• Title/Summary/Keyword: 큰 수

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Summer-Time Behaviour and Flux of Suspended Sediments at the Entrance to Semi-Closed Hampyung Bay, Southwestern Coast of Korea (만 입구에서 부유퇴적물 거동과 플럭스: 한반도 서해 남부 함평만의 여름철 특성)

  • Lee, Hee-Jun;Park, Eun-Sun;Lee, Yeon-Gyu;Jeong, Kap-Sik;Chu, Yong-Shik
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.2
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    • pp.105-118
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    • 2000
  • Anchored measurements (12.5 hr) of suspended sediment concentration and other hydrodynamic parameters were carried out at two stations located at the entrance to Hampyung Bay in summer (August 1999). Tidal variations in water temperature and salinity were in the range of 26.0-27.9C and 30.9-31.5, respectively, indicating exchange offshore and offshore water mass. Active tidal mixing processes at the entrance appear to destroy the otherwise vertical stratification in temperature and salinity in spite of strong solar heating in summer. On the contrary, suspended sediment concentrations show a marked stratification with increasing concentrations toward bottom layer. Clastic particles in suspended sediments consist mostly of very fine to fine silt (4-16 μm) with a poorly-sorted value of 14.7-25.9 μm. However, at slack time with less turbulent energy, flocs larger than 40 μm are formed by cohesion and inter-collision of particles, resulting in a higher settling velocity. Strong ebb-dominated and weak flood dominated tidal currents, in the southwestern and the northeastern part, respectively, result in a seaward residual flow of -10-20 cm s1 at station H1 and a bayward residual flow less than 5.0 cm s1 at station H2. However, mean concentration of suspended sediments at station H1 is higher at flood (95.0-144.1 mg 11) than in ebb (75.8-120.9 mg 11). On the contrary, at the station H2, the trend is reversed with higher concentration at the ebb (84.7-158.4 mg 11) than that at the flood (53.0-107.9 mg 11). As a result, seaward net suspended sediment fluxes (fs) are calculated to be -1.7 -15.6103 kg m2 s1 through the whole water column. However, the stations H1 and H2 show definitely different values of the flux with higher ones in the former than in the latter. Alternatively, depth-integrated net suspended sediment loads (\cQs) for one tidal cycle are also toward the offshore with ranges of 0.37×103 kg m1 and 0.21×103 kg m1, at station H1 and H2, respectively. This seaward transport of suspended sediment in summer suggests that summer-time erosion in the Hampyung muddy tidal flats is a rather exceptional phenomenon compared to the general deposition reported for many other tidal flats on the west coast of Korea.

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Characteristics of Spatio-temporal Variation of the Water Quality in the Lower Keum River (금강 하류역에서 수질의 시공간적 변화특성)

  • YANG Han-Soeb;KIM Seong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.3
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    • pp.225-237
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    • 1990
  • Various chemical constituents were measured from April to August 1988 at the down-ward 20 stations of Keum River, which is located in the Midwest of Korea, to understand the characteristics of water quality with respect to spatio-temporal variations of each constituent. The 24-hrs continuous measurements with 2-hrs interval were made simultaneously at station 2 near the estuary weir and station 9(Ganggyeong) of 35 km upstream from the weir in April. By the results observed for one day in April at station 2, salinity has a range of 7.88\~22.14% and its temporal variability is identical to the pattern of tidal cycle in the neigh-bouring Kunsan Harbor. However, turbidity shows relatively high values only at an interval of 4~5 hours after the lowest salinity time, though hourly fluctuation of pH is very small. Silicate and dissolved inorganic nitrogen have inversively linear correlationships with salinity, implying the concentration of the two nutrients strongly regulated by estuarine mixing of sea and river waters. In contrast, phosphate sustains roughly a constant level over a wide salinity range and distinctly lower values than those corresponding to nitrate in the oceans. Such distributions of phosphate have been observed in some estuaries, and interpreted as driven by removal of dissolved phosphate into bottom sediments and the bufforing of phosphate by particulate matter. COD values at station 2 are relatively high in day-time(particularly afternoon) and in high-salinity periods. At station 9, saltwater intrusion was never found but water level changed to the extent of 2.5 m for one day. Although each parameter at this station exhibits very slight variations in their abundance for 24 hours compared with station 2, the contents of COD, silicate and ammonia are significantly higher than at station 2. Concentration of suspended matter is relatively high in the brackish water region up to \~20 km above the river mouth, probably due to strong tidal stirring of the bottom de-posits. Also, relatively high pH, COD and O2 saturation at the upward stations of 40\~50 km from the weir are presumably attributable to active photosynthesis of plants in the region. In general, COD and nutrients except phosphate are higher values at the upper stations than in the estuary zone, and show the highest abundances in July nearly at all stations. Finally, in the estuarine region tidal mixing of sea-river waters seems to be an important factor controlling the distributions of turbidity, COD, silicate and nitrate as well as salinity. However, water quality in the upward fresh-water zone is remarkably variable according to months or seasons.

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STUDIES ON THE UTILIZATION OF ANTARCTIC KRILL 2. Processing of Paste Food, Protein Concentrate, Seasoned Dried Product, Powdered Seasoning, Meat Ball, and Snack (남대양산 크릴의 이용에 관한 연구)

  • PARK Yeung-Ho;LEE Eung-Ho;LEE Kang-Ho;PYEUN Jae-Hyeung;KIM Se-Kweun;KIM Dong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.13 no.2
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    • pp.65-80
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    • 1980
  • Processing conditions of the krill products such as paste food, krill protein concentrate, seasoned dried krill, powdered seasoning, meat ball, and snack have been examined and the quality was evaluated chemically and organoleptically. In the processing of paste food, krill juice was yielded 71% and krill scrap 29%. The yields of paste and broth from the krill juice showed 53% and 43%, respectively. In amino acid composition of the krill paste, proline, glutamic acid, aspartic acid, lysine, and leucine were abundant, while histidine, methionine, tyrosine, serine and threonine were poor. The optimum condition for solvent extraction in the processing of krill protein concentrate was the 5 times repetitive extraction using isopropyl alcohol at 80C for 5 mins. The yield of krill protein concentrate when used fresh frozen materials was 10.2% in isopropyl alcohol solvent and $8.8\% in ethyl alcohol, and when used preboiled frozen materials, the yield was 13.0% in isopropyl alcohol and 11.8% in ethyl alcohol. Amino acid composition of krill protein concentrate showed a resemblance to that of fresh frozen krill meat. In quality comparison of the seasoned dried krill, hot air dried krill was excellent as raw materials and sun dried krill was slightly inferior to hot air dried krill, but preboiled frozen krill showed the poorest quality. The result of quality evaluation for seasoning made by combination of dried powdered krill, parched powdered sesame, salt, powdered beef extract, monosodium glutamate, powdered red pepper and ground pepper showed that the hot air dried krill was good in color and sundried krill was favorable in flavor. When krill meat ball was prepared using wheat flour, monosodium glutamate and salt as side materials, the quality of the products added up to 52% of krill meat was good and the difference in quality upon the results of the organoleptic test for raw materials was not recognizable between fresh frozen and preboiled frozen krill. In the experiment for determining the proper amount of materials such as dried Powdered krill, αstarch, sweet potato starch, sugar, salt, monosodium glutamate, glycine, potassium tartarate, ammonium bicarbonate, and sodium bicarbonate in processing krill snack, sample B(containing 7.7% of dried powdered krill) and sampleC (containing 10.8% of dried powdered krill) showed the most palatable taste from the view point of organoleptic test. Sweet potato starch in testing side materials was good in the comparison of suitability for processing krill snack. Corn starch and kudzu starch were slightly inferior to sweet potato starch, while wheat flour was not proper for processing the snack. In the experiment on frying method, oil frying showed better effect than salt frying and the suitable range of frying temperature was 210215C.

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Inhomogeneity correction in on-line dosimetry using transmission dose (투과선량을 이용한 온라인 선량측정에서 불균질조직에 대한 선량 보정)

  • Wu, Hong-Gyun;Huh, Soon-Nyung;Lee, Hyoung-Koo;Ha, Sung-Whan
    • Journal of Radiation Protection and Research
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    • v.23 no.3
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    • pp.139-147
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    • 1998
  • Purpose: Tissue inhomogeneity such as lung affects tumor dose as well as transmission dose in new concept of on-line dosimetry which estimates tumor dose from transmission dose using the new algorithm. This study was carried out to confirm accuracy of correction by tissue density in tumor dose estimation utilizing transmission dose. Methods: Cork phantom (CP, density 0.202gm/cm3) having similar density with lung parenchyme and polystyrene phantom (PP, density 1.040gm/cm3) having similar density with soft tissue were used. Dose measurement was carried out under condition simulating human chest. On simulating AP-PA irradiation, PPs with 3 cm thickness were placed above and below CP, which had thickness of 5, 10, and 20 cm. On simulating lateral irradiation, 6 cm thickness of PP was placed between two 10 cm thickness CPs additional 3 cm thick PP was placed to both lateral sides. 4, 6, and 10 MV x-ray were used. Field size was in the range of 3×3 cm through 20×20 cm, and phantom-chamber distance (PCD) was 10 to 50 cm. Above result was compared with another sets of data with equivalent thickness of PP which was corrected by density. Result: When transmission dose of PP was compared with equivalent thickness of CP which was corrected with density, the average error was 0.18 (±0.27) % for 4 MV, 0.10 (±0.43) % for 6 MV, and 0.33 (±0.30) % for 10 MV with CP having thickness of 5 cm. When CP was 10 cm thick, the error was 0.23 (±0.73) %, 0.05 (±0.57) %, and 0.04 (±0.40) %, while for 20 cm, error was 0.55 (±0.36) %, 0.34 (±0.27) %, and 0.34 (±0.18) % for corresponding energy. With lateral irradiation model, difference was 1.15 (±1.86) %, 0.90 (±1.43) %, and 0.86 (±1.01) % for corresponding energy. Relatively large difference was found in case of PCD having value of 10 cm. Omitting PCD with 10 cm, the difference was reduced to 0.47 (±1.17) %, 0.42 (±0.96) %, and 0.55 (±0.77) % for corresponding energy. Conclusion When tissue inhomogeneity such as lung is in tract of x-ray beam, tumor dose could be calculated from transmission dose after correction utilizing tissue density.

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Effects of Hysteroscopic Septotomy on Pregnancy in Patients with History of Infertility or Recurrent Spontaneous Abortion (불임 또는 습관성 유산 환자에서 중격자궁의 치료가 임신에 미치는 영향)

  • Koo, Hwa-Seon;Cha, Sun-Hwa;Yang, Kwang-Moon;Bae, Ju-Youn;Ahn, Hyun-Suk;Han, Ae-Ra;Park, Chan-Woo;Kang, Inn-Soo;Koong, Mi-Kyoung;Lee, Kyung-Sang
    • Clinical and Experimental Reproductive Medicine
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    • v.37 no.4
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    • pp.361-368
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    • 2010
  • Objective: The aim of this study was to evaluate the influences of uterine septum and their elimination on the reproductive outcomes in women who have history of recurrent spontaneous abortion (RSA) and/or infertility. Methods: The medical records of reproductive outcomes in patients who have had history of RSA and infertility who were diagnosed with uterine septum only by hysterosalpingogram (HSG) between January 2008 and December 2009 were retrospectively analyzed. The subjects who have had severe male factor, tubal factors, other uterine factors, endocrine abnormalities, peritoneal factors, and abnormal karyotyping among both partners were excluded. In 27 patients, confirmation of diagnosis by laparoscopy and elimination of uterine septum by trans-vaginal hysteroscopy was done. Seventeen patients were strongly suspected to uterine septum on HSG but tried to get pregnancy without any other procedure for evaluation and management of uterine anomaly. Age matched 42 patients who have history of RSA and/or infertility and diagnosed to normal HSG finding at same period were randomly selected as control. The medical records of reproductive outcomes were analyzed and compared between groups. Results: The mean time of observation after diagnosis was 21.8 months (10 to 32). 55.6% (15/27) of patients in patients who received trans-vaginal hysteroscopic uterine septotomy were success to get pregnancies and was significantly higher than that of 17 patients who did not receive proper management (23.5%, 4/17, p<0.05). In control population, 40.5% (17/42) were success to pregnancies and the differences were not statistically significant compared to both two study groups. The live birth rate which was excluded pregnancy loss by abnormal fetal karyotyping and congenital anomaly were 75% (9/12) in treated septated uterus group and 84.6% (11/13) in control group each which have no statistically significant different. In patients with septated uterus who did not receive proper management showed lower delivery rate (50%, 2/4) than that of other groups but was not statistically significant. Conclusion: According to present data, women with a uterine septum have an increased chance of successful pregnancy with improved obstetric outcome after proper management of the uterine cavity. And these results were showed in patients with no regard to their reproductive history. But, in case of failed to receive proper management, uterine septum can affect not only pregnancy ongoing but successful pregnancy too.

Nutritional Effects of Paper Board Sludge on the Soybean(Glycine max. L.) (대두(大豆)에 대(對)한 제지(製紙) Sludge의 영양학적(營養學的) 연구(昭究))

  • Kim, Moon Kyu;Chang, Ki Woon;Choi, Woo Young;Ham, Suon Kyu;Nam, Yun Kyu;Lee, Chang Jun
    • Korean Journal of Agricultural Science
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    • v.17 no.1
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    • pp.1-8
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    • 1990
  • The paper board sludge(PBS) itself and compost sludge manure(CSM) mixed with sawdust, fowl droppings and urea to the PBS were treated to soybean plants to find the effects of growing characters, yield components, and nutritional compounds in the plant tissues. 1. Percentages of missing plants were 5-9% and 3.6-4.1% in the treatments of PBS and CSM, respectively. After that, the plants were restored to normal conditions. Anyway it is not desirable to use the paper board sludge and immature compost sludge manure in seeding time or to young seedlings. 2. Growth of the plant height was retarded in early growing phase, but it was normal in later stages. And the width and length of the largest leaf, numbers of main stem nodes and pods were not significant among the treatments. 3. The yield intends to increase through the treatments of 1,200, 1,600, and 2,000Kg PBS per 10a. In the CSM treatments with high rate of sawdust, fowl droppings and urea, the numbers of pods and grains were higher than the treatment of high content of PBS. 100-grain and one liter weights were opposite intention. It was suggested that the excess nitrogen amounts from the compost sludge manure than conventional fertilization affected to the yield components. 4. The contents of the main chemical compounds such as N, P2O5, K2O, Ca, Mg were determined. The concentrations of nitrogen were higher in the treatment of PBS and CSM than none and control. 5. In conclusion, the nutritional effects of PBS were in evidence. To use the sludges, it should be fermented with adequate additives to improve the aeration, C/N ratio, activity of microbial, and other conditions. The sludges could be used to crops as a fertilizers effectively.

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Studies on the Cropping system of the Field Crop in Chungnam Area (충남지방(忠南地方)의 전작물(田作物) 작부체계확립(作付體系確立)에 관(關)한 연구(硏究))

  • Choi, Chang Yeol;Kim, Dal Ung;Lee, Jae Chang;Kim, Young Rae
    • Korean Journal of Agricultural Science
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    • v.3 no.1
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    • pp.39-51
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    • 1976
  • As an accempt to increase thc efficiency of land use and the food production to achieve the national goal in the food self-sufficiency, nine cropping systems on the upper-land were examined in pure-stand and in mixtures of soybean, corn, potato and radish. The important conclusions of this study were summarized as follows; 1. The flowering date of soybean was two or three days earlier in pure-stand than in the mixture with corn. The maturing date two days earlier in the pure-stand than in the mixture with corn. The flowering and maturing dates were not different among various cropping systems in corn. 2. The stem length of soybean was significantly different among various cropping systems. Soybean in pure-stand was shorter in stem length than with corn. 3. The number of pods per soybean plant did not give any significant differences among various cultivation methods. 4. The length of internode and the number of nodes per soybean plant in the mixture with corn were greater than in the pure-stand. In the number of branches per plant this was reversed. 5. The average stem dry weight of soybean per 10a was not significantly different among various cultivation methods. 6. The soybean yield per 10a in the pure-stand was obviously greater than the mixture and there were significant differences among cultivation method within the mixture with corn in soybean yield. 7. The 1,000-grain weight of soybean was significantly different and those in the pure-stand was heavier than those in the mixture with corn. 8. Grain weight per soybean plant and the stem diameter in the pure-stand were significantly lesser than those in the mixture with corn. 9. In the comparisons of corn in the pure-stand and in the mixture with soybean, plant height, number of ear per 10a, mean ear weight and remember of grain per plant, 100-grain weight, ear length, ear girth and number of ear pel plant were not significantly different among various cultivation methods except for the grain yield per 10a. 10. In the economic analysis, the mixture with soybean and corn gave the greatest gross income. The combination 7 was the best which was 47.6% increase income comparing with the soybean pure-stand. 11. As it can be assumed, soybean plant was influenced greatly than corn by various cropping system. It is necessary to study more complex cropping system finding and giving more desirable multiple cropping system for the farmer.

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The Variation of Natural Population of Pinus densiflora S. et Z. in Korea (V) -Characteristics of Needle and Wood of Injye, Jeongsun, Samchuk Populations- (소나무 천연집단(天然集團)의 변이(變異)에 관(關)한 연구(硏究)(V) -인제(麟蹄), 정선(旌善), 삼척집단(三陟集團)의 침엽(針葉) 및 재질형질(材質形質)-)

  • Yim, Kyong Bin;Kwon, Ki Won;Lee, Kyong Jae
    • Journal of Korean Society of Forest Science
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    • v.36 no.1
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    • pp.9-25
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    • 1977
  • As a successive work of the variation studies of natural Pinus densiflora stands, some characteristics of individual trees of the three natural populations selected from the Kwang-won Province, the middle-east part of Korean peninsula, as shown in the location map, were investigated. And the statiscal differences between individuals within population, and between populations were analysed. Twenty trees from each population were selected for this study purpose. Doing this, those trees lagged in growth, usually showing poorer form, were eliminated. The results obtained are summarized as follows: 1. Though the average population ages had the ranage between 50 and 63, the growth of height or diameter was similar. Population No.9 is, however, considered to have better tree forms at glance. Population No.8 showed the heighest value not only in the clear-stem-length ratio. 0.53 but also in the crown-index 0.91. The higher value can be result from those trees having long lateral branches and relatively short crown height, meaning undesirable crown shape. In regard to the fine branchedness and the acuteness of branching angle, the population No.9. is considered to be a better one, whereas there was almost no difference in crown height among populations. 2. Checking the frequency distributions of the ratio of the clear-stem-height to the total height and the crown-indices, some difference between populations are considered. These might be attributed to the previous way of stand mangement which alters the density. 3. In the serration density, the average number of 54 per 1cm needle length, the significant differences exist between individual trees within population but not between populations. A few trees which extremly high serration density were observed. As in serration, so tendencies were in the number of stomata row and resin duct. 4. The population 8 had the resin duct index value of 0.074 as the highest which was twice or triple of the other ones. 5. The patterns of increasing process of the average 10-year-ring-segment were not similar till the 30 years of age, but beyond this, the tendency lines were aggregated. 6. Regading the average summer wood ratio, no diffrence between populations, but in the ranges, i.e. 23 to 30 in population No.8. and 16 to 36 in population No.9., with regad to the specific gravity of wood, there were hardly observed any difference between populations even in the ranges values. As the increase of tree ages, the increase of specific gravity was followed but the increasing patterns were not similar between populations. 7. No significant differences between populations in the average tracheid length and the range were detected. However, the length was increased according to the age increase. The increasing pattern was same between populations.

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Comparison of Heart Rate Variability Indices between Obstructive Sleep Apnea Syndrome and Primary Insomnia (폐쇄성 수면무호흡 증후군과 일차성 불면증에서 심박동률 변이도 지수의 비교)

  • Nam, Ji-Won;Park, Doo-Heum;Yu, Jaehak;Ryu, Seung-Ho;Ha, Ji-Hyeon
    • Sleep Medicine and Psychophysiology
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    • v.19 no.2
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    • pp.68-76
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    • 2012
  • Objectives: Sleep disorders cause changes of autonomic nervous system (ANS) which affect cardiovascular system. Primary insomnia (PI) makes acceleration of sympathetic nervous system (SNS) tone by sleep deficiency and arousal. Obstructive sleep apnea syndrome (OSAS) sets off SNS by frequent arousals and hypoxemias during sleep. We aimed to compare the changes of heart rate variability (HRV) indices induced by insomnia or sleep apnea to analyze for ANS how much to be affected by PI or OSAS. Methods: Total 315 subjects carried out nocturnal polysomnography (NPSG) were categorized into 4 groups - PI, mild, moderate and severe OSAS. Severity of OSAS was determined by apnea-hypopnea index (AHI). Then we selected 110 subjects considering age, sex and valance of each group's size [Group 1 : PI (mean age=41.50±13.16 yrs, AHI <5, n=20), Group 2 : mild OSAS (mean age=43.67±12.11 yrs, AHI 5-15, n=30), Group 3 : moderate OSAS (mean age 44.93±12.38 yrs, AHI 16-30, n=30), Group 4 : severe OSAS (mean age=45.87±12.44 yrs, AHI >30, n=30)]. Comparison of HRV indices among the four groups was performed with ANCOVA (adjusted for age and body mass index) and Sidak post-hoc test. Results: We found statistically significant differences in HRV indices between severe OSAS group and the other groups (PI, mild OSAS and moderate OSAS). And there were no significant differences in HRV indices among PI, mild and moderate OSAS group. In HRV indices of PI and severe OSAS group showing the most prominent difference in the group comparisons, average RR interval were 991.1±27.1 and 875.8±22.0 ms (p=0.016), standard deviation of NN interval (SDNN) was 85.4±6.6 and 112.8±5.4 ms (p=0.022), SDNN index was 57.5±5.2 and 87.6±4.2 (p<0.001), total power was 11,893.5±1,359.9 and 18,097.0±1,107.2ms2(p=0.008), very low frequency (VLF) was 7,534.8±1,120.1 and 11,883.8±912.0ms2 (p=0.035), low frequency (LF) was 2,724.2±327.8 and 4,351.6±266.9ms2(p=0.003). Conclusions: VLF and LF which were correlated with SNS tone showed more increased differences between severe OSAS group and PI group than other group comparisons. We could suggest that severe OSAS group was more influential to increased SNS activity than PI group.

Effects of Molecular Weight of Polyethylene Glycol on the Dimensional Stabilization of Wood (Polyethylene Glycol의 분자량(分子量)이 목재(木材)의 치수 안정화(安定化)에 미치는 영향(影響))

  • Cheon, Cheol;Oh, Joung Soo
    • Journal of Korean Society of Forest Science
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    • v.71 no.1
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    • pp.14-21
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    • 1985
  • This study was carried out in order to prevent the devaluation of wood itself and wood products causing by anisotropy, hygroscopicity, shrinkage and swelling - properties that wood itself only have, in order to improve utility of wood, by emphasizing the natural beautiful figures of wood, to develop the dimensional stabilization techniques of wood with PEG that it is a cheap, non-toxic and the impregnation treatment is not difficult, on the effects of PEG molecular weights (200, 400, 600, 1000, 1500, 2000, 4000, 6000) and species (Pinus densiflora S. et Z., Larix leptolepis Gordon., Cryptomeria japonica D. Don., Cornus controversa Hemsl., Quercus variabilis Blume., Prunus sargentii Rehder.). The results were as follows; 1) PEG loading showed the maximum value (137.22%, Pinus densiflora, in PEG 400), the others showed that relatively slow decrease. The lower specific gravity, the more polymer loading. 2) Bulking coefficient didn't particularly show the correlation with specific gravity, for the most part, indicated the maximum values in PEG 600, except that the bulking coefficient of Quercus variabilis distributed between the range of 12-18% in PEG 400-2000. In general, the bulking coefficient of hardwood was higher than that of softwood. 3) Although there was more or less an exception according to species, volumetric swelling reduction was the greatest in PEG 400. That is, its value of Cryptomeria japonica was the greatest value with 95.0%, the others indicated more than 80% except for Prunus sargentii, while volumetric swelling reduction was decreased less than 70% as the molecular weight increase more than 1000. 4) The relative effectiveness of hardwood with high specific gravity was outstandingly higher than softwood. In general, the relative effectiveness of low molecular weight PEG was superior to those of high molecular weight PEG except that Quercus variabilis showed more than 1.6 to the total molecular weight range, while it was no significant difference as the molecular weight increase more than 4000. 5) According to the analysis of the results mentioned above, the dimensional stabilization of hardwood was more effective than softwood. Although volumetric swelling reduction was the greatest at a molecular weight of 400. In the view of polymer loading, bulking coefficiency reduction of swelling and relative effectiveness, it is desirable to use the mixture of PEG of molecular weight in the range of 200-1500. To practical use, it is recommended to study about the effects on the mixed ratio on the bulking coefficient, reduction of swelling and relative effectiveness.

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