• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.35-43
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• 2004

Reduction of fresh water consumption and effluent discharge provide diverse advantages in raw materials and energy savings. Papermaking system closure, however, reduces the efficiency of additives, decreases retention and dewatering, and causes many other Problems in papermaking. Accumulation of inorganic and organic substances in the process white water is the prime cause of these problems. Understanding of the accumulation phenomena of the detrimental substances in the papermaking process is of great importance for papermaking system closure. In this study a process simulation method was employed to analyze the accumulation phenomena of anionic starch in the process white water as the reuse rate of dry broke and pick up of surface sizing agent is increased. Steady state simulation studies were carried out based on the model developed in previous study. The variation of dissolved starch concentration in each process unit was monitored as a function of reuse rate of dry broke and surface sizing agent pick up rate. The result showed that dissolved starch concentration Increased as reuse rate of dry broke and surface sizing agent pick up rate was increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.23-29
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• 1999

The effect of dilute sulfuric acid treatment was examined to improve recyclability of coated brokes. Turbidity , electric conductivity , and cationic demand of the white water from coated broke prepared from an alkaline base paper was determined. Sulfuric acid treatment was found to be effective in dissolving undisintegrated substances such as binders, pigments, and fibers. The properties of papers prepared by adding the broke to pulp stock up to 30% dry weight were examined . With the increase of broke addition, retention, sizing degree and smoothness were improved ; on the other hand, formation uniformness, air permeability and internal bonding strength were decreased. The extent of improvement by broke addition was greater for the surfuric acid-treated broke than the control broke. It was concluded that the use of coated broke should be limited within 10-15% weight of the product for either type of broke.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.16-23
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• 2006

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.3
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• pp.36-40
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• 2007

It has been problematic to repulp the dry broke treated with permanent wet strength agents like PAE, UF and MF. Solution type GPAM has the benefit of easy repulping but it has problems of cocross-linking and tends to gel. Therefore, the product concentration must be lower than 10% to reduce the gel generation problem. We developed emulsion type GPAM by an inverse emulsion technology to resolve both the repulping problem with permanent wet strength agents and the stability problem of GPAM solution products.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.105-112
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• 1979

Effect of gibberllin on the breaking of bud dormancy of root and growth of aerial parts were investigated under laboratory and field condition for the prolongation of shoot growth duration, shortening of fruit bearing age and the increase of root yield. Drop application of GA (0.5ml of 50ppm) on rhizome of one year old root broke bud dormancy better than by low temperature. Soaking for one hour of one year old roots which wintered in the field in GA (50-200ppm) greatly accelerated the emergence of new buds while kinetin was only effective at low level (50ppm). GA substantially increased stem length in early stage and petiole length later on while kinetin increased stem diameter. Under the field condition with polythylene film tunnel (PET) in early spring the soaking in GA (50ppm for 1 hour) of rhizome of 4 year old root with replanting and dropping GA (50ppm, 1ml) on rhizome without replanting brought earlier emergence (29days) in comparison with that in the usual field. PET alone caused 14 day-early emergence. GA increased the length of stem and petiole only in early stage and replanting decreased only petiole length in later stage. Soaking in GA with replanting caused the Pronounced decrease in peduncle length, percentage of (ruin set and dry weight of reproductive organ (fruits and peduncle). Dropping without replanting showed significant decrease only in dry weight of reproductive organ. Fruit maturing was 20 days earlier than in usual held with little difference between GA and PET. It is well expected that GA could be used for early emergence of bud, shortening of root dormancy period, thinning of fruit and higher root yield according to application amount and methods.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.498-504
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• 2011

The purpose of this study was to investigate and develop an eco-frendly wood adhesive based on vegetable oil (especially soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The waste soybean oil (WSBO) was reacted with $O_3$ at the rate of $450m{\ell}$(acetone) : $50m{\ell}$ (WSBO) for different times, 1, 2, 3 hrs. The investigation of the modified chemical strecture of the ozonied WSBOs were conducted using FT-IR. As ozonification time increased, the peak of the unsaturated double bonds was disappeared especially ozonized-3hrs and aldehyde or carboxyl peak appeared because ozonification broke the oil into small molecules. The plywood were made at $150^{\circ}C$ with 4 minutes hot-press time using the different ozonized 3 hrs WSBO/pMDI adhesives and were tested for the dry, wet, cyclic boil test according to the Korea Industrial Standard F3101 Ordinary plywood. The bond strengths gradually increased until 1 : 0.5~1 : 3, but it decreased 1 : 4, as the contents of pMDI increased. The results of the dry, wet and cyclic bond strengths the equivalent ratio was formed approximately between 1 : 2~1 : 3. And the 1 : 1~1 : 4 strengths met constantly the standard requirement of 7.0kgf/$cm^2$ (KS F3101). From the comprehensive view on the results of above experiment, it could be confirmed that ozonized WSBO/pMDI has characteristics of effective reactivity and wet stability showed as an excellent candidate of wood adhesive applications.

• Magazine of the Korean Society of Agricultural Engineers
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• v.9 no.2
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• pp.1296-1300
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• 1967

This study was made through the utilization of heavy soil taken from the experimental plot of heavy soil in Konkuk University, Changan-dong, Sungdong-ku, Seoul. The soil used in the experiment has the following physical characteristics: 1. The soil is very compact, impervious, and unfit for any plant growth, 2. For improvement of the soil, tile drainage practice has been employed, 3. According to the general theory of tile drainage, it is unnatural that the effect of drainage is actually observed in such a soil. The followings are the results of the experiment: 1. Water moved to crosswise when the plotted soil profile was not broke. In this case the upper sloped part was dry while the bottom part was moistned. The upper part of the tile was also moistned. 2. The crosswise movement of water was not observed in the artificially broken plot of subsoil. However, the water flow from the tile was observed for long period as a result of the increase of soil void, seepage, aeration, and water holding capacity. However, the water flow from the tile in the plot of unbroken subsoil was observed only in short period and soon the flow was stopped. 3. the distance between the tile laid in the heavy soil should not exceed 10m for the efficient drainage. 4. When the pF is 2.5 in the subsoil the moisture content was between 23.97% and 28.20%. However, when the water saturated in the subsoil the moisture content was between 34.30% and 22.10%. Accordingly without the higher pF than 2.5 the water can not be absorbed and therefore the drainage can not be occured.

• Transactions on Electrical and Electronic Materials
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• v.12 no.2
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• pp.60-63
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• 2011

We investigated the etching characteristics of zinc oxide (ZnO) and the effect of additive gases in a $Cl_2$-based inductively coupled plasma. The inert gases were argon, nitrogen, and helium. The maximum etch rates were 44.3, 39.9, and 37.9 nm/min for $Cl_2$(75%)/Ar(25%), $Cl_2$(50%)/$N_2$(50%), and $Cl_2$(75%)/He(25%) gas mixtures, 600 W radiofrequency power, 150 W bias power, and 2 Pa process pressure. We obtained the maximum etch rate by a combination of chemical reaction and physical bombardment. A volatile compound of Zn-Cl. achieved the chemical reaction on the surface of the ZnO thin films. The physical etching was performed by inert gas ion bombardment that broke the Zn-O bonds. The highly oriented (002) peak was determined on samples, and the (013) peak of $Zn_2SiO_4$ was observed in the ZnO thin film sample based on x-ray diffraction spectroscopy patterns. In addition, the sample of $Cl_2$/He chemistry showed a high full-width at half-maximum value. The root-mean-square roughness of ZnO thin films decreased to 1.33 nm from 5.88 nm at $Cl_2$(50%)/$N_2$(50%) plasma chemistry.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.56-64
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• 2009

The purpose of this study was to investigate and develop an eco-friendly wood adhesive based on vegetable oil (especially soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The soybean oil (SBO) was reacted with $O_3$ at the rate of 7.13 g/h for different times, 15 minutes, 30 minutes, 60 minutes, and 120 minutes. The investigation of the modified chemical structure of the ozonized SBOs were conducted using FT-IR, $^1H$-NMR, MALDI-TOF MS, and GC/MS. As ozonification time increased, the peak of the unsaturated double bonds was disappeared and aldehyde or carboxyl peak appeared because ozonification broke the oil into small molecules. The plywoods were made at $110^{\circ}C$ with 30 seconds/mm hot-press time using the different ozonized SBO/pMDI adhesives and were tested for the dry, wet, cyclic boil test according to the Korea Industrial Standard F3101 Ordinary plywood. The bond strengths gradually increased with increasing ozonification time. The weight ratio 1:1 (ozonized SBO/pMDI), all strengths in 15, 30 and 60 minuets, exceeded constantly the dry, wet, cyclic boiling standard requirement. The range of ozonification time and weight ratio can fulfil1 the requirment of the wet test standard were 30~60 minutes and more than 0.5 pMDI. From the comprehensive view on the results of above experiments, it could be confirmed through experiments that ozonized SBO/pMDI has characteristics of effective reactivity and wet stability showed as an excellent candidate of wood adhesive applications.

• Fire Science and Engineering
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• v.25 no.4
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• pp.8-21
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• 2011

This study surveyed historical records on outbreak and features of forest fires during Chosun Dynasty's 518 years in being and analyzed the Annals of the Chosun Dynasty; The Diaries of the Royal Secretariat, archives from Records of the Border Defense Council, The Compilation of Ministry Proposals, Posthumous Records of King Cholchong etc. Forest fires were most prevalent and extreme during King Hyunjong (14 cases) and King Sunjo (13 cases) due to strong wind, and the biggest-ever forest fire broke out in the fourth year of King Soonjo (1804) in the east coast of Korea in Kangwon province. The fire had resulted in 61 fatalities and 2,600 destroyed houses. Forest fire in the east coast of Korea, Kangwon province, in the $13^{th}$ year of King Hyeonjong (1672) is recorded to have caused the highest number of deaths, 65people. The most frequent cause of forest fires during Chosun Dynasty was unidentified (42 cases), followed by accidental fire (10 cases), arson or lightning (3 cases), fire during hunting (2 cases), play with fire by children, destruction of patty fields and dry fields by fire and house fire (1 case respectively). By region, 56 % of forest fires erupted in the east coast (39 cases) and this was followed by the west sea (9 cases), Seoul and central region (8 cases) and the southern part of Korea (7 cases). By season, spring was found to be most vulnerable to forest fire as it accounted for 73 % of the total amounting to 46 cases. Behind were summer (11 cases), winter (6 cases) and autumn (0 case). Specifically, most forest fire broke out on April and May, which is the same as today. Archives and literature indicate that the person who involved in forest fire by accidental as well as arson had to be punished by banishment, expulsion from government office and public hanging. Also, officials in charge of the region that suffered forest fire were subject to reprimand. In conclusion, risk and gravity of forest fires were evident during the Chosun Dynasty as specified in historical archives and share many similarities with today's forest fires in terms of the duration and regional patterns.