost