• Journal of Aquaculture
• /
• v.3 no.1
• /
• pp.79-88
• /
• 1990

In order to obtain the basic data fir the effective seed production of sea squirt, Halocynthia roretzi(Drasche), the influence of water temperature and light intensity on spawning induction, egg development and seed settling were investigated during the Period from December 24, 1906 to February 24, 1987. The maximum number of eggs spawned was obtained at $14^{\circ}C$. The relationships between the water temperature (T, $^{\circ}C$) and the required time (h, hour) in each egg developmental stage were given as follows : Up to 8 cell 1/h =0.0147 T-0.0069(.=0.9816), Up to 32 cell 1/h =0.0100 T-0.0017(r=0.9672), Up to early tadpole 1/h =0.0043 T+0.0024(r=0.9913), Up to hatching larva 1/h =0.0021 T-0.0021 (r=0.9898). The highest rate of seed attachment was obtained at $14^{\circ}C$ of water temperature.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.2 no.3
• /
• pp.1-13
• /
• 1982

Transition process of plastic region. displacements, stresses and strains ahead the flaw tips were analysed by the finite element method on the steel plate with the circular hole and the one with the elliptical hole under completely alternating load (repetition of tensile loading, unloading and compressive loading). As the results, the followings were obtained. Transition process of elastic failure (yielding) region was estimated. From this the tendency was confirmed that the fracture would be initiated from ahead the flaw tip, and propagated along the $45^{\circ}$ direction. The fundamental data available in estimating the stress intensity factor that was considered as the core in analysing the fracture mechanism of steel plates were obtained. It was indicated that when unloading after tension the effect of compressive loading, and even the compressive reyield, was occured ahead the flaw tip. Similarly it was indicated that when unloading after compression the effect of tensile loading, and even the tensile reyield, was occured ahead the flaw tip. It was considered that these phenomena were occured because the unloading effect was constrained by the residual strains when unloading. It was considered that the fatigue phenomenon was occured ahead, the flaw tip by repetition of tensile yield, the above compressive reyield, compressive yeild and the above tensile reyield. In addition, the tendency was confirmed that the fracture ahead the flaw tip was occured as the flaw was changed from the circular hole to the elliptical hole and became to be the crack lastly.

• Progress in Medical Physics
• /
• v.27 no.4
• /
• pp.220-223
• /
• 2016

Generally, it is recommended that the dosimetric effect of carbon fiber couch should be considered especially for an intensity-modulated therapy with a large portion of monitor units from posterior angles. Even a flattening filter free (FFF) beam has been used for stereotactic body radiation therapy (SBRT), the effect of carbon fiber couch for FFF beam is not well known. This work is an effort to evaluate the dosimetric effect of carbon fiber couch for flattened and FFF beam of Elekta linac empirically. The absorbed doses were measured with Farmer type chamber and water-equivalent phantoms with and without couch. And differences of the absorbed doses between with and without couch defined as "couch effect". By comparing calculated dose in treatment planning system (TPS) with measured dose, the optimal density of couch was evaluated. Finally, differences on patient's skin dose and target dose by couch were evaluated in TPS. As a result, the couch effect for 6 and 10 MV flattened beam were -2.71% and -2.32%, respectively. These values were agreed with provided data by vendor within 0.5%. The couch effect for 6 and 10 MV FFF beam were -3.75% and -2.80%, respectively. The patient's skin dose was increased as 18.6% and target dose was decreased as 0.87%, respectively. It was realized that the couch effect of FFF beam was more severe than that of flattened beam. Patient's skin dose and target dose were changed by the couch effect.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.440-453
• /
• 2020

Given the dynamics of the changing economic or financial conditions in Chungcheong province in the domestic capital market, foreign and domestic investments are expected to continually increase their investments in volume and size in this particular province. Considering the unprecedented business climate, it may be essential to examine the primary financial aspects, such as corporate profitability, growth rate, and capital structure, which may work as effective catalysts to enhance corporate value. Concerning the outcomes, five proposed variables, such as market-value based leverage ratio, growth rate, Tobin's Q, business risk, and R&D intensity, highlighted the significant effects to determine the current level of profitability. Moreover, two variables, such as profitability and firm size, shared commonalities to discriminate between firms in the Chungcheong province (96 firms) and their counterparts (746 firms) in the other domestic provinces in terms of the growth rate and financial leverage. In contrast, three variables, including the interaction effect and firm size, had pronounced effects on profitability. The results of the study are expected to help enhance the corporate value in Chungcheong province by controlling the level of each significant factor.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2002.11a
• /
• pp.147-153
• /
• 2002

Due to the growth of population and industrial development at the coastal cities, there has been much increase in necessity to effective control of the wastes into the coastal water and river. The amount of disposal at those waters has been increased rapidly and it is necessary for us to track of it in order to keep the water clean. The investigation and research related to the water quality in this region have been conducted continuously but the systematic survey of the disposed wastes at the bottom was neglected and/or minor. In this study we surveyed the status of disposed waste distribution at the bottom coastal water and river from the scanned images. The intensity of sound received by the side scan sonar tow vehicle from the sea floor provides information as to the general distribution and characteristics of the superficial wastes. The port and starboard side scanned images produced from a transducer borne on a tow fish connected by tow cable to a tug boat have the area with width of 22m∼112m, and band of 44m∼224m. All data are displayed in real-time on a high-resolution color display (1280 ${\times}$ 1024 pixels) together with position information by DGPS. From the field measurement and analysis of the recorded images, we could draw the location and distribution of bottom disposals. Furthermore, we made a database system which might be fundamental for planning the waste reception and process control system.

• Journal of Surface Science and Engineering
• /
• v.45 no.1
• /
• pp.15-19
• /
• 2012

Tris(8-quinolinolato)aluminum(III); $Alq_3$ has been frequently used as an electron transporting layer in organic light-emitting diodes. Either Ba with a low work function or Au with a high work function was deposited on $Alq_3$ layer in vacuum. And then, the behaviors of electron transition at the $Alq_3$/Ba and $Alq_3$/Au interfaces were investigated by using the near edge x-ray absorption fine structure (NEXAFS) spectroscopy. In the each interface, the energy levels of unoccupied obitals were assigned as ${\pi}^*$(LUMO, LUMO+1, LUMO+2 and LUMO+3) and ${\sigma}^*$. And the relative intensities of these peaks were investigated. In an oxygen atom composing $Alq_3$ molecule, the relative intensities for a transition from K-edge to LUMO+2 were largely increased as Ba coverage (${\Theta}_{Ba}$, 2.7 eV) with a low work function was in-situ sequentially increased on $Alq_3$ layer. In contrast, the relative intensities for the LUMO+2 peak were reduced as Au coverage (${\Theta}_{Au}$, 5.1 eV) with a high work function were increased on $Alq_3$ layer. This means that the electron transition by photon in oxygen atom which consists in the unoccupied orbitals in $Alq_3$ molecule, largely depends on work function of a metal. Meanwhile, in the case of electron transition in a carbon atom, as ${\Theta}_{Ba}$ was increased on $Alq_3$, the relative intensity from K-edge to ${\pi}_1{^*}$ (LUMO and LUMO+1) was slightly decreased, and from K-edge to ${\pi}_2{^*}$ (LUMO+2 and LUMO+3) was somewhat increased. This rising of the energy state from ${\pi}_1{^*}$ to ${\pi}_2{^*}$ exhibits that electrons provided by Ba would contribute to the process of electron transition in the $Alq_3$/Ba interfaces. As shown in above observation, the analyses of NEXAFS spectra in each interface could be important as a basic data to understand the process of electron transition by photon in pure organic materials.

• Journal of Korean Society of Environmental Engineers
• /
• v.37 no.4
• /
• pp.240-245
• /
• 2015

This study aimed to provide the basic data to establish measures for the management of the public toilets and reduction of the offensive odor through the air dilution olfactory method and instrumental analysis about offensive odor dilution rate of public toilets, focusing on the Dong-gu, Daejeon Metropolitan City, Korea. The offensive odor intensities ranged from 10 degree to 669 degrees in the urinal toilets and from 31 to 464 in closet bowl toilets. Meanwhile, toilets that had offensive odor of more than 2.5, of which a civil complaint can be filed, were researched 6 (33%). Offensive odor intensities were different according to the closet bowl toilets of the flush, fermented and conventional methods and the year of their installation, but not according to the area of the toilets. As a result of the instrumental analysis targeting 6 public toilets to identify the offensive odor substance, the maximal concentration of $NH_3$ was 2.04 ppm and the average concentration was 0.67 ppm, but $H_2S$, $CH_3SH$ and $(CH_3)_3N$ were not detected. In the fermented and conventional public toilets were not soaps, air fresheners and wastebaskets. Just 50% of the flush toilets had toilet tissue.

• Economic and Environmental Geology
• /
• v.41 no.3
• /
• pp.315-326
• /
• 2008

Recently, the occurrence and intensity of Asian Dust have dramatically increased in Korean peninsula, resulting in severe damages to the domestic social and economic field. The most useful way to prevent the damage of Asian Dust is the restraint of the occurrence of Asian Dust itself. However, Asian dust is the one of the natural phenomena, thus there is a basic limit to manage the Asian Dust. Though it is impossible to restrain the occurrence of Asian Dust in short time at present, it is a urgent matter to minimize the damage of Asian Dust. It is necessary to construct the basic data for understanding the harmfulness of Asian Dust, and to elucidate the source area of Asian Dust in connection with the maleficence of itself. In this study, the source area of Asian Dust in spring, 2007, is investigated using the Sr-Nd isotopic ratios which is the most common method to trace the source of geological materials. The relationships of Sr-Nd isotope ratios indicate that Asian Dust was originated from Central Loess Plateau and/or Ordos desert in spring, 2007.

• Journal of Environmental Science International
• /
• v.26 no.1
• /
• pp.47-54
• /
• 2017

We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.

• The Journal of Korean Society for Radiation Therapy
• /
• v.20 no.2
• /
• pp.115-122
• /
• 2008

Purpose: The cancer treatment which uses radiation from next year when the X-ray is discovered with the fact that it is started. The radiation treatment technique for a cancer treatment is developed ceaselessly without and it is come and, with advancement of the computer and electromagnetic engineering it joins in and quickly, it was made to do a many development from radiation treatment field. Accordingly, this study is examine in the radiotherapy technique which is developed that importance to therapeutic principles and methods. Materials and Methods: We had investigated record for radiotherapy technique which is developed and we had acquired information widely at clinical experience data. Results: The cancer treatment which uses the radiation of today is repeating a dazzling development. Past the treatment which is two-dimensional it does not correspond in therapeutic objective but currently 3 dimension three-dimensional moulding treatment or centurial control radiation treatment this the fourth dimension therapeutic technique which is in parallel to be introduced the complication solution in compliance with a normal organization protection and the radiation which are a difficult problem of during that time radiation treatment possibly did. Conclusion: 3-dimensional and 4-dimensional modern radiation treatment which is developen is that corresponding in objective of radiation treatment and the evaluation that again it does thick, judges in about the cancer treatment which uses radiation with the fact that the protection of normal organization is almost become accomplished.