• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.769-776
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• 2006

Recently, owing to the development of industry and the improvement of building techniques, concrete structures are becoming larger and higher. In hardening of these large connote structures, the heat of hydration gives rise to considerable thermal stress depending on the size and environmental condition of concrete, which might cause thermal cracking. Especially, the crack may cause severe damage to the safety and the durability of concrete structure. This study investigates the thermal properties of concrete according to several binder conditions, such as OPC, Belite rich cement(BRC), slag cement(SC), blast furnace slag(B) added cement fly ash(F) added cement and blast-furnace-slag and fly ash added cement. As a result of this study, the properly of concrete is most better BRC than others, and fly ash(25%) added cement and BFS(35%)-fly ash(15%) added cement gets superior effect in the control of heat hydration. But synthetically considered properties of concrete, workablity, strength heat hydration, etc, it is more effective to use mineral admixture. Especially, to be used Blast Furnace slag is more effective.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.48-54
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• 2008

Biochemical weapons, called as a poor nation's nuclear-weapon, are most favorable Weapons of Mass Destruction(WMD). At the beginning of war, these biochemical weapons, which can threaten the operations of our forces and cause the anxiety and chaos of people, should be used to attack our principle facilities. And these attacks might be conducted as a long term scenario over the war. Consequentially, our military training as well as civilian-military joint training have been focused on these circumstances to improve defense capability against the invasion of biochemical weapons. Add to these efforts, there have been a lot of researches to develop advanced decontaminations that can secure our troops and equipments. In this study, applicability of the water-soluble decontaminant for the contaminated aircraft was evaluated. The water-soluble decontaminant has been applied to the military stations and ground weapon systems only. According to the theoretical analyses and published papers, the water-soluble decontaminant has been shown better decontamination capability than commercial cleaner by roughly 50%. Furthermore, as a result of experiment efforts in this study, it was showed that the water-soluble decontaminant can reduce corrosion risk which is primary concern for the aircraft structures.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.29-34
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• 2008

Generally, for conventional 3-D Hall sensor it is general that the sensitivity for $B_z$ is about 1/10 compared with those for $B_x$ or $B_y$. Therefore, in this work, we proposed 3-D Hall sensor with new structures. We have increased the sensitivity about 6 times to form the trench using anisotropic etching. And we have increased the sensitivity for the $B_z$ by 80 % compared with those of $B_x$ and $B_y$ using deposition of the ferromagnetic thin films on the bottom surface of the wafer to concentrate the magnetic fluxes. Sensitivities of the fabricated sensor with Ni/Fe film for $B_x,\;B_y$, and $B_z$ were measured as 361mV/T, 335mV/T, and 286mV/T, respectively. It has also showed sine wave of Hall voltages over a $360^{\circ}$ rotation. A packaged sensing part was $1.2{\times}1.2mm^2$. The measured linearity of the sensor was within ${\pm}3%$ of error. Resolution of the fabricated sensor was measured by $1{\times}10^{-5}T$.