bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic and Mössbauer Studies in Molecular-Based Magnets NBu4MAII[FeIII(OX)3](MA=Co, Fe)
Authors: Lin Qing , Zhang Qing Mei , Tang Guo Dong , He Yun , Long Xue Hui
Published: March 2013

The mixed valency character and antiferromagnetic coupling in molecule magnets materials NBu4MAII[FeIII(OX)3]（MA=Co、Fe） were investigated by magnetic measurements and Mössbauer spectroscopy .In the sample NBu4CoII[FeIII(OX)3],the appearence of temperature point of spin-glass phase transition and magnetic phase transition under the zero-field-cooled AC magnetic measurements with the temperature range 5-100 K.The sample NBu4FeII[FeIII(OX)3] were carried out in the cooling modes in a field,and the sample exhibits multiple magnetic pole reversals in the warming mode magnetic measurements.The phenomenon of multiple magnetic pole reversals occurs in some of those ferrimagnetic materials consisting of magnetic anisotropy ions and two or more types of antiferromagnetically ordered magnetic ions.The compound NBu4FeII[FeIII(OX)3] contains two different spin carries; ie: Fe(II) (SFe(II)= 2), Fe(III) (SFe(III)= 5/2) comes from the Mössbauer studies.
Synthesis and Microwave Dielectric Properties of Mg5Nb4TiO17 Ceramics
Authors: Yao Guo Guang , Ma Hong , Tian Xiu Lao
Published: March 2013

Mg5Nb4TiO17 ceramic was prepared by the conventional solid-state route for the first time and its microwave dielectric properties were investigated. The crystal structure and microstructure were analyzed using X-ray diffraction and scanning electron microscopy techniques. With increasing sintering temperature, the dielectric constant (εr) and quality factor (Q×f) increased firstly and then decreased, while the τf nearly unchanged. Mg5(NbTi)4O15-MgNb2O6 composite ceramics sintered at 1200 oC exhibits microwave dielectric properties of εr=15.1, Q×f=34,266.6 GHz (at 8.5GHz), τf=-63.8 ppm/oC.
Effects of Thermal Annealing in Nitrogen on Photoluminescence of Sol-Gel Derived ZnO Nanocrystals
Authors: Ma Qing Lan , Zhai Bao Gai , Xiong Rui , Huang Yuan Ming
Published: March 2013

The synthesis of ZnO nanocrystals is carried out in alkaline alcoholic solution of zinc acetate dihydrate by sol-gel method. Effects of thermal annealing in nitrogen on photoluminescence (PL) properties of the sol-gel derived ZnO nanocrystals were investigated by PL spectroscopy. With increasing annealing temperature in nitrogen, UV emissions of the ZnO nanocrystals red-shifted from 378 nm to 388 nm while deep-level luminescent bands ranging from 450 to 700 nm with three emission centers at about 502 nm, 538 nm and 602 nm are enhanced, and the green luminescent band gains its intensity at the expense of the yellow and orange luminescent bands. Our results have demonstrated that the origin yellow-green color PL was tuned towards the cyan color PL with increasing the thermal annealing temperature in nitrogen from 344 oC to 813 oC.
Optical Properties of ZnS Embedded into Polyvinyl Alcohol Films
Authors: Ma Qing Lan , Xiong Rui , Zhai Bao Gai , Huang Yuan Ming
Published: March 2013

A polyvinyl alcohol (PVA) nanocomposite thin film embedded with zinc sulfide (ZnS) quantum dots was fabricated by a drop-casting method. The ZnS-embedded PVA films were characterized with polarized optical microscopy (POM), ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy. The POM study clearly exhibits the photo-elasticity effects of the ZnS/PVA film when stress is added. Optical absorption spectra showed strong red shift for the ZnS quantum dots in the PVA matrix. Room-temperature PL spectra demonstrated that the pure ZnS quantum dots show cyan emission at 517 nm while ZnS/PVA thin film gives off blue PL with a strong broad peak at 478 nm and a shoulder peak at 536 nm.
A Multichannel Filter Based on the Finite Plasma Photonic Crystal
Authors: Wu Chien Jang , Lee Ya Ju , King Tzu Chyang , Kuo Wen Kai
Published: March 2013

A design of multichannel transmission filter at microwave is proposed. It is based on the use of the finite plasma photonic crystal operating at frequency below the plasma frequency. We consider a design structures of (AB)qA, where A is the dielectric material, B is the plasma layer, and q is the number of periods. It is found that the number of channels is equal to q-1. We show that the locations such multiple channels are in the pass band of the infinite plasma-dielectric photonic crystal. The idea of such design is thus to engineer the photonic pass band, which is fundamentally different from the usual design by engineering the photonic stop band like the multilayer Fabry-Perot transmission filter. The physical mechanism of multiple channels is also discussed.
Microstructures and Photoluminescence of Electrochemically-Deposited ZnO Films on Porous Silicon and Silicon
Authors: Chen Lan Li , Tang Zhong Ke , Shi Ming Ji
Published: March 2013

ZnO films covered with microrods were grown on silicon and porous silicon through electrochemical deposition with silicon or porous silicon as cathode, a platinum wire as anode, and zinc chloride solution of 0.05mol/L as electrolyte. The morphologies by SEM and the crystal structures by XRD were studied. The photoluminescence spectra were also measured. And the mechanisms of the growth and the photoluminescence of the ZnO thin films were analyzed and compared. Studies showed that the luminous intensity of ZnO thin films is different under different conditions, but its peak is located between 370-385nm, luminous intensity of the ZnO film deposited on porous silicon and then annealed is weaker.
Ge-Chalcogenide Glasses – Properties and Application as Optical Material
Authors: Petkova Tamara , Ilcheva Vania , Ilchev P. , Petkov P.
Published: March 2013

The great interest toward chalcogenide materials is due to the simple technology of preparation in bulk forms and thin films; good thermal and mechanical properties; transparency and photo-sensibility in the IR spectral range. These advantages determine the possibilities for potential application of these materials like optical storage media, memory devices, optical elements (lenses, waveguides, gratings, etc). The idea of present study is to trace the impact of gallium or indium as metal introduction on the behaviors of the glasses from germanium - chalcogenide system.
Fabrication and Characterization of p-CuI/n-Si Heterojunction Diode
Authors: Xiong Chao , Xu An Cheng , Lu Xing Zhong , Chen Lei , Zhu Xi Fang , Yao Ruo He
Published: March 2013

The p-CuI /n-Si heterojunction diode have been prepared at a low cost by chemical method. The prepared hexagonal γ-CuI films are polycrystalline nature and observed preferential orientation along the (111) axis aligning with the growth direction. The heterojunction shows a good rectifying behavior and photovoltaic effects. The current and 1/C2 versus voltage curve of the p-CuI/ n-Si heterojunction diode was shown. The linear relationships of 1/C2 versus voltage curve imply that the built-in potential Vbi and the conduction band offset of the heterojunction ware found to be 1.5 eV and 0.98 eV, respectively. The current transport mechanism is dominated by the space-charge limited current (SCLC) conduction at forward bias voltages. The electronic potential barrier in p-CuI/n-Si heterojunction interface higher than hole at forward bias voltages. In this voltages area, a single carrier injuction was induced and the main current of p-CuI/n-Si heterojunction is hole current.This heterojunction diode can be good used for light emission devices and photovoltaic devices.
Transmission Spectrum of Two-Dimensional Self-Assembled SiO2 Photonic Crystals
Authors: Huang Yuan Ming , Zhai Bao Gai , Ma Qing Lan
Published: March 2013

Controlling the photon propagation in materials by photonic crystals lies at the heart of quantum optics. The motivation of our work is to investigate the direct control of the photon confinement in the self-assembled two-dimensional SiO2 photonic crystals. Here we demonstrate the realization of transmitted light controls in the self-assembled two-dimensional SiO2 PCs. Our experimental results agree well with the theoretical calculations on the photonic band gaps in the spectral region of 400-1100 nm. These results present experimental evidence on the direct control of the photon confinement in the self-assembled two-dimensional SiO2 PCs.
Antireflection and Scattering Properties of Two-Dimensional Hexagonal AZO Gratings on Glass Substrates
Authors: Liu Ren Chen , Wu Yong Gang , Xia Zi Huan
Published: March 2013

With photoresist dot arrays fabricated by a two-beam interference lithography as an etch mask, two-dimensional (2-D) hexagonal aluminum-doped zinc oxide（AZO）submicron gratings (SMG) with 160nm height (h) and different periods (P) were produced using lift-off transfer process. Results show that as P decreased to 487nm, SMG exhibited excellent antireflection properties, which reduced the average total reflectivity (Rtotal) from 11.8% of AZO thin film to 4.7% in the wavelength range of 400nm-1050nm, and promoted the total transmittance (Ttotal) significantly, especially in the long spectral range of 750nm-1050nm. On the other hand, as P increased from 487nm to 985nm, the haze parameters of reflectance (HR) or transmittance (HT) improved from 25.5% to 40.2% or from 15.1% to 36.8%, respectively. Nevertheless, P increased from 985nm to 1435nm, both Rtotal (or Ttotal) and HR (or HT) varied very slightly. Bidirectional distribution functions at normal incidence not only verified that the larger the P was, the part of diffuse reflectance (or transmittance) were much higher, but also further demonstrate the larger the P, the smaller the diffaction angle. In summary, 2-D hexagonal AZO SMG show promising antireflection effects at P less than 487nm, and show promising scattering abilities at P about 985nm.
Preparation and Electrochromic Properties of Polythiophene Derivatives
Authors: Zhong Yi Ping , Zhao Xue Quan , Guan Li , Liu Ping , Deng Wen Ji
Published: March 2013

Polythiophene derivatives, poly(2,2′:5′,2″:5″,2″′:5″′,2″″-quinquethiophene) (P5T), poly (2,3,4,5-tetrathiopenyl-thiophene) (PX5T) and poly(1,3,5-tristhienyl-benzene) (P3TB), were prepared via the electropolymerization. The electrochromic properties of polythiophene derivative films were investigated. The results showed that P5T, PX5T and P3TB films exhibited reversible, clear colour change in liquid electrolyte on electrochemical doping and dedoping. Moreover, solid state electrochromic device, indium tin oxide (ITO)/polythiophene derivative films/conducting gel /ITO, were fabricated with polythiophene derivative films as the active electrochromic layer. The color change of polythiophene derivative films based on gel electrolyte on electrochemical doping and dedoping were similar with the color change based on liquid electrolyte.
Synthesis and Thermal-Optic Properties of Azo Polyurethane Containing Chiral Unit
Authors: Qiu Feng Xian , Wang Qing , Chen Cai Hong , Zhao Hao , Liu Jin Hua , Yang Dong Ya
Published: March 2013

A new chromophore containing azo group, 3,3'-dichloro-4,4'–di-(4-amino-azo-phenyl) -diphenylmethane (CAAPM), was synthesized based on 3,3'-dichloro-4,4'-diamino– diphenylmethane, sodium nitrite and benzenamine via diazo-coupling reaction. Azobenzene polyurethane (PU) containing chiral unit was obtained from CAAPM, chiral reagent L(-)-tartaric acid and isophorone diisocyanate (IPDI). The chemical structures of CAAPM and PU were characterized by FT-IR and UV-Vis spectroscopy. The measurements of refractive index (n) and thermo-optic coefficient (dn/dT) of polyurethane were demonstrated at complex light. The values of n and dn/dT were used to calculate the dielectric constant (ε) and its variation with temperature (dε/dT). The dn/dT is 4.2000～-3.7000×10-4°C-1. The conclusion has a little significance to develop new the digital optical switch (DOS).
Abnormal Phenomena and Mechanisms for Silicon Photomultipliers
Authors: Zhang Guo Qing , Han De Jun , Zhu Chang Jun , Zhai Xue Jun
Published: March 2013

Some deviant breakdown-quenching characteristics of silicon photomultipliers are demonstrated and their physical mechanisms are explored. “Twice breakdown” phenomenon, “flat-topped” avalanche pulses are analyzed. These characteristics are explained in terms of avalanche threshold current based on the Haitz’s equivalent circuit model. The results show that the maximum over-voltage for a normal operating silicon photomultiplier equals the product of the avalanche threshold current and the quenching resistor of the avalanche photo-diode (APD) pixel, approximately.
The Preparation of p-PS and its Photoluminescence Properties
Authors: Chen Lan Li , Wang Hai Hong , Shi Ming Ji , Wang Sheng Zhao , Si Wen Fang
Published: March 2013

In this research, p-type porous silicon was successfully fabricated with a typical electrochemical etching method. The mixed solution of HF and absolute ethyl alcohol with different volume ratio was used as the electrolyte in this experiment. The anodic current density was 20 mA/cm2～60 mA/cm2. The luminous intensity of the PS samples increased with the increasing of the current density, the peaks of PL first red shift (from 692.1nm to 727.9nm) then blue shift (from 727.9nm to719.6nm). With the increasing of the concentration of HF, PS luminous intensity gradually decreases, and the peaks of PL gradually occurs red shift. And possible mechanisms of the growth and the photoluminescence of porous silicon were proposed to explain the experimental result．
Enhancing the Thermoelectric Properties in Carbon Fiber/Cement Composites by Using Steel Slag
Authors: Zuo Jun Qing , Yao Wu , Qin Jun Jie
Published: March 2013

Thermoelectric properties of steel slag-carbon fiber/cement composites were studied in this paper. The effect of steel slag content on thermoelectric properties was focused on especially. The experimental results show that the addition of steel slag leads to an increase in the positive thermoelectric power of the cabon fiber/cement composites. The highest absolute thermoelectric power of carbon fiber/cement composites was rendered as positive as 14.4µV/°C by using steel slag, which had a high concentration of holes. Beside, a good linear relationship was observed between thermoelectric power and temperature differential on the specimen.
The Effect of Fly Ash on TSA of Cementitous Material: Based on Three Years Results
Authors: Liu Ben Wan , Yang Chang Hui , Xiang Xiao Bin , Yu Lin Wen , Zhang Jing
Published: March 2013

The thaumasite form of sulfate attack of cementitous material (TSA) is a new kind of sulfate attack and it is more harmful than traditional sulfate attack. By means of Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), the effect of dosage and fineness of fly ash on TSA of cementitous material were investigated in this paper. The specimens had been immersed in magnesium sulfate solution of 5% mass concentration at 5±2° C for three years. The results showed that fly ash could not restrain the formation of thaumasite but it delayed the occurrence of TSA in cementitous material when 30% fly ash takes place of cement. Fly ash could enhance the resistance of cementitous material to TSA through secondary hydration reaction to optimizing the pore structure of hardened cement paste and lowering the C/S of C-S-H gel.
Study of Mechanical Force on Coal Gangue Reactivity
Authors: Zhang Chang Sen , Liu Xue Feng , Wu Qi Sheng , Deng Yo Xin , Li Lei
Published: March 2013

The property of raw kaolinite-coal-gangue is very stable, and reactivity of kaolinite-coal-gangue is enhanced by mechanical force. The SEM, XRD and IR were used to analyze mechanochemical changes during kaolinite-type-coal gangue grinding. The results showed that mechanical force plays a dominant role in the enhanced reactivity, by inducing dehydration reactions the lattice OH grouping decreased with the extension of grinding time. The separation of tetrahedral and octahedral layers combined with the increasing disorder of the kaolinite crystal structure, resulting in kaolinite-type-coal gangue particles become "loose" aggregates. Moreover, due to destroy to tight Si-O and Al-O bond, the mechanical force increases the solubility of SiO2 and Al2O3, which enhanced the reactivity of coal gangue.
Study on Hydration Degree of Portland Cement-Slag Complex Binders
Authors: Liu Reng Guang , Yan Pei Yu
Published: March 2013

Abstract. The hydration degree of Portland cement-slag complex binders was investigated by hydration heat, chemically bound water amount, EDTA selective dissolution and mortar compressive strength. Different hydration degree of complex binders was obtained with different methods. Hydration heat and EDTA method indicated that reaction degree of slag was much lower than cement and the total reaction degree of complex binders was also lower than neat cement. However, chemically bound water amount and mortar compressive strengths of complex binders blended with slag within certain limit were higher than neat cement at late age.
The Preparation and Pozzolanic Activity of Metakaolin Admixtures
Authors: Wang Bao Min , Zhang Yuan , Li Ming
Published: March 2013

The optimum burning temperature of kaolinite and the optimum proportion of metakaolin (MK) in cement paste were studied by the compressive strength ratio method. Metakaolin was obtained at different burning temperature of 700°C, 750°C, 800°C and 850°C for 4 hours, and mixed into cement with the incorporation of 0, 5wt.%, 10wt.%, 15wt.% and 20wt.%. At last, the mechanical properties were researched. The influence of different burning temperature on hydration products of metakaolin cement mortar were analyzed. The results show that the compressive strength ratio of metakaolin cement mortar and the metakaolin pozzolanicity reach the maximum when the metakaolin obtained by heat treating of 750°C, the optimum proportion of metakaolin in cement is 10%~15%.
Environmentally Friendly Cellular Concrete for Wall Insulation
Authors: Jiang Ya Qing , Yang Jun , Chen Yun
Published: March 2013

Cellular concrete characterizes low mass density and low thermal conductivity is one of the durable and economic wall insulation materials which have good market prospects. The present paper investigated the composition of ternary cementitious materials, mixture design and production process of cellular concrete panel (CCP). Experimental results indicated that a higher compressive strength of CCP may be obtained by blended PⅡ52.5 Portland cement with pulverized low temperature clinker (PLWC) made of water treatment sludge and fly ash in the mass ratio of 0.70: 0.15: 0.15. CCP with dry density of 226 kg/m3, thermal conductivity of 0.056 W/ (m•K), compressive strength of 0.6 MPa and water absorption ratio of 7.6 vol. % was modified by high range water reducer, polypropylene fiber and water resistant agent. Mathematic models for controlling temperature of mixing water and for calculation quantity of gas forming admixture were established. Insulated moulds were specially designed for taking advantage of hydration heat of cement to speed up moulds turnover. Meanwhile, internal microcrack of CCP was avoided. CCP incorporating PLWC and fly ash may be used as external insulation material of walls.
Relationship between Internal Relative Humidity and Autogenous Shrinkage of Cement Paste with Supplementary Cementitious Materials (SCM)
Authors: Li Yue , Yan Qian Qian
Published: March 2013

The influence of water to binder (W/B), types and dosage of supplementary cementitious materials (SCM) on the internal relative humidity (IRH) and autogenous shrinkage (AS) of cement pastes caused by self-desiccation were investigated, and their relationship was discussed. The results show that, W/B is a main factor that affects IRH change and AS of cement pastes with SCM. With the decrease of W/B, IRH of cement pastes decreases, but AS of cement pastes increases. Different types and dosages of SCM affect the IRH differently; fly ash (FA) reduces AS, silica fume (SF) increases AS, and the effect of GBFS on AS is between FA and GBFS. The linear correlation between the change of IRH and AS of cement pastes with SCM is established.
Shrinkage of Blended Cement Pastes with Mineral Additions
Authors: Chen Yi , Yao Wu , Jin Dan
Published: March 2013

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.
Effects of Rubber Powder and Fly Ash on Mechanical Properties of Recycled Mortars
Authors: Meng Yun Fang , Wei Yong Qi , Wang De Zhi , Gao Ke
Published: March 2013

The effects of rubber powder (RP) and fly ash (FA) with various dosages on flexural and compressive strength of recycled mortars were investigated. Experimental results indicated that the single addition of 4 wt.% RP helped to improve the flexural strength of recycled mortars, but the compound addition of RP and FA in recycled mortars reduced the strength, whatever the compressive or flexural strength; the mechanical properties of recycled mortars with or without RP or FA were better than that of ordinary mortars.
Micromechanical Properties of Calcium Silicate Hydrate
Authors: Yao Wu , He Li
Published: March 2013

The indentation modulus of several cementitious materials is discussed with the assumption that the C-S-H gel is an aggregation of precipitated, colloidal-sized particles. At least two kinds of structurally distinct but compositional similar phases are found existent during the hydration process. In addition, the C-S-H originated from the pozzolanic reaction of fly ash is found to be the same to that of cement hydration in micromechanical properties; however, the C-S-H gel formed from the secondary hydration is inclined to develop into high density packing configuration, due to the limitation of reaction zone available.
Experimental Research of Uniaxial Compression Bearing Capacity on Large Diameter CFST Columns
Authors: Ren Xiao Qiang , Chen Yan Jiang , Yan Wei Ming , Gu Da Peng , Wang Jin Jie
Published: March 2013

This paper focused on the uniaxial ultimate-bearing-capacity of large size concrete filled steel tubular (CFST) columns. Two aspects were investigated experimentally. To verify the feasibility of similarity principles for large size components, a series of uniaxial compressive experiments were conducted using different scaled specimens, the prototype of which is a CFST arch rib in an authentic arch bridge. Meanwhile, two specimens with same scale were tested axially and eccentrically to investigate the difference of bearing capacity resulted from the pierced-column. The experimental results show that the size effect on the bearing capacity of the rib is so insignificant that the scaled specimen can be used to obtain the maximum capacity of the full-scale component. The inserted steel tubes in the middle of the column cause the reduction of its capacity and the reduction factor from axial loading is bigger than that from bias load. Moreover, the eccentricity reduces the effect of piercing on the capacity of CFST column.
Experimental Study of Flexural Behavior of RC Beams Strengthening with BFRP Sheets
Authors: Qin Li Hui , Wang Zong Lin , Wu He , Zhang Lan
Published: March 2013

This paper presented the results of testing reinforced concrete beams strengthening with the BFRP sheets. Five specimens were cast and tested. All specimens were 2600 mm total span with a cross section of 150mm width and 250mm depth. Out of the specimens, two specimens were designed as reference specimens. The rest specimens were repaired with the BFRP sheets. The variables examine in the experiment were the longitudinal tensile reinforcement ratio, the different layers of the BFRP sheets and the anchoring measures of BFRP sheets. All specimens were tested under simply supported condition. 3D nonlinear finite element (FE) numerical models by ANSYS10.0 software were conducted to accurately predict the ultimate bearing capacity and response of reinforced concrete specimens strengthening with BFRP sheets subjected to four-point bending loading. The nonlinear constitutive material properties of concrete and steel reinforcement were considered in the finite element model. The results of the FEM simulation were compared with that of the experimental specimens. The results showed that it was significantly effective for the flexural capacity of the BFRP sheet-bonded reinforcement in tensile zone for reinforced concrete beams. Moreover, it implied excellent results on the stiffness of the reinforced concrete beams. The flexural strength enhancement of the reinforced concrete beams strengthening with the BFRP sheets varied between 19% ~ 44% over the control beam. This study further identified that the BFRP sheet technique significantly enhanced the stiffness and flexural capacity of reinforced concrete beams.
Seismic Performance Analysis of a Multi-Span Continuous Girder Bridge under Multi-Excitation
Authors: Sun Hang , Wang De Jun , Li Yong
Published: March 2013

Although the seismic response analysis under the multi-excitation was widely focused on the long-span flexible bridges, it is still necessary to pay more attention to this point of continuous girder bridges since the dynamic behavior of this type of bridges are different with either long-span bridges or simple support bridges. Based on the nonlinear dynamic time history analysis, a four-span continuous beam FEM was built, and the effect of excitation types and structure size on seismic response was studied. And results indicate that the structural performance of continuous girder bridges is sensitive with the space correlation of different location of seismic excitation. So its necessary to consider the space effect of excitation while carrying out a seismic design of continuous beam.
Impact Analysis of the Flexural Rigidity on the Frequency and Tension of the Stay Cable
Authors: Sun Yong Ming , Sun Hang
Published: March 2013

Research and practice show that frequency method is still the most practical and accurate method among all kinds of cable force measurements. Based on the classical string vibration theory, the finite element model of stay cable was created, and a method of iteratively computing stay cable balance curve considering with flexural rigidity was proposed. How dose the flexural rigidity affects the balance curve of stay cable was discussed, and the changing curves of the distance-to-sagging ratio following the pull-to-bend ratio were plotted, which indicated the bigger flexural rigidity, the smaller sagging. 25 pairs cable modality of Xichang cable stayed bridge were accurately analyzed, mode crossover was testified by finite element method, changing curves of frequency and mode shape following the cable force were separately plotted, and changing rule was induced, practical cable force computing method was given. Frequency difference is suitable to judge the rank of actual measurement frequency, and the second frequency is recommended to compute cable force. Engineering instance analysis testified, the method of practical cable force measurement could rule out errors by mode crossover, and be applied to cable with any lengths and any force.
Dynamic Amplification Factor Measuring of T-Girder Bridges
Authors: Yang Jian Rong , Bai Yu , Yang Xiao Dong , Feng Yun
Published: March 2013

Field measurement was conducted on the evaluation of dynamic amplification factors (DAF) for four existing T-girder bridges. Both ambient vibration testing and vehicle impact testing were carried out on the bridges. Ambient vibration testing is relatively easier to conduct and can provide detailed vibrating information of the structure. However vehicle impact testing is indispensable to obtain the impact factor of the traffic load. The measured vibration frequencies matched well to those of calculated values. This means that the finite element model may enable good predictions of the actual behavior of the bridge. The measured DAF for these bridges located in the interval [1.05, 1.22].
Resistance and Time-Variant Reliability Updating of Existing Bridge Structures Based on Proof Loads
Authors: Lu Da Gang , Fan Xue Ping , Li Dong Fang
Published: March 2013

Based on the characteristics of existing structures, the analyses were presented for an effect on the resistance of existing structures by using deterministic loads and stochastic loads. The calculating equations of the normal distribution and logarithmic normal distribution resistance under the deterministic proof load and the stochastic proof load were presented. Some valuable conclusions have been obtained for the calculating reliability of the existing structures. Based on the conclusions, time-dependent reliability model of the existing bridges was updated, the time-dependent reliability indices were solved with time integrated-discretized approach, and finally the numerical examples were presented.
Sensor Optimal Placement for Structural Health Monitoring Based on Stabilization Diagram
Authors: Wu Chun Li , Liu Han Bing , Li Yan
Published: March 2013

A novel stabilization diagram method was presented for sensor placement in structural health monitoring of bridges. The aim of the method is to select the optimal locations which can achieve the best identification of modal frequencies and mode shapes. A single parents genetic algorithm was adopted to optimize the sensor locations from a set of coordinate positions. Five fitness functions taken as the objective function are proposed based on effective independence, modal assurance and modal energy criterion, in which the combined fitness functions can obtain more comprehensive properties to reduce the noise interference. The proposed method puts forward a universal way for sensor placement of the civil engineering structure. The effectiveness of the method was proved by a simply supported beam and a continuous beam bridge in the An Longquan interchange overpass.
3D Microtomography Characterization of Dental Implantology Bone Substitutes Used In Vivo
Authors: Bedini Rossella , Meleo Deborah , Pecci Raffaella
Published: March 2013

After a short introduction to bone substitute biomaterials and X-ray microtomography, this article describes a research work carried out for in-vitro characterization of bone substitute biomaterials as well as for in-vivo investigation of human bone grafted with biomaterials. Three different bone substitute biomaterials have been analyzed in-vitro by means of 3D microtomographic technique, while human bone samples grafted with bone substitute biomaterials are investigated by 3D microtomography and histological techniques. 3D images of bone substitutes and human bone samples with biomaterials have been obtained, together with morphometric parameters, by microtomography . 2D histological images have also been obtained by traditional technique only for human bone samples with biomaterials. Compared to traditional histological analysis, 3D microtomography shows better results for investigating bone tissue and bone substitute biomaterial, and in a short time. Nevertheless, histological analysis remains the best technique for the observation of soft tissue and blood vessels.
Application of Composite Materials in Modern Constructions
Authors: Pastuszak Przemysław D. , Muc Aleksander
Published: March 2013

The paper presents the general review of application of composite materials including the distinction of their specific features. Also short overview of history of composite materials is conducted. The major subject is the explanation, what is advantage of the composites over traditional materials. Additionally, a lot of examples demonstrate in which areas of current industry they are applied.
Innovative Construction of 3-Component Aerodynamic Balance
Authors: Ryś Jan , Augustyn Marcin
Published: March 2013

This paper deals with a description of a new type an aerodynamic balance used in a wind tunnel for measuring forces acting on a model. A concept of the strain gauge balance in which the three component of aerodynamically force can be measured was presented. The tests proved good measuring accuracy of this construction. On the basis of such a solution three component of force and aerodynamic load factors can be easily evaluated.
Certain Solution of Contact Problem for Spherical Shell
Authors: Sanecki Henryk , Wachowicz Łukasz
Published: March 2013

A formulation of a contact problem for a spherical shell is presented in the paper. It uses a certain analytical-numerical solution for the analysis of an elastic complete sphere subjected to a concentrated force and associated body forces. Assumptions and equations of thin shell theory of small deformations and displacements are applied to the problem. Good numerical efficiency is achieved due to a solving functionZintroduced in a complex form while the concentrated force was distributed over a small finite area. Some examples are presented to illustrate the solution and an influence of the size of assumed area of load distribution. An application of the solution to the formulation of the contact problem of the spherical shell resting on several separate supports is presented.
Damage Detection, Localization and Assessment in Multilayered Composite Structure with Delaminations
Authors: Stawiarski Adam , Muc Aleksander , Kędziora Piotr
Published: March 2013

In this paper the dynamic behavior of composite multilayered cylindrical panel with a single, square, interlaminar delamination is considered with using finite element method. Based on numerical results it is possible to determine the effect of the delamination on the guided wave propagation in curved structures. The results are used to quantify the difference of response signal in the case of perfect and defected structures. The results indicates that the size and orientations of the defect have a significant influence on overall dynamic behavior and they should be taken into account to design appropriate and effective non-destructive damage test methods and algorithms.
Carbon Nanotube/Polymer Nanocomposites: A Brief Modeling Overview
Authors: Chwał Małgorzata , Kędziora Piotr , Barski Marek
Published: March 2013

Efforts in the field of polymeric nanocomposites reinforced by carbon nanotubes are presented in the literature from many years. The discussed problems are connected with the characterization of nanocomposites and the modeling of elastic and fracture behavior at the nanoscale. The experimental investigations and the theoretical modeling are conducted simultaneously. The theoretical approaches try to elucidate the experimental observations. In the present paper a brief overview of the analytical and numerical modeling of polymeric nanocomposites reinforced with carbon nanotubes is presented. The attention is mainly focused on the molecular dynamic models, the continuum mechanics approaches and finally the multi-scale models are discussed. The good and wrong sides of the models are pinpointed. Also a comparison between values of Young's modulus of carbon nanotube/polymer nanocomposites for various methods is presented.
Stress Modification in Multi-Layer Walls of Expanded Pressure Vessels
Authors: Krasiński Maciej , Stodulski Marek , Trojnacki Andrzej
Published: March 2013

The paper deals with a stress modification in thick-walled multi-layer pressure vessels widely used in every field of high pressure technology. The stress modification is obtained by means of initial (residual) stresses which are introduced into the vessel structure during the manufacturing process. Certain technological parameters are determined. Their realization leads to the equivalent stresses being more uniformly distributed across the vessel wall under the operating pressure. As a consequence the load carrying capacity of the multi-layer vessel increases as compared with the solid wall without additional treatment. The analytical approach as well as the finite-element method are used to solve the problem. A special attention is focused on the unconventional original Polish technology in which the internal pressure is applied to form the thick multi-layer cylinder wall through subsequent expansion of thin layers. The advantages of the proposed method are illustrated by the numerical example of the expanded multi-layer high-pressure vessel with modified initial stress distribution.
Hydro-Pneumatic Accumulator Study with the Use of Thermodynamic Model Simulation
Authors: Kucybała Piotr
Published: March 2013

The presented paper deals the simulation model of hydro-pneumatic accumulator. Mathematical model of the system uses the motion and flow continuity equations as well as formulas determining hydro-pneumatic piston accumulator behavior. In accumulator model heat transfer phenomena are included and Van der Waals real gas low, to calculate gas parameters during its operation. Modeling and simulation tests are performed for different work cycles to determine the key parameters of hydrostatic system associated with energy saving, such as: piston velocity, working pressure and heat flux. The aim of the research program is to determine the efficiency of energy accumulation in the assumed work cycles and to find which parameters are significant and how they can be changed to increase accumulator efficiency.
Photochemically-Driven Methods for the In Situ and Site-Specific Fabrication of Monolithic-Based Electrochromatographic Microsystems
Authors: Georgiadou Violetta , Guerrouache Mohamed , Zlotea Claudia , Dendrinou-Samara Catherine , Latroche M. , Millot Marie Claude , Carbonnier Benjamin
Published: March 2013

This paper reports on thein-situsynthesis of reactive polymeric monolith and its subsequent surface functionalization. Poly (N-acryloyloxysuccinimide-co-ethylene dimethacrylate) was prepared through free radical photopolymerization of the respective monomers. The grafting procedure is based on the preliminary grafting of alkyne units on the monolith surface and the further radical photoaddition of functional thiol molecules. Implementation of UV-driven polymerization and grafting methods enabled the locally controlled immobilization of generic monolith within the confines of the capillary channel, and the site-specific immobilization of ligands on the pore surface of the monolith. Our results suggest that such a synthesis methodology is promising for integrating multiple analytical modules within microstructures for on-line analysis.
Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range
Authors: Korostynska Olga , Gandhi Abbasi A. , Mason Alex , Al-Shamma'a Ahmed , Tofail Syed A.M.
Published: March 2013

Hydroxyapatite (HA) is a leading biocompatible material extensively used for bone implants as a porous ceramic graft and as a bioactive coating. Electrical characteristics of HA can be employed in implantable devices for real-time in vivo pressure sensor applications such as in knee or hip prosthesis. In particular, high piezo and pyroelectricity of HA, its polarisation by electron beam and selective adsorption of proteins on polarised domains indicate the potential for real-time biosensing applications of HA. For this purpose, a comprehensive understanding of the dielectric behaviour of different forms of HA over a frequency range relevant for biomedical sensing is critical. Such information for HA, especially its frequency dependent dielectric behaviour over the GHz range, is rare. To this end, we report on novel investigations of properties of HA in powder and film forms in the GHz frequency range.
Aerosol-Assisted CVD of SnO2 Thin Films for the Room-Temperature Detection of Hydrogen Sulfide
Authors: Liu Huan , Li Min , Wan Jiu Xiao , Zhao Jun , Fu Qiu Yun , Gong Shu Ping , Wu Shu Xi , Hu Yun Xiang , Zhou Dong Xiang
Published: March 2013

High-quality SnO2 thin-film materials capable of detecting H2S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO2 thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl2·2H2O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H2S at room temperature was achieved. At room temperatures, the resistance upon the H2S gas exposure could recover to 90% of the initial resistance of the sensor when the H2S gas flow was turned off.
Sensing Nanoparticulate ZnO with Benzimidazole Derivative by Fluorescence
Authors: Jayaraman Jayabharathi , Karunamoorthy Jayamoorthy
Published: March 2013

A sensitive benzimidazole derivative fluorescent sensor for nanoparticulate ZnO has been designed and synthesized. The nanocrystalline ZnO, Ag doped ZnO and Cu doped ZnO have been synthesised by sol-gel method and characterized by powder X-ray diffraction, scanning electron microscopy (SEM) and UV-visible diffuse reflectance, photoluminescence and electrochemical impedance spectroscopies. The synthesized sensor emits fluorescence at 360 nm and this fluorescence is selectively enhanced by nanocrystalline ZnO. This technique is sensitive to detect and estimate ZnO at micro molar level. Impurities such as Ag and Cu do not hamper the sensitivity of this technique significantly. Keywords: Sensor, SEM, EDX, Impedance, Fluorescence
Effect of Vitique Esthetic Cementation on Tetracycline Stained Teeth-Mask with Different Simulated Staining Levels Following IPS-Empress II Ceramic Veneers
Authors: Fan Hua , Liu Ruo Yu , Jing Dong Dong , Chen Liang Jiao , Zhang Yao Kun , Lai Ling Zhi , Shao Long Quan
Published: March 2013

Abstract. To evaluate the color changes of tetracycline stained teeth after restored with IPS-EMPRESS Ⅱ ceramics. Simulated tetracycline stained teeth were divided according to staining degree into four groups: mild, moderate, severe, and very severe groups; each group had ten specimens which were repaired with IPS-EMPRESS Ⅱ ceramics veneers, bonded with Vitique Esthetic Cementation System. The ShadeEye-NCC color system was used to analyze the change in L, a and b. ΔE were calculated to compare color difference among the four groups.Before and after bonding, the values of L, a, b were significantly different (P <0.05). Mild tetracycline stained teeth bonded using resin adhesive without opaque bonding have a better effect than moderate and severe tetracycline stained teeth bonded with opaque resin adhesive; while, it is best to use other restorations to repair very severe tetracycline stained teeth. The IPS-EMPRESS Ⅱ ceramics can effectively improve the color of discolored tooth, however , the final color of the veneered teeth is easily influenced by the color of the abutment teeth. Aluting agent with color masking ability can do some improvements in the final color. An appropriate bonding agent should be chosen to perfect the final results of the veneered tooth.
Preparation and Properties of Bacteriostatic Sponge
Authors: Yang Nan , Zhang Qiu Ming , Wang Yi Fan
Published: March 2013

In this paperthe silver particle was adhered to the sponge by different ways and the sponge became to resistance bacterium. The AgNO3 reduced by SnCl2 is the best way via testing the weight gain rate and the antibacterial effect. By comparing the weight gain rate and the antibacterial effect at different concentration, it was found that, when the sponge was soaked in SnCl2 solution at a concentration of 0.10mol/L and AgNO3 solution at a concentration of 1.00mol/L, the sponge prepared by this method had the best antibacterial effect of 99.9%, in which adhered silver particle had uniform distribution and are difficult to fall off.
Study on Joining of ZrO2 Tape-Casting Substrates and Adhesive Mechanism
Authors: Tu Yue , Hou Wei Hua , Feng Tao , Jiang Dan Yu , Li Qiang
Published: March 2013

Planar zirconia automotive oxygen sensor consists of three layers of ZrO2 tape-casting substrates which possess different function after sintering, so it is important for us to research the joining of these substrates. Through SEM and EDS measurements, the essay mainly discussed the joining of ZrO2 tape-casting substrates and the adhesive mechanism when chose ZrO2 slurry as joining materials.
Preparation and Characterization of Hydrophobic Silica Aerogel by Ambient Pressure Drying Method
Authors: Xu Hui , Fu Gui Ln , Guo Yu Qiang , Tu Jing Chun , Chen Yong
Published: March 2013

Silica aerogel has been prepared by ambient pressure drying technique using water glass as starting materials. Solvent exchange and surface modification were simultaneously conducted by immersing the wet hydrogel in EtOH/TMCS(Tri Methyl Chloro Silane)/hexane solution. The silica aerogel was obtained with the density of 0.110g•cm-3 and 95.2% porosity. The specific surface area of the silica aerogel was 472.5m2•g-1 with a average pore size distrubution of 27.5nm. FT-IR spectrum analysis showed that the surface of the silica aerogel was modified by Si-CH3 groups, which allowed the aerogel to be hydrophobic.
Study on the Gemological Characteristics of Amber from Myanmar and Chinese Fushun
Authors: Xing Qiu Yu , Yang Miao , Yang Hui Xuan , Zu En Dong
Published: March 2013

This paper researches on the gemological characteristics of amber from Myanmar and Chinese Fushun by using of the basic instruments of gemology, SEM and FT-IR. The results show that the refractive index is approximately 1.54 both in Myanmar and Fushun amber, resin glossy as well as conchoidal fracture. While the hardness of Myanmar amber is much higher and it has a dark lyons blue ultraviolet fluorescence; Fushun amber is much more transparent, medium kashima ultraviolet fluorescence and coal coveres on its surface. In addition, the fracture in Myanmar amber is more obvious compared with Fushun amber.The infrared spectrums prove that Myanmar amber has the absorption peak of CO stretching vibration at 1730cm-1, while Fushun amber is at 1700cm; the absorption peak of CH3asymmetric stretching at 2950cm-1of Myanmar amber is also different from Fushun amber which is at 2960cm-1. As a result, this paper provides basic identification between Myanmar amber and Chinese Fushun amber in gemology.
Microstructure Observation and Analysis of Sintered SiC Ceramics by SEM
Authors: Jiang Yong , Wu Lan Er , Huang Zhen Kun
Published: March 2013

Comparison of microstructures between LPSed and SSSed SiC ceramics were made. Several kinds of structure defects for LPSed SiC were emphasized to discuss. They related with whole flow path of processing, compositional design of powder mixture, spray granulation of powder mixture, milling, shaping, and sintering control. All could affect the microstructure and mechanical property of resultant ceramics.
Textural Properties of Nanocrystalline Hydroxyapatite Synthesized via a Microwave-Hydrothermal Process
Authors: Wang Yong Zai , Luo Shao Hui , Fu Ying
Published: March 2013

Textural properties of nanocrystalline hydroxyapatite (HAP) prepared by microwave-hydrothermal (M-H) method have been comparatively studied as a function of synthesis conditions. Field emission scanning electron microscopy measurement reveals that the material is composed of rod or prism-like nanoparticles. N2-sorption analysis shows that the as-prepared HAP samples are textural mesoporous materials. The porous networks of aggregated nanoparticles are derived from the interparticle space. HAP samples prepared at 100 °C for 30 min exhibited a narrow pore size distribution with a high surface area (up to 92 m2g-1). As the increase of synthesis temperature and/or time, the total pore volumes and surface areas of the HAP samples decrease, the pore size distributions become broader. It was observed that the textural evolution of the products is closely related to its crystallite size. The present study shows the microstructural features of nano HAP powders can be tuned by synthesis conditions.