Phosphorus is one of the limiting nutrients for the growth of phytoplankton and algae and is therefore one of leading causes of eutrophication. Most phosphorous in water is present in the form of phosphates. Different technologies have been applied for phosphate removal from wastewater, such as physical, chemical precipitation by using ferric, calcium or aluminum salts, biological, and adsorption. Adsorption is one of efficient method to remove phosphates in wastewater. To find the optimal media for phosphate removal, physical characteristics of media was analysed, and the phosphate removal efficiency of media (silica sand, slag, zeolite, activated carbon) was also investigated in this study. Silica sand showed highest relative density and wear rate, and phosphate removal efficiency. Silica sand removed about 36% of phosphate. To improve the phosphate removal efficiency of silica sand, Fe coating was conducted. Fe coated silica sand showed 3 times higher removal efficiency than non-coated one.
Wastewater treatment using ferrate (Ⅵ) solution is becoming a promising technology for several years, because it is high efficient and harmless technology. In this study, the ferrate (Ⅵ) solution was tested to treatment of desulfurization wastewater. The effluent from desulfurization wastewater treatment process of power plant was used as raw water, and the COD and T-N removal efficiency of ferrate(Ⅵ) solution were investigated. In the test, as the injection rate increased from 0.1 to 1.0%, the removal efficiency of COD also slightly increased, about 80% of COD were removed in 1.0% of injection rate. In the case of T-N, about 50% of T-N was removed in the condition of 1.0% of injection rate. The removal efficiency of COD and T-N also affected by reaction time,maximum removal efficiency was shown in 30 min of treatment. From these results, the wastewater treatment with ferrate(Ⅵ) solution can be great solutions for treatment of non-biodegradable pollutants in wastewater, especially for the 3rd treatment of wastewater.
This study aims to analyze the process of how Chinese students practice collaborative writing and to figure out whether collaborative writing is useful to Korean language learners for academic purposes. In total, 15 Chinese students of Korean language for academic purposes participated in the research and they were divided into Groups A and B, respectively. Five participants of Group A were individually assigned with writing tasks while ten participants of Group B conducted collaborative writing tasks in pairs. Groups A and B conducted both tasks of a data commentary and an argumentative essay. The result was that fluency and complexity were not significantly different between Groups A and B. However, accuracy was higher in Group B. Accordingly, for students of Korean language in an advanced level, collaborative writing activities did not result in longer texts or more complex linguistic practices but led to more accurate texts. Whether this accuracy will strengthen grammatical knowledge of language students in an advanced level in the long-term is unknown, so follow-up studies are needed.
The purpose of this research was to study treatment characteristics of main odor substances, such as Trimethylamine and Acetaldehyde, by using 600 Wand 200 W microwave plasmas. Ar and air were used as plasma gases and a cylindrical SiC/Zeolite filter having several Ø 2~3 ㎜ size holes was used as a trigger to obtain a stable plasma even with a relatively low microwave power. The 600 W Ar plasma was used to destroy relatively high concentrated TMA and acetaldehyde from 500 ppm to 2200 ppm and their DREs (Destroy and Removal Ratios) were measured. The 200 W air plasma was also used to measure DREs for TMA and acetaldehyde Jowly concentrated in 4.5 odor strength. The results demonstrated that the Ar plasma produced 70% to 90% efficiency in removing odors substances. The 200 W Air plasma, which was operated at the relatively lower energy level, produced 90% or even above higher efficiency for the odorous materials. It was expected that the air plasma was effectively used to control odorous materials emitted from relatively a small size plant process.
울릉도와 독도 근해 해수의 이화학적 특성과 광합성 색소의 변화를 5월, 6월, 8월과 11월에 울릉도 5개 정점, 6월, 8월과 11월에 독도의 3개 정점에서 계절별로 조사하였다. 수온은 수심에 따른 변화가 적었으며, 8월에는 수온 약층의 형성이 두드러졌고, 특징적으로 울릉도에서 11월의 표층수온(20.5℃)이 기상의 기온(9.9℃)보다 높게 나타났다. 이러한 계절적 변화는 염분에서도 나타났으며, 5월에는 저온 고염
In this study, we analyzed 2-day food records of the 1990 Korean National Nutrition Survey data for 2,000 households, and investigated most popular menu patterns by area, income, meal. The basic menu patterns of Korean, excluding side dishes, were Rice+Soup, Rice+Stew, Rice, Others, Rice+Soup+Stew in the order of proportion for all analyzed sectors. And the proportion of menus with the rice as a main dish was about 90% on the whole. The most popular menus of Korean were Rice+Soup+Kimchi(4.52%), Noodle+Kimchi(4.30%). When they ate rice as a main dish, they had soup, kimchi, and 1 or 2 other side dishes. At large cities, Noodle+Kimchi was the most frequent menu(5.20%). On the other hands, small cities and rural areas, Rice+Soup+Kimchi+Cooked vegetable was common. For the households which salaries less than 5 million won, Rice+Stew+Kimchi is the most prevalent, but households which salaries higher than 5 million won, Noodle+Kimchi was most frequent. At breakfast and dinner, the proportion of Rice+Stew+Kimchi+Cooked vegetable was 4.70%. But at lunch, Noodle+Kimchi was the most frequent and other menu combinations based on noodle were also common. Therefore most households showed conventional rice based menu patterns, but these patterns were decreasing for the large cities, and high income households. Especially at lunch, they used various menus which were not based on rice.
In this report, we investigated meal patterns by area, age, profession from the data of the Korean National Nutrition Survey which had been carried out in 1989. The proportion of home prepared meal was about 90% at breakfast and dinner, and 46.3% at lunch. People had meals outside of home mainly at lunch(31.1%), and usually ate restaurant meal(17.7%). The proportion of meal skipped was 7.1% at breakfast, 3.9% at lunch, and 1.2% at dinner. At large city, 10.3% of people skipped breakfast, it was the highest proportion among three areas(large city, small city, and rural area). Also, the proportion of meal outside of homes was the highest among all areas. In rural area, home prepared meal was prevalent for all meals. Among all age groups, people between 20 and 49 ate out most frequently. For people between age 16 and 19, meal skipping was frequent for breakfast and dinner, especially, 20.5% of girl skipped breakfast. At lunch, the proportion of meal skipping was the highest in age higher than 50 groups. Among all professions, people in service job skipped lunch and dinner at the highest proportion. Manager and deskworker skipped breakfast by 12.9% and they ate out at lunch by 82.5%.
This paper aims at revisiting the information structure of sentences in languages such as Korean, English, Spanish and Russian. For this purpose, we refered to three types of focus structure, suggested by Lambrecht (1994), which include predicate-focus, argument-focus and sentence-focus structures. The information structure can be represented by the categorical statement and the thetic statement. The first is divided into two information segments- and , which typically corresponds to predicate-focus structure, while the second can not be divided but constitutes only one unit , which represents the sentence-focus structure. Given that the existence of `topic` is the factor of determining categorical/thetic statements, there`ll be possibility of interpreting certain argument-focus structures as secondary thetic sentences and of considering some of Lambrecht`s thetic structures as categorical sentences. On the other hand, the linguistic ways to realize the information division vary across languages, even if they are commonly available in affirming or negating the existence of `topic`.