http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
SHIELD DESIGN OF CONCRETE WALL BETWEEN DECAY TANK ROOM AND PRIMARY PUMP ROOM IN TRIGA FACILITY
Khan, M J H,Rahman, M,Ahmed, F U,Bhuiyan, S I,Haque, A,Zulquarnain, A The Korean Association for Radiation Protection 2007 방사선방어학회지 Vol.32 No.4
The objective of this study is to recommend the radiation protection design parameters from the shielding point of view for concrete wall between the decay tank room and the primary pump room in TRIGA Mark-II Research Reactor Facility. The shield design for this concrete wall has been performed with the help of Point-kernel Shielding Code Micro-Shield 5.05 and this design was also validated based on the measured dose rate values with Radiation Survey Meter (G-M Counter) considering the ICRP-60 (1990) recommendations for occupational dose rate limit ($10{\mu}Sv/hr$). The recommended shield design parameters are: (i) thickness of 114.3 cm Ilmenite-Magnetite Concrete (IMC) or 129.54 cm Ordinary Reinforced Concrete (ORC) for concrete wall A (ii) thickness of 66.04 cm Ilmenite-Magnetite Concrete (IMC) or 78.74 cm Ordinary Reinforced Concrete (ORC) for concrete wall B and (iii) door thickness of 3.175 cm Mild Steel (MS) on the entrance of decay tank room. In shielding efficiency analysis, the use of I-M concrete in the design of this concrete wall shows that it reduced the dose rate by a factor of at least 3.52 times approximately compared to ordinary reinforced concrete.
Self-powered transparent flexible graphene microheaters
Khan, U.,Kim, T.H.,Lee, K.H.,Lee, J.H.,Yoon, H.J.,Bhatia, R.,Sameera, I.,Seung, W.,Ryu, H.,Falconi, C.,Kim, S.W. Elsevier 2015 Nano energy Vol.17 No.-
Transparent and flexible (TF) microheaters are required in wearable devices, labs-on-chip, and micro-reactors. Nevertheless, conventional microheaters are rigid or opaque or both. Moreover, the resistances of conventional metallic microheaters are too low to be effectively powered by wearable energy harvesters. Here, we demonstrate the first TF microheaters by taking advantage of chemical vapor deposition (CVD)-grown graphene heating tracks and of a hexagonal boron nitride (h-BN) sheet for passivation; the h-BN sheet increases the maximum temperature by ~80%. Our TF microheaters show excellent temperature uniformity and can reach temperatures above 200<SUP>o</SUP>C in just 4s, with power consumption as low as 39mW. Additionally, since the CVD-graphene sheet resistance is orders of magnitude higher than that of typical metallic heaters, our devices can be effectively powered by wearable energy harvesters. As a proof-of-concept, we demonstrate the first self-powered, wearable microheater which achieves a temperature increase of 8<SUP>o</SUP>C when operated by a sound driven textile-based triboelectric nanogenerator. This is a key milestone towards next generation microheaters with applications in portable/wearable personal electronics, wireless health, and remote and mobile environmental sensors.
Khan, U.A.,Lee, J.G.,Seo, I.J.,Amir, F.,Lee, B.W. North-Holland 2015 Physica. C, Superconductivity Vol.518 No.-
Voltage source converter-based HVDC systems (VSC-HVDC) are a better alternative than conventional thyristor-based HVDC systems, especially for developing multi-terminal HVDC systems (MTDC). However, one of the key obstacles in developing MTDC is the absence of an adequate protection system that can quickly detect faults, locate the faulty line and trip the HVDC circuit breakers (DCCBs) to interrupt the DC fault current. In this paper, a novel hybrid-type superconducting circuit breaker (SDCCB) is proposed and feasibility analyses of its application in MTDC are presented. The SDCCB has a superconducting fault current limiter (SFCL) located in the main current path to limit fault currents until the final trip signal is received. After the trip signal the IGBT located in the main line commutates the current into a parallel line where DC current is forced to zero by the combination of IGBTs and surge arresters. Fault simulations for three-, four- and five-terminal MTDC were performed and SDCCB performance was evaluated in these MTDC. Passive current limitation by SFCL caused a significant reduction of fault current interruption stress in the SDCCB. It was observed that the DC current could change direction in MTDC after a fault and the SDCCB was modified to break the DC current in both the forward and reverse directions. The simulation results suggest that the proposed SDCCB could successfully suppress the DC fault current, cause a timely interruption, and isolate the faulty HVDC line in MTDC.
Common fixed point theorems for compatible and weakly compatible maps in fuzzy cone metric spaces
S. U. Rehman,S. Jabeen,F. Abbas,H. Ullah,I. Khan 원광대학교 기초자연과학연구소 2020 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.19 No.1
In this paper, we present some common fixed theorems for compatible and weakly compatible four self-mappings in fuzzy cone metric spaces in which $h$ is a continuous self-map. We extend and improve some results given in the literature.
Ultra-high capacity hydrogen storage in a Li decorated two-dimensional C2N layer
Hashmi, A.,Farooq, M. U.,Khan, I.,Son, J.,Hong, J. Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.6
<P>Owing to naturally existing uniform periodic pores in two-dimensional (2D) C2N layers, they can be an ideal candidate for hydrogen storage materials among other 2D materials. Here, we explored the potential application of ultra-high capacity hydrogen storage using the first principles method. Remarkably, Li was strongly bonded with the C2N layer via a Kubas-type interaction with a large binding energy of 3-5 eV. This unique interaction does not exist in graphene or other 2D materials, and it rules out the possibility of Li alkali metal cluster formations. We found that the Li-decorated C2N could show a very high theoretical gravimetric density of 13 weight percentage (wt%). Very interestingly, this gravimetric density is not only 40% and 30% higher than those found in MgH2 and C-60 but also significantly higher than the values obtained in alkali metal decorated graphene, MoS2 and phosphorene. Irrespective of the theoretical capacity, the most important physical quantity is the practical capacity (the difference in the number of adsorbed and desorbed hydrogen molecules) under ambient conditions of pressure and temperature. Our thermodynamic analysis showed that 75% of the adsorbed hydrogen molecules could be released under practical conditions of temperature and pressure and the practical capacity is about 10 wt%. Our findings suggest that the Li decorated C2N can be a very promising material for room-temperature hydrogen storage under realistic conditions.</P>
The Recovery, In Vitro Maturation and Fertilization of Nili-Ravi Buffalo Follicular Oocytes
Samad, H.A.,Khan, I.Q.,Rehman, N.U.,Ahmad, N. Asian Australasian Association of Animal Productio 1998 Animal Bioscience Vol.11 No.5
Four types of serum supplements viz. estrus cow serum (ECS), estrus buffalo serum (EBS), pro-estrus buffalo serum (PrBS) and post-estrus buffalo serum (PtBS), added to TCM-199, were evaluated for in vitro maturation and fertilization of buffalo follicular oocytes. The oocytes were recovered from buffalo ovaries after slaughter, using either aspiration or scoring (multiple incisions) method. The recovered oocytes were categorized as A, B and C based on their cumulus investment and ooplasm homogeneity and cultured in four media. The in vitro matured oocytes were inseminated with $1{\times}10^6$ spermatozoa washed in 2.9% sodium citrate solution. The scoring method yielded greater number of morphologically good oocytes than the aspiration method (3.85 vs 1.76 per ovary, p < 0.01). The maturation rates of three categories of oocytes did not differ from one another. The maturation rates of 80.00, 82.08, 78.77 and 66.23%, while the fertilization rates of 54.54, 55.38, 52.80 and 36.76% were recorded for media containing ECS, EBS, PrBS, and PtBS, respectively. The medium containing PtBS gave lower maturation, as well as fertilization, rates than the other three media (p < 0.05). Thus, the scoring method was better than the aspiration method for the recovery of follicular oocytes. The oocytes categorized A, B and C had similar maturation capabilities. The TCM-199 containing buffalo/cow serum collected at pro-estrus or estrus appeared better for in vitro maturation and fertilization of buffalo follicular oocytes than that containing serum collected at post estrus.
Hyun-Joo Kim,Amali U. Alahakoon,Dinesh D. Jayasena,Muhammad I. Khan,남기창,조철훈,정사무엘 한국가금학회 2015 韓國家禽學會誌 Vol.42 No.3
Chicken breast meat samples were injected with marinade solution (salt, sugar, phosphate, monosodium glutamate, and nucleic acid) with or without 2% citrus peel extract (CPE), and then a subset were irradiated with a 1 or 2 kGy electron beam (EB) and/or subjected to high-pressure (HP) at 300 or 400 MPa. The initial total aerobic bacterial (TAB) count of the control sample was 4.57 log CFU/g and reached 7.17 log CFU/g after 3 days of storage at 4°C. The 2 kGy EB reduced the TAB count to 4.61 log CFU/g after 7 days. The 400 MPa HP treatment was also effective in reducing the TAB count, but the effect was slightly less than that noted with the 2 kGy EB. The CPE, in combination with the EB and HP, decreased the TAB count by 1.71 and 1.32 log CFU/g at the initial stage and further decreased the count during storage. The 2 kGy EB and the HP (300 and 400 MPa) increased the thiobarbituric acid-reactive substances value, whereas the CPE did not show an antioxidative effect. The EB and HP caused no difference in the sensory qualities. In contrast, the CPE decreased all sensory qualities tested. Sensory panelists commented that the samples with CPE were not in the “rejection” category but were “unfamiliar” for chicken breast meat. In conclusion, the EB was more effective than HP in improving the microbial quality of marinated chicken breast meat. The use of CPE in the marinade solution may synergistically increase the shelf life; however, it is necessary to develop an appropriate formulation to ensure that the sensory qualities are maintained.