An omnidirectional retroreflector based on the transmutation of dielectric singularities (2009)
Ma, Yun Gui, Ong, C. K., Tyc, Tomas, Leonhardt, Ulf
In the field of transformation optics, metamaterials mimic the effect of coordinate transformations on electromagnetic waves, creating the illusion that the waves are propagating through a virtual...
We experimentally verified the phenomena of photonic jets generated by plane-electromagnetic-wave-illuminated dielectric micro-cylinders with diameter comparable to the corresponding wavelength at...
Water Infiltration, Conductivity and Runoff under Fallow Agroforestry on Sloping Terraces (2009)
Siriri, D, Tenywa, M.M, Ong, C.K, Black, C.R, Bekunda, M.A
Appropriate management of available water supplies is essential to prolong the growing season and optimize the effectiveness with which rainfall is used for agricultural production. The present study...
C. K. Ong, K. T. Cheng, Carsten Wegener, Michael Peter Kennedy
pp. 237–246.
Visual Observation and Quantitative Measurement of the Microwave Absorbing Effect at X band (2008)
Zhao, L., Chen, X., Ong, C. K.
We have setup a simple field mapping measure system to describe graphically the 2D quasi-free-space electromagnetic wave in a parallel plate waveguide at the X-band frequencies. Our apparatus...
Zhao, L., Ma, Y. G., Ong, C. K.
In this paper, we discussed the current experiments on the tunneling effect of electromagnetic energy through narrow channels of $\epsilon$-near-zero(ENZ) medium in the microwave range. Using the...
Water use of tree lines: importance of leaf area and micrometeorology in sub-humid Kenya (2006)
Radersma, S., Ong, C.K., Coe, R.
In this research the relative importance of leaf area and microclimatic factors in determining water use of tree lines was examined in sub-humid Western Kenya. Measurements of tree water-use by a...
Nernst Effect and Superconducting Fluctuations in Zn-doped YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ (2005)
Xu, Z. A., Shen, J. Q., Zhao, S. R., Zhang, Y. J., Ong, C. K.
We report the measurements of in-plane resistivity, Hall effect, and Nernst effect in Zn doped YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ epitaxial thin films grown by pulsed laser deposition technique. The...
Evaporation from soils below sparse crops in contour hedgerow agroforestry in semi-arid Kenya (2005)
Kinama, J.M., Stigter, C.J., Ong, C.K., Ng'ang'a, J.K., Gichuki, F.N.
In many agricultural systems in the semi-arid tropics, crops use only a small fraction of the total rainfall. Agroforestry can greatly reduce some losses, especially on hill slopes, where soil...
Theory of Upper Critical Field without Energy Quantization (2004)
Wang, L., Lim, H. S., Ong, C. K.
Conventional theories for determining upper critical fields are inevitably related to the lowest eigenvalues of appropriate equations. In this Letter, a new theory of upper critical fields is...
Stigter, C.J., Mungai, D.N., Ong, C.K., Kinama, J.M., Oteng'i, S.B.B.
Alley cropping tested by Mungai et al. on flat land, with prunings incorporated into the soil and one in every four rows of maize replaced by trees in the agroforestry plots, showed already in the...
In-Plane Magnetic Anisotropy In RF Sputtered Fe-N Thin Films (2003)
Nie, H. B., Xu, S. Y., Ong, C. K., Zhan, Q., Li, D. X., Wang, J. P.
We have fabricated Fe(N) thin films with varied N2 partial pressure and studied the microstructure, morphology, magnetic properties and resistivity by using X-ray diffraction, atomic force...
Temperature Dependence of Resistivity of $Sr_2CoMoO_{6-\delta}$ Films (2003)
Yuan, C. L., Zeng, Z. Y., Zhu, Y., Ong, P. P., Shen, Z. X., Ong, C. K.
We investigate the temperature dependence of the resistivity and magnetoresistance of a polycrystalline $Sr_2CoMoO_{6-\delta}$ film deposited on (100)-$SrTiO_3$ substrate prepared by the pulsed laser...
Nie, H. B., Xu, S. Y., Wang, S. J., You, L. P., Yang, Z., Ong, C. K., ...
TaN thin film is an attractive interlayer as well as a diffusion barrier layer in [FeN/TaN](n) multilayers for the application as potential write-head materials in high-density magnetic recording. We...
Magnetic anisotropy and magnetoresistance of sputtered [(FeTaN)/(TaN)](n) multilayers (2003)
Nie, H. B., Xu, S. Y., Li, J., Ong, C. K., Wang, J. P.
We studied the in-plane magnetic anisotropy of rf (radio frequency) sputtered [(FeTaN)/(TaN)](n) multilayers synthesized on Si substrates. In the multilayers where n=5, the FeTaN thickness is fixed...
Evolution of In-Plane Magnetic Anisotropy In Sputtered FeTaN/TaN/FeTaN Sandwich Films (2003)
Nie, H. B., Ong, C. K., Wang, J. P., Li, Z. W.
FeTaN/TaN/FeTaN sandwich films, FeTaN/TaN and TaN/FeTaN bilayers were synthesized by using RF magnetron sputtering. The magnetic properties, crystalline structures, microstructures and surface...
Chong, K. B., Kong, L. B., Chen, LinFeng, Yan, L., Tan, C. Y., Yang, T., ...
Al2O3-Ba0.5Sr0.5TiO3 (Al2O3-BST) thin films, with different Al2O3 contents, were deposited on (100) LaAlO3 substrate by pulsed laser deposition (PLD) technique. The Al2O3-BST films was demosnstrated...
Pulsed Laser Deposition of LaAlO3-Ba0.5Sr0.5TiO3 Thin Films for Tunable Device Applications (2003)
Kong, L. B., Yan, L., Chong, K. B., Tan, C. Y., Chen, L. F., Ong, C. K.
LaAlO3-Ba0.5Sr0.5TiO3 (LAO-BST) thin films, with different LAO contents, were deposited on Pt/Ti/SiO2/Si and (100) LaAlO3 substrate, via a pulsed laser deposition (PLD). Phase composition and...
Subwavelength imaging by a left-handed material superlens (2003)
In this work, finite-difference time-domain (FDTD) method is employed to justify the superlensing effect of left-handed material (LHM) slabs. Our results demonstrate that subwavelength resolution can...
Amplification of evanescent waves in a lossy left-handed material slab (2003)
We carry out finite-difference time-domain (FDTD) simulations, with a specially-designed boundary condition, on pure evanescent waves interacting with a lossy left-handed material (LHM) slab. Our...
Water and nitrogen dynamics in rotational woodlots of five tree species in western Tanzania (2003)
Nyadzi, G.I., Janssen, B.H., Otsyina, R.M., Booltink, H.W.G., Ong, C.K., Oenema, O.
The objective of this study was to compare the effects of woodlots of five tree species, continuous maize (Zea mays L.) and natural fallow on soil water and nitrogen dynamics in western Tanzania. The...
Magneto- and Electrotransport Properties of Nd0.67Sr0.33Mn1-xFexO3 (x = 0.00, 0.05) (2002)
Simultaneous studies on the magnetic and electrotransport properties of Nd_{0.67} Sr_{0.33} Mn_{1-x} Fe_x O_3 polycrystalline bulk and epitaxial thin films (x = 0.00 and 0.05) have been carried out....
Determinations of upper critical field in the c-a plane (2002)
Wang, L., Lim, H. S., Ong, C. K.
Within a continuous Ginzburg-Landau model for layered superconductors, two procedures are proposed to determine the upper critical field parallel to the $c$-$a$ crystal plane with an angle $\theta$...
Determinations of upper critical field in continuous Ginzburg-Landau model (2002)
Wang, L., Lim, H. S., Ong, C. K.
Novel procedures to determine the upper critical field $B_{c2}$ have been proposed within a continuous Ginzburg-Landau model. Unlike conventional methods, where $B_{c2}$ is obtained through the...
Properties of parallel upper critical field within Continuous Ginzburg-Landau model (2002)
Wang, L., Lim, H. S., Ong, C. K.
In this paper, we employ a continuous Ginzburg-Landau model to study the behaviors of the parallel upper critical field of an intrinsically-layered superconductor. Near $T_c$ where the order...
Reversible Structural Transition in Epitaxial Manganite Film (2001)
Zhan, Q., Yu, R., He, L. L., Li, D. X., Li, J., Xu, S. Y., ...
A reversible structural transition of an epitaxial La2/3Sr1/3MnO3 film deposited on the LaAlO3 substrate has been investigated by means of in situ high-resolution transmission electron microscopy...
Testing Second-order Delta-sigma Modulator Using Pseudo-random Pattern (2001)
C. K. Ong, J. L. Huang, K. T. Cheng
Single-bit second-order delta-sigma modulators are commonly used in high-resolution ADCs. This type of modulator requires high-resolution test stimulus, which is difficult to generate. This paper...
Q-Factor Measurement of Nonlinear Superconducting Resonators (2000)
Rao, X. S., Ong, C. K., Feng, Y. P.
A novel method, which combined a multi-bandwidth measurement and an extrapolation procedure, is proposed for extracting the loaded Q-factor (Q_{L}) with improved accuracy from non-Lorentzian...
Rao, X. S., Ong, C. K., Jin, B. B., Feng, Y. P.
The anomalous decrease in microwave surface resistance, R_{s}, of superconducting YBa_{2}Cu_{3}O_{7-d} (YBCO) thin films in the presence of a low dc magnetic field is studied using a microstrip...
Ong, C. K., Siek, L., Ng, L. S.
Employing multi-stage sigma–delta modulators has provided an effective means of eliminating stability problems while achieving highresolution analog-to-digital conversion. However, component...
Rao, X. S., Ong, C. K., Jin, B. B., Tan, C. Y., Xu, S. Y., Chen, P., ...
We have studied an anomalous microwave (mw) response of superconducting YBa_{2}Cu_{3}O_{7-delta} (YBCO) microstrip resonators in the presence of a weak dc magnetic field, H_{dc}. The surface...
Oh, K. H., Le Gressus, C., Gong, H., Ong, C. K., Tan, B. T. G.
Scanning electron microscopy is used to study dielectric relaxation processes in alpha-SiO2 by measuring the leakage current in the sample surrounded by a metallic aperture. A transient time of a few...
Ong, C. K., Tan, H. S., Sin, E. H.
Authors are with Dept. of Physics, National Univ. of Singapore, Singapore.
The Response of Groundnut (Arachis hypogaea L.) to Timing of Irrigation (1989)
STIRLING, C. M., ONG, C. K., BLACK, C. R.
A timing-of-irrigation experiment was conducted in controlled-environment glasshouses, in which a finite quantity of water was applied to four stands of groundnut (Arachis hypogaea L.) at different...
STIRLING, C. M., BLACK, C. R., ONG, C. K.
Finite quantities of water were applied at different growth stages of groundnut stands (Arachis hypogaea L.) grown in controlled environment glasshouses. Soil moisture deficits were imposed between...
MOHAMED, H. A., CLARK, J. A., ONG, C. K.
Mohamed, H. A., Clark, J. A. and Ong, C. K. 1988. Genotypic differences in the temperature responses of tropical crops. I. Germination characteristics of groundnut (Arachis hypogaea L.) and pearl...
MOHAMED, H. A., CLARK, J. A., ONG, C. K.
Mohamed, H. A., Clark, J. A. and Ong, C. K. 1988. Genotypic differences in the temperature responses of tropical crops. II. Seedling emergence and leaf growth of groundnut (Arachis hypogaea L.) and...
MOHAMED, H. A., CLARK, J. A., ONG, C. K.
Mohamed, H. A., Clark, J. A. and Ong, C. K. 1988. Genotypic differences in the temperature responses of tropical crops. III. Light interception and dry matter production of pearl millet (Pennisetum...
Responses to Saturation Deficit in a Stand of Groundnut (Arachis hypogaea L.) 1. Water Use (1987)
Stands of groundnut were grown in computer-controlled glasshouses on water stored in an undisturbed soil profile. The maximum saturation vapour pressure deficit (D) of the air was either 1.0, 2.0,...
ONG, C. K., SIMMONDS, L. P., MATTHEWS, R. B.
Stands of groundnut were grown in four glasshouses with the maximum saturation deficit (D) of the air limited to 1.0, 2.0, 2.5 or 3.0 kPa. The soil was near field capacity when plants emerged and no...
The development of individual tillers in stands of pearl millet was investigated in a suite of temperature-controlled glasshouses maintained at mean air temperatures of 19, 22, 25, 28 and 31 �C....
The partitioning of dry matter to stems, leaves and pods of groundnut was examined as a function of mean air temperature and water stress. Different levels of stress were imposed by growing plants on...
An index which incorporates rates of plant growth and of development—a thermal interception rate (TIR)/is used to analyse final spikelet and grain number in pearl millet. Growth rate was...
The leaf extension rate of millet plants was measured with auxanometers in temperature-controlled glasshouses. Temperature was the dominant environmental factor governing the rate of leaf extension....
Thermal time is used to analyse hourly differences in leaf extension rate of pearl millet. The procedure enables the effects of the environment on leaf extension to be examined when temperature is...
SQUIRE, G. R., BLACK, C. R., ONG, C. K.
This paper describes how the dominant relation between leaf extension and temperature in pearl millet is modified by atmospheric saturation vapour pressure deficit (SD) and irradiance. Stands of...
The rate/temperature relation of several developmental processes in groundnut was examined in a suite of temperature-controlled glasshouses maintained at mean air temperatures of 19, 22, 25, 28...
Environmental Control of a Glasshouse Suite for Crop Physiology (1983)
MONTEITH, J. L., MARSHALL, B., SAFFELL, R. A., CLARKE, D., GALLAGHER, J. N., GREGORY, P. J., ...
Five commercial glasshouses, each with a floor area of 10 m × 5 m, are equipped for control of temperature, humidity, carbon dioxide concentration and ventilation rate using a PDP 11 computer....
Response to Temperature in a Stand of Pearl Millet (Pennisetum typhoides S. & H. ) (1983)
Stands of millet were grown in temperature-controlled glasshouses maintained at mean air temperatures of 19-31 °C and sub-plots were heated or cooled to examine the effect of soil temperature on...
Response to Temperature in a Stand of Pearl Millet (Pennisetum typhoides, S. & H.): (1983)
Spikelet production and the duration of the early and late reproductive phases of millet plants were measured at five mean air temperatures (ranging from 19-31 °C) in temperature-controlled...
The Growth and Survival of Severely-shaded Tillers in Lolium perenne L. (1979)
The effect of shading a single tiller to below its compensation point for a period of 5 weeks in vegetative plants of Lolium perenne L. cv. S23, was studied in two different experiments each...
Assimilation of 14CO2 by the Inflorescence of Poa annua L. and Lolium perenne L. (1978)
ONG, C. K., COLVILL, K. E., MARSHALL, C.
The relative assimilatory activity of the inflorescence, its individual components, and the leaves of flowering tillers of Poa annua L. and Lolium perenneL. was determined over the period from...
Physiological aspects of flowering in grasses with special reference to Poa Annua L. (1975)
Thesis (Ph. D.).
Thesis (doctoral)--University of Wales, 1975.
Ong, C K, Chan, S Y, Campo, M S, Fujinaga, K, Mavromara-Nazos, P, Labropoulou, V, ...
Papillomaviruses are an ideal model system for the study of DNA virus evolution. On several levels, phylogenetic trees of papillomaviruses reflect the relationship of their hosts. Papillomaviruses...
Chan, S Y, Bernard, H U, Ong, C K, Chan, S P, Hofmann, B, Delius, H
Papillomaviruses are attractive models for studying the molecular evolution of DNA viruses because of the large number of isolates that exhibit genomic diversity and host species and tissue...
Chan, S Y, Ho, L, Ong, C K, Chow, V, Drescher, B, Dürst, M, ...
We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval...
Ong, C K, Chan, S Y, Campo, M S, Fujinaga, K, Mavromara-Nazos, P, Labropoulou, V, ...
Papillomaviruses are an ideal model system for the study of DNA virus evolution. On several levels, phylogenetic trees of papillomaviruses reflect the relationship of their hosts. Papillomaviruses...
Chan, S Y, Bernard, H U, Ong, C K, Chan, S P, Hofmann, B, Delius, H
Papillomaviruses are attractive models for studying the molecular evolution of DNA viruses because of the large number of isolates that exhibit genomic diversity and host species and tissue...
Chan, S Y, Ho, L, Ong, C K, Chow, V, Drescher, B, Dürst, M, ...
We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval...
Tree-crop interactions: manipulation of water use and root function
Ong, C. K., Wilson, J., Deans, J. D., Mulayta, J., Raussen, T., Wajja-Musukwe, N.
Muthuri, C.W., Ong, C.K., Black, C.R., Mati, B.M., Ngumi, V.W., Van-Noordwijk, M.
The WaNuLCAS (Water, Nutrient and Light Capture in Agroforestry Systems) model was used to investigate the impact of tree leafing phenology on the growth and water use of selected agroforestry tree...