Research And Development Of Diode-Pumped Passively Q-Switched Nd:Yvo4 Lasers Using Cr4+:Yag Crystal As Saturable Absorber,
2017
Universiti Brunei Darussalam
Research And Development Of Diode-Pumped Passively Q-Switched Nd:Yvo4 Lasers Using Cr4+:Yag Crystal As Saturable Absorber, Nghia Nguyen Trong, Huy Trinh Dinh, Nga Le Thi Thanh, Hung Nguyen Dai
ASEAN Journal on Science and Technology for Development
The results in research and development of diode-pumped passively Q-switched Nd:YVO4 lasers are presented with Cr4+:YAG crystal used as an intra-cavity saturable absorber. Using a-cut Nd:YVO4 laser crystals, the passively Q-switched lasers have been successfully developed and provided stable single shortest pulses of 40 ns at the repetition rate of 18.5 kHz, the maximal average output power of 180 mW was achieved corresponding to the optical efficiency of 9% and the slope efficiency of 16%. The dependences of average output power, repetition rate, pulse width and peak power on pump diode power for different transmissions of output mirror are also …
Preparation Of The Single Mode Planar Optical Splitter Modules And Their Characterizations,
2017
Universiti Brunei Darussalam
Preparation Of The Single Mode Planar Optical Splitter Modules And Their Characterizations, Mien Vu Doan, Nghiem Vu Thi, Truong Pham Van
ASEAN Journal on Science and Technology for Development
Optical splitter modules have been prepared based on 1x8 single mode silica planar waveguide optical splitter chips with 250 µm spacing and v-groove fiber arrays for applications in fiber optic communications. We report the technology of precise optical coupling and packaging of the splitter modules and the measurements of the insertion loss (< 11 dB), uniformity (< 0.80 dB) and polarization dependence loss (PLD < 0.10 dB) as well as the lateral profile and the image of the input and output lights for the wavelengths of 1310 nm and 1550 nm. The main characteristics of the prepared splitter modules are about the same for the commercial available products. The prepared modules have been tested for operation in the conditions of wide temperature range (5–80°C) and humidity range (50–98%) and no changes in the main characteristics were observed.
Europium Silicate Thin Films Fabricated By Rf Magnetron Sputtering And Thermal Treatment,
2017
Universiti Brunei Darussalam
Europium Silicate Thin Films Fabricated By Rf Magnetron Sputtering And Thermal Treatment, Shin Young Chul, Kim Eun Hong, Kim Tae Geun
ASEAN Journal on Science and Technology for Development
We report the fabrication and optical characteristics of europium silicate thin films. Layer structures of Eu2O3/SiOX/Si (100) were deposited by an rf-sputtering method and annealed at 1100°C by rapid thermal annealing (RTA). Two methods were used for the deposition of SiOX layer: One was deposited by sputtering using SiO2 target (Ar gas at a rate of 50 sccm) and the other was deposited by reactive sputtering using Si target (Ar gas at a rate of 45 sccm, with an O2 gas at a rate of 5 sccm). Photoluminescence peak at 430 nm was observed in the sample composed of SiOx …
Peculiar Optical Properties Of Co2mnga Alloys,
2017
Universiti Brunei Darussalam
Peculiar Optical Properties Of Co2mnga Alloys, Rhee Joo Yull, Kudryavtsev Y.V., Kim K.W., Lee Y.P.
ASEAN Journal on Science and Technology for Development
Co2MnGa alloy was prepared by the conventional arc-melting method. The optical conductivity (OC) spectrum of the alloy was measured by a rotating-analyzer spectroscopic ellipsometer. The OC spectrum was also calculated based on the electronic structure by using the full-potential linearized-augmented-plane-wave method within the local-spin-density approximation to the density-functional theory. The calculated OC spectrum does not agree well with the experimental one. Since the Co2MnGa alloy could be a strongly-correlated material, the so-called 'LDA+U' method was applied with U = 5.4 eV. The calculated OC spectrum using the 'LDA+U' method agrees very well with the experimental one. The inclusion of the …
Photoluminescence Of Zno Nanostructure Prepared By Catalyst - Assisted Vapor - Liquid - Solid Technique,
2017
Universiti Brunei Darussalam
Photoluminescence Of Zno Nanostructure Prepared By Catalyst - Assisted Vapor - Liquid - Solid Technique, Hoa Tran Thi Quynh, Canh Ta Dinh, Long Nguyen Ngoc, Tuyen Nguyen Viet, Phuong Nguyen Duy
ASEAN Journal on Science and Technology for Development
ZnO semiconductor nanostructures have been synthesized by thermal evaporation of mixture of ZnO and graphite powders. The thin layer of gold coated on Si substrates was used as a catalyst. The structure analysis shows high crystallinity of ZnO, their preferred orientation along the (0 02) plane of the wurtzite phase and their chemical purity. The scanning electron microscopy (SEM) images of products indicate that ZnO nanowires have a diameter of about 40 - 150 nm and a length of up to tens of micrometers. The morphology and structure of ZnO nanowires and nanorods depend on the thicknesses of the Au …
Optical And Structural Properties Of Optical Thin Films With Various Columnar Microstructures,
2017
Universiti Brunei Darussalam
Optical And Structural Properties Of Optical Thin Films With Various Columnar Microstructures, Woo Seouk-Hoon, Park Yong Jun, Hwangbo Chang Kwon
ASEAN Journal on Science and Technology for Development
In this study, optical and structural properties of the thin films prepared using glancing angle deposition (GLAD) are investigated. Various glancing angles and substrate rotations are employed to control the columnar microstructure of the films. The results show that as the glancing angle increases, the column angle and the porosity of TiO2 films increase and the refractive index decreases, due to shadow effects. The optical anisotropy of tilted and zigzag microstructure TiO2 films have a large anisotropy and reaches a maximum at a glancing angle of 60°, while that of helical microstructure TiO2 film deposited at 60° with substrate rotation …
Experimental Study Of 3d Self-Assembled Photonic Crystals And Colloidal Core-Shell Semiconductor Quantum Dots,
2017
Universiti Brunei Darussalam
Experimental Study Of 3d Self-Assembled Photonic Crystals And Colloidal Core-Shell Semiconductor Quantum Dots, Nga Pham Thu, Chinh Vu Duc, Nghia Nguyen Xuan, Huy Nguyen Viet, Thuan Dao Nguyen, Cuong Pham Thai, Ha Chu Viet, Chi Do Do, Dat Nguyen Nhu, Anh Le A Lan, Barthou C., Benalloul P., Romanelli M., Maã®Tre A.
ASEAN Journal on Science and Technology for Development
In this contribution we present an experimental study of 3D opal photonic crystals. The samples are opals constituted by colloidal silica spheres, realized with self-assembly technique. The sphere diameter is selected in order to obtain coupling of the photonic band gap with the emission from CdSe/ZnS colloidal quantum dots. The quantum dots infiltrated in the opals is expected to be enhanced or suppressed depending on the detection angle from the photonic crystal. The structural and optical characterization of the SiO2 opal photonic crystals are performed by field-emission scanning electron microscopy and reflectivity spectroscopy. Measurements performed on samples permits to put …
Synthesis And Characteristics Of Poly(Para-Phenylenevinylene),
2017
Universiti Brunei Darussalam
Synthesis And Characteristics Of Poly(Para-Phenylenevinylene), Chau Pham Thi Minh, Jin Jung Il
ASEAN Journal on Science and Technology for Development
Poly(para-phenylenevinylene) [PPV] films and nanotubes were prepared via chemical vapor deposition polymerization (CVDP) by vapor phase pyrolysis of α, α'-dichloro p-xylene on the quartz plate, silicon wafers and Al2O3 membrane substrate with the pore size f = 100 nm. We prepared graphitic carbon films and carbon nanotubes by carbonizing the poly(para-phenylenevinylene) [PPV] films and nano parterns under thermal treatment range from 500°C to 900°C. When the PPV films on quartz plate were treated at 900°C highly oriented graphitic carbon films were obtained. The characterization of the PPV nanotube and nanotube carbon has been investigated by means of IR, SEM, AFM …
Cathodic Electrodeposition Of Cu 4 Sns 4 Thin Films From Acidic Solution,
2017
Universiti Brunei Darussalam
Cathodic Electrodeposition Of Cu 4 Sns 4 Thin Films From Acidic Solution, Kassim Anuar, Min Ho Soon, Tee Tan Wee, Abdullah Abdul Halim, Sharif Atan, Haron Md. Jelas, Nagalingam Saravanan, Kuang
ASEAN Journal on Science and Technology for Development
In this work the synthesis of copper tin sulfide thin films by electrodeposition is carried out. The films were deposited onto ITO glass substrates from anaqueous solution bath containingcopper sulfate, tin chloride and sodium thiosulfate at pH 1 and room temperature. Prior to the deposition, a cyclic voltammetry experiment was carried out between two potential limits (+1000 to -1000 mV versus Ag/AgCl) to probe the effect of the applied potential and to determine the most likely suitable electrodeposition potential for the deposition of copper tin sulfide. The deposition was attempted at various cathodic potentials such as -400, -600, -800, -1000 …
New Approach Of Highly Efficient Fermentation Process For Bio Ethanol Using Xylose As Agricultur E Residues,
2017
Universiti Brunei Darussalam
New Approach Of Highly Efficient Fermentation Process For Bio Ethanol Using Xylose As Agricultur E Residues, Ahmed Abu Saleh, Watanabe Seiya, Hamdan Sinin, Kodaki Tsutomu, Makino Keisuke
ASEAN Journal on Science and Technology for Development
Agricultural waste biomasshas already been transferred to bioethanol and used as energy related products, although many issues such as efficiency and productivity still exist to be overcome. In this study, the protein engineering was applied to generate enzymes with completely reversed coenzyme specificity and developed recombinant yeasts containing those engineered enzymes for construction of an efficient biomass-ethanol conversion system. Recombinant yeasts were constructed with the genes encoding a wild type xylose reductase (XR)and the protein engineered xylitol dehydrogenase (XDH)(with NADP) of Pichiastipitis. These recombinant yeasts were characterized based on the enzyme activity and fermentation ability of xylose to ethanol. The …
S Tudies On The Phase Transitions And Properties Of Tungsten (Vi) Oxide Nanoparticles By X - Ray Diffraction (Xrd) And Thermal Analysis,
2017
Universiti Brunei Darussalam
S Tudies On The Phase Transitions And Properties Of Tungsten (Vi) Oxide Nanoparticles By X - Ray Diffraction (Xrd) And Thermal Analysis, Abdullah S.F., Radiman S., Abdul Hamid M.A., Ibrahim N.B.
ASEAN Journal on Science and Technology for Development
Tungsten (VI) oxide, WO3nanoparticles were synthesized by colloidal gas aphrons(CGAs) technique.The resultant WO3nanoparticleswere characterized by thermogravimetric-differential thermal analysis (TG-DTA) and X-Ray diffraction (XRD) measurements in order to determine the phase transitions, the crystallinity and the size of theWO3nanoparticles. As a comparison, transmission electron microscope (TEM) was used to investigate the size of the WO3nanoparticles. The result from XRD and DTA show that the formation of polymorphsWO3nanoparticles have the following sequence: orthorhombic (b-WO3)®monoclinic (g-WO3) ®triclinic (d-WO3) ®monoclinic (e-WO3) with respect to the calcination temperature of 400, 500, 600 and 700°C. No diffraction peaks were found in the X-Ray diffraction measurements for …
Mixed - Mode Operating System For Real - Time Performance,
2017
Universiti Brunei Darussalam
Mixed - Mode Operating System For Real - Time Performance, M. Hasan M., S. Sultana, C.K. Foo
ASEAN Journal on Science and Technology for Development
The purpose of the mixed-mode system research is to handle devices with the accuracy of real-time systems and at the same time, having all the benefits and facilities of a matured Graphic User Interface(GUI)operating system which is typicallynon-real-time. This mixed-mode operating system comprising of a real-time portion and a non-real-time portion was studied and implemented to identify the feasibilities and performances in practical applications (in the context of scheduled the real-time events). In this research an i8751 microcontroller-based hardware was used to measure the performance of the system in real-time-only as well as non-real-time-only configurations. The real-time portion is an …
Energy Cost Of Seed Drying,
2017
Universiti Brunei Darussalam
Energy Cost Of Seed Drying, Jittanit Weerachet, Srzednick George, Driscoll Robert
ASEAN Journal on Science and Technology for Development
In this work, the energy costs of drying corn, rice and wheat seeds between 3 drying options were compared. They consisted of 1) two-stage drying by using fluidised beddrye (FBD) in the 1ststage and in-store dryer (ISD) in the 2ndstage, 2) single-stage drying by fixed bed dryer (FXD) and 3) two-stage drying by using FXD in the 1ststage and ISD in the 2ndstage. The drying conditions selected for comparison were proved to be safe for seed viability by the previous studies. The results showed that the drying options 2 and 3 consumed less energy than option 1. However, the benefits …
Study On Moisture-Cur Ed Polyurethane As Undercoating Layer For Metallization,
2017
Universiti Brunei Darussalam
Study On Moisture-Cur Ed Polyurethane As Undercoating Layer For Metallization, Mohamad Ibrahim M.N., Izat M.E., Wahida A.R., Sipaut C.S.
ASEAN Journal on Science and Technology for Development
In this work a technique of metallizing substrate via electroless plating using moisture-cured polyurethane (MCPU) system as the undercoat is presented. MCPU prepolymer was prepared by mixing polyethylene glycol divinyl ether and diphenylmethane-4, 4’-diisocyanate in 1:1 ratio. The effects of etching time as well as curing period on the surface characteristic of MCPU undercoating were investigated. Contact angle measurements, FTIR and SEM were employed to study the changes on the surface of the treated MCPU undercoatsprior to electroless nickel plating. Electroless plating was performed using nickel bath and visual inspection was performed after completing the electroless plating cycles. Relative increase …
A Comparison Of The Push And Pull Production Systems At Their Opti Mal Designs Under The Economic Consideration,
2017
Universiti Brunei Darussalam
A Comparison Of The Push And Pull Production Systems At Their Opti Mal Designs Under The Economic Consideration, Chiadamrong N., Kohly P.
ASEAN Journal on Science and Technology for Development
The term “push” and “pull” have been used to explain a wide variety of production inventory systems. The distinction refers to a specific attribute, which can be identified by observing the mechanisms for controlling material flow on the shop floor and a specific policy for the management of inventories and production schedules. This paper gives an attempt to compare these systems under their optimal settings under a constraint resource. Two optimal-seeking methods (Taguchi method and Response Surface Methodology) are used to suggest the optimized design of the system under an economic term, which is the profit generated from the system. …
Studies On Fucoidan And Its Production From Vietnamese Brown Seaweeds,
2017
Universiti Brunei Darussalam
Studies On Fucoidan And Its Production From Vietnamese Brown Seaweeds, Minh Ly Bui, Quoc Buu Ngo, Duy Nhut Nguyen, Duc Thinh Pham, Thi Thanh Van Tran
ASEAN Journal on Science and Technology for Development
Sulfated fucans are among the most widely studied of all the sulfated polysaccharides of plant origin that exhibit biological activities in mammalian systems. In this report fucoidans from some Vietnamese Sargassumspecies such as S.polycystum, S.oligocystum, S.mcclurei, S. Swartzii and denticaprum were extracted and fractionated on a DEAE-Sephadex A-25 column. On the basis of chemical and spectral analyses, the fucoidan fractions obtained were found to be the sulfated fucogalactans containing sulfate ester groups and uronic acid, and composed essentially of fucose and galactose, as well as a minor amount of other sugars. The polysaccharide fractions were tested for anticancer activity. The …
Medium Optimization For The Production Of Biomass By Cunninghamella Sp. 2a1 Using Response Surface Methodology,
2017
Universiti Brunei Darussalam
Medium Optimization For The Production Of Biomass By Cunninghamella Sp. 2a1 Using Response Surface Methodology, Sulaiman Siti Aminah, Hamid Aidil Abdul, Yusoff Wan Mohtar Wan
ASEAN Journal on Science and Technology for Development
A statistical design approach has been used to optimize the production of biomass byCunninghamellasp. 2A1, evaluated based on lipidless biomass. A 23full factorial centralcomposite design (CCD) was chosen to study the combined effects of three factors; ammoniumtartrate, peptone and glucose concentrations. The p-value for each factors was < 0.05 suggestingthat these factors have significant effect on the production of lipidless biomass. The productionis represented by a linear model with p-value < 0.0001. The optimized medium consists of 3.86g/l ammonium tartrate, 55.84 g/l glucose and 7.73 g/l peptone predicted 16.83 g/l lipidlessbiomass. Results from four replications based on the optimized medium produced 18.48 g/llipidless biomass, which are in close agreementwith the predicted value. The coefficient forglucose was the highest indicating it as the most significant factoraffecting lipidless biomassproduction.
Spot Welding Copper - 1% Cr Electrode Tips Produced Via Equal Chan Nel Angular Pressing,
2017
Universiti Brunei Darussalam
Spot Welding Copper - 1% Cr Electrode Tips Produced Via Equal Chan Nel Angular Pressing, Hussain L.B., Aljuboury Ali A., Gebril M.A.M., Sharif Nurulakmal Moh
ASEAN Journal on Science and Technology for Development
A sharp 120o Equal channel angular pressing (ECAP) was applied at room temperature to refine the grains sizes of pure copper and copper - 1% Chromium alloy for spot welding electrode tips application. Initially deformation behavior was investigated with the position using colorful plasticine as work piece followed by copper alloy. It was found the deformation at the central part of the work piece is heavily sheared than the outer part. Optical and Scanning electron microscopy were used to study the progress of grain refining under the influence of rotation and number of passes during pressing. The influence of elongated …
Suitability Of Sago Starch Blended With Acrylamide As An Additive On Handsheets Made From Recycled Pulp Fibers,
2017
Universiti Brunei Darussalam
Suitability Of Sago Starch Blended With Acrylamide As An Additive On Handsheets Made From Recycled Pulp Fibers, Sin Yeng Wong, Tahir Paridah Md., Kang Chiang Liew
ASEAN Journal on Science and Technology for Development
This study was carried out to determine the suitability of sago starch blended with acrylamide as paper additive. Solutions of unmodified and blended sago starch with acrylamide, were prepared at 5% weight over volume (w/v) basis before the basic properties (i.e., pH, viscosity and solid content) were determined. Thestarches were thenused to coat on laboratory made handsheets from recycled pulps. Various effects were studied, namely, modification of sago starch, addition of different types of initiator and further curing at different temperatures. The incorporation of acrylamide into sago starch through blending signif icantly increased the pH and viscosity of the solutions. …
The Effects Of Palmvitee On Human Nasal Septal Chondrocytes Culture Expansion And Cartilage Reconstruction,
2017
Universiti Brunei Darussalam
The Effects Of Palmvitee On Human Nasal Septal Chondrocytes Culture Expansion And Cartilage Reconstruction, Ruszymah B.H.I., Aminuddin B.S., Gapor A., Fuzina H.
ASEAN Journal on Science and Technology for Development
Palmvitee may act as a beneficial supplement to cartilage tissue engineering which is currently still has certain limitation on chondrocyte expansion and dedifferentiation. Our objectives in thisstudy were to evaluate the effects of Palmvitee on the growth kinetic and phenotype gene expression of human nasal septal chondrocytesin monolayer expansion as well as cartilage reconstruction via tissue engineering technology. Human chondrocytes were cultured inmediums containing various Palmvitee concentrations. Among the different test groups, the medium containing Palmvitee at 3 μg/ml supported the highest chondrocyte growth rate. The gene expression in monolayer chondrocytes culture supplemented with 3 μg/ml Palmviteedemonstrated similar results as …
