bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug Therapies for Cognitive Impairment and Dementia
Authors: Howland Robert H.
Published: March 2010

Drugs currently approved by the U.S. Food and Drug Administration (FDA) for the treatment of Alzheimer's disease include acetylcholinesterase inhibitor drugs (tacrine [Cognex
®
], donepezil [Aricept
®
], rivastigmine [Exelon
®
, Exelon Patch
®
], and galantamine [Reminyl
®
, Razadyne
®
]) and glutamate-modulating drugs (memantine [Namenda
®
]). They do not halt the underlying degenerative process but can slow disease progression. Piracetam is a nonprescription nootropic drug designated by the FDA as an orphan drug for myoclonic seizures. Clinical trials in a diverse group of patients with age-related dementia or cognitive impairment demonstrated a significant benefit, but the methodology of these studies is poor, and long-term effects are unknown. Other therapies discussed in this article include Ginkgo biloba, a nonprescription natural supplement, and Axona
®
, designated by the FDA as a medical food.
Los límites de lo político en Hannah Arendt
Authors: Sorrentino Sergio
Published: March 2010

Lo político en H. Arendt constituye el horizonte en el que se desarrolla el drama de la acción humana y no una esfera de actividad entre otras. Sus coordenadas esenciales son los principios, el poder y las instituciones. Su función es poner límites a la violencia invasora del mundo, interpretada no tanto como lucha de unos contra otros, cuanto como lucha contra la caducidad que amenaza todas las cosas humanas. La razón que instituye la política es la afirmación de sí realizada por la vía de la creación de un mundo común. La problemática de este concepto proviene de la falta de contenido y posibilidades objetivas de sociabilidad diversa de la estrictamente política, así como de que grava lo político con una significación excesiva: tiene que hacerse cargo de la liberación de la contingencia radical y del sentido último.
Historia de la voluntad y banalidad del mal
Authors: Prior Olmos Ángel
Published: March 2010

El artículo plantea las conexiones entre la tesis de la banalidad del mal y la historia de la voluntad presente en La vida del espíritu. Interpreta Eichmann en Jerusalén como una obra sobre el mal burocrático, pero sobre todo como estudio acerca de la responsabilidad, tanto jurídica como moral. De la historia de la voluntad resalta tres aspectos que pueden ser puestos en conexión con el problema de la responsabilidad: la ontología de la contingencia, la idea de individualidad vinculada a la voluntad y la capacidad de trascendencia y resistencia subyacentes en la teoría de Duns Escoto de la libertad como indiferencia. Por último, sugiere una vinculación entre la banalidad del mal y la ontología del bien desarrolladas en “Algunas cuestiones de filosofía moral”, de 1965-1966, la lucha contra el gnosticismo y la defensa de una relación entre moralidad e inteligibilidad del mal.
H. Arendt y Th. W. Adorno: pensar frente a la barbarie
Authors: Zamora José A.
Published: March 2010

Dos de los pensadores más importantes del siglo XX, Hannah Arendt y Theodor W. Adorno, cuyo pensamiento pretendió medirse con el horror más extremo que conoció dicho siglo –Auschwitz–, se negaron a comunicarse y a considerar la obra del otro. Este artículo intenta ponerlos en diálogo a partir de lo que constituyó el núcleo de su obra: pensar frente a la barbarie de los campos de exterminio - pensar y actuar para que esa barbarie no se repita. Tras presentar la forma en que ambos piensan la singularidad del genocidio y los vínculos con los procesos históricos y sociales que lo hicieron posible, trata de analizar las diferencias de fondo, aquéllas que tienen que ver con dos enfoques teóricos irreconciliables.
Arendt, Eichmann y la banalidad del mal
Authors: López Marina
Published: March 2010

En el texto se describen las características que Hannah Arendt, a través de la figura de Eichmann, atribuye a los agentes SS durante el régimen nazi alemán de mediados del siglo XX. Con la caracterización se persigue mostrar, en principio, que no hay una ruptura en el pensamiento de Hannah Arendt respecto a su manera de considerar el mal, desde Los orígenes del Totalitarismo hasta Eichmann en Jerusalén, un estudio sobre la banalidad del mal, sino una continuidad y, por otra parte, seguir las pistas que Arendt propone en torno a la “banalidad” que define el comportamiento de individuos como Eichmann. Ambas premisas nos permitirán poner de relieve lo que, a nuestro parecer, implica la banalización de la humanidad no sólo en el contexto del Holocausto judío, sino en cada una de las sociedades en las que la eliminación de la espontaneidad es una realidad.
La dialéctica del amor-odio en Empédocles y Schopenhauer
Authors: Morales Troncoso David Emilio
Published: March 2010

El pensamiento dialéctico se puede describir como un modo de concebir una idea que involucra la necesaria coexistencia de su contrario o complementario. En las filosofías de Empédocles y en Schopenhauer se da una semejanza en este sentido, que es advertida por este último y que apunta a la reivindicación de la experiencia moral como soporte de una representación del devenir del mundo de la vida.
El final de una tensión esencial: analíticos y continentales. Herméutica filosófica y teorías de la argumentación
Authors: Navarro María G.
Published: March 2010

La autora presenta la hipótesis de que es en la hermenéutica filosófica donde se encuentran los fundamentos especulativos de las llamadas teorías de la argumentación. Para mostrar la consistencia de esta hipótesis no sólo se exploran las más famosas tesis históricas sobre la conexión entre analíticos y continentales, sino que se presenta un análisis de conceptos (plausibilidad, dialéctica, retórica, razonamiento heurístico, razonamiento tópico) del que se desprenden las bases hermenéuticas de los desarrollos en el campo de las teorías de la argumentación.
Preparation of Cf/SiC Composites by Liquid Silicon Infiltration
Authors: Wang Chun Peng , Tang Jie , Liu Hai Lin , Huo Yan Li , Chen Yu Feng , Peng Xiao Ying
Published: March 2010

The Cf/SiC made from carbon fiber preforms infiltrated by phenol resin, pure carbon slurry and aqueous C/SiC slurry showed different binding strength between carbon fiber and SiC matrix, thus influenced the fracture behavior of the composite. The fracture toughness of the Cf/SiC composites with the value of 9.82MPa•m1/2,improved remarkably compared with reaction- bonded silicon carbide (RBSC). But the flexural strength was less than 100 MPa, because of the existence of considerable amount of pores in C/SiC composites.
Oxidation Behavior of TiC/ Fe Ceramics Produced by Self-Propagating High-Temperature Synthesis
Authors: Li Bin , Liu Zong De , Zhao Li Ping , Bao Yan Rong
Published: March 2010

The key problem about the application of TiC/Fe composite ceramics in high temperature is the oxidation resistance. With an aim to investigate oxidation properties, the high density TiC/Fe ceramics was produced by self-propagating high-temperature synthesis method combined with pseudo hot iso-static pressing (SHS/PHIP). The oxidation kinetics of TiC/Fe ceramics were investigated by means of conducting the isothermal oxidation experiments in air at temperature of 550°C  900°C for up to 150 hours, and measuring the variations of the weight gains of the composites with the oxidation times. The microstructure evolution of the composites during the oxidation processing was studied by using SEM/EDS and XRD. Experimental results show that TiC/Fe ceramics basically follows a parabolic rule at high temperature. A detailed characterization of the microstructure and distribution of the phases within the scale following oxidation studies has been undertaken to suggest the possible mechanism for the oxidation of TiC/Fe ceramics.
Ultra-High-Hard Composites of TiC-TiB2 Prepared by Combustion Synthesis under High Gravity
Authors: Qu Zhen Sheng , Yang Quan , Zhao Zhong Min , Zhang Long , Pan Chuan Zeng , Wang Min Quan
Published: March 2010

The large-bulk solidified TiC-TiB2 composites were prepared by combustion synthesis in high-gravity field. XRD, FESEM, SEM and EDS results showed that TiC-TiB2 composites were mainly composed of TiC matrix in which a number of fine TiB2 platelets were embedded, surrounded by the boundary regions consisting of (Cr, Ti) C0.63 carbides. The hardness, flexural strength and fracture toughness of TiC-TiB2 composites measured 28.5GPa, 750±25MPa and 6.2±0.5MPa•m1/2. High hardness of the composites benefits from the absence of the intermediate borides and the achievement of stoichiometric TiC phases due to rapid solidification, whereas the achievement of high strength benefits the refinement and homogeneity of the microstructures due to rapid separation of liquid oxides in high-gravity field and rapid coupled growth of TiC and TiB2 phases.
Detection of Amorphous Silica in Air-Oxidized Ti3SiC2 at 500–1000°C by NMR and SIMS
Authors: Pang Wei Kong , Low It Meng , Hanna J.V.
Published: March 2010

The use of secondary-ion mass spectrometry (SIMS), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti3SiC2 oxidised at 500–1000°C is described. The formation of an amorphous SiO2 layer and its growth in thickness with temperature was monitored using dynamic SIMS. Results of NMR and TEM verify for the first time the direct evidence of amorphous silica formation during the oxidation of Ti3SiC2 at 1000°C.
Effects of Carbon Black on Microstructure and Mechanical Properties of Hot Pressed ZrB2-SiC Ceramics
Authors: Sun Xin , Zhang Xing Hong , Wang Zhi , Han Wen Bo , Hong Chang Qing
Published: March 2010

Abstract. ZrB2-SiC ultra-high temperature ceramics (UHTCs) was hot-pressed at a temperature of 1900°C with the addition of carbon black as a reinforcing phase. Microstructure and mechanical properties were investigated. Analysis revealed that the amount of carbon black had a significant influence on the sinterability and mechanical properties of ZrB2-SiC ceramics. When a small amount ( < 10 vol.%) of carbon black was introduced, it may react with oxide impurities (i.e. ZrO2, B2O3 and SiO2) present on the surface of the starting powder, thus promote the densification and grain refining of ZrB2-SiC ceramics. As a result, the mechanical properties including flexural strength and fracture toughness were improved. However, with the further adoption of carbon black, mechanical properties were not improved much, which could be attributed to the redundant phase at grain boundaries. The results presented here point to a potential method for improving densification, microstructure and mechanical properties of ZrB2-based ceramic composites.
Synthesis and Luminescent Properties of Mn2+-Doped Zinc Silicate Phosphors by Sol-Gel Method
Authors: Zhang Ji Ming , Zhao Dong Lin , Shen Zeng Min
Published: March 2010

Abstract. Green light emitting Mn2+-doped Zn2SiO4 (Zn2SiO4:Mn2+) phosphor nano-particles were synthesized by sol-gel method combined with a furnace firing from the sol-gel solution made with ZnO, MnCO3 and tetraethoxysilan. The influences of annealing temperatures on the microstructures and photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were investigated. The structural details of the phosphors were examined through XRD and SEM. The photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were characterized by excitation and emission spectra. The results indicate that the XRD patterns of the Zn2SiO4:Mn2+ phosphors exhibit a willemite structure (-Zn2SiO4). Green photoluminescence whose emission peak is located at 525 nm were observed from the synthesized phosphor particles under UV excitation. The photoluminescent mechanisms of the Zn2SiO4:Mn2+ phosphors were discussed.
The Influence of Oxygen Plasma Treatment on the Electrical Properties of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 Thin Films
Authors: Chen Kai Huang , Yang Cheng Fu
Published: March 2010

The (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 (BSTZ) thin films are deposited using radio frequency (RF) magnetron sputtering, then oxygen gas plasma is treated on the surface of BSTZ thin films. The influence of oxygen plasma on the structure of BSTZ thin films is studied using X-ray diffraction patterns and the influence on the electrical characteristics is developed using an Al/BSTZ/Pt/Ti/SiO2/Si capacitor structure. As compared to that of the BSTZ thin films are not subjected to oxygen plasma treatment, experimental results reveal that the leakage current density of the BSTZ thin films in oxygen plasma treatment decreases as much as two orders in magnitude. In addition, the dielectric constants apparently increase and the leakage current density critically decrease as the oxygen-plasma-treated time increases. These results clearly indicate that the electrical characteristics of the BSTZ films are effectively improved using the process of oxygen plasma surface treatment.
Ferroelectric Properties and Microstructures of Pr6O11-Doped Bi4Ti3O12 Thin Films
Authors: Chen Min , Cai A.H. , Mei X.A. , Su K.L. , Huang Chong Qing , Wan Z.M. , Liu J.
Published: March 2010

Pr6O11-doped bismuth titanate (BixPryTi3O12: BPT) thin films with random oriention were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicated that all of BPT films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. For samples with y=0.06, 0.3, 1.2 and 1.5, ferroelectric hysteresis loops were characterized by large leakage current, whereas for samples with y=0.6 and 0.9, ferroelectric hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BPT Film with y=0.9 were above 35μC/cm2 and 80KV/cm , respectively. After 3×1010 switching cycles, 20% degradation of 2Pr is observed in the film with y=0.9.
Memory Properties of SrBi2Ta2O9/ Ba(Zr0.1Ti0.9)O3 Thin Films Prepared on Si Substrate
Authors: Tzou Wen Cheng , Chen Kai Huang , Yang Cheng Fu , Chen Ying Chung
Published: March 2010

In this study, ferroelectric thin films of SrBi2Ta2O9 (SBT) or bilayered SrBi2Ta2O9/ Ba(Zr0.1Ti0.9)O3 (SBT/BZT) are successfully deposited on Si substrate under the optimal RF magnetron sputtering conditions, and their electrical and ferroelectric characteristics are discussed. Ferroelectric thin films are deposited on Si substrate under the RF power of 80 W, chamber pressure of 10 mTorr, substrate temperature of 550oC, and different oxygen concentrations. The surface morphology of deposited thin films is observed from the FESEM images, and the memory windows and leakage current of the Al/SBT/BZT/Si (MFS) structure are measured by an impendence phase analyzer and a semiconductor parameter analyzer, respectively. The memory window, capacitance and leakage current density of MFS structures under different oxygen concentrations are also reported. We find that the memory window of bilayered SBT/BZT structure shows larger than one of single layer SBT structure.
Preparation of BiFeO3 Nanopowders Using Acetylacetone as Stabilizer
Authors: Xu Jia Huan , Ke Hua , Jia De Chang , Wang Wen , Zhou Yu
Published: March 2010

The present investigation reports on the preparation of BiFeO3 nanopowders by a sol-gel method using acetylacetone as a stabilizer. Single-phase BiFeO3 nanopowders without any impurity or amorphous phases were obtained when the precursor was thermal treated at temperatures as low as 400 oC for 2 h. Acetylacetone (acac) plays an important role on lowering the formation temperature of pure phase BiFeO3 nanopowders. It is found that Bi/acac molar ratio of 1/30 was favorable for a stable sol and for the lowest crystallization temperature of pure BiFeO3 nanopowders. X-ray diffraction and Fourier transform infrared spectroscopy revealed that thermally induced crystallization process of BiFeO3 nanopowders from Bi-Fe polymeric precursor. When the thermal treated temperature was below 200 oC, only amorphous phase existed. With the temperature increasing up to 300 oC, crystallized phase, carbonate, were detected. After annealed at 400 oC, Bi-Fe precursor totally changed to rhombohedral BiFeO3 nanopowders. Scanning electron microscopy characterized morphologies of BiFeO3 nanopowders calcined at 400 oC and 500 oC. The ferroelectric transition of BiFeO3 nanopowders at 827 oC has been detected by differential thermal analysis.
Microstructure and Electrical Properties of Bi3+ Modified ZnO Ceramics
Authors: Guerra J.D.S. , Leyet Y. , Guerrero F. , Romaguera Y. , Pérez J. , Aguilera L.
Published: March 2010

High-quality bismuth modified zinc oxide ceramics were obtained by conventional ceramic method. The phase analysis revealed pure hexagonal ZnO phase in all the samples. High relative density (above 95%), when compared with theoretical density of ZnO, was achieved by the Arquimides’ method. Non-linear coefficients, obtained from the J-E curves, shown an increase in their values as the bismuth content increases. Complex impedance analysis revealed an increase of the semicircle diameters with the increase of the bismuth content. The obtained results will be discussed within the framework of the current theoretical model proposed in the literature.
Structure and Performance of Self-Reactive Spray Formed Ti(C,N)-TiB2 Multi-Phased Ceramic Materials
Authors: Wang Jian Jiang , Liu Hong Wei , Hu Wen Bin , Wen J.H. , Lou H.F.
Published: March 2010

Based on the Ti-B4C-sucrose(precursor of carbon) -5wt.% Al sprayed system, the self-reactive spray formed multi-phased structural ceramic preforms tests were done. And the organization, structure and performances of the products were studied. The results show that the products are composed of continuous matrix phase TiC0.3N0.7, dispersed micro/nanometric rodlike grains TiB2, some of Al2O3, pores and intermetallic phase Ti3Al which is hard to identify by SEM. Aluminum is benefit to improve organization, structure and performances of the products. The average density of the products is 97.7%, the Vickers hardness is 20.6GPa, and the flexural strength is 425MPa. There are crack deflection and grain bridging toughening mechanisms owing to the rodlike grains of TiB2 in the products, which makes their fracture toughness is as high as 7.3MPa•m1/2.
Preparation and Characteristics of BiFeO3 Ceramics Doped by MnO2 and Co2O3
Authors: Yu Xiao Hua , Gu Hong Xing , Wu Bo Lin , Wang Jian , Shao Gang Qin , Ouyang Shi Xi , Li Xi Bao
Published: March 2010

BiFeO3-based single-phase multiferroics have been widely studied in both ceramics and films. However, the macroscopic magnetic properties of BiFeO3 ceramics were now most very weak. In this work, MnO2 and Co2O3 were used as B-site substitutes in BiFeO3 ceramics in order to the enhancement of magnetic properties. The change of magnetization was analyzed based on the phase composition and the microstructure of ceramics.
Microwave Assisted Deposit Oxide Ceramic Coating onto Metal
Authors: Cheng Zhen Qian , Liu Jia Chen , Wang Cai Fen , Xu Hai
Published: March 2010

A new way to deposit oxide ceramic coating on the metal was prepared by Gel-casting and microwave assisted heating. The oxide ceramic coating was obtained by dipping the metal substrate whose surface carried positive charge through acid treatment to the gel slurry which was composited by oxide powder with negative charge, and then gelating, drying and heating by microwave. It was showed that it was feasible to realize coating of ceramics on metal surface through microwave heating.
Effects of CeO2 on the Mechanical Property and Microstructure of 3Y-TZP Nanocomposite Ceramic Die Material
Authors: Zhao Shi Kui , Xu Chong Hai
Published: March 2010

Thermal stability and wear resistance of nanoceramic materials are excellent, so it is an ideal die material and has become one of the increasingly important topics in the field of die research. A new 3Y-TZP nanocomposite die material was prepared with hot pressing technique by using 3Y-TZP, CeO2, Al2O3 and nanometer sized TiC as raw materials. Effects of CeO2 on the mechanical property and microstructure of 3Y-TZP nanocomposite die material were investigated. The addition of CeO2 has obvious effect on the flexural strength and fracture toughness. When the content of CeO2 is 2mol%, the fracture toughness of the composite material reaches 11.22MPa•m1/2. With the increase of CeO2 content, the fracture toughness becomes lower, the flexural strength and hardness first increase and then decrease. When the CeO2 content is 6mol%, the maximum flexural strength reaches 866MPa. The reason for the improvement of mechanical property can be attributed to the effect of CeO2 on the phase transformation of t-ZrO2 and microstructure and the resulted phase transformation toughening mechanism.
Analysis and Test of An Optical Scanner Actuated by PZT Films
Authors: Yuan Song Mei , Liu Wei Dong , Zhuang Chi
Published: March 2010

The structure and principle of an optical scanner actuated by PZT films have been presented in this paper. FEA software (ANSYS9.0) has been used to analyze the modal and harmonic characteristics of the scanner to acquire its dynamic characteristic and deformation, on which we base to optimize its structure. Finally, its resonance frequency and displacement were measured through experiment to testify its feasibility. It shows that the piezoelectric scanner can realize two-dimensional scanning at high frequency, and it can be fabricated conveniently because of its simple structure.
First Principle Study of the Electronic Structure of Gd2SrAl2O7
Authors: Feng J. , Pan Wei , Xiao B. , Wu Rui Fen , Wan Chun Lei , Chen Jing Chao , Zhou R.
Published: March 2010

The ground state electronic structure of Gd2SrAl2O7 are calculated using first principles, we found that only the Density functional theory (DFT) + U can correctly describe the Gd2SrAl2O7 as a charge-transfer type insulator. Gd-O and Al-O bonds have strong covalent character and Sr-O is a perfect ionic bond. The band gap of Gd2SrAl2O7is 3.9 eV, and it is opened due the large U correction for 4f orbit.
Preparation and Thermal Conductivity of Hf6Ta2O17 Ceramic
Authors: Li M. , Xu Qiang , Wang L.
Published: March 2010

Hf6Ta2O17 ceramic powder was prepared by solid state reaction at 1600°C for 10 hours. The phase and microstructure of Hf6Ta2O17 ceramics were observed. The XRD results revealed that the sintered sample of the ceramic powder had single phase and the SEM results showed that the sintered sample was comparative dense. The thermal conductivity of the sintered sample was investigated and the value was comparative low.
Fabrication of Textured β-Si3N4 and β-Sialon by Slip Casting in a Strong Magnetic Field and Reaction-Sintering
Authors: Sakka Yoshio , Zhu Xin Wen
Published: March 2010

This paper reviews the most important results by the authors on the processing of textured -Si3N4 and -sialon by slip casting in a strong magnetic filed of 12 T and reaction-sintering. The a, b-axis textured -Si3N4 and -sialon have been obtained using the static magnetic field because of the magnetic susceptibility of ca, b > c c for -Si3N4. However, the c-axis textured -Si3N4 has also been successfully obtained using a rotating magnetic field. The -Si3N4 crystal was found to exhibit substantially stronger orientation ability than the a-Si3N4 crystal regardless of the Si3N4 raw powders. It reveals that the -Si3N4 nuclei play a key role in the texture development in -Si3N4/-sialon.
Influence of Annealing Temperatures on the Properties of Dual-Layer W-TiO2 Thin Films
Authors: Huang Chia Cheng , Wang Fang Hsing , Yang Cheng Fu , Huang Hong Hsin , Chen Cheng Yi , Huang Ping Chih
Published: March 2010

W-TiO2 (W, tungsten) dual-layer thin films are deposited by RF magnetron sputtering onto glass substrates and annealed at 150oC~400oC for 4hrs. The crystal structure, morphology, and trans- mittance of annealed W-TiO2 dual-layer thin films are investigated by X-ray diffraction, FESEM, and UV-Vis spectrometer, respectively. The annealing temperatures have large effect on the properties of W-TiO2 dual-layer thin films. The band gap energy values of W-TiO2 dual-layer thin films are evaluated from (h)1/2 versus energy plots. The energy gap for un-annealed W-TiO2 dual-layer thin film is 3.16 eV. As the annealing temperature increases from 150oC to 400oC, the energy gap decreases from 3.16 eV to 3.10 eV.
Structure and Morphology of Sol-Gel Nanocrystalline TiO2 Films Coated on Glass Substrates
Authors: Ji G.J. , Shi Zhi Ming , Zhao G.
Published: March 2010

The Ce3+-doped and undoped nanocrystalline TiO2 films were prepared on glass substrates surface by sol-gel dip coating technique. The crystal structure and surface morphology of TiO2 films were characterized by means of X-ray diffractometer (XRD), transmission electron microscopy (TEM) and atomic force microscope (AFM). The results indicated that the Ce3+-doped TiO2 films were solely composed of the anatase phase whereas in the undoped films small amount of the rutile phase of TiO2 were present. The average crystallite size of the undoped TiO2 films was about 30nm and was decreased with Ce3+-doping in the TiO2 films. Moreover, the grains distributed more uniform and the surface roughness was smaller in the Ce3+-doped TiO2 films than in the undoped one. The action mechanism of Ce3+-doping inhibits the crystallization of the rutile phase and decreases the anatase granularity of TiO2 films is associated with its physicochemical properties, as well as ionic diffusion and valance change of Ce3+ to Ce4+ in the sintering process.
Mineralization of Bone-Like Apatite in Chitosan Hydrogel
Authors: Li Bao Qiang , Huang Yan Ming , Wang Yong Liang , Zhou Yu
Published: March 2010

Polymers with negative charge groups, such as carboxylic or phosphatic groups, were frequently used to induce or promote the apatite deposition. However, chitosan with potentially chelated calcium ions, were ignored. Inspired by layer by layer technology, chitosan hydrogel without any surface modification process was used as framework to mineralize bone-like apatite. XRD and IR results shown that in situ synthesis bone-like apatite, similar to apatite in rib of rabbit, was carbonate ions partially substituted apatite and preferred growth orientation in direction of their c-axis. Bone-like apatite with nano-flake shape with size of 1um fully covered chitosan in short period of time. In case of chelation effect of amino groups, chitosan hydrogel provided heterogeneous apatite nucleation sites, which supported by fact that bone-like apatite tended to deposit on porous wall of chitosan, rather than grow in form of free-standing.
Preparation of Carbon Fiber Reinforced Si-HA Bone Cements Composites
Authors: Li Juan Ying , Huang Jian Feng , Cao Li Yun
Published: March 2010

Carbon fiber reinforced silicon-substituted hydroxyapatite (C(f)/Si-HA) bone cements composites were prepared by microwave chemical reaction with a later solidification process using carbamide, calcium nitrate, ammonium dibasic phosphate and ethyl silicate as raw materials, and buffer solutions of acrylic acid and itaconic acid as gelling agent. The influences of carbon fibers volume fraction, contents of coupling agents, sodium citrate contents on the flexural strength of silicon- substituted hydroxyapatite bone cements composites were particularly investigated. The phase composition, microstructures and flexural strength of the composites were characterized by X-ray diffraction, scanning electron microscope and universal testing machine analyses. And the flexural strength of the prepared composites reach the maximum value 41.5MPa when the carbon fibers volume fraction, silane agent KH550 and sodium citrate mass fraction arrive to 3.0, 0.6 and 3.0%, respectively.
DSCs Modules Fabricated by Screen Printing
Authors: Zhang Jing , Lin Hong , Li Jian Bao , Li Xin , Zhao Xiao Chong
Published: March 2010

Screen printing has been considered to be the simplest and quickest way to fabricate dye- sensitized solar cells (DSCs) modules for an assembly line. 20cm×10cm DSCs modules with W-type series connection and parallel connection were fabricated. The whole fabricating process was all operated by screen-printing except for the injection of electrolyte. The optimized TiO2 electrode thickness, sealant thickness and platinum counter electrode thickness were investigated. The modules showed a reliable performance.
Development of Transparent MgAl2O4 Spinel Ceramics
Authors: Li Fa Hui , Li Jian Bao , Lin Hong , Huang Cun Xin , Lei Mu Yun , Du Hong Bing
Published: March 2010

The present paper summarizes the technology and basic process for fabricating transparent ceramic MgAl2O4 spinel and introduces a scalable production technique. Fully transparent polycrystalline spinel has been prepared by combined vacuum sintering, hot-pressing, sintering in H2 atmosphere and hot isostatic pressing(HIP). The optical transmittance of the specimen sintered at 1500°C following HIP at 1800°C was nearly the same as that of single crystal spinel. When radiated by γ-ray and X- ray, colorless spinel became brown due to V-type color centers, which decreased its transmittance. On the other hand, the spinel ceramics’ resistance to radiation improved by doping CeO2.
Effects of Vacuum Heat Treatment of Nano Powder on Sintering of Transparent Nano-Crystalline MgAl2O4 Ceramics
Authors: Chang Xiang Hui , He Duan Wei , Zhang Jie , Zou Yong Tao , Wang Jiang Hua , Lu Tie Cheng
Published: March 2010

Nano-sized MgAl2O4 powders were treated at 500~1000 oC in a vacuum of 10-3Pa for 2 h, and then sintered at 500~900 oC under 1~6 GPa. The powders with and without vacuum-heat-treatment were investigated by means of Transmission Electron Microscope (TEM) and Sedimentation Test. It was found that the vacuum-heat-treatment of nano powder could effectively get rid of the absorbed gas on the surface of nano-particles. Bulk nanostructured transparent ceramics without cracks were sintered easily with the treated nano-sized powder. The success rate of nano-sinterning of bulk transparent ceramics was greatly increased when a suitable vacuum-heat-treatment process was used for the starting nano-sized powder.
Fabrication and Optical Properties of Cr3+:YSAG Transparent Ceramics
Authors: Feng Tao , Jiang Dan Yu , Shi Jian Lin
Published: March 2010

Cr-doped Y3ScxAl(5-x)O12(Nd:YSAG) powder have been prepared with a combustion method. The powders are nanosized and a pure cubic phase when calcined at 900°C. Transparent Cr:YSAG ceramics were successfully fabricated by sintering the powder compact at 1800°C under H2 atmosphere. The optical properties were investigated in detail. It was found that after Sc substitute for Al, the The octahedral crystal-field parameter Dq and Dq/B was reduced, and that is why the absorption peak move to the longer wavelength side but the emission peak not moved.
Influence of Thickness on Oxide Ionic Conductivity in Sm3+ and Nd3+ Co-Doped CeO2 Electrolyte
Authors: Liu Wei , Li Bin , Pan Wei
Published: March 2010

Sm3+ and Nd3+ co-doped CeO2 solid electrolytes with various thicknesses were prepared by citric-nitrate combustion process. The electrical conductivity as a function of electrolyte thickness was determined by ac impedance spectroscopy. The results showed that the ionic conductivity increases with the decrease of the electrolyte thickness approximately and it was estimated that the conductivity enhancement was due to the increased grain boundary conductivity.
W Gradedly-Doped Diamond-Like Carbon Thin Films
Authors: Wang Cheng Biao , Peng Zhi Jian , Wu Su Dong , Fu Zhi Qiang , Chen Xin Chun
Published: March 2010

W gradedly-doped diamond-like carbon films were deposited on silicon and stainless steel by a hybrid technique combining ion beam deposition with magnetron sputtering. The structure, mechanical performance, friction coefficient, and wear loss were investigated. With increasing W target current applied, the structure of the as-prepared films changed from amorphous DLC to a composite of metal-containing DLC and metal carbides; the content of sp3 structure decreased from 31.26% to 22.3%; the nanohardness increased from 12 GPa to 28 GPa; the elastic modulus increased from 170 GPa to 310 GPa; and the critical loads were in the range of 80~100 N. The comprehensive tribological property of the as-prepared samples was improved after W doping.
Fabrication of Tailored Powder Structures by Electrophoretic Deposition and Sintering
Authors: Olevsky Eugene , Wang Xuan
Published: March 2010

To enable sintering net-shape capabilities, a novel procedure for the fabrication of net-shape functionally graded composites by electrophoretic deposition and sintering are developed. The initial shape of the green specimen produced by electrophoretic deposition is designed in such a way so that the required final shape is achieved after sintering-imposed distortions. The shaped components can be metals, ceramics, polymers, and their combination as long as the material is in the form of powders. Through adjustment of an externally applied electric field and the shielding of electrical filed, the particles in the slurry are selectively deposited onto the porous mold which defines the desired geometry. By changing the slurries’ composition, the deposited component’s composition can be precisely tailored.
Finite Element Modeling of Temperature Distribution in Spark Plasma Sintering
Authors: Wang Cao , Zhao Zhe , Cheng Lai Fei
Published: March 2010

A finite element model (FEM) is developed to simulate the temperature distribution in the sample/die/punch assembly during the spark plasma sintering (SPS) process. A thermal–electrical coupled model with temperature dependent thermal and electrical properties is implemented. The simulation studies were conducted using COMSOL and a range of heating-rates and die sizes were considered. Also, both temporary and equilibrium condition during heating process were evaluated in order to express the real temperature development in the sintering. During the spark plasma sintering process, the temperature difference between the sample center and the die surface depend on the heating-rate and die size. The simulation results also revealed that the temperature gradient during the heating process is much bigger than that in the dwelling period. It is necessary to consider the temporary state during the spark plasma sintering process in order to guarantee a well–controlled microstructure, especially in non-conductive ceramic materials.
Properties of Nanosize Aluminum Nitride Powders Synthesized by Chemical Vapor Synthesis
Authors: Pee Jae Hwan , Park Jong Chul , Hwang Kwang Taek , Kim Soo Ryong , Cho Woo Seok
Published: March 2010

AlN powders by the chemical vapor synthesis (CVS) process in the AlCl3-NH3-N2-H2 system were successfully synthesized. Gasified AlCl3 as a starting material was generated by pre-heating system and transported to the tube furnace in NH3-N2-H2 atmosphere. High crystalline AlN was synthesized at over 900°C. The average particle size of spherical AlN powders decreased from 250 to 40nm with increasing the reaction temperature of the tube furnace. Porous nano-size particles synthesized at high reaction temperature have low oxygen contents.
Phase Relationships of Al2O3-ZrO2-SiO2 System with Microwave Heating
Authors: Zhao Ying Na , Zhang Peng Yu , Xu Hai , Jia Qi Hui , Liu Jia Chen
Published: March 2010

Based on the Al2O3-ZrO2-SiO2 system, the conventional pre-sintering samples were reheated by microwave to investigate the influence of microwave to the thermodynamic equilibrium and phase equilibrium relationships. It was found that microwave can accelerate transitions to thermodynamic equilibrium. The phase equilibrium of the samples prepared by microwave heating was identical with the traditional phase diagram. In addition, the amount of tetragonal zirconia in the prepared samples remained constant as the microwave heating time prolonging. All of the observed phenomenon can be explained by microwave nonthermal effects.
Unusual Reuniting of Barium Titanate Nanoparticles
Authors: Zhang Xiao Quan , Wang Xiao Hui , Sun Tie Yu , Cui Ai Li , Li Long Tu
Published: March 2010

A solvothermal method to synthesize barium titanate nanoparticles is employed. In this method many raw materials such as oleic acid, surfactant, sodium hydroxide, alkali barium acetate, alcohol, tetrabutyl titanate are used. When the samples are collected, oleic acid which has mush an account will cover the whole particles. To make the samples cleaner, nitric acid is used to transition oleic acid to elaidic acid which is lighter than water then it will float up to be removed. In the progress to wash off the oleic acid the particles were found to reunite unusually: bigger and cubic particles are formed and the shape seems like single crystal but they are reunitions indeed, we used HTEM to prove this. It means self–assembling might happen through the progress, the spontaneous polarization orient, polarity of molecules will affect this progess.
Illusions under an Alien Sky: Paul Scott’s precursor to the Raj Quartet
Authors: Wijesinha Rajiva
Published: March 2010

Paul Scott's second novel, The Alien Sky, foreshadows the interest with the subject of Indian independence that dominates his final great achievement, The Raj Quartet. Though in this single novel Scott's obvious concern is the British reaction to independence, I believe in his presentation of his characters he also explores some of the moral concepts relating to colonialism and independence that he analyses so illuminatingly in the Quartet. In particular he shows how elements in the individual human psyche contribute to actions and reactions within relationships based on power, which are the dominant feature of the imperial situation. One of Scott's principle themes is that, because of the power factor, even for the most idealistic of those within the system there were boundaries that could not be crossed. While Scott exposes then those who have no qualms about abusing their power, I suggest that he reserves his sharpest criticism for those who fail to live up to their expressed ideals because of their reliance on the system with which in the end they must show solidarity. DOI: 10.4038/suslj.v6i1.1688 Sabaragamuwa University Journal, vol 6, no. 1, pp 35-49
The feeding value of grain screenings for ruminants: Chemical composition and nutrient utilization
Authors: Marx T. A. , McKinnon J. J. , Mustafa A. F. , Christensen D. A. , Racz V. J.
Published: March 2010

The objectives of this study were to determine the chemical and nutrient utilization characteristics of grain screening pellets (GSP) for ruminants. One ruminally fistulated cow was used to determine ruminal nutrient degradability characteristics of GSP relative to barley grain. Twenty-one growing lambs were used to determine voluntary intake and total tract nutrient digestibility coefficients for GSP relative to regular and thin barley. Seven diets were formulated with different levels of GSP, and thin or regular barley at ratios of 100:0; 75:25; 50:50; 25:75. On a dry matter (DM) basis, GSP contained 337 ± 17.4 g kg−1 neutral detergent fiber (NDF), 209 ± 21.1 g kg−1 acid detergent fiber (ADF), 151 ± 11.1 g kg−1 crude protein (CP), and 262 ± 61.5 g kg−1 starch. Ruminal degradability of DM and NDF of GSP was lower (P < 0.05) while that for CP was higher (P < 0.05) than barley grain. Effective ruminal degradability of starch for GSP and barley exceeded 900 g kg−1. Results of the sheep trial showed that as the level of GSP increased, voluntary intake increased (P < 0.05) and total tract digestibility coefficients of DM, NDF, and gross energy (GE) decreased (P < 0.05). The digestibility coefficients of DM, NDF, and GE for GSP were 666 g kg−1, 294 g kg−1, and 698 J kJ−1, respectively. The digestible energy (DE) content of GSP (13.8 MJ kg−1) was similar to that of thin barley and 11% lower (P < 0.5) than that of regular barley. It was concluded that while GSP exhibited reduced ruminal and total tract nutrient utilization relative to regular barley, this feed product is a good source of energy and protein for growing ruminants. Key words: Grain screening pellets, barley, thin barley, nutrient utilization
Assessment of the value of cannulated pigs for measuring intestinal protein digestibility of ruminal undegraded protein of canola meal
Authors: Mustafa A. F. , Qiao S. Y. , Thacker P. A. , McKinnon J. J. , Christensen D. A. , Chaplin R. K.
Published: March 2010

The intestinal digestibility of ruminal undegraded protein (RUP) from canola meal heated at 125 or 145 °C for 0, 10, 20, and 30 min was measured using either duodenally cannulated steers or pigs. Cannulated pigs accounted for 96% (P < 0.05) of the variation in intestinal digestibility of RUP by steers with a standard error of prediction of 0.073%. The pig model overpredicted intestinal digestibility of RUP by only 6%. Key words: Ruminal undegraded protein, cannulated pigs, mobile nylon bag, intestinal digestibility
The effect of fasting and diet on fecal shedding of Escherichia coli O157:H7 by cattle
Authors: Buchko S. J. , Holley R. A. , Olson W. O. , Gannon V. P. J. , Veira D. M.
Published: March 2010

Cattle naturally infected with Escherichia coli O157:H7 were used to assess the effects of diet and feed withdrawal on the fecal shedding of E. coli O157:H7. Animals were fed an 80% concentrate diet (80% barley and 20% alfalfa silage), fasted for 48 h, fed a 100% forage diet (alfalfa silage), fasted for 48 h, and subsequently re-fed 100% forage (alfalfa silage). There were no differences in the numbers of animals positive for the shedding of E. coli O157:H7 when fed an 80% barley diet or an all-forage diet (P > 0.05) or during the fasting periods following each diet (P > 0.05). Upon re-feeding an all-forage diet following a 48-h fast, animals positive for E. coli O157:H7 shedding increased (P < 0.05), with 42.5% of the animals shedding the pathogen after 5 d. Re-feeding 100% forage following fasting appeared to have increased the number of animals shedding E. coli O157:H7 in their feces, which may have been influenced by diet in addition to fasting. Key words: Escherichia coli O157:H7, fasting, diet, cattle, fecal shedding
Effects of dietary fish silage and fish fat on growth performance and meat quality of broiler chicks
Authors: Kjos N. P. , Herstad O. , Øverland M. , Skrede A.
Published: March 2010

Two experiments were conducted to study the effect of concentrated fish silage and additional fish fat on growth performance (exp. 1) and meat quality (exp. 2) of broiler chicks. In exp.1, 600 day-old male and female chicks with an initial weight of 36.3 g ± 0.6 SD were allocated to five treatment groups. The treatments were a control diet, two test diets with 50 g kg−1 fish silage and different levels of fish fat (6 or 8 g kg−1), and two diets with 100 g kg−1 fish silage and different levels of fish fat (8 or 10 g kg−1). In exp. 2, 150 day-old female chicks with an initial weight of 36.3 g ± 0.7 SD were allocated to five treatment groups. The treatments were a control diet, and one of four test diets containing 50 g kg−1 fish silage and different levels of fish fat (2, 9, 17 or 25 g kg−1). In exp. 1, chicks fed diets with fish silage had a greater weight gain (P < 0.001), a greater feed intake (P < 0.05) and a lower feed-to-gain (MJ ME kg−1) (P < 0.001) than those fed the control diet. In exp. 2, no significant differences in weight gain or carcass weight were found among diets. The proportions of the fatty acids C18:3, C20:1, C20:5, C22:5 and C22:6 in abdominal fat, and C20:1, C22:1, C22:5 and C22:6 in breast meat, increased by the dietary inclusion of fish silage and fish fat. Increasing levels of dietary fish fat decreased blood plasma levels of vitamin E and ceruloplasmin. The diets containing the highest levels of fish fat (16.8 or 24.8 g kg−1) caused off-odour and off-taste of thigh meat stored at −16 °C for both six months and one month. Key words: Fish silage, fish fat, broilers, growth performance, sensory quality
Multiple crossfostering: effects on prolactin, growth hormone and cortisol in lactating sows
Authors: Farmer C. , Robert S.
Published: March 2010

Crossfosterings of three piglets were done on days 1, 4, 7, 10, and 13 of lactation in seven litters. On day 3 of lactation, serum cortisol increased in sows during piglet isolation when compared to before (P = 0.02) or after (P = 0.08) adoption, while GH and prolactin were not affected by isolation (P > 0.1). Mean or maximal values of all hormones were not different after than before adoption (P > 0.1). Key words: Sows, lactation, crossfostering, prolactin, cortisol, growth hormone, nursing
The effects of grade, gender, and postmortem treatment on beef. I. Composition, cutability, and meat quality
Authors: Jeremiah L. E. , Aalhus J. L. , Robertson W. M. , Gibson L. L.
Published: March 2010

A total of 195 beef carcasses of two genders (steers and heifers) and four Canadian carcass grades (A1, A2, B1, and B2) were evaluated to examine the effects of carcass grade, gender, and postmortem electrical stimulation on carcass composition, cutability (yield of specific primal cuts), and meat quality traits (traits related to appearance, palatability, yield, and consumer appeal). Cutability was not influenced by either grade or gender. Increased fatness appeared to be distributed equally in all portions (segments) of the carcass. Canadian beef carcass grades effectively segregated carcasses according to grade definitions for both composition and quality. Gender differences in quality generally reflected compositional differences observed between steers and heifers. High voltage electrical stimulation reduced shear force values, but exerted a greater influence on steer than heifer carcasses. Key words: Beef, composition, cutability, quality, grades, gender, electrical stimulation
Serum mineral concentrations in relation to estrus and conception in beef heifers and cows fed conserved forage
Authors: Small Julie A. , Charmley E. , Rodd A. V. , Fredeen A. H.
Published: March 2010

A study was undertaken to examine serum mineral concentrations in relation to estrus and first service conception (FSC) in beef cattle fed conserved forage. Blood samples were taken from yearling nulliparous heifers, and suckled 2-yr-old primiparous heifers and multiparous cows at first service which occurred within 12 h of observed standing heat and 21 d after. Serum was analyzed for calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sulfur (S), sodium (Na), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) concentrations by ICAP. Heifers were fed in four groups based on parity and given 3.0 and 2.5 kg hd d–1 of a grain supplement, respectively, plus free-choice grass hay (1.71% K; 0.20% P; 8% protein; 41% ADF). Cows were individually fed ad libitum (21 g kg–1 body weight) grass-legume silage (2.82% K; 0.35% P; 14% protein, 34% ADF). Heifers and cows gained body weight over the breeding season and at turnout had body condition scores of 5 to 6 for heifers and 6 to 7 for cows. Rates of FSC were 53% (10/19), 48% (10/21) and 64% (18/28) for nulli-, primi- and multiparous groups, respectively. Serum Ca, Na, S, Cu, Fe, Zn and Mn did not differ (P > 0.05) between FSC groups, but Na and Cu were higher (P < 0.05) at estrus than at day 21, especially in nulliparous heifers. Concentrations of serum Mg were low (<0.74 mmol L–1) and K high (>4.5 mmol L–1) in heifers and cows but in nulliparous heifers only, serum Mg and K were lowest (P < 0.05) at estrus for those that conceived. Serum B concentrations were generally higher (P < 0.05) in animals that conceived especially on day 21 when B concentrations were higher (P < 0.05) than at estrus. Serum P concentrations were high (>3.5 mmol L–1), but highest in animals that conceived especially on day 21. It is concluded that P and B may be dietary factors limiting first service conception in beef cows fed conserved forage. Key words: Beef cattle, estrus, conception, minerals, boron, phosphorus