bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation Test of Equipment of Non-Contact Detection with GPR
Authors: Yang Yan Qing , He Shao Hui , Jiang Bo , Qi Fa Lin
Published: August 2011

The composite lining model of railway tunnel is set up and then simulation test is presented by non-contact detection with the simple detection equipment of ground penetrating radar (GPR) to study the main technique parameters of the equipment. The results show that the lining can be detected by the way, and the quality of GPR scan obtained in the simulation test decreases with the detection distance increasing. In the GPR scan obtained when keeping ground-coupled shielding antenna of 400MHz 20cm away from the ground(the distant from the bottom of GPR antenna to the surface of lining specimen), a variety of work conditions that has been preset in the experimental design can be identified, moreover, the location and range of both uncompacted backfill and cavity behind the lining etc. approach those that can be get when the antenna sticking to the lining, thus providing satisfactory qualitative interpretation of GPR scan. In addition, the deviation range of GPR non-contact detection is close to that when the antenna sticking to the lining, thus ensuring the detection value accuracy of lining thickness.
Investigation of Consumer-Oriented Product System Design
Authors: Hu Xiao Qing , Gao Yun Fang
Published: August 2011

This paper deeply discussed consumer kansei system and demand, based on Kansei Engineering system; it researched method of product system design. This method used application theory of Kansei Engineering: consumer decision-aid system and designer decision-aid system, which investigated consumers’ preference adjectives in terms of kansei image, then used product system design, and outputted corresponding specific form of product system. On the other hand, product system designed by designers would induce the awareness of consumers for products, thus it affected consumers’ preferences, finally it worked out with product system which matched with consumer demand, and guided follow-up product design.
The Modeling Analysis and Dynamics Simulation of Load-Sensing Hydraulic Systems
Authors: Wei Cong Mei , Lian Jin Yi , Li Jing Jie
Published: August 2011

This paper analyzes the mathematical model of load-sensing hydraulic system based on power linkage graph method and builds the simulation model AMESim of the system. The load sensitive hydraulic system is applied in the working device of loader, and the simulation model AMESim with ADAMS is built by combining the dynamics analysis system with ADAMS,. The study of simulation on the dynamics is completed under different working conditions and the results of simulation analysis are given.
Investigate on Micro-EDM in Air (Dry MEDM) by External Blowing Mode Based on RC Pulse Generator
Authors: Li Li Qing , Zhu Guo Zheng
Published: August 2011

Experiments of micro-EDM in gas (dry MEDM) were conducted on the conditions of an external supplying gas mode based on a RC pulse generator. The objective of the work is to optimize machining parameters of the dry MEDM and investigate the machining performance of the ultrasonic induced workpiece vibration. Micro solid copper electrodes were fabricated on line by the block grinding method. Range analysis results of the Taguchi approach indicate that capacitance, servo feed speed have great effect on the material remove rate (MRR); and capacitance and open voltage are main influencing factors on the tool relative wear ratio (TWR). An optimal parameters combination was obtained under the experimental conditions. The experimental results of the ultrasonic induced workpiece vibration demonstrate that high frequency workpiece vibration with a suitable input current could improve MRR and TWR of the dry MEDM.
The Comparison of Two Stereo Vision Sensor Calibration Methods
Authors: Chen Gang , Chen Hua , Guo Yu Bo , Ye Dong
Published: August 2011

This paper presents and comparison two stereo vision sensor calibration methods: Volume template based calibration method and the calibration based on virtual stereo pattern. First method use a premade volume template. Second method use a group of random spatial points that are formed by an infrared LED moved with the probe of CMM. Two methods adopt an ideal pin-hole model that ignores the nonlinear distortion of the cameras. Through compare two calibratioin methods, we can draw conclusion that the first method can be applide to stereo sensor calibration in measurement field and the second method could gain higher calibrating precision.
The Setting Method of Project Buffer in Critical Chain Management of Mould Manufacturing Project Based Reworking
Authors: Hu Chang Wei , Chen Xin Du , Wu Li Hua
Published: August 2011

In the mould manufacturing projects, there are large numbers of uncertainties, such as change of customer demand, change of drawing, bad quality of products etc., and they often lead to numerous task reworked. Because of the random task reworking, the complete time of the project is uncertainty. Based on the critical chain project with task reworking, the paper carried out the research on setting of project buffer. We presented a new idea that the project buffer was calculated based on safety time and possible reworking time, and proposed a method to calculate the buffer of project reworking based on Discrete-time Markov chain. The problem that the classical method to setting critical chain project buffer is infeasible concerning task reworking was solved efficiently. The proposed method can set the project buffer more reasonable.
Design and Performance Evaluation of Haptic Master Device Using ER Spherical Joint
Authors: Cho Han Jun , Oh Jong Seok , Choi Seung Bok
Published: August 2011

This study presents the configuration and modeling of haptic mater device for minimally invasive surgery (MIS) using ER fluid. The haptic device has 3-DOF rotational motion which is realized by the ER spherical joint. The ER spherical joint is designed based on Bingham model. The haptic master device that consists of spherical joint as an inner electrode and sphere housing as an outer electrode is manufactured. Generated torque of the manufactured haptic master device is then experimentally evaluated with respect to applied electric field.
Freehand 3D Ultrasound Calibration Based on Two-Layer Z-Fiducial Phantom
Authors: Wang Xiao Yu , Wu Dong Mei , Du Zhi Jiang
Published: August 2011

Spatial calibration is a key technique in Freehand 3D Ultrasound. In this article, a two-layer Z-fiducial phantom with one “Z” shaped fiducial in each layer is used to perform spatial calibration. After freehand scanning above the phantom, the intersections of the scan plane and Z-fiducial plane in B-scans are segmented, and the calibration transformation matrix between the coordinate system of the position sensor receiver and B-scan is calculated using the least-squares fitting algorithm. At last, the calibration result is evaluated on two criteria: precision and accuracy. The result shows that our phantom is convenient as well as reliable for freehand spatial calibration.
The Modeling and Flow Simulation of 40BZ6-15 Centrifugal Pump
Authors: Shang Xiao Feng , Tong Liang , Wang Zhi Jian
Published: August 2011

The three-Dimensional model of 40BZ6-15 centrifugal pump is built by the Solidworks software. This paper employs three-D Navier-Stokes equation and standard equation, and uses MRF and STMPLE algorithm to simulate the internal flowing of the 40BZ6 centrifugal pump. The velocity field and pressure field are gained. Through a further analysis, the rule of the internal flow of the centrifugal pump is unveiled, and then the simulative results are compared with the experimental ones, which can provide the base for the further improvement of the centrifugal pump.
Kinematic Analysis of a Novel Three Degree of Freedom Parallel Mechanism
Authors: Huang Xiu Qin , Shen Hui Ping , Xin Xiu Mei
Published: August 2011

A novel 3 degree of freedom(1-Translation and 2-Rotation) parallel mechanisms is investigated. The forward and inverse position of the mechanism are studied. The influences by the three input variables on the three output variables are analyzed carefully and the valid working ranges of input and output variables are given by discussing structural parameter. These provide a solid foundation for selecting structural designs and kinematics parameters accurately and for realizing the control and industrial application of the mechanism.
The Effect of Confining Pressures on Rock Fracturing under Dynamic Loads
Authors: Zhu Zhe Ming , Zhou Zhi Rong , Li Yong Qian , Li Ye Xue
Published: August 2011

In order to investigate the effect of confining pressures on rock dynamic fracturing under dynamic loads, a 2D finite difference dynamic numerical model for a circular rock sample with a single centralized borehole is developed. According to the material properties and loading conditions, shock and linear equations of state are combined and applied to the rock material in this model. A modified principal stress failure criterion is applied to determining material status. It is shown that as the increase of mining depth, the extent of blasting-induced damage of rock increases significantly.
Optimal Shape Design of a Body Located in Stokes Flow
Authors: Duan Xian Bao , Qian Fu Cai , Guo Ya Qin
Published: August 2011

Formulations and numerical results for optimal shape design of a body located in the incompressible Stokes fluid flow are presented. The study is based on an optimal control theory. The optimal state is defined by the reduction of drag forces subjected to the body. The cost functional should be minimized satisfying the Stokes equations. The Shape sensitivity analysis of the cost functional was derived based on the adjoint method. For the numerical study, the optimal shape of the body which has a circular shape as an initial state can be finally obtained as the streamlined shape.
First Principles Study of Metal-Encapsulated Silicene-Like Nanotubes
Authors: Zhang Chuan Hui , Ran Qiong , Shen Jiang
Published: August 2011

We systematically investigated the structural stability and electronic properties of silicene-like nanotubes by potassium atoms encapsulated using density functional theory. The calculations show that all the structures of KnSi8(n+1) (n=2-12) nanowires are stable, the structural stable is proportional to the lengths of the nanowires. Electronic population analysis shows that K atoms gain electrons and Si atoms lose electrons as a whole, some electrons transferred from Si to K atoms. Because the peaks of d levels in DOS are contribution from the 3d hybridization levels of K and Si atoms, the magnetic moments derived from the orbitals hybridization. Maybe these kinds of nanowires will play an important role in spintronics and nanoelectronics.
Approaches to the Determination of Oil Content in Oil Shale
Authors: Yuan Zhi Yang
Published: August 2011

Oil and gas are important energy minerals and strategic resources. Moreover, as their substitute, oil shale is the non-renewable fossil fuel resource. In this paper, regarding the oil shale of Huadian in Jilin Province as raw material, we made a research on the approaches to extracting shale oil from oil shale as well as an experimental determination on the impact of heating temperature, shale grain size and holding time.
Evaluation of Chinese New Manufacturing Development Based on Factor Analysis
Authors: Sun Wei
Published: August 2011

By selection of a series of indicators, this paper study evaluation of Chinese new manufacturing development. Factor analysis method is used to evaluate the status of the development of new manufacturing. The theoretical framework and practical application of the evaluation system is studied in detail in the paper. Empirical analysis is used in the paper based on statistics of manufacturing industry from 2003 to 2008. The results show that manufacturing industry is sustainable development. Research results are consistent with the actual situation. It shows that this study is scientific and objective.
Design and Implementation of Metal Detection Based on Eddy Current Sensor
Authors: Pan Fu Wen , Zhang Jin Ling , Lu Ying Hua , Qiao Wei Kang , Mi Qiang
Published: August 2011

We present metal detection using eddy current sensors by combining 2 high-frequency sensors and 1 low-frequency transducer together on the basis of eddy current effect. The two high frequency sensors in this design work at different frequencies which implement the complementary of linear range of the detection and the analog signal is transformed into digital signal by ADC for further processing using ARM9 processor to achieve wide range, high sensitivity, and precise metal detection.
Synthesis, Structural Characterization and Luminescence Property of Ring-Like Zinc(II) Complex of N-Paratoluensulfonyl-Glycine Acid and 1,10-Phenanthroline
Authors: Tai Xi Shi
Published: August 2011

A novel ring-like zinc (II) complex of N-paratoluensulfonyl-glycine acid and 1,10-phenanthroline was synthesized and characterized by elemental analysis, IR spectrum and molar conductivity. The crystal structure of Zn (II) was determined by X-ray single crystal diffraction. The results show that each zinc (II) atoms is in a distorted trigonal bipyramidal geometry and form 16-membered chelate ring with the tridentate ligand. Intermolecular weak interactions in complex link molecules into a one-dimensional infinite chain supramolecular structure. The luminescence property of the complex was investigated in solid.
Fabrication of Self-Organized TiO2 Nanotubes by Anodization and its Photocatalytic Properties
Authors: Wu Tian Yu , Tan Xin , Huang Juan Ru , Yu Tao , Zhao Lin
Published: August 2011

Titania nanotube arrays(TNT) was extensively studied due to its good photocatalytic activity. This article focused on the fabrication of highly ordered TNTs. TNTs were fabricated in an electrolyte of ethylene glycol(EG), water and NH4F for 1, 2, 3, 4h and then annealed at 400°C. The influence of anodic time on the morphology and photocatalytic performance of TNT was investigated. The results indicated that the TNT could be successfully fabricated by using the electrolyte, and the diameter and length of TNT were about approximately 140nm, 5-13μm, separately. Furthermore, the results also showed anatase phase was dominant, TNT with good morphology displayed good photocatalitic properties. When the initial concentration of Rhodamine B(RhB) was 7×10−6mol﹒L−1, the removal of RhB reached 88.1% by TNT anodized for 2h with length of 9.5μm. In addition, the results showed that the photocatalytic reaction fitting the first-order reaction in good agreement with the literature, and the apparent rate constant(kapp) was 0.0251 min-1(the length of 9.5μm)．
Effect of Bile and Nalidixic Acid on Growth of Selected Probiotics
Authors: Shu Guo Wei , Ma Zhen Xing , Wang Zhao Wei , Chen He
Published: August 2011

Effect of bile and nalidixic acid on growth of Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus bulgaricus, Lactobacillus casei and Lactobacillus rhamnosus was studied by measuring the optical density at 600nm (OD600) and pH using De Man, Rogosa and Sharpe (MRS ) broth as the control. The addition of bile (%, w/v) was 0.03%, 0.06%, 0.09%, 0.12% and 0.15% and the addition of nalidixic acid (%, w/v) was 0.003%, 0.009%, 0.015%, 0.045% and 0.075%. Results were as follows: addition of bile at the concentration above 0.06% has a significant inhibition on the growth of L. bulgaricus and B. bifidum at incubation 24h. The optimum selective concentration of bile in MRS media was 0.06% for L. bulgaricus and B. bifidum. Addition of nalidixic acid has no effect on the growth of the five selected probiotics at incubation 24h. Addition of nalidixic acid in MRS can not use to realize selective enumeration in yogurt product containing probiotics.
Microstructure and Mechanical Properties of Weld in 980MPa Grade Steel by Ultra-Narrow Gap Welding
Authors: Zhao Li , Zhang Fu Ju , Feng Shao Hua
Published: August 2011

980MPa grade high strength low alloy steel was welded by ultra-narrow gap welding. Observed by optical metalloscope, there were large majority of equiaxial crystals in weld centers, which was the weld cross-section of 18.3%. Each weld could be compartmentalized into original microstructure zone, over heated zone and normalizing zone under next weld thermal cycle, in which the microstructures were almost the same. Through quantificational metallographic analysis, it was found there was more than 98.9% of acicular ferrite in weld metal, and other microstructures were fine. Mechanical test indicated that the strength of weld metal was higher than body material, and had outstanding plasticity. What is more, the toughness of weld metal was better than solder wire.
Synthesis, Spectral and Luminescence Properties of Complexes Europium with N-benzenesulphonyl-L-phenylalanine and 1,10-Phenanthroline
Authors: Tai Xi Shi
Published: August 2011

The complexes of europium with N-benzenesulphonyl-L-phenylalanine (complex 1), N-benzenesulphonyl-L-phenylalanine and phenanthroline (complex 2) were synthesized and characterized by IR spectroscopy, UV and molar conductivity. The luminescence spectra of two europium complexes were investigated in solid and in DMSO solution, respectively. The results show that complex 1 exhibits low luminescence emission and complex 2 exhibits high luminescence emission in red region. And phenanthroline could enhance the luminescence intensity of europium complexes.
The Development and Property Studies of Nonwoven Filtering Materials for Car Air-Conditioner
Authors: Qian Cheng
Published: August 2011

With the development of automotive industry, automotive air-conditioning filter became the essential equipment in people’s daily life. On today’s market, there is half of the filtration equipment made from non-woven materials because of its small resistance, good filtration efficiency, high yield and low cost advantages. In this paper, based on the comparison and analyses of the web structure, fiber distribution and finesse, permeability, thickness and filtration efficiency of the newly developed nonwoven composites and other imported materials, the results were got that the finer fibers, more porosity, thinner thickness and smaller holes together would make an ideal filtering product for using in the cleaner car.
Effects of EDTA, EDDS and Oxalic Acid on Catalase and Peroxydase Activities of Soil
Authors: Cheng Guo Ling , Liu He , Wang Qun Hui
Published: August 2011

EDTA, EDDS and oxalic acid were added to soil to control the concentrations of the three chelators in soil at 2, 5, 10, 15, 20, 30 mmol/kg, then catalase and peroxydase activities of the soil were determined after 24h to identify the effects of three chelators on enzyme activity of soil. The results showed that the catalase activities of soil treated with oxalic acid and EDTA decreased with the increase of the concentrations (p＜0.01, p＜0.05 respectively), while it rised with the increase of the concentration of EDDS (p＜0.01). EDTA, EDDS and oxalic acid all showed significant stimulation on peroxidase activity of soil, especially at low concentration (2 mmol/kg).
Mechanical Properties of the Knitted Fabric of SPF/Modal Blended Yarn
Authors: Yang Qing Bin , Dou Yu Kun
Published: August 2011

In order to understand the influence of the blended ratio of the soybean protein fibers to the properties of blended fabrics, five soybean protein fiber/modal blended fabrics are knitted and tested. By the analysis of the results, the relationship between the properties of the blended fabrics and the blended ratio of the soybean protein fibers are obtained. With the increase of the ratio of the soybean protein fibers, the tensile strength and the elongation of the blended fabrics increase and the tearing strength and bursting strength of the fabric decrease. With the increase of the ratio of soybean protein fibers, the softness increases and the bending length, abrasion resistance of the knitted fabrics decrease.
Self-Adaptive Wavelet Based on Parametric Equation in Manufacturing Engineering
Authors: Jiang Yong , Wang Ya Ping , Zhao Dong Mei
Published: August 2011

The paper analyzes the difference between useful signal and noise signal in dissemination characteristic inside wavelet space in manufacturing engineering, and then puts forward a search algorithm based on wavelet decorrelation white noise testing and involved with the parameters in a parametric equation. The algorithm can select wavelet transform to realize the best noise reduction effect in a self-adaptive way according to the characteristic of signal containing noise and signal to noise ratio. At last, simulation experiment and engineering application are made, and their results are compared with the decomposition result of Daubechies wavelet. It’s concluded that self-adaptive wavelet basis can more adequately separate useful information from signal.
Research Summary of Re-Manufacturing Logistics System in China
Authors: He Mei Dan
Published: August 2011

This paper reviews the main literature researches on remanufacturing logistics system in recent years in china, outlines the main research results from three aspects: the nature and characteristics of re-manufacturing logistics system, the layout of re-manufacturing logistics network and re-manufacturing logistics system management, and makes further research prospects in the end.
Analysis of Electron-Beam Crystallized Large Grained Si Films on Glass Substrate by EBIC, EBSD and PL
Authors: Seifert Winfried , Amkreutz Daniel , Arguirov Tzanimir , Krause Hans Michael , Schmidt Manfred
Published: August 2011

The properties of electron-beam crystallized, large-grained silicon layers of about 10 µm thickness on glass have been studied by combining EBIC, EBSD and photoluminescence. It is found that most grains are free of dislocations. From a detailed analysis based on the dependence of EBIC collection efficiency on beam energy we conclude that the recombination properties of the layers are mainly determined by the bulk diffusion length. The estimated bulk diffusion length in the dislocation-free layer regions is in the range of roughly 5 – 7 µm, depending on the recombination velocity assumed for the rear surface. In dislocated regions the diffusion length drops to 1 µm or less. Close to some twin boundaries, an unsusual improvement of the electrical layer properties has been observed. In addition, wave-like inhomogeneities of the layer properties have been established, resulting probably from instabilities during the crystallization process.
1207cm-1 Infrared Absorption Band in Carbon-Rich Silicon Crystal
Authors: Chen Lin , Yu Xue Gong , Chen Peng , Gu Xin , Lu Jing Gang , Yang De Ren
Published: August 2011

Silicon wafers with different carbon contents have been characterized by Fourier transform infrared spectroscopy technique. An infrared absorption band at 1207cm-1 can be newly observed in the case of carbon content being above 1.7×1017/cm3, whose intensity increases with an increase of carbon concentration in silicon crystal. More interestingly, the 1207cm-1 band cannot be influenced by the long-time annealing in the temperature range of 450-1250oC, suggesting the high thermal stability of this carbon-related defect, which might be related to the presence of silicon carbide in silicon crystals.
Photocurrent and Photoluminescence of Amorphous Silicon Nanoclusters Embedded in Silicon Suboxide Matrix
Authors: Sreseli Olga M. , Gusev Oleg B. , Vainshtein Julia S. , Undalov Yurii K. , Yeltsina Olga S. , Sitnikova Alla A. , Terukov Eugenii I.
Published: August 2011

We have presented a technique, based on magnetron sputtering of silicon target in the mixture of argon, silane, and oxygen. Addition of oxygen gas was shown to cause formation of silicon suboxide layers with amorphous silicon nanoclusters without subsequent annealing. The layers exhibit significant photoluminescence at room temperature. Their photoluminescence spectra reveal special features predicted in the preceding well-known theoretical works. Heterostructures, fabricated with such layers, show high photocurrent efficiency in short-wavelength spectral region. Our results demonstrate that the investigated structures are promising for photoelectric and photovoltaic applications.
Acceptor Deactivation in Silicon Nanowires Analyzed by Scanning Spreading Resistance Microscopy
Authors: Kögler Reinhard , Ou Xin , Geyer Nadine , Das Kanungo Pratyush , Schwen Daniel , Werner Peter , Skorupa Wolfgang
Published: August 2011

Vertical p-type Si nanowires (NWs) "in-situ" doped during growth or "ex-situ" by B ion implantation are investigated regarding their acceptor activation. Due to the much higher surface to volume ratio of the NW in comparison to bulk material the surface effect plays an important role in determining the doping behaviour. Dopant segregation and fixed positive charges at the Si/SiO2 interface result in an acceptor deactivation. The B concentration introduced into the NW has to balance the deactivation effects in order to reach the intended electrical parameters. Scanning spreading resistance microscopy is used for the electrical characterization of the NWs. This analysis method provides images of the local resistivity of NW cross sections. Resistivity data are converted into acceptor concentration values by calibration. The study demonstrates that scanning spreading resistance microscopy is a suitable analysis method capable to spatially and electrically resolve Si NWs in the nanometer-scale. The NW resistivity is found to be size dependent and shows a significant increase as the NW is below 25 nm in diameter. The obtained data can be explained by a core-shell model with a highly conductive NW core and low conductive shell.
Synthesis of Light Emitting Ge Nanocrystals by Reactive RF Sputtering
Authors: Hernandez-Hernandez Arturo , Rangel-Kuoppa Victor Tapio , Plach Thomas , De Moure-Flores Francisco , Quiñones-Galvan Jose G. , Nieto Zepeda Karen E. , Zapata-Torres Martin , Meléndez-Lira Miguel
Published: August 2011

In this work we report the results of the synthesis, structural and optical characterization of SiO2/Ge/SiO2heterostructures by reactive RF sputtering. The SiO2films were grown by reactive sputtering employing a plasma mixture of oxygen and argon. The Ge layer was grown employing an Ar atmosphere. The samples were prepared on p-type Si (1 1 1) substrates by reactive sputtering. The effect of the partial pressure of oxygen on the electronic properties of the heterostructure is reported[1]. Structural characterization was carried out by grazing angle X-ray difraction. Surface roughness was quantified by atomic force microscopy. The presence of Ge nanocrystals (Ge-NCs) was evidenced by X-ray diffraction. The vibrational properties were studied by Raman spectroscopy. The Raman spectra showed modes associated to germanium indicating the formation of low dimensionality germanium particles embedded within a SiO2matrix. Photoluminescence emission is observed around ~1.7 eV and it is associated to the quantum confinement of carriers in Ge-NCs. Ohmic contacts were deposited using a van der Pauw geometry employing an a AuSb alloy for the contacts. Temperature dependent Hall (T-Hall) measurements were done between 35 K and 150 K, using the van der Pauw method. The results indicated low resistivity values that could be explained due to some variable range hopping conduction mechanism.
Coefficient of Diffusion in Crystals of Si1-xGex: Role of Preexponential Factor
Authors: Gusakov Vasilii E.
Published: August 2011

In the present work the results of theoretical analysis of the process of diffusion of covalently bonded atoms (interstitial oxygen atoms) in Si1-xGex alloys are presented. The diffusion coefficient (activation energy and pre-exponential factor) was calculated by means of quantum-chemical simulations (Hartree–Fock, NDDO, PM5) and the dependences of the activation energy and pre-exponential factor on Ge atoms concentration (x) were analyzed with the use of the percolation theory. The study has revealed that the diffusivity of impurities (defects) in alloys can decrease considerably at low concentration (x<0.05) of a minor alloy component and this variation results from the fact that the pre-exponential factor depends on the concentration of component elements of the alloy. The alloy-induced decrease in the pre-exponential factor is associated with removal of the degeneracy of the number of equivalent diffusion paths. It is found that a sharp decrease in the pre-exponential factor causes experimentally observed decreases in the coefficient of diffusion of interstitial oxygen atoms and in the rate of formation of oxygen thermal donors in Si1‑xGex crystals at x~0.01.
Functional Gap Junctions Accumulate at the Immunological Synapse and Contribute to T Cell Activation
Authors: Mendoza-Naranjo Ariadna , Bouma Gerben , Pereda Cristián , Ramírez Marcos , Webb Kevin F. , Tittarelli Andrés , López Mercedes N. , Kalergis Alexis M. , Thrasher Adrian J. , Becker David L. , Salazar-Onfray Flavio
Published: August 2011

Gap junction (GJ) mediates intercellular communication through linked hemichannels from each of two adjacent cells. Using human and mouse models, we show that connexin 43 (Cx43), the main GJ protein in the immune system, was recruited to the immunological synapse during T cell priming as both GJs and stand-alone hemichannels. Cx43 accumulation at the synapse was Ag specific and time dependent, and required an intact actin cytoskeleton. Fluorescence recovery after photobleaching and Cx43-specific inhibitors were used to prove that intercellular communication between T cells and dendritic cells is bidirectional and specifically mediated by Cx43. Moreover, this intercellular cross talk contributed to T cell activation as silencing of Cx43 with an antisense or inhibition of GJ docking impaired intracellular Ca2+ responses and cytokine release by T cells. These findings identify Cx43 as an important functional component of the immunological synapse and reveal a crucial role for GJs and hemichannels as coordinators of the dendritic cell–T cell signaling machinery that regulates T cell activation.
Separation of Mutational and Transcriptional Enhancers in Ig Genes
Authors: Kothapalli Naga Rama , Collura Kaitlin M. , Norton Darrell D. , Fugmann Sebastian D.
Published: August 2011

Secondary Ig gene diversification relies on activation-induced cytidine deaminase (AID) to create U:G mismatches that are subsequently fixed by mutagenic repair pathways. AID activity is focused to Ig loci by cis-regulatory DNA sequences named targeting elements. In this study, we show that in contrast to prevailing thought in the field, the targeting elements in the chicken IGL locus are distinct from classical transcriptional enhancers. These mutational enhancer elements (MEEs) are required over and above transcription to recruit AID-mediated mutagenesis to Ig loci. We identified a small 222-bp fragment in the chicken IGL locus that enhances mutagenesis without boosting transcription, and this sequence represents a key component of an MEE. Lastly, MEEs are evolutionarily conserved among birds, both in sequence and function, and contain several highly conserved sequence modules that are likely involved in recruiting trans-acting targeting factors. We propose that MEEs represent a novel class of cis-regulatory elements for which the function is to control genomic integrity.
Collections of extant cetaceans in Italian museums and other scientific institutions. A comparative review
Authors: Cagnolaro Luigi , Podestà Michela , Affronte Marco , Agnelli Paolo , Cancelli Fabrizio , Capanna Ernesto , Carlini Rossella , Cataldini Giorgio , Cozzi Bruno , Insacco Gianni , Maio Nicola , Marsili Letizia , Nicolosi Paola , Olivieri Vincenzo , Poggi Roberto , Renieri Tommaso , Wurtz Maurizio
Published: August 2011

This paper summarizes more than four decades of cetacean research data collected by the Museo Civico di Storia Naturale di Milano and, between 1986 and 2003, by the Centro Studi Cetacei of the Società Italiana di Scienze Naturali. It is the result of the collaboration among scientists of several Italian museums. A detailed analysis concerning the amount and taxonomic representative- ness of the extant cetacean collections in Italian naturalistic museums and analogous institutions up until and including 2007 has been carried out. Adequately preserved and anatomically most significant specimens only have been taken into consideration. On the whole 1033 specimens representing 41 species are considered herein. They are housed in 53 institutions, of which the following ones hold the most important collections: the museums of Calci (Pisa), Genova, Firenze, Milano, Roma Zoology, Siena, Comiso and Napoli. All the surveyed institutions are listed, with a short introduction about their material and an inven- tory of it. Specimens are then arranged in systematic order and some further data are provided in a table for each species. Such tables report the items of each museum with regard to quantity, preserva- tion techniques and, whenever possible, collecting data. Finally, a comparative analysis of the results is presented under multiple profiles: historical, preservation techniques, suitability of the specimens for research, place of origin, and the importance of the Italian cetacean collections for research and education.

 
Ecoregion and farm size differences in dairy feed and manure nitrogen management: A survey
Authors: Sheppard S. , Bittman S. , Swift M. , Beaulieu M. , Sheppard M.
Published: August 2011

Sheppard, S. C., Bittman, S., Swift, M. L., Beaulieu, M. and Sheppard, M. I. 2011. Ecoregion and farm size differences in dairy feed and manure nitrogen management: A survey. Can. J. Anim. Sci. 91: 459–473. This paper describes the activity of dairy farmers in Canada in 2005 related to the use of nitrogen (N) and especially practices that led to loss of ammonia (NH3). The data were obtained from a large-scale, statistically structured survey conducted across Canada. The survey sampling was stratified into 10 Ecoregions and across farm size. Numbers of lactating cows per farm were nearly twofold more in the west than the east. In western Canada less than 31% of barns were “tie-stall” type whereas 80% were tie-stall in the St. Lawrence Lowlands. The numbers of hours lactating cows spent in barns, standing yards, exercise fields and pasture varied with Ecoregion and farm size, important data in relation to NH3 emissions. Pasturing was more common in the east than west. Matching feed crude protein concentrations to physiological needs seems a potential best management practice, and smaller farms with tie-stalls seemed more prone to adjusting feed to individual cows compared with large farms with loose housing. Manure handling was divided, with slurry prominent especially in the west. Manure spreading practices also varied by Ecoregion. Overall, it is clear that national averages do not well represent dairy farm management: Ecoregion and farm size differences are significant.
The role of the Vlax Roma in shaping the European Romani maternal genetic history
Authors: Salihović Marijana Peričić , Barešić Ana , Klarić Irena Martinović , Cukrov Slavena , Lauc Lovorka Barać , Janićijević Branka
Published: August 2011

The Roma are comprised of many founder groups of common Indian origins but different socio‐cultural characteristics. The Vlax Roma are one of the founder Roma populations characterized by a period of bondage in the historic Romanian principalities, and by the archaic Romanian language. Demographic history suggests different migration routes of Roma populations, especially after their arrival in Mesopotamia and the eastern boundary of the Byzantine Empire. Although various genetic studies of uniparental genetic markers showed a connection between Roma genetic legacy and their migration routes, precise sampling of Roma populations elucidates this relationship in more detail. In this study, we analyzed mitochondrial DNA of 384 Croatian Vlax Roma from two geographic locations in the context of 734 European Roma samples. Our results show that Roma migration routes are marked with two Near‐Eastern haplogroups, X2 and U3, whose inverse proportional incidence clearly separates the Balkan and the Vlax Roma from other Roma populations that reached Europe as part of the first migration wave. Spatial and temporal characteristics of these haplogroups indicate a possibility of their admixture with Roma populations before arrival in Europe. Distribution of haplogroup M35 indicates that all Vlax Roma populations descend from one single founder population that might even reach back to the original ancestral Indian population. Founder effects followed by strict endogamy rules can be traced from India to contemporary small, local communities, as in the case of two Croatian Vlax Roma populations that show clear population differentiation despite similar origins and shared demographic history.Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Rheology of poly(vinyl chloride) plastisol for super‐high‐shear‐rate processing. II
Authors: Nakajima N. , Harrell E. R.
Published: August 2011

Capillary flow of poly(vinyl chloride) plastisol was examined at low, high, and superhigh shear rates. At the low to intermediate shear rates, the flow was pseudo‐plastic, but the measured viscosity was not reproducible and widely scattered. The flow behavior was explained as the breakup of the particle network into network‐fragments of varying size. At high shear rates, the measured viscosity was reproducible and increased with shear rate, indicating that the particles were, by and large, separated from each other. At superhigh shear rates, the viscosity decreased with the increase of shear rate. The particles cease to participate in flow because rotation becomes more difficult. A plug‐flow ensues with a thin layer of lubricating plasticizer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Cationically cured natural oil‐based green composites: Effect of the natural oil and the agricultural fiber
Authors: Pfister Daniel P. , Larock Richard C.
Published: August 2011

Green composites were produced from various cationically cured natural oil‐based resins and agricultural fibers. The natural oils and agricultural fibers of interest included corn, soybean, fish, and linseed oils and corn stover, wheat straw (WS), and switchgrass fibers. The effects of the types of natural oil and agricultural fiber on the structure and thermal and mechanical properties of the composites were studied using Soxhlet extraction, thermogravimetric and dynamic mechanical analysis, and tensile testing. The green composites, with agricultural fiber loadings of 75 wt %, have thermal stabilities up to 275°C. The Young's moduli and tensile strengths of the composites ranged from 1590 to 2300 and 5.5 to 11.3 MPa, respectively. In general, an increase in the degree of unsaturation of the natural oil resulted in improvements in the thermal and mechanical properties of the composites. The WS fibers tended to give composites with the best thermal and mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Styrene–butadiene rubber membranes for the pervaporative separation of benzene/cyclohexane mixtures
Authors: Benguergoura Hassiba , Moulay Saad
Published: August 2011

Styrene–butadiene rubber membranes with methylene bridges, stemming from the concomitant in situ Friedel–Crafts alkylation during a chloromethylation reaction, were prepared and used in the pervaporative separation of benzene/cyclohexane mixtures. A set of four membranes with different crosslinking extents was achieved by the variation of the [Trimethylchlorosilane (TMCS)]/[Paraformaldehyde (PF)] molar ratios with respect to the styrene (St) unit. Study of the swelling of membranes by the mixture components individually and by their feed mixture compositions, 1 : 1 and 1 : 9, was conducted. The total flux (J) and the separation factor (α) were assessed as a function of the feed composition, temperature, and [St unit]/[TMCS]/[PF] molar ratios. The highest J and α measured in this study were 1401 g m−2 h−1 and 28.50, respectively. The diffusion selectivity was found to depend on the crosslinking extent of the membrane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of polystyrene oligomers by nitroxide‐mediated radical polymerization using diethylketone triperoxide as a multifunctional radical initiator
Authors: de Anda Carlos , de los Santos Gladys , Morales Graciela
Published: August 2011

Styrene oligomers (Mn, 2500–3000 g/mol) with low polydispersity index and containing peroxidic groups within their structure were synthesized using a novel trifunctional cyclic radical initiator, diethylketone triperoxide (DEKTP), through nitroxide‐mediated radical polymerization (NMRP), using OH‐TEMPO. During the synthesis of the polystyrene (PS) oligomers, camphorsulfonic acid (CSA) was used to inhibit the thermal autoinitiation of styrene at the evaluated temperatures (T = 120–130°C). The polymerization rate, which can be related to the slope of the plot of monomer conversion with reaction time, was monitored as a function of OH‐TEMPO, DEKTP, and CSA concentrations. The experimental results showed that all the synthesized polymers presented narrow molecular weight distributions, and the monomer conversion and the molecular weight of the polymers increased as a function of reaction time. Under the experimental conditions, T = 130°C, [DEKTP] = 10 mM, and [DEKTP]/[OH‐TEMPO] = 6.5, PS oligomers containing unreacted OO sites in their inner structure were obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Influence of extrusion temperature on molecular architecture and crystallization behavior of peroxide‐induced slightly crosslinked poly(L‐lactide) by reactive extrusion
Authors: Takamura Masumi , Sugimoto Masataka , Kawaguchi Seigou , Takahashi Tatsuhiro , Koyama Kiyohito
Published: August 2011

The influence of temperature during reactive extrusion of poly(L‐lactide) (PLLA) on the molecular architecture and crystallization behavior was investigated for OO‐(t‐butyl) O‐(2‐ethylhexyl) peroxycarbonate‐modified polymer. The long chain–branched PLLA (LCB‐PLLA) content and its structure in the resulting slightly crosslinked PLLA (χ‐PLLA) containing linear and LCB‐PLLA were characterized by both analyses, size exclusion chromatography equipped with multiangle laser light scattering and rheological measurements. A reduction of LCB‐PLLA content in χ‐PLLA and an increase of number of branches in LCB‐PLLA were found with increasing the extrusion temperature. An increase of extrusion temperature induces different process in the polymer: decrease of the lifetime of peroxide, increase of the radical concentration due to rapid peroxide decomposition rate, and increase of the chain diffusion to the amorphous phase. Among these indices, the lifetime of peroxide is a good index for crosslinking behavior of PLLA during extrusion. As for the isothermal crystallization behavior from the melt, the Avrami crystallization rate constant of χ‐PLLA increases as an increase of LCB‐PLLA content in χ‐PLLA. This implies that LCB‐PLLA acts as a nucleating agent for PLLA. Furthermore, regime analysis and the free energy of nucleus of χ‐PLLA were investigated using Hoffman–Lauritzen theory. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation and prediction on the nonlinear viscoelastic behaviors of nylon1212 toughened with elastomer
Authors: Wang Wanjie , Lu Zhanling , Cao Yanxia , Chen Jinzhou , Wang Jingwu , Zheng Qiang
Published: August 2011

Studies on the nonlinear viscoelastic behaviors of nylon1212 toughened with styrene‐[ethylene‐(ethylene‐propylene)]‐styrene block copolymer (SEEPS) were carried out. The linear relaxation curves at relatively low shear strains show good overlap, the relaxation time and modulus corresponding to the characteristic relaxation modes were also acquired through simulating the linear relaxation modulus curves using Maxwell model. The nonlinear relaxation curves of nylon1212 blends at different shear strains have been obtained and their damping functions were evaluated. Meanwhile, it is found that most blends in the experimental windows follow the strain‐time separation principle and Laun double exponential model can predict damping curves well. The successive start‐up of shear behavior was investigated. The results showed that Wagner model, derived from the K‐BKZ (Kearsley‐Bernstein, Kearsley, Zapas) constitutive equation, could simulate the experiment data of nylon 1212 blend with 10 wt % SEEPS well, but there exists some deviation for experiment data of nylon1212 blends with high SEEPS concentrations. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The relationship between acquaintanceship and coauthorship in scientific collaboration networks
Authors: Pepe Alberto
Published: August 2011

This article examines the relationship between acquaintanceship and coauthorship patterns in a multi‐disciplinary, multi‐institutional, geographically distributed research center. Two social networks are constructed and compared: a network of coauthorship, representing how researchers write articles with one another, and a network of acquaintanceship, representing how those researchers know each other on a personal level, based on their responses to an online survey. Statistical analyses of the topology and community structure of these networks point to the importance of small‐scale, local, personal networks predicated upon acquaintanceship for accomplishing collaborative work in scientific communities.
Secondary Metabolites from Saussurea deltoidea and Their Inhibitory Activity on Lipopolysaccharide‐Induced Tumor Necrosis Factor Production
Authors: Tung Yu‐Lin , Cheng Ming‐Jen , Hu Nai‐Yun , Shih Ying‐Chu , Chiou Shu‐Jiau , Chen Ih‐Sheng
Published: August 2011

Bioassay‐guided fractionation of the whole plants of Saussurea deltoidea led to the isolation and structure elucidation of one new sesquiterpene, deltoidealactone (1), together with 23 known compounds 2–24. Their structures were established on the basis of extensive 1D‐ and 2D‐NMR analyses in combination with HR‐MS experiments. Deltoidealactone (1) inhibits tumor necrosis factor (TNF‐α) production in U937 cells in vitro with an IC50 value of 1.47 μg/ml.
Chemical Composition of the Leaf and Flower Essential Oils of Tunisian Lavandula dentata L. (Lamiaceae)
Authors: Touati Bechir , Chograni Hnia , Hassen Imed , Boussaïd Mohamed , Toumi Lamjed , Brahim Nadia Ben
Published: August 2011

Essential oils of Lavandula dentata, a Tunisian native plant, were isolated from leaves and flowers by hydrodistillation in a Clevenger‐type apparatus and characterized by GC‐FID and GC/MS analyses. The average essential oil yields, means of five replicates, were higher for the flowers (8.60 mg/g) than for the leaves (6.56 mg/g). A total of 72 compounds were identified, accounting for 98.1 and 97.7% of the total oil composition of the leaves and flowers, respectively. The main essential oil constituents were 1,8‐cineole, camphor, and L‐fenchone, accounting for 33.54, 18.89, and 8.36% in the leaf oils and for 19.85, 23.33, and 7.13% in the flower oils, respectively. Besides this quantitative variation, the results also showed considerable qualitative variation between the essential oils of the two plant parts analyzed. These differences might be adaptative responses to ecological exigencies.