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Search Results: 1 - 10 of 30001 matches for " Chin Kui Cheng "
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Hydrogen as Carbon Gasifying Agent During Glycerol Steam Reforming over Bimetallic Co-Ni Catalyst  [PDF]
Chin Kui Cheng, Rwi Hau Lim, Anabil Ubil, Sim Yee Chin, Jolius Gimbun
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B043
Abstract: Alumina-supported bimetallic cobalt-nickel catalyst has been prepared and employed in a fixed-bed reactor for the direct production of synthesis gas from glycerol steam reforming. Physicochemical properties of the 5Co-10Ni/85Al2O3 catalyst were determined from N2-physisorption, H2-chemisorption, CO2 and NH3-temperature-programmed desorption measurements as well as X-ray diffraction analysis. Both weak and strong acid sites are present on the catalyst surface. The acidic:basic ratio is about 7. Carbon deposition was evident at 923 K; addition of H2 however has managed to reduce the carbon deposition. Significantly, this has resulted in the increment of CH4 formation rate, consistent with the increased carbon gasification and methanation. Carbon deposition was almost non-existent, particularly at 1023 K. In addition, the inclusion of hydrogen also has contributed to the decrease of CO2 and increase of CO formation rates. This was attributed to the reverse water-gas-shift reaction. Overall, both the CO2:CO and CO2:CH4 ratios decrease with the hydrogen partial pressure.
Biodiesel Production from Rubber Seed Oil Using A Limestone Based Catalyst  [PDF]
Jolius Gimbun, Shahid Ali, Chitra Charan Suri Charan Kanwal, Liyana Amer Shah, Nurul Hidayah Muhamad Ghazali, Chin Kui Cheng, Said Nurdin
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B036
Abstract:

This paper presents the potential of limestone based catalyst for transesterification of high free fatty acid (FFA) rubber seed oil (RSO). Pre-calcinated limestone known as clinker was activated using methanol and transesterification was performed under reflux with constant stirring. Mineral composition of the catalyst was analysed using x-ray fluorescence (XRF) with in build x-ray diffraction (XRD). The rubber seed oil was obtained using both microwave and soxhlet extraction using hexane as solvent. FFA content and fatty acid methyl ester content were determined using gas chromatography mass spectrometry (GC-MS). The results showed an efficient conversion (up to 96.9%) of high FFA rubber seed oil to biodiesel. The results suggest that the catalyst employed in this work is not negatively affected by moisture and free fatty acids and can be recycled very easily without significant loss in its activity. The highest conversion of 96.9% was achieved from catalyst activated at 700°C, with catalyst loading of 5 wt. %; methanol to oil molar ratio of 5:1; reaction temperature of 65°C and reaction time of 4 hours. The biodiesel produced in this work is within the limits of specification described by American standard test method (ASTM D6751).


Tanshinone IIA Could Inhibit Pancreatic Cancer BxPC-3 Cells through Increasing PERK, ATF6, Caspase-12 and CHOP Expression to Induce Apoptosis  [PDF]
Chin-Cheng Su
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.83015
Abstract: Tanshinone IIA (Tan-IIA) is extracted from Dan-Shen. Tan-IIA could inhibit human pancreatic cancer BxPC-3 cells through decreasing TCTP, Mcl-1 and Bcl-xl expression in vitro. Our previous study showed that Tan-IIA can inhibit hepatocellular carcinoma hep-J5 cells and human breast cancer BT-20 cells through inducing endoplasmic reticulum (ER) stress. In the present study, we investigated the ER stress related protein expressions in human pancreatic cancer BxPC3 cells were treated with Tan-IIA. The ER stress related protein expressions in human pancreatic cancer BxPC-3 cells were evaluated by western blotting. The results showed that Tan-IIA can increase the protein expressions of PERK, ATF6, Caspase-12 and CHOP, but decrease Bip, PDI, Calnexin, Calreticulin and Bcl-2 expression. These findings indicated that Tan-IIA can inhibit human pancreatic cancer BxPC-3 cells by inducing ER stress to induce apoptosis.
Universal scaling of Efimov resonance positions in cold atom systems
Cheng Chin
Physics , 2011,
Abstract: Recent cold atom experiments report a surprising universal scaling of the first Efimov resonance position a_{-}^1 by the two-body van der Waals length r_{vdW}. The ratio C=-a_{-}^1/r_{vdW}=8.5~9.5 for identical particles appears to be a constant regardless of the atomic spin configuration, the Feshbach resonance employed to tune the scattering length, and even the atomic species, with K-39 being the only exception. This result indicates that the Efimov energy structure is insensitive to the details of the short range potential. We suggest that the universality results from the quantum reflection of the Efimov wavefunciton by the short-range molecular potential. Assuming Born-Oppenheimer approximation and strong quantum reflection, we obtain an analytic result of C=9.475... for three identical particles. We suspect the exceptional case of K-39 is a result of resonant coupling between the Efimov state and a short-range molecular state.
A simple model of Feshbach molecules
Cheng Chin
Physics , 2005,
Abstract: We present a two-channel model to describe the quantum state of two atoms with finite-range interaction near a Feshbach resonance. This model provides a simple picture to analytically derive the wave function and the binding energy of the molecular bound state. The results agree excellently with the measurements and multichannel calculations. For small binding energies, the system enters a threshold regime in which the Feshbach molecules are identical to long range atom pairs in single channel. According to their threshold behavior, we find Feshbach resonances can be classified into two types.
A simple mean field equation for condensates in the BEC-BCS crossover regime
Cheng Chin
Physics , 2004, DOI: 10.1103/PhysRevA.72.041601
Abstract: We present a mean field approach based on pairs of fermionic atoms to describe condensates in the BEC-BCS crossover regime. By introducing an effective potential, the mean field equation allows us to calculate the chemical potential, the equation of states and the atomic correlation function. The results agree surprisingly well with recent quantum Monte Carlo calculations. We show that the smooth crossover from the bosonic mean field repulsion between molecules to the Fermi pressure among atoms is associated with the evolution of the atomic correlation function.
Atherosclerosis in the elderly: a heavy burden to bear

Sze Piaw Chin,Kui Hian Sim,

老年心脏病学杂志(英文版) , 2005,
Abstract: The World Health Organization estimates there are over thirty-two million major atherothrombotic events oc-cur worldwide each year with nearly seventeen million di-rectly attributable deaths.' Atherothrombosis as the name refers to blood clot formation within an arterial vessel. It may occur de novo, usually over an atherosclerotic seg-ment of the vessel, or embolised from a proximal source." These clots cause the blood vessel lumen to be-come totally or sub-totally occluded and, depending on the site and supply, lead clinically to unstable angina and myocardial infarction, ischemic strokes or leg claudica-tion. Acute myocardial infarction ( AMI) alone account for 25% of all deaths in the United States and is the leading cause of death in the world including many of the developing countries.3 It is of little suiprise therefore that from the cardiologists' standpoint, the bulk of our work whether as researchers or clinicians have been channeled towards the prevention, regression or at least delaying the process of atherothrombosis and minimizing its risk of re-currence. Yet we must be mindful that atherothrombosis is a generalized and progressive disease. Indeed over a quarter of patients with vascular disease would involve 2 or more vascular beds in their lifetime.4 For example, patients with a first stroke or peripheral arterial disease (PAD) has a 2 to 4-fold increased risk of AMI. Patients who have had an AMI are themselves at 5-fold increased risk of a further heart attack. The life-expectancy of pa-tients with a history of stroke, PAD or myocardial infarc-tion is also reduced.4'5 But to screen all patients with suspected cardiovascular disease for concomitant peripher-al disease would lead to unnecessary risks from longer ra-diation exposure, higher amount of contrast used and costs. Hence the original article by Rigatelli et al in this issue addresses an important issue on which patient scheduled for coronary angiogram should also undergo aorto-iliac studies.6 Indeed the clinical issue of whether it is justified to perform additional scans is also highlighted here.
索引編製芻議 A Proposal for the Index Compilation
Chin-cheng Soong
Journal of Educational Media & Library Sciences , 1977,
Abstract: 無 無
七十年來中文圖書館學著作書目(上) Literatures of Library Science in Chinese in Last Seventy Years(Cont.)
Chin-cheng Soong
Journal of Educational Media & Library Sciences , 1978,
Abstract: 無 無
Thermal equilibrium and efficient evaporation of an ultracold atom-molecule mixture
Cheng Chin,Rudolf Grimm
Physics , 2003, DOI: 10.1103/PhysRevA.69.033612
Abstract: We derive the equilibrium conditions for a thermal atom-molecule mixture near a Feshbach resonance. Under the assumption of low collisional loss, thermodynamical properties are calculated and compared to the measurements of a recent experiment on fermionic lithium experiment. We discuss and evaluate possible collision mechanisms which can lead to atom-molecule conversion. Finally, we propose a novel evaporative cooling scheme to efficiently cool the molecules toward Bose-Einstein condensation.
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