Selective Growth of a C-70 Crystal in a Mixed Solvent System: From Cube to Tube

Cube- and tube-shaped C-70 crystals were obtained selectively by reprecipitation using a combination of mesitylene (good solvent) and isopropyl alcohol (poor solvent). Both crystals include mesitylene molecules in their lattices; the ratios of C-70 to mesitylene were 1:2 in C-70 cubes and 1:0.7 in C-70 tubes. The volume ratio of mesitylene to IPA is a key parameter for the selective growth of C-70 cubes and C-70 tubes, rather than the supersaturation ratio, which governs crystal morphology in many other cases. Thus, we propose that the absolute amount of mesitylene near C-70 molecules determines the crystallization pathways for forming the C-70 2(mesitylene) or C-70 0.7(mesitylene) phase, which finally result in C-70 cubes or C-70 tubes, respectively.X111411Ysciescopu

Unique Crystallization of Fullerenes: Fullerene Flowers

Solution-phase crystallization of fullerene molecules strongly depends on the types of solvent and their ratios because solvent molecules are easily included in the crystal lattice and distort its structure. The C-70 (solute)-mesitylene (solvent) system yields crystals with various morphologies and structures, such as cubes, tubes, and imperfect rods. Herein, using C-60 and C-70 dissolved in mesitylene, we present a novel way to grow unique flower-shaped crystals with six symmetric petals. The different solubility of C-60 and C-70 in mesitylene promotes nucleation of C-70 with sixfold symmetry in the early stage, which is followed by co-crystallization of both C-60 and C-70 molecules, leading to lateral petal growth. Based on the growth mechanism, we obtained more complex fullerene crystals, such as multi-deck flowers and tube-flower complexes, by changing the sequence and parameters of crystallization.1134Ysciescopu

Optical Absorption Characteristics of Silicon Nanowires for Photovoltaic Applications

Solar cells have generated a lot of interest as a potential source of clean renewable energy for the future. However a big bottleneck in wide scale deployment of these energy sources remain the low efficiency of these conversion devices. Recently the use of nanostructures and the strategy of quantum confinement have been as a general approach towards better charge carrier generation and capture. In this article we have presented calculations on the optical characteristics of nanowires made out of Silicon. Our calculations show these nanowires form excellent optoelectronic materials and may yield efficient photovoltaic devices

Chemical ordering in PtNi nanocrystals

We investigated the chemical ordering in PtNi nanocrystals fabricated on sapphire substrate using in-situ synchrotron X-ray scattering. Nanocrystals with composition close to 1:1 were ordered in the tetragonal L1(0) structure at low temperatures. The transition to disordered FCC structure occurred at around 640 degrees C and substantial hysteresis of about 50 K was observed. Nanocrystals of smaller sizes fabricated under the same conditions were Ni rich and ordered into Cu3Au type L1(2) structure. Significantly higher degree of chemical ordering was observed in L1(2) structure than in L1(0) structure. (C) 2016 Elsevier B.V. All rights reserved.1144Ysciescopu

An efficient approach to generating location-sensitive recommendations in ad-hoc social network environments

Social recommendation has been popular and successful in various urban sustainable applications such as online sharing, products recommendation and shopping services. These applications allow users to form several implicit social networks through their daily social interactions. The users in such social networks can rate some interesting items and give comments. The majority of the existing studies have investigated the rating prediction and recommendation of items based on user-item bipartite graph and user-user social graph, so called social recommendation. However, the spatial factor was not considered in their recommendation mechanisms. With the rapid development of the service of location-based social networks, the spatial information gradually affects the quality and correlation of rating and recommendation of items. This paper proposes spatial social union (SSU), an approach of similarity measurement between two users that integrates the interconnection among users, items and locations. The SSU-aware location-sensitive recommendation algorithm is then devised. We evaluate and compare the proposed approach with the existing rating prediction and item recommendation algorithms subject to a real-life data set. Experimental results show that the proposed SSU-aware recommendation algorithm is more effective in recommending items with the better consideration of user's preference and location.This work was supported by the National Natural Science Foundation of China under Grant 61372187. G. Min’s work was partly supported by the EU FP7 CLIMBER project under Grant Agreement No. PIRSES-GA-2012-318939. L. T. Yang is the corresponding author

A Study of Initialization in Linux and OpenBSD

The code that initializes a system can be notoriously difficult to understand. In secure systems, initialization is critical for establishing a starting state that is secure. This paper explores two architectures used for bringing an operating system to its initial state, once the operating system gains control from the boot loader. Specifically, the ways in which the OpenBSD and Linux operating systems handle initialization are dissected

Soil-Structure Interaction on the Response of Jacket Type Offshore Wind Turbine

Jacket structures are still at the early stage of their development for use in the offshore wind industry. The aim of this paper is to investigate the effect of the soil-structure interaction on the response of an offshore wind turbine with a jacket-type foundation. For this purpose, two different models of flexible foundation-the p-y model and the p-y model considering pile groups effect-are employed to compare the dynamic responses with the fixed-base model. The modal analysis and the coupled dynamic analysis are carried out under deterministic and stochastic conditions. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the loads of the offshore wind turbine structure well. It is suggested that during fatigue analysis the pile group effect should be considered for the jacket foundation.None1174Ysciescopu

High Fidelity Tape Transfer Printing Based On Chemically Induced Adhesive Strength Modulation

Transfer printing, a two-step process (i.e. picking up and printing) for heterogeneous integration, has been widely exploited for the fabrication of functional electronics system. To ensure a reliable process, strong adhesion for picking up and weak or no adhesion for printing are required. However, it is challenging to meet the requirements of switchable stamp adhesion. Here we introduce a simple, high fidelity process, namely tape transfer printing(TTP), enabled by chemically induced dramatic modulation in tape adhesive strength. We describe the working mechanism of the adhesion modulation that governs this process and demonstrate the method by high fidelity tape transfer printing several types of materials and devices, including Si pellets arrays, photodetector arrays, and electromyography (EMG) sensors, from their preparation substrates to various alien substrates. High fidelity tape transfer printing of components onto curvilinear surfaces is also illustrated

1000 nm tunable acousto-optic filter based on photonic crystal fiber

Author name used in this publication: W. JinAuthor name used in this publication: J. Ju2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Value-added Synthesis of Graphene: Recycling Industrial Carbon Waste into Electrodes for High-Performance Electronic Devices

We have developed a simple, scalable, transfer-free, ecologically sustainable, value-added method to convert inexpensive coal tar pitch to patterned graphene films directly on device substrates. The method, which does not require an additional transfer process, enables direct growth of graphene films on device substrates in large area. To demonstrate the practical applications of the graphene films, we used the patterned graphene grown on a dielectric substrate directly as electrodes of bottom-contact pentacene field-effect transistors (max. field effect mobility similar to 0.36 cm(2).V-1.s(-1)), without using any physical transfer process. This use of a chemical waste product as a solid carbon source instead of commonly used explosive hydrocarbon gas sources for graphene synthesis has the dual benefits of converting the waste to a valuable product, and reducing pollution.111714Ysciescopu