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H‐301 tubes for thermal cracking heater were subjected to metallurgical analysis on 2nd October 2007. Results of this analysis indicate that these tubes are of ASTM A355P5 specification. A hard oxide layer formed on the outer surface that is exposed to high temperature and the hardness value on this surface was 250 HB30. The hardness value of other part of the metal was 128.5 HB30. The inner surface was deposited with by‐product of cracking process. The tube expanded in the direction of tube axis causing a little bend to this tube. The change in metal thickness was considered insignificant. Difference in hardness between exposed and new tube was only 10 HB30, which means that the difference in mechanical properties between these tubes were very small. According to the class of damage, the microstructure is still in the class between C and D. This means that only 2.5%—10% of life fraction the material has been consumed. Thus, the remaining life of the tube is about 90%. Based on these results, the tube still may be used for another 10 to 15 years if operating temperatures are in the recommended ranges (400–550°C).

The application of Infrared Thermography (IRT) as passive method is widely used and accepted by industry. However, IRT technology as transient or active method is considerably new for industry in term of measuring defect in Non‐Destructive Testing (NDT) activities. The primary objective of this paper is to present an experimental study of determination of artificial defect in material using active thermography, in particular to pulsed thermal NDT (TNDT). Both terminology and basic principles in TNDT will be discussed. It is shown that several factors may influences TNDT results. As a conclusion, this study has confirmed the ability and potential of TNDT as a technique for defect determination in material.

The corrosion inhibition of aluminum and its alloys is the subject of remarkable technological importance due to their increased industrial applications. This paper reports the results of the corrosion inhibition properties of AA6061 and AA6063 aluminum alloys in tropical seawater using sodium benzoate as an inhibitor. It was found that the corrosion inhibition occurred through the adsorption on the surfactant on the metal surface without modifying the mechanism of corrosion processes.

The catalytic behaviour of undoped NiO and doped Pr2O3‐NiO catalysts toward CO2/H2 methanation reaction has been performed. The result showed 100% conversion of CO2 to CH4 in the presence of H2 for doped 60Ni‐40Pr at 300 °C, while for undoped NiO, there was only 40% of CO2/H2 methanation at the same temperature. The result corresponds to the presence of higher specific surface area of 60Ni‐40Pr compared to undoped NiO catalyst. The XRD analysis showed that this catalyst has some degree of amorphous properties and the existence of individual phases of cubic NiO and cubic Pr2O3, which serves more active site for CO2/H2 methanation. In addition, complimentary results obtained from SEM showed the present of homogeneous smaller particle size, which support the good performance of 60Ni‐40Pr catalyst towards CO2/H2 methanation.

The monolayer of carbon atoms in a hexagonal lattice is called graphene. It is a monoatomic layer of graphite. The stacking of hexagons one over the other creates a variety of layers. We can stack in such a way that the hexagons of the first layer coincide with the hexagons of the next layer or they may be displaced. In this way we are able to make three types of layer stacks of graphene. These are called A, B and C types. We have found that a single layer of graphene shows a small gap of 27.212 meV. In the two layers of the AA type also the crossing is avoided. The energy from the apparent crossing point towards higher energies is not equal to that towards lower energies. The energy levels are not symmetric with respect to the apparent crossing point. In the AB type stacking for two layers the energy gap is 4.8 meV. The energy gap for a variety of stacking of layers has been obtained from the non‐relativistic Schrodinger theory.

Typically, most of the commercially available GaN‐based LEDs (Light Emitting Diodes) are grown on sapphire as their substrates. Due to the insulating substrate, lateral current injection is employed so that the anode and cathode contacts are in side‐by‐side configuration. During the etching process, the possibility of slanted mesa sidewall to form is higher. In this work, the influence of slanted mesa sidewall are studied while its light emitting area size and contacts position are maintained. The comparison for optical output power, current‐voltage, thermal dissipation and distribution characteristics of different angles of slanted mesa sidewall are performed. Angles of slanted mesa sidewall are varied from angle‐in and angle‐out with reference to 90° at mesa edge. The simulation results revealed that with the increment of slanted angle, the LEDs performed better due to improved overall emission intensity and uniform current distribution of the devices. The angled sidewalls efficiently deflect photons that are initially guided laterally within the GaN epilayer in the off‐surface direction. As such, devices showed better overall performance.

1g chitosan was dissolved in l00 mL of 1% acetic acid solution to prepare a chitosan acetate solution. The solution was then mixed with oleic acid. This chitosan acetate‐oleic acid was then made into thin film by the solution cast technique. The conductivity of the samples was measured from ambient to elevated temperature. The highest conductivity of the chitosan‐salt with 10 wt % oleic acid (OA) at room temperature was 8.35×10−9 Scm−1. The addition of OA has increased the dielectric constant, which implies the increase of dissociation of the salt thereby producing more free ions for conducting and hence increases the ionic conductivity.

We illustrate the optimization of the growth of multi‐wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm‐based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over iron/nickel/manganese, iron/nickel/magnesium and iron/nickel/chromium trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol‐gel method. MWCNTs produced were characterized by using Field Emission Scanning Electron Microscope (FE‐SEM) to indicate the production of nanotubes growth from palm DHSA. The density of the yield of MWCNTs produced differs with changes of the catalyst used during the nucleation process of MWCNTs. The crystallinity of MWCNTs was studied by X‐Ray Diffraction (XRD). Fourier Transform Infrared (FTIR) study was also been done for the prepared MWCNTs to check on the bonding occur in the produced MWCNTs.

In the current paper, we not only explain the fabrication and properties of an organic humidity sensitive field effect transistor using physical vapor deposition but also discuss the fabrication and properties of a photocapacitor made through spin‐coating technique. We also describe: (i) conduction mechanisms in organic semiconductors as hopping, band and/or tunneling one, and (ii) the possible ways to increase the mobility of charge carriers.

Nanocrystalline anatase and amorphous Titanium Dioxide (TiO2) thin film have been prepared using sol‐gel method and deposited by spin coater technique. The influence of annealing temperature on the structural, surface morphology and electrical properties of the thin film is characterized by Scanning Electron Microscopy (SEM) and I‐V measurement. The result indicates that nanocrystalline anatase phase can be obtained at annealing temperature of 300 °C or above. Titanium dioxide thin films were deposited on silicon substrates. Annealing temperature at T = As deposited, 100 °C, 300 °C and 500 °C have been observed. As deposited substrates is also observed. The result indicated electrical properties of titanium dioxide thin films were changed with annealing temperatures. As the annealing temperature rises, the resistivity will be decreased. The SEM investigation showed that grain size of titanium oxide increased with higher annealing temperature. Furthermore, the SEM result indicated lattice matching between titanium dioxide and substrate is important to produce good quality titanium dioxide thin film after annealing process. The results suggest that surface porosity, electrical properties and surface morphology of titanium dioxide could be affected by changing annealing temperatures for electronic devices application.

Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350∼500 °C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and current‐voltage (I‐V) measurement scanning for surface morphology and electrical properties study respectively. The SEM investigation shows that zinc oxide thin films are denser at higher annealing temperature. The result indicates electrical properties of aluminum doped zinc oxide thin films are improved with annealing temperatures. The resistivity of aluminum doped zinc oxide thin films are decreased with annealing temperature up to 500 °C.

The Cengal wood samples which are obtained from Tenaga National Berhad (TNB), is a raw material for heavy construction industry. The compression test is carried out by using an Instron Machine Series‐IX at different temperatures for the purpose of determining and understanding the mechanical properties of Cengal wood under fiber saturated point and as dried samples. Analysis is made from the results in the form of Young's modulus, E plotted against the temperature. From the test, the Cengal wood does not show a glass transition or softening when dried up to 140 °C because there is no significant decrease in the value of E during heating. For fiber saturated point, the glass transition temperature occurs at 40 °C when the E value is about 190 MPa while the second rapid drop occurs at 60 °C (155 MPa), which is due to the softening temperature of lignin. After the softening point, the wood becomes too soft and undergoes the process of decomposition due to small value of E.

The effects of immersion time and quantity of Erbium plated on Nanostructured Silicon (NSi) have been studied. Nanostructured Silicon was prepared by electrochemical method with an electrolyte composed of Hydrofluoric acid and Ethanol. The Erbium plating process was carried out by immersion technique with electrolyte composed of ErCl3 and Ethanol. The photoluminescence (PL) effect on NSi samples have been studied and shows a PL intensity is improves at certain immersion time and the PL peak shifts to the blue luminescence. The presence of Erbium conformed by X‐ray Photoelectron Spectroscopy (XPS). Fourier Transform Infrared Spectroscopy (FTIR) was also performed to study the chemical functional group changes after the plating process. The possible mechanism of the effects will be discussed in this paper.

This paper discusses the phase analysis of interference pattern from coherent light Nd:YAG 532 nm laser source. The Twyman‐Green Interferometer set‐up is used for generating the fringe pattern in the phase calibration. The piezoelectric transducer (PZT) is used to achieve the required phase shift of the fringe pattern. It was found that the system required 8.8 volts of out‐put DC voltage to shift 2π radians phase. The accuracy of optical phase measurement of the interference pattern is analyzed by wrapped phases of three‐phase stepping and four‐phase stepping procedures. Comparison of the experimental phase measurement data and the theoretical phase calculations are also highlighted.

Electron beam lithography is one of the most promising of nanolithographic techniques. The setup is similar to a Scanning Electron Microscope (SEM) and often a scanning electron microscope is used. EBL is able to provide high resolution patterning. However, the effect of electron scattering in resist and substrate leads to an undesired influence in the regions adjacent to those exposed by the electron beam. This effect is called the proximity effect. In this paper, we investigated the effect of dose exposure in Electron beam lithography (EBL) and proximity effect. We also show the image for several of dose exposure.

This paper describes the results of ultrasonic goniometry measurement in Aquilaria (gaharu) wood. Ultrasonic wave was transmitted into the surface of gaharu wood and the reflected amplitudes by corner reflection were measured. The measurements were performed on gaharu sample with dimension of about 3 mm×15 mm×25 mm by attaching to corner reflector goniometer made of mild steel. The measurement results are explained and discussed.

Oxygen sensing properties of Er123 ceramic material utilizing hot‐spot phenomenon have been investigated. Bulk Er123 ceramic with relative density of 72 % was synthesized using solid‐state method and single‐phase structure of the material was confirmed by X‐ray diffraction. The Er123 sensor was fabricated by cutting the bulk sample into a rectangular rod shape. I‐V characterizations of the sensor before and after appearance of the hot spot were conducted in a chamber with controlled flow rate and partial pressure of oxygen and nitrogen gases. After appearance of the hot spot, the output current strongly depended on oxygen partial pressure (pO2) at a particular selected voltage. The sensor showed good sensing properties with minimum required electric field of about 1.7 V/cm for 0.025% to 100% pO2. The sensor showed very good reproducibility and stability of output current. The oxygen sensing properties are explained in terms of absorption of oxygen gas by the hot spot before dissociating into oxide ions an...

This paper describes the construction and testing at room temperature of a resonant photoacoustic cell which may be used to carry out photoacoustic measurements of opaque samples at various temperatures from 77 K to 300 K. It has the shape of the Helmholtz resonator with a microphone separated from the sample by a long narrow tube. An optical fiber leads the laser light to the sample. The photoacoustic cell was tested by measuring thermal diffusivity of various solid samples at room temperature. The testing shows that the photoacoustic cell is successful in measuring thermal diffusivities of various opaque samples.

Photoluminescence and morphology studies of Zinc Oxide (ZnO) thin films prepared by using Thermal Chemical Vapor Deposition (Thermal‐CVD) were investigated. The ZnO compound was synthesized from zinc acetate dehydrate which act as a starting material to form the ZnO thin films. It was deposited on silicon with low deposition temperature ranging from 400–600 °C with Au as a catalyst assisted. Surface morphology of the samples was examined by Scanning Electron Microscope and photoluminescence properties were studied using Photoluminescence Spectrometer. The surface morphologies of the ZnO nano‐flower structure was obviously obtained at deposition temperature of 400 °C. The individual nano‐rods diameter of nano‐flower is about 100–350 nm, but the end of nano‐rods are very sharp which is the size is less than 50 nm. Possible growth mechanism of ZnO nano‐flower also discussed. Room temperature PL spectra from the ZnO nano‐flower revealed a strong UV emission and broad green emission. This result is very useful...

Porous GaP have studied fabricated by using an argon‐ion laser beam (LIE) of energy 2.41 eV. We have studied the surface morphology of porous layers obtained using a Scanning Electron Microscope (SEM). The morphology of porous GaP layers changes rapidly with laser power densities and irradiation times. This advanced fabrication method have been used for synthesis porous silicon (p‐Si). The optical characteristic was used to illustrate changes in surface morphology and the intensity of emission of porous form as a function of etching conditions. The surface morphology studies have demonstrated the characterization of porous silicon. As well as both the size and shape of the structure depend on the nature concentration of etchant solution. The different size of pores form at different area of GaN shows that the etching rate is not uniform through out the whole surface of GaN. The porous GaN generated by electrochemical etching technique does not always produce similar surface morphology. However, the averag...

lead sulfide nanostructured thin film was prepared from colloidal lead sulfide nanoparticles with natural deposition technique. The size of PbS nanoparticles has been determined in the base of optical absorption spectrum. The influence of preparation method on the film surface morphology was studied by atomic force microscopy, and x‐ray diffraction. Experimental results have shown that the thin film uniformity has been improved when the number of deposited layer increased. Double layered PbS nanothin film has a self assembly morphology and can be used for surface plasmon applications.

In the present study, five systems of samples have been prepared by the solution casting technique. Polymethylmethacrylate (PMMA) is used as a based polymer. Ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. The salt that was selected for this study is lithium triflate (LiCF3SO3). The pure PMMA sample is taken as a reference. The five systems are the (PMMA–EC) system, the (PMMA–PC) system, the (PMMA‐LiCF3SO3) system, the ([PMMA‐EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system. The conductivity for each system is characterized using impedance spectroscopy. The conductivity of the pure PMMA, the (PMMA–EC) system and the (PMMA–PC) system at room temperature is 2.37×10−9 Scm−1, 3.63×10−8 Scm−1 and 4.18×10−8 Scm−1 respectively. On addition of salt in the (PMMA–LiCF3SO3) system, the conductivity is increased by two orders of magnitude. The conductivity for the ([PMMA–EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system is 3.54×10−5 Scm−1 and 2.06×10−5 Scm−1 respectively. The cond...

Aluminium and zinc target were co—sputtered on silicon (111) substrates using DC magnetron sputtering in the pure argon atmosphere. These films were then underwent the thermal annealing in different ratios of nitrogen and oxygen for 1 hour to form thin oxide films. P—type conduction in ZnO thin films have been realized by the Al—N codoping method, whereby the lowest resistivity of 3.41×10−3 Ω⋅cm and the highest carrier concentration of 1.54×1022 cm−3 was achieved for sample prepared at annealed temperature of 300 °C.

The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 200 °C to 600 °C for 1 hour in nitrogen and oxygen gas mixture. P—type conduction of Al—N codoped ZnO thin films were obtained at 300 °C with the lowest resistivity of 3.412×10−3 Ω⋅cm and highest carrier concentration of 1.54×1022 cm−3. Structural investigation was carried out by atomic force microscope (AFM) and X—ray diffraction (XRD). Results showed that heat treatment had influenced the structure of the films.

This paper presents the influence of polysilicon depletion effect (PDE) on the potential drop across polysilicon gate. The effect of the gate doping and oxide thickness variations on the PDE has been investigated using MINIMOS 6.1 respectively. These parameter variations have been shown to be the factors that contribute to the polysilicon‐gate depletion effect that lead to the increase of the potential drop and degradation in device performance. Besides that, polysilicon depletion effect can be improved by reducing the oxide thickness (tox) and gate doping concentration (Np).

In articular cartilage, Ca, P, K and S are among some of the well known co‐factors of the metalloproteinases enzymatic family, the latter playing a pivotal role in the growth and degeneration of the collagenous bone‐cartilage interface of articulating joints. Current study forms part of a larger investigation concerning the distribution of these and other key elements in such media. For the purpose of evaluating these low atomic number elements (Z⩽20), use was made of the capabilities of the LUCIA Station, located at the synchrotron facility of the Paul Scherrer Institute (PSI). Using an incident radiation energy of 4.06 keV, a synchrotron radiation micro x‐ray fluorescence (SR‐μXRF) technique was applied in examining the distribution of the essential elements Ca, P, K and S in the bone‐cartilage interface of both healthy and diseased (osteoarthritic) areas of an equine metacarpophalangeal joint. The SR‐μXRF mappings and line profile patterns have revealed remarkable changes in both the pattern and absolu...

Multi‐wall carbon nanotubes (MWCNTs) were synthesized by thermal chemical vapor deposition (CVD) and were intercalated with iodine at several different temperatures. Iodine doping was achieved by immersing the nanotubes in molten iodine. The sample produced was characterized by means of infrared IR as a point to the presence of covalent C‐I bonds in the sample with retention of the sp2‐hybridizated carbon atoms. For all samples doped at different temperatures, the C‐I bonding happen to occur based on IR spectra which was indicated by peaks around 600–650 cm−1. X‐ray diffraction (XRD) characterization was used to study on the crystallinity of the undoped and iodine‐doped MWCNTs. It was shown that, iodine‐doping of the MWCNTs gives significant changes in the XRD spectra compared to the undoped MWCNTs. With various doping temperature, the XRD spectra shows the different crystallinity.

Superconducting fluctuation behavior has been studied in sintered polycrystalline samples of Yb‐substituted Tl0.5Pb0.5Sr2−xYbxCaCu2O7−δ (x = 0.1–0.4) by electrical resistivity measurements. Data of Δσ was obtained from linear fitting of the normal state resistivity in a suitable temperature region. Analysis of excess conductivity behavior based on Aslamazov‐Larkin (AL) theory revealed transition from 2‐D to 3‐D behavior of the superconducting fluctuation in the mean field region for all samples. This study also suggests that there is a close correlation between the amounts of Yb substitution and the behavior of AL constant (A) both for 2D and 3D fluctuations.

P‐N junction is a basic building block for many important electron devices from as simple as a solar cell to very complicated integrated circuit. In this work, spin‐on dopant (SOD) was used as the diffusion source in order to create p‐n junction. SOD was prepared by using sol gel method. The spin‐on dopant solution ingredients contain tetraethylorthosilicate (TEOS), isopropanol (IPA), distilled water (H2O), acetone and phosphoric acid (H3PO4). The coated silicon wafers were put inside the conventional furnace for predepostion and drive in oxidation. Effect caused by varying the molarity of the acid were observed and studied using Hall Effect measurement by comparing their differences in sheet resistance, mobility, resistivity as well as sheet and bulk concentaration.

This paper presents the investigation carried out to study the formation of silicon nitride and silicon carbide compound from the reaction of silica sand powders with carbon in nitrogen with 5% hydrogen atmosphere at temperatures between 1350 °C to 1550 °C. The effect of mechanical milled silica sand and different temperature during carbothermal reduction process was determined. The morphology of the synthesis products was characterized using scanning electron microscopy and its composition was determined by elemental and X‐ray phase analysis. The formation of silicon nitride compound was facilitated by using silica sand with distorted structure by mechanical milling method. Further increased on temperature will lead to the formation of silicon carbide compound.

The effect of Ba‐substitution at Sr site on the structure, magnetoresistance and magnetic properties of La0.67(Sr1−xBax)0.33MnO3 samples with x = 0.00, 0.25, 0.50, 0.75 and 1.00 has been investigated. Single phase samples were obtained by a conventional solid state reaction method with rhombohedral (x = 0.00) and orthorombic (x = 1.00) structure. The grain size increases with Ba content. Low field magnetoresistance phenomenon at low temperature can be observed for all samples. However it vanishes at 300 K for x = 0.75 and 1.00. The variation of MR% value is small ranging between 16 to 18% at 100 K in an applied field of 1 T. All samples show a single magnetic transition from the ferromagnetic (FM) state to the paramagnetic (PM) state as the temperature increases. Curie temperature, Tc decrease with increasing Ba concentration.

Bismuth borate glass is of great interest in optoelectronic devices due to its low melting temperature (600–800 °C), extensive glass formation range, high refractive index ranging from 1.9 to 2.3, high physical and chemical stability, and nonlinear optical property. A systematic bismuth borate glass series in the systems of (Bi2O3)x−(B2O3)1−x have been successfully prepared by melt quenching technique over a wide range of composition (x = 35–70 mol%). Their elastic properties have been measured from their densities as well as longitudinal (VL) and shear ultrasonic wave velocities (Vs) which have been determined at room temperature by the MBS8000 Ultrasonic Data Acquisition system at a frequency of 5 MHz. The variation of ultrasonic wave velocities and elastic modulus such as longitudinal, Young's, bulk and shear modulus, Poisson's ratio, and micro hardness are discussed with respect of the Bi2O3 content.

In this work, the ion conducting films of polyacrylonitrile (PAN) containing plasticizer and dopant salts were prepared by the solution casting technique. The salts selected for this study are lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3). The ionic conductivity measurements were carried out using impedance spectroscopy. The room temperature conductivity for pure polyacrylonitrile film is 1.51×10−11 S cm−1. The room temperature conductivity for the highest conducting film in the PAN‐LiCF3SO3 system and the PAN‐NaCF3SO3 system is 3.04×10−4 and 7.13×10−4 S cm−1, respectively. The conductivity‐temperature studies were performed in the temperature range between 303 K and 373 K. The variation of the conductivity with temperature is obeys the Arrhenius rule. The increase and decrease in the number of ions can be implied from the plots of dielectric constant, er‐frequency and dielectric loss, ei‐frequency.

This paper presents a detailed analysis of the fully and partially depleted silicon‐on‐insulator (SOI) n‐MOSFET for radio frequency (RF) applications. The analysis focused on the dependence of off‐state leakage current on temperature, oxide thickness, silicon film thickness, channel length, and buried oxide insulator of SOI n‐MOSFET respectively. The effect of varying each of this device's parameters on off‐state leakage current of SOI n‐MOSFET was investigated by using MINIMOS 6.1. The simulation results proved that decreasing of the buried oxide thickness and temperature lead to the reduction of the leakage current of the device.

Growth of Nd:YAG single crystals by the Czochralski method in an argon atmosphere with ADC (Automatic Diameter Control) r.f. heating was investigated. The conditions required to grow Nd:YAG single crystals are described. The relationship of the latter to the growth mechanism is discussed and a mechanism proposed which provides an explanation of the manner in which the crystals grow and reject impurities. The Nd:YAG single crystal with growth direction of 〈111〉 was produced by effective control of growth conditions.

The development of water quality fiber sensor through spectroscopy analysis utilizes the emission of incident light and detection of backscattered light through fiber optic cables as key elements of the design. The system has the capability to detect the light scattered 180° away from the incident light when there is an interaction between the light and the solids suspended in the water. The empirical analysis is conducted for the measurement of the capacity of clay suspended in water (in mg/L). The system consists of two separate light detector circuitry that is sensitive to blue (470 nm) and red (635 nm) monochromatic light. The heart of the system is the sensor, TSLB257 and TSLR257 that having a peak response at wavelength of 470 nm and 635 nm respectively. The final result of detection is submitted to Basic Stamp 2 microcontroller for processing and analysis. The level of turbidity is then defined and displayed by the microcontroller.

This research was designed to form better dielectric composite material using one steady state dielectric with a good dielectric material. Distinct dielectric composite was successfully produced using locally sourced kaolinite clay. The samples were made using kaolinite as the base matrix and Strontium Titanate (ST) added in varying ratios. Strontium Titanate were synthesized via solid‐state reaction using Strontium Carbonate and rutile Titanium (IV) Oxide with sintering at 1300 °C. Local white kaolinite was used to fuse the barium titanate material in varying weight ratios. The powders were dry‐mixed and made into pellets for calcination at 1000 °C. The dielectric measurements were carried out using the HP 4291B Impedance Analyzer dielectric setup. Three samples were prepared, namely 10%ST, 20%ST and 30%ST. The dielectric measurements were carried out at room temperature. Microwave region measurements showed steady state and linear dielectric relaxation ranging from 7 in the control sample and dropping d...

Properties of the influence on the zeolite as the support towards the starting carbon materials by using thermal chemical vapor deposition (Thermal‐CVD) to produced carbon nanotubes (CNTs) are investigated. The CNTs derived from camphor oil (C10H16O), a botanical hydrocarbon, has been found to be a promising precursor of carbon nanotubes (CNTs). Multi‐wall CNTs have been grown from simple pyrolysis of camphor oil in the temperature 650 °C in argon atmosphere at normal pressure using zeolite as a supported on Fe/Ni/Mn catalyst. On the other hand, multi‐wall nanotubes of uniform diameter (∼20–30 nm) could be produced with a yield as high as 90%. Structural characterizations have been done by FESEM, and FTIR analyses. Good crystallinity, high purity, and absence of amorphous carbon and metallic particles are the essential features of camphor oil‐grown nanotubes; which indirectly may be cost effective. The major parameters are also evaluated in order to obtain high‐yield and high‐quality CNTs.

Low energy vibrational excitations represent an universal feature of amorphous solids and cause anomalies in the acoustic and thermal properties glasses. The excitations associated to the local mobility of structural defects, the defect modes, originate a vibrational and relaxation dynamics in glasses which differ considerably from those of their crystalline counterparts. Unfortunately, the microscopic nature of structural defects is unknown mainly because the anomalies observed in the physical properties of amorphous solids are quite independent of their microscopic structure and stoichiometry. Some experimental results concerning the acoustic and thermal properties of glasses are provided with the aim to illustrate the possible physical nature of the defect modes. Moreover it will be shown that, besides tunneling and classical activation of structural defects, vibrational anharmonicity is playing a significant role in governing the acoustic behaviors.

The characteristics of a defect counting tool, COMNET< based on scattering light measurement, is presented. This prototype supports the development of defect-free EUV blanks. Thanks to new improvements, it becomes possible to detect PSL particles having a diameter as low as 100 nm, with a video CCD camera, on silicon substrates or on EUV blanks. To reach this sensitivity, one of the enhancements consists in a laser irradiation close to 65°. The present configuration and the use of a CCD camera, with a variable exposure time, should lead to the detection of 80 nm PSL particles deposited on silicon substrate. This extrapolation is based on experimental results and on a simple model. To detect 100 nm particle and smaller particles, it is essential to reduce the level of stray light and to increase the signal to noise ratio. In our application, the stray light essentially comes from three sources: the noise induced by the roughness of the sample, the Rayleigh scattering of the atmosphere, and the stray light in the room. The restrictions induced by these phenomena are described in some detail. All the improvements are not only available for the characterization of silicon substrates but also for transparent blank substrates and for EUV mask blanks. The additional noise induced by the tranparent substrate is analyzed. The defects, whatever the compoent sizes and the component shapes can be detected. A cross characterization achieved with a commercial tool on silicon substate is reported. Counting measurements performed on EUV blanks are shown. Furthermore, a more explicit definition of added defects is proposed.

Vitreous GeO(2), one of the main prototypes of strong glasses, was densified at several pressures up to 6 GPa, achieving more than 20% of densification. The density dependence of the vibrational density of states and of the low temperature properties of these glasses was investigated by means of inelastic neutron scattering and calorimetric measurements. With increasing density, both the boson peak and the bump in c(p)/T(3) versus T plot exhibit variations which are stronger than the elastic medium expectation. If one reduces the measured spectra to a common master curve, one finds that this is only possible for the densified samples; the first densification step has an additional effect, similar to other cases in the literature. Nevertheless, the existence of a master curve for the three densified samples proves that the total number of excess modes remains constant on further densification. The experimental data are discussed in the framework of different theoretical models.

This paper addresses the fabrication technique of two‐dimensional (2D) photonic crystal (PhC) membrane with nanocavity structures. Hexagonal lattice of air holes with periodical variation of refractive index embedded in high‐index semiconductor results in strong dispersion of light. Electron beam lithography (EBL) technique was employed to transfer high resolution pattern onto a sample coated with electronic resist. The e‐beam is deflected to direct write the chosen pattern. The sample consists of three‐layer semiconductor with the top layer being the 320 nm‐thick GaAs with MBE grown InAs quantum dots (QD) at the center of the layer, followed by the sacrificial 1.5 μm‐thick Al0.7Ga0.3As layer and GaAs layer as the substrate. A 234 nm‐diameter cavity 2D PhC suspended membrane was fabricated with about 12 μm diameter of the chamber below it.

In this paper, we present the study of the structural, optical and electrical of n‐type GaN grown on silicon (111) by RF plasma‐assisted molecular beam epitaxy (RF‐MBE). X‐ray diffraction (XRD) measurement reveals that the GaN was epitaxially grown on silicon. For the photoluminescence (PL) measurement, a sharp and intense peak at 364.5 nm indicates that the sample is of high optical quality. Hall effect measurement shows that the film has a carrier concentration of 3.28×1019 cm−3. The surface of the n‐type GaN was smooth and no any cracks and pits.

We describe a holographic method for measuring very high viscosities, up to 1015 poise, or higher. The method consists of detecting small displacements, due to the sample deformation, by the holographic double exposure technique. Measurements performed on amorphous selenium are reported and compared with those obtained with the usual technique, showing that our method gives the correct results. The advantages of the proposed technique are briefly discussed.

High-energy transmission x-ray diffraction techniques have been applied to investigate the crystal quality of CdZnTe (CZT). CdZnTe has shown excellent performance in hard x-ray and gamma detection; unfortunately, bulk nonuniformities still limit spectroscopic properties of CZT detectors. Collimated high-energy x-rays, produced by a superconducting wiggler at the National Synchrotron Light Source’s X17B1 beamline, allow for a nondestructive characterization of thick CZT samples (2–3 mm). In order to have complete information about the defect distribution and strains in the crystals, two series of experiments have been performed. First, a monochromatic 67 keV x-ray beam with the size of 300×300 µm2 was used to measure the rocking curves of CZT crystals supplied by different material growers. A raster scan of a few square centimeter area allowed us to measure the full-width at half-maximum (FWHM) and shift in the peak position across the crystal. The rocking curve peak position and its FWHM can be correlated with local stoichiometry variations and other local defects. Typically, the FWHM values ranging from 8.3 arcsec to 14.7 arcsec were measured with the best crystal used in these measurements. Second, transmission white beam x-ray topography (WBXT) was performed by using a 22 mm×200 µm beam in the energy range of 50 keV to 200 keV. These types of measurements allowed for large area, high-resolution (50 µm) scans of the samples. Usually, this technique is used to visualize growth and process-induced defects, such as dislocations, twins, domains, inclusions, etc. the difference in contrast shows different parts of the crystal that could not be shown otherwise. In topography, good contrast is indicative of a high quality of the sample, while blurred gray shows the presence of defects. Correlation with other techniques (e.g., infrared (IR) mapping and gamma mapping) was also attempted. Our characterization techniques, which use highly penetrating x-rays, are valid for in-situ measurements, even after electrical contacts have been formed on the crystal in a working device. Thus, these studies may lead to understanding the effects of the defects on the device performance and ultimately to improving the quality of CZT material required for device fabrication. It is important to study crystals from different ingot positions (bottom, center, and top); consequently, more systematic studies involving scans from center to border are planned.