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751.
Zaharudin?AhmadEmail author Zal?U’yun?Wan Mahmood Hidayah?Shahar Mei?Wo?Yii Ahmad?Sanadi?Abu Bakar 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):329-334
Large volumes of surface seawater samples were collected from thirty locations in the Exclusive Economic Zone (EEZ) of the
east coast Peninsular Malaysia on June 2008 to study the activity concentrations of 137Cs. The results will serve as additional information to the existing baseline data and is very useful for monitoring fresh
input of anthropogenic radionuclide into Malaysian marine environment. In this study, the activity concentrations of 137Cs were determined using co-precipitation technique, followed by Gamma Spectrometry measurement. The mean activity concentration
of 137Cs ranged between 3.40 and 5.89 Bq/m3. Higher activity concentrations were observed at the coastal and towards the south of Peninsular Malaysia and were aligned
with the high turbidity. These may due to the rapid diffusion of 137Cs from suspended particulates and fine sediments into surface seawater. The activity concentrations of 137Cs observed in this study were slightly higher than the concentrations reported in seawater at the Straits of Malacca, Vietnam
and Philippines. This might be because the study area received more input of 137Cs that originated from global fallout and then deposited on land which later being transported subsequently into the coastal
zone due to siltation and erosion processes. It could also be attributed to the intrusion of river waters containing higher
concentrations of 137Cs. 相似文献
752.
Bromodimethylsulfonium bromide acts as an efficient catalyst for one pot three component condensation reactions of aldehydes, 2-naphthol, and thiols in acetonitrile at room temperature. Various aliphatic and aromatic thiols undergo conjugate addition with in situ generated enone in acetonitrile and provide good yields. The main features of this procedure are mild reaction conditions, good yields, and operational simplicity. 相似文献
753.
Shafiquzzaman Siddiquee Nor Azah Yusof Abu Bakar Salleh Soon Guan Tan Fatimah Abu Bakar 《Mikrochimica acta》2011,172(3-4):357-363
An electrochemical DNA biosensor was developed that is based on a gold electrode modified with a nanocomposite membrane made from an ionic liquid, ZnO nanoparticles and chitosan. A single-stranded DNA probe was immobilized on this electrode. Acridine orange was used as the hybridization probe for monitoring the hybridization of the target DNA. The biosensor was capable of detecting target DNA in the concentration range from 1.0?×?10?C14 to 1.8?×?10?C4?mol?L-1, with a detection limit of 1.0?×?10?C15?mol?L-1. The approach towards constructing a DNA biosensor allows studies on the hybridization even with crude DNA fragments and also to analyze sample obtained from real samples. The results show that the DNA biosensor has the potential for sensitive detection of a specific sequence of the Trichoderma harzianum gene and provides a quick, sensitive and convenient method for the study of microorganisms. Figure
Suggested interaction mechanism of modified electrode (IL/ZnO/CHIT/AuE) between immobilization and hybridization 相似文献
754.
Composition Dependence of Surface Phonon Polariton Mode in Wurtzite InxGa1-xN (0≤x≤1) Ternary Alloy 下载免费PDF全文
We present a theoretical study on the composition dependence of the surface phonon polariton (SPP) mode in wurtzite structure α-InxGa1-xN ternary alloy over the whole composition range. The SPP modes are obtained by the theoretical simulations by means of an anisotropy model. The results reveal that the SPP mode of α-InxGa1-xN semiconductors exhibits one-mode behaviour. From these data, composition dependence of the SPP mode with bowing parameter of -28.9cm-1 is theoretically obtained.. 相似文献
755.
Abdulaziz M. Al-Hetar Abu Sahmah M. Supa’at A.B. Mohammad I. Yulianti 《Optics Communications》2008,281(23):5764-5767
A 2 × 2 MZI-MMI switch based on thermo-optic effect with a ridge in the silicon substrate was proposed and the performance of switch was simulated. The main purpose behind this change in substrate layer is to localize the heating at a heated arm single mode waveguide and limit the increasing temperature at a second one. The switch performance of the device should be improved, compare to the usual one. Using finite difference beam propagation method (FD-BPM) and thermal computing simulation based on finite element method (FEM), the results clearly indicate that the MZI-MMI switch can satisfy −31 dB crosstalk at two states. 相似文献
756.
利用等离子辅助分子束外延系统研究了生长在硅(111)衬底的氮化镓pn结,并将其应用于光学器件.硅和镁分别用做n和p掺杂,反射高能电子衍射图像显示氮化镓pn结层具有良好的表面形貌,结层厚度约为0.705 nm,且为六方结构.室温下X射线衍射对称摇摆曲线中(0002)面的ω/2θ显示,半峰宽为0.340,说明氮化镓pn结质量高.另外,在硅和镁掺杂样品中没有A1峰淬灭.光致发光光谱表明pn结样品具有良好的光学性能.镍和铝作为分别作为正面和背面的电极接触应用于光学器件,该器件的电流电压特性显示了典型的异质结整流特性.正向接触镍经过氮气中退火处理10 min,结果表明,600 oC处理的样品比400 oC处理和未经处理的样品具有更高的增益. 相似文献
757.
N. Md. Yusoff M. H. Abu Bakar S. J. Sheih F. R. Mahamd Adikan M. A. Mahdi 《Laser Physics》2010,20(8):1747-1751
Erbium-doped fiber amplifier with flat gain over 30 nm bandwidth is demonstrated using flexible selective band methods. The
band optical amplifier was designed to cater 44 wavelength division multiplexing channels which were separated into bands
of 4 nm. Without using any gain flattening filter, the gain of optical amplifier was maintained at 19 dB with a maximum gain
variation of less than 1.6 dB even though the input signal power was varied from −19 to −6 dBm. The amplifier was able to
maintain 1 dB gain flatness with 83% chance for any selective bands of 4 nm within the wavelength range from 1530 to 1565
nm. This feature is very attractive to support band optical networks. 相似文献
758.
Bidhan Pandit Emad S.Goda Mahmoud H.Abu Elella Aafaq ur Rehman Sang Eun Hong Sachin R.Rondiya Pranay Barkataki Shoyebmohamad F.Shaikh Abdullah M.Al-Enizi Salah MEl-Bahy Kuk Ro Yoon 《Journal of Energy Chemistry》2022,(2):116-126
An eco-friendly, new, and controllable approach for the preparation of manganese oxide(a-MnO2) nanorods has been introduced using hydrothermal reaction for supercapacitor application. The in-depth crystal structure analysis of α-MnO2 is analyzed by X-ray Rietveld refinement by using Full Prof program with the help of pseudo-Voigt profile function. The developed a-MnO2 electrode attains a remarkable capacitance of 577.7 F/g recorded at a current density value of 1... 相似文献
759.
Tahani A. Alrebdi Amir Fayyaz Haroon Asghar Samira Elaissi Lamia Abu El Maati 《Molecules (Basel, Switzerland)》2022,27(15)
We report a quantitative analysis of various plant-biochar samples (S1, S2 and S3) by utilizing a laser-induced breakdown spectroscopy (LIBS) technique. For LIBS analysis, laser-induced microplasma was generated on the target surface by using a focused beam through a high-power Nd: YAG laser and optical emission spectra were recorded using a charged coupled device (CCD) array spectrometer, with wavelength ranges from 200 nm to 720 nm. The spectroscopical analysis showed the existence of various ingredients, including H, Li, Ca, Na, Al, Zn, Mg, Sr, Si, and Fe, along with a CN molecular emission band due to B2Σ+ − X2Σ+ electronic transition. By assuming conditions of the plasma is optically thin and in LTE, calibration-free laser-induced breakdown spectroscopy (CF-LIBS) was utilized for the compositional analysis of the ingredients present in the three plant-biochar samples. To lower the uncertainties, we used an average composition (%) of the three plant-biochar samples. The quantitative study of the plant-biochar samples was also achieved using the energy dispersive X-ray (EDX) technique, showing good agreement with the CF-LIBS technique. In addition, statistical analysis, such as principal component analysis (PCA), was performed for the clustering and classification of the three plant-biochar samples. The first three PCs explained an overall ~91% of the variation in LIBS spectral data, including PC1 (58.71%), PC2 (20.9%), and PC3 (11.4%). These findings suggest that LIBS is a robust tool for rapid measurement of heavy as well as light elements, such as H, Li, and nutritional metals in plant-biochar samples. 相似文献
760.
Mohamed R. El-Aassar Ahmed K. Alezbaway Ibrahim O. Althobaiti Mohamed Y. El-Sayed Hend S. Abu Salem Hassan M. A. Hassan Rawan F. Alolaimi Emam F. El Agammy Mohamed S. Mohy-Eldin Fathy M. Mohamed 《Molecules (Basel, Switzerland)》2022,27(21)
The arsenic (As) pollution of water has been eliminated via intensive scientific efforts, with the purpose of giving safe drinking water to millions of people across the world. In this study, the adsorption of As(V) from a synthetic aqueous solution was verified using a Bentonite-Anthracite@Zetag (BT-An@Zetag) composite. The SEM, FT-IR, XRD, DSC, TGA, and SBET techniques were used to characterize the (BT-An@Zetag) composite. The adsorption of As(V) was explored using batch adsorption under varied operating scenarios. Five kinetic modelswere used to investigate kinetic data, whereas three isotherms had been used to fit empirical equilibrium data. According to the findings, the adsorption mechanism of As(V) was best described by the Freundlich isotherm with a maximum monolayer coverage of 38.6 mg/g showing pseudo-second-order mode. The estimated enthalpy (H°) indicates that the adsorption process is both chemical and endothermic.The calculated free energy (G°) indicates that the reaction is nonspontaneous. After four sequential adsorption cycles, the produced BT-An@Zetag composite demonstrated good reusability and a greater adsorption affinity for As(V) ions. Overall, the BT-An@Zetag composite is suited for removing arsenic from wastewater using adsorption as a cost-effective and efficient technique. 相似文献