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Studies on the Effect of Fiber Reinforcing upon Mechanical Properties of Concrete and Crack Mode of Reinforoed Concrete (섬유보강이 콘크리트의 역학적 특성과 철근콘크리트의 균열성상에 미치는 영향에 관한 연구)

  • 박승범
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.20 no.2
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    • pp.4645-4687
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    • 1978
  • This study was attempted to investigate the mechanical properties of concrete and crack control effects of reinforced concrete with steel and glass fiber. The experimental program includes tests on the properties of fresh concrete containing fibers, compressive strength, tensile strength, flexural strength, Young's modulus, Shrinkage and deformation of steel or glass fiber reinforced concrete. Also this study was carried out to investigate the effect of steel or glass fiber to retard the development in reinforced concrete subject to uniaxial tension and thus facilitate the use of steels of higher strength. The major conclusions that can be drawn from the studies are as follows: 1. The effect of the fibers in various mixes on fresh concrete confirmed that fibers do have a significant effect on the properties of fresh concrete, bringing much more stable and exhibiting a signiflcant reduction in surface bleeding, and that the cohesion is greatly improved and the internal resistance increases with fiber concentration. But the addition of an excess contents and length of fibers brings about the reduction of workability. 2. With the addition of steel fibers(1.5% Vol.) to concrete, the compressive strength as compared with plain concrete showed a very slight increase, but excess addition, over 1.5% Vol. of steel and glass fiber reduced its strength. 3. Splitting tensile strength of fiber reinforced concrete showed a significant increase tendency, as compared with plain concrete. In case of containing steel fiber (2.5%, 30mm), it showed that the maximum increase rate of 1.48 times as much rate, and in case of containing glass fiber (2.5%, 30mm), the increase rate of strength was 1.25 times as much rate. 4. Flexural strength of fiber reinforced concrete showed a significant tendency, as compared with plain concrete. Containing steel fiber (2.5%, 30mm) showed the maximum increase rate of 1.64 times as much rate and containing glass fiber (2.5%, 30mm) showed the increase rate of strength of 1.32 times as much rate, and in general, the 30mm length brougth the best results. 5. The strength ratio ($\sigma$b/$\sigma$c and $\sigma$t/$\sigma$c) increased, when steel fiber's average spacing was up to 3.05mm, but decreased when beyond 3.05mm, and it was confirmed that tensile or flexural strengths of steel fiber reinforced concrete are apparently governed by fiber's average spacing. 6. The compressive strain of fiber reinforced concrete showed a significant increasing tendency as the fiber was added, but Young's modulus. with the addition of steel and glass fibers, showed a slight decrease tendency. And according to the increase of flexural strength, a considerable increase was seen in toughness. 7. With the addition of fiber's the shrinkage of concrete was significantly decreased, in both case of adding steel fibers 12.5%, 30mm, and showed a significant decrease ratio, in average 30.4% and 36.7%, as compared with plain concrete. 8. With the increase of fiber volume fraction and length, the gained stress in reinforcing bar in concrete specimens increased in all crack widths, but at different rates, with the decrease of fiber diameter, the stress showed a considerable increasing tendency. And the duoform steel fibers showed the greatest improvement, as compared with the other types tested. 9. The influence of fiber dimensions in order of significanse on the machanical properties of concrete and the crack control of reinforced concrete was explained as follows: content, length, aspect ratio and dimeter.

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A Study on Efficiently Designing Customer Rewards Programs (고객 보상프로그램의 효율적 구성에 관한 연구)

  • Kim, Sang-Cheol
    • Journal of Distribution Science
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    • v.10 no.1
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    • pp.5-10
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    • 2012
  • Currently, the rewards programs offered by many companies to strengthen customer relationships have been working quite well. In addition, many companies' rewards programs, designed for stabilizing revenue, are recognized to be effective. However, these rewards programs are not significantly differentiated between companies and there are no accurate conclusions currently, which can be made about their effects. Because of this, a company with a customer rewards program may not comprehend the true level of active participation. In this environment some companies' rewards programs inadvertently hinder business profitability as a side effect while attempting to increase customer loyalty. In fact, airline and oil companies pass on the financial cost of their programs to the customer, and as a result, they have been criticized publicly. The result of this is that the corporations with bad rewards programs tend to get a bad image. In this study of stores' rewards programs, we centered our focus on the design of the program. The main problem in this study is to recognize the financial value of the rewards program and whether it can create a competitive edge for the companies despite the cost issues experienced by them. Customers receiving financial rewards for their business may be just as satisfied with a particular company or store versus those who are not, and the program, perhaps, does not form a distinctive competitive advantage. When the customer is deciding between competing companies to secure their product needs with, we wanted to figure out how much of an affect a valuable reward program had on their decision making. To evaluate this, we set the first hypothesis as, "based on the level of involvement of the customers, there is a difference between customers' preferences for rewards programs." In the results of Experiment 1 we saw that in a financial compensation program for high-involvement groups and low-involvement groups, significant differences appeared and Hypothesis 1 was partially supported. As for the second hypothesis that "customers will have different preferences between a financial rewards programs (SE) and a joint rewards programs (JE)," the analysis showed that the preference for JE was significantly higher than that for other programs. In addition, through Experiment 2, we were able to find meaningful results, which revealed that consumers have shown a significant difference in their preferences between SE and JE. The purpose of these experiments was to enable the designing of a rewards program by learning how to enhance service information distribution and strengthen customer relationships. From the results, there should be a great amount of value for future service-related endeavors and academic research programs. The research is significant, because the results can be found to have a positive effect on reward program designs however, it does have the following limitations. First, this study was performed using an experiment, and all experiments have limitations. Second, although there was an individual evaluation and a joint evaluation, setting a proper evaluation criteria was difficult. In this study, 1,000 Korean won (KRW) in the individual evaluation had a value of 2 points, and, in the joint evaluation, 1,000 KRW had a value of 1 point. There may have been alternative ways to differentiate the evaluations to obtain the proper results. In this study, since there was no funding, the experiments were performed orally however, this was complementary to the study. Third, the subjects who participated in this experiment were students. Conducting this study through experimentation was unavoidable for us, and future research should be conducted using an actual program with the target customers.

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Etiology, Management, and Prognosis of Severe Hyperbilirubinemia (Serum Bilirubin Level=25 mg/dL) in Newborn (중증 고빌리루빈혈증(혈청 빌리루빈 >25 mg/dL)의 발병 원인과 치료 및 예후)

  • Hwang, Jong Hee;Lee, Ji Hyun;Kim, Yu Jin;Koo, Su Hyun;Lee, Jang Hun;Choi, Chang Won;Chang, Yun Sil;Park, Won Soon
    • Clinical and Experimental Pediatrics
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    • v.48 no.10
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    • pp.1102-1106
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    • 2005
  • Purpose : The present study examined the etiology, management, and the difference of prognosis according to methodology of treatment in severe hyperbilirubinemia with total serum bilirubin levels of more than 25 mg/dL. Methods : Medical records of severe hyperbilirubiemia in newborns(serum level=25 mg/dL) admitted to the NICU of Samsung Medical Center between October 1994 and June 2004 were reviewed retrospectively. Infants were grouped according to methodology of treatment : Group I(phototherapy only, n=42), Group II(exchange transfusion, n=6). And In addition, we evaluated the etiology and the difference of prognosis. Results : A total of 48 documented cases of severe hyperbilirubinemia were identified. Birth weight was significantly lower in Group 2($2,852{\pm}1,085g$) compared to Group 1($3,137{\pm}437g$)(P<0.05). There were no significant differences in gestational age, sex, mode of delivery, inborn, age at presentation, and age at first examination and admission between the two study groups. Maximal bilirubin level was significantly higher in Group 2($45{\pm}16mg/dL$) compared to Group 1($29{\pm}6mg/dL$) (P<0.05). But there were no significant differences in neurologic outcome. Conclusion : Our study suggests that the present guidelines for managing hyperbilirubinemia in newborns should be effective but follow-up with the first postnatal week would be necessary for each detection and treatment in the newborn infants with high risk of severe hyperbilirubinemia.

Predicting Migration of a Heavy Metal in a Sandy Soil Using Time Domain Reflectometry (TDR을 이용한 사질토양에서의 중금속 이동 추정)

  • Dong-Ju Kim;Doo-Sung Baek;Min-Soo Park
    • Journal of Korea Soil Environment Society
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    • v.4 no.1
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    • pp.109-118
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    • 1999
  • Recently, transport parameters of conservative solutes such as KCl in a porous medium have been successfully determined using time domain reflectometry (TDR) . This study was initiated to Investigate the applicability of TDR technique to monitoring the fate of a heavy metal ion in a sandy soil and the distribution of its concentration along travel distance with time. A column test was conducted in a laboratory that consists of monitoring both resident and flux concentrations of $ZnCl_2$in a sandy soil under a breakthrough condition. A tracer of $ZnCl_2$(10 g/L) was injected onto the top surface of the sample as pulse type as soon as a steady-state condition was achieved. Time-series measurements of resistance and electrical conductivity were performed at 10 cm and 20 cm of distances from the inlet boundary by horizontal-positioning of parallel TDR metallic rods and using an EC-meter for the effluent exiting the bottom boundary respectively. In addition. Zn ions of the effluent were analyzed by ICP-AES. Since the mode and position of concentration detected by TDR and effluent were different, comparison between ICP analysis and TDR-detected concentration was made by predicting flux concentration using CDE model accommodating a decay constant with the transport parameters obtained from the resident concentrations. The experimental results showed that the resident concentration resulted in earlier and higher peak than the flux concentration obtained by EC-meter, implying the homogeneity of the packed sandy soil. A close agreement was found between the predicted from the transport parameters obtained by TDR and the measured $ZnCl_2$concentration. This indicates that TDR technique can also be applied to monitoring heavy metal concentrations in the soil once that a decay constant is obtained for a given soil.

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A Study on the Cooking in 'The Kosa-sibi Jip' (2) ("고사십이집(攷事十二集)"의 조리가공에 관한 분석적 연구(2))

  • 김성미
    • Journal of the East Asian Society of Dietary Life
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    • v.4 no.3
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    • pp.1-19
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    • 1994
  • In this paper, twenty-five kinds of food presented in Sooljip(戌集) 5 and 6 of Food collections of 'Kosa-sibi Jip(攷事十二集)' have been classified into four : Staple food, subsidiary food, Tuck(rice cake) and Han-gwa(Korean confectionery), and Tang-jng and tea. Cooking processes have been examined and scientifically analyzed in terms of cooking, Fourteen kinds of Jook (thick gruel with cereal) as well as Urak-Jook were presented among the methods of making Jook, one of staple foods. Milk and ground rice were boiled together into Urak-Jook, which was nutritious because of carbohydrate, added to milk. Hong-sa Myun was mode of ground shrimps, ground bean, ground rice and flour which were kneaded together. It was a nutritiously balanced food. Nineteen kinds of Kimchi presented in this book were classified by the recipes. The five of Jook-soon Ja, U-so Ja, Tam-bok Ja and Jo-gang were made by adding red malt and cereals(boiled rice or candies). Jo-gang, Jo-ga and Jo-gwa-chae were made by adding salt and rice wine. With salt and fermenters added, eight were made. Chim-jup-jeo-ga was made by adding Jang(soy-bean sauce) and the inner chaff of wheat instead of salt. The four of Ka-za-san, Hwang-gwa-san, Tong-gwa-san and Jo-gang were made by adding salt and vinegar. Jo-gang was made by adding salt, rice wine, residue of rice wine and candies. The four of Kae-mal-ga, Ku-cho-chim-chae, Un-gu-hwa and Suk-hwa-chim-chim-chae were made by adding salt and spices. San-got-Kimchi was made without salt. San-got-Kimchi and Suk-hwa-chim-chae were made originally in Korea. Suk-hwa-chim-chae, in particular, was first classified as a kind of Kimchi in this book and oysters were added, which is notable. Pork could be preserved longer when smoked oven the weak fire of thatch ten days and nights. Dog meat was sauced and placed on the bones in a pot. A porcelain was put on the top of the pot. Flour paste sealed the gap between the porcelain and the pot. Some water was poured into the porcelain, and the meat was steamed, with two or three thatched sacks burned, which was a distilled dry steaming. This process has been in use up to now. Various cooking methods of chicken were presented from in Umsik-dimi-bang to in Chosun Musang Sinsik Yori Jebup. These methods were ever present regardless of ages. Such measuring units as Guin(斤) and Nyang(兩) were most frequently used in cooking processes of this book, except in case of Jang(soy bean sauce), vinegar and liquor. Twenty eight kinds of kitchenware and cookers were used, of which porcelains wee most used and pans and sieves followed. The scientific eight cooking methods were as follows. First, salt was refined through saturated solution. Next, it was recommended Hong-sa Myun containing shrimps should not be taken along with pork, which is thought to be a proper diet in terms of cholesterol contained by shrimps and pork. Third, meat was coated with thin gruel and quickly roasted and cleared of the dried gruel membrane, which prevented nutrients from exuding and helped to make the meat well-done. Fourth, The fruit of paper mulberry trees has the protease which can soften meat. Therefore when meat was boiled with th fruit of paper mulberry trees, it can be softened easily. Fifth, pork was smoked over the weak fire of thatch. Sixth, in cooking dog meat, distilled dry steaming raised the boiling point and made it possible to preserve meat longer. Seventh, in boiling the sole of a bear, lime was added, which made meat tender by making the pH lower or higher than that of raw meat. Finally, in boiling down rice gluten, a porcelain in the pot prevented boiling over the brim, which is applied to pots in which to boil medical herbs.

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Current status, mechanism and control of herbicide resistant weeds in rice fields of Korea (한국 논에서 제초제 저항성잡초의 발생 현황, 메카니즘 및 방제)

  • Park, Tae Seon;Seong, Ki Yeong;Cho, Hyun Suk;Seo, Myung Chul;Kang, Hang Won;Park, Kee Woong
    • Korean Journal of Agricultural Science
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    • v.41 no.2
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    • pp.85-99
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    • 2014
  • Sulfonylurea (SU)-resistant weeds of eight annual weeds, Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and four perennial weeds, Scirpus planiculmis, Sagittaria pigmaea, Eleocharis acicularis and Sagittaria trifolia as of 2013 since identification Monochoria korsakowii in the reclaimed rice field in 1998. And the resistant Echinochloa oryzoides to ACCase and ALS inhibitors has been confirmed in rice fields of the southern province, Korea in 2009. In the beginning, the M. vaginalis, S. juncoides and C. difformis of these SU-resistant weeds were rapidly and individually spreaded in different fields, however, these resistant weeds have been occurring simultaneously in the same filed recently. The resistant biotype by weed species demonstrated about 10-to 1,000-fold resistance, based on $GR_{50}$ values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on $GR_{50}$ values. The products and applied area of SU-included herbicides have been increased rapidly, and have accounted for about 69% and 96% in Korea, respectively. In Korea, the main cause of SU-resistant weed is extensive use of these herbicides. The top ten herbicides by applied area were composed of all SU-included herbicides by 2003. The concentrated and successive treatment of ACCase and ALS inhibitors for control of barnyardgrass in rice led up to the resistance of E. oryzoides. Also, SU-herbicides like pyrazosulfuron-ethyl and imazosulfuron which effective to barnyardgrass can be bound up with the resistance of E. oryzoides. The ALS activity isolated from the resistant biotype of M. korsakowii to SU-herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity ($I_{50}$) of the SU-resistant M. korsakowii was 14-to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of [$^{14}C$]bensulfuron uptake and translocation. Acetolactate synthase (ALS) genes from M. vaginalis resistant and susceptible biotypes against SU-herbicides revealed a single amino acid substitution of proline (CCT), at 197th position based on the M. korsakowii ALS sequence numbering, to serin (TCT) in conserved domain A of the gene. Carfentrazone-ethyl and pyrazolate were used mainly to control SU-resistant M. vaginalis by 2006 in Korea. However, the alternative herbicides such as benzobicyclone, to be possible to control simultaneously the several resistant weeds, have been developing and using broadly, because the several resistant weeds have been occurring simultaneously in the same fieled. The top ten herbicides by applied area in Korea have been occupied by products of 3-way mixture type including herbicides with alternative mode of action for the herbicide resistant weeds. Mefenacet, fentrazamide and cafenstrole had excellent controlling effects on the ACCase and ALS inhibitors resistant when they were applied within 2nd leaf stage.

Radiographic examination of the Osseous Abnormalities of the Mandibular Condyle Using Cone Beam Computed Tomography (Cone Beam CT를 이용한 하악 과두의 골 이상에 대한 방사선적 분석)

  • Kim, Yu-jin;Kim, Yun-sang;Kim, Min-jeong;Sim, Hun-Bo;Oh, Sang-chun
    • Journal of Dental Rehabilitation and Applied Science
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    • v.25 no.3
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    • pp.211-224
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    • 2009
  • The objective of this study is to examine the condylar surfaces in order to find out the types, the incidence and common occurrence area of the osseous abnormalities of the condyles according to the age, genders and the purpose of CT taking, and to compare those between the groups for TMD diagnosis and the other groups. 3D CT images of 199 patients which were scanned with the $i-CAT^{TM}$ Cone Beam Computed Tomography were collected from Sanbon Dental Hospital of Wonkwang university and the MPR images were transfered to the TMJ mode to be showed serial sagittal images and coronal images. The images were macroscopically examined by three independent observers for the types and incidences of the osseous abnormalities, their common occurrence area and general shapes of the condyles. As a result, type F is most common ever than type N. The common occurrence area in sagittal images is antero-superior and superior area except for type D-C which were showed on postero-superior area commonly. In coronal images, latero-superior and superior area is most common except for type E which were present on mesio-superior and superior area most frequently. The osseous abnormalities of the condyles are more common in TMD diagnosis group except for type D-C, that is type N and type D-C are more common in the other groups. In this study, abnormalities of the condyles are classified into 6 types and it has a common occurrence area each. And TMD diagnosis group shows a tendency to have higher rate for osseous abnormalities except for type D-C.

Comparative study on effects of volume-controlled ventilation and pressure-limited ventilation for neonatal respiratory distress syndrome (신생아 호흡곤란 증후군에서 volume-controlled ventilation과 pressure-limited ventilation의 효과에 관한 비교연구)

  • Kim, Jae Jin;Hwang, Mun Jung;Lee, Sang Geel
    • Clinical and Experimental Pediatrics
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    • v.53 no.1
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    • pp.21-27
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    • 2010
  • Purpose : In contrast with traditional time-cycled, pressure-limited ventilation, during volume-controlled ventilation, a nearly constant tidal volume is delivered with reducing volutrauma and the episodes of hypoxemia. The aim of this study was to compare the efficacy of pressure-regulated, volume controlled ventilation (PRVC) to Synchronized intermittent mandatory ventilation (SIMV) in VLBW infants with respiratory distress syndrome (RDS).Methods : 34 very low birth weight (VLBW) infants who had RDS were randomized to receive either PRVC or SIMV with surfactant administration : PRVC group (n=14) and SIMV group (n=20). We compared peak inspiratory pressure (PIP), duration of mechanical ventilation, and complications associated with ventilation, respectively with medical records. Results : There were no statistical differences in clinical characteristics between the groups. After surfactant administration, PIP was significantly lower during PRVC ventilation for 48hrs and accumulatevive value of decreased PIP was higher during PRVC ventilation for 24hrs (P<0.05). Duration of ventilation and incidence of complications was no significant difference. Conclusion : PRVC is the mode in which the smallest level of PIP required to deliver the preset tidal volume in VLBW infants with RDS, adaptively responding to compliance change in lung after surfactant replacement.

Epidemiological Studies on Giardia Infection Associated with environmental Pollution (Giardia에 의한 환경오염(環境汚染)과 감염(感染)에 관한 역학적(疫學的) 연구(硏究))

  • Lee, Keun-Tae;Kim, Seok-Chan;Song, Jong-Sool;Chung, Pyung-Rim
    • Journal of agricultural medicine and community health
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    • v.9 no.1
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    • pp.56-66
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    • 1984
  • Giardia lamblia is a pathogenic flagellate causing intestinal disorders such as diarrhea, abdominal pain and malabsorption of nutrients. Giardia is mainly infected by the ingestion of contaminated foods per os. Craun (1979) has recently reported that mass infection of this flagellate through the contaminated water supply systems is one of public health hazards. Also, so-called traveller's diarrhea is sometimes caused by Giardia infection (CDC, U.S.A., 1971). However, a few epidemiological studies figuring out the mode of infection or control measures of Giardia infection has been done so far in Korea. The present study was aimed to know the prevalence of Giardia infection in several Korean populations, detectability of this flagellate in water systems and the viability of the cysts against sewages and disinfectants applying to drinking water. In the present study, 388 stool specimens from orphanage children in Chun-joo, Chung-joo, On-yang and Chun-an areas and 538 stool specimens from inhabitants in Woo-do, In-chon, and Chun-joo were examined by formalin-ether concentration technique to detect out Giardia cysts. On the other hand, water samples from 14 sites of Han River and its tributaries were collected in May through July, 1984. Fifty liter of water sample in each sampling site was then filtered through water filtering system deviced by U.S. Environmental Proutection Agency and the sediments rinsed out from the thread rolls, a part of water filtering system, were examined to detect out the Giardia cysts. In order to observe the viability of Giardia cysts in the sewage samples, the cysts were treated in it at $4^{\circ}C$ or $25^{\circ}C$ for 7 through 28 days. For this purpose, the cysts were also exposed to various concentrations of disinfectants such as chlorine, iodine and ozone gas for proper time intervals. After treatment, the viability test of the Giardia cysts were carried out by method of Rice and Schaefer (1981) with minor modification. The results obtained in this study were as follows : 1) The detection rates of G lamblia cysts in the stool specimens were 18.3% in orphans and 4.3% in general examinees. 2) The prevalences of Giardia Infection were higher in the young age groups than in-adults. The highest positive rate was 18.4% in the age group less than 10. 3) Of 14 water specimens sampled from Han River system and its tributaries around the Seoul area, the Giardia cysts were detected from 4 samples, and no cyst was found in the water supply systems. 4) The cysts treated in the sewage survived for 28 days at $4^{\circ}C$ and for 13 days at $25^{\circ}C$. 5) The cysts were completely destroyed within 60 minutes by exposure to 8 mg/l of residual chlorine at 4g and within 30 minutes by exposure to the same concentration of chlorine at $25^{\circ}C$. 6) The cysts were all dead when exposed to 1 mg/1 of iodine for 60 minutes at $4^{\circ}C$ or $25^{\circ}C$. 7) The cysts were destroyed after 10 minute exposure in 0.15 mg to 0.25mg of residual ozone gas per liter. Summarizing the above results, it is considered that Giardia infection is regarded as water-borne disease and the cysts are able to be controlled by the application with the disinfectants in the water supply systems.

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A Study on Recovery from Potentially Lethal Damage Induced by $\gamma-Irradiation$ in Plateau-phase Vero Cells in vitro (평형기의 Vero세포계에서 방사선($\gamma$-선) 조사 후 발생한 잠재치사 손상의 회복에 관한 연구)

  • Kim, Il-Han;Choi, Eun-Kyung;Ha, Sung-Whan;Park, Charn-Il;Cha, Chang-Yong
    • Radiation Oncology Journal
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    • v.6 no.1
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    • pp.1-11
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    • 1988
  • Recovery from potentially lethal damage (PLDR) after irradiation was studied in plateau-phase culture of Vero cells in vitro. Unfed plateau-phase cells were irradiated with dose of 1 to 9Gy using Cs-137 irradiator. Cells then were incubated again and left in situ for 0, 1, 2, 3, 4, 5, 6, and 24 hours and then were trypsinized explanted, and subcultured in fresh RPMI-1640 media containing $0.33\%$ agar. Cell survival was measured by colony forming ability. An adequate number of heavily irradiated Vero cells were added as feeder cells to make the total cell number constant in every culture dish. As the postirradiation in situ incubation time increased, surviving fraction increased by PLDR. The rate of PLDR was so rapid that increased surviving fraction reached saturation level at 2 to 4 hours after in situ incubation. As the radiation dose increased, the rate of PLDR fastened and the magnitude of increased surviving fraction at saturation level by PLOR also increased. In analysis of cell survival curve fitted to the linear-quadratic model, the linear inactivation coefficient $(\alpha)$ decreased largely and reached nearly to zero but the quadratic inactivation coefficient $(\beta)$ increased minimally by increment of postirradiation in situ incubation time. So PLDR mainly affected the damage expressed as $\alpha$, In the multitarget model, significant change was not obtained in $D_0\;but\;in D_q$. Therefore, shoulder region in cell survival curve was mainly affected by PLDR and terminal slope was not influenced at all. And dose-modifying factor by PLDR was relatively higher in shoulder region, that is, in low dose area below 3 Gy.

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