• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.151-152
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• 2023

This study investigates the effect of nano-silica and nano-calcite on the hydration properties and mechanical performance of limestone calcined clay cement (LC³) paste. The pastes were synthesized by replacing limestone with nano-silica and nano-calcite in order to enhance the mechanical properties in both early and late stages of hydration. The nano-calcite enhanced the strength of LC³ pastes at 1 day of hydration, however, the strength decreased compared to the ordinary LC³ pastes afterwards due to excessive amount of carboaluminate produced in the pastes. On the other hand, nano-silica improved the mechanical properties of LC³ pastes at all ages of hydration. This is mainly due to the nucleation effect and pozzolanic reaction of nano-silica, affecting the early age and late ages of hydration, respectively. The nucleation effect of both nanomaterials were confirmed by the analysis of hydration heat, supporting the enhanced early age strength of nanomaterial incorporated LC³ pastes. Furthermore, the dense matrix was shown in the pore size distribution, and the increased C-S-H due to the pozzolanic reaction evidence the improved compressive and splitting tensile strength of nano-silica incorporated LC³ pastes.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.69-77
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• 2002

The purpose of this study was to determine the probability of overweight throughout childhood in relation to the presence of overweight at birch or in early childhood, and presence of overweight in children's parents. Weight and height measures were collected at birth and at ages of 7, 10, 12 years from 655 6th grade primary schoolchildren. Childhood overweight was defined as a body mass index at or above the 85th percentile for age and sex, and overweight in children's parents as a body mass index at or above 27. The prevalence of overweight increased with age of the children. Overweight at birth was not associated with overweight at 12 years of ages. However, overweight at 12 years old was already related to overweight at 7 years old. In comparison to non-overweight peers, overweight children at ages 7(OR = 7.64, 95% CI = 4.32-13.51) and 10 years(OR = 19.69, 95% CI = 11.42-33.94) had a higher rick of becoming overweight at 12 years of age. Among children who was overweight at age 7years, 60.7% remained overweight 5 years later, Yearly increment in BMI of overweight children was larger than that of non-obese children (1.15-1.65kg/m$^2$vs 0.50-0.71kg/m$^2$. As compared with the lower case in mealy increment of BMI, the probability of being overweight at age of 12 years was greater in higher case. BMI values at age 7years were positively correlated with BMI values at age of 10 and 127ear,i, and with annual increments in BMI. But those relationships with birth weight were not observed. Children were at greater risk for overweight if at least ogle parent was overweight. The odds ratio for child overweight associated with maternal overweight was 2.41(95% CI = 1,13-5.IS), and those associated with paternal overweight 1.70(95% CI = 0.92-3.17). And parents' BMIs were positively correlated with children's BMI values and yearly BMI increment. In conclusion, overweight at early childhood and annual inclement in BMI can be important in predicting the prevalence of overweight and the risk that overweight will remain after 7 years of age. The risk of being overweight throughout the childhood increases by the parents'overweight.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.503-511
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• 2018

Background: Sampling a healthy reference population to generate reference intervals (RIs) for complete blood count (CBC) parameters is not common for pediatric and geriatric ages. We established age- and sex-specific RIs for CBC parameters across pediatric, adult, and geriatric ages using secondary data, evaluating patterns of changes in CBC parameters. Methods: The reference population comprised 804,623 health examinees (66,611 aged 3-17 years; 564,280 aged 18-59 years; 173,732 aged 60-99 years), and, we excluded 22,766 examinees after outlier testing. The CBC parameters (red blood cell [RBC], white blood cell [WBC], and platelet parameters) from 781,857 examinees were studied. We determined statistically significant partitions of age and sex, and calculated RIs according to the CLSI C28-A3 guidelines. Results: RBC parameters increased with age until adulthood and decreased with age in males, but increased before puberty and then decreased with age in females. WBC and platelet counts were the highest in early childhood and decreased with age. Sex differences in each age group were noted: WBC count was higher in males than in females during adulthood, but platelet count was higher in females than in males from puberty onwards (P <0.001). Neutrophil count was the lowest in early childhood and increased with age. Lymphocyte count decreased with age after peaking in early childhood. Eosinophil count was the highest in childhood and higher in males than in females. Monocyte count was higher in males than in females (P <0.001). Conclusions: We provide comprehensive age- and sex-specific RIs for CBC parameters, which show dynamic changes with both age and sex.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.3
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• pp.35-62
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• 2008

Objectives : This study has been carried out to look into the methods of early treatment of cerebral palsy and the treatment effect by ages. Methods : The fifteen theses dealing with treatment effects by ages were analyzed, which were selected from the 121 theses retrieved out of the wu-ruan(五軟), wu-chi(五遲), wu-ying(五硬), naotan(腦癱), naoxing-tanhuan(腦性癱癱), during the period between the January 2004 to August 2008 by using the China Academic Journal(CAJ) of China National Knowledge Infrastructure(CNKI). Results : 1. Among the study objects in the 15 theses, it was identified that there were 1.97 times more boys with cerebral palsy than that of girls, and it appeared that there was no significant relationship between gender and the treatment. 2. The early treatment referred to the treatment which was carried out based on the early diagnosis within 6 months to one year after the birth. This is the time when the adaptability and plasticity of the brain are high, and it was found out that the treatment effective as babies are young. 3. For the treatment of cerebral palsy, the combination of Traditional Chinese and Western Medicine Therapy was more frequently used than the exclusive Chinese medical treatment method, and it was more effective. Especially in the case, the Chinese medical treatment was focused on the acupuncture and the Tuina Massage. Conclusions : 1. For the treatment of cerebral palsy, when the age between one and two years old was established as the standard. The younger the babies were, the higher treatment effects were obtained. 2. It appeared that the early treatment of oriental medicine had relatively excellent effects on cerebral palsy, but it turned out that we needed more studies for accurate results.

• Korea journal of population studies
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• v.26 no.1
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• pp.115-141
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• 2003

The aim of this paper is to describe a long-term trend toward earlier retirement and its reversal since 1985 in the United States, together with changes in socioeconomic conditions and social-policy programs which have contributed to this new development. The American people's recent propensity to retire at relatively younger ages was mainly a result of secular increase in individual wealth that had made it possible for them to enjoy higher standard of living without their participation in labor market activities at older ages. In addition to the introduction of compulsory retirement system, both social security retirement pension program and corporate pension system have also contributed significantly to the declining retirement age and its reversal around the mid-1980s. This paper pays full attention to the set of social policy programs which are currently being used to sustain the recent reversal in ages at retirement. The basic question to be raised here, however, is about whether or not the U. S. government will ave to continue to implement the social policies and programs used to discourage the elderly from retiring at relatively younger ages in the future. In this paper, it is argued that labor productivity growth and improvement in work attitude prior to retirement will help the elderly find little difficulties in having higher standard of living, despite their further lengthening of life expectancy at birth and post-retirement survival chances, the latter being often called the "third life". Most American people hope that the social-policy programs that have promoted early retirement will remain unchanged in the first part of the 21st century while they will put significant financial burden on their future descendants who have to work in the paid labor market. Taking this observation in consideration, this paper concludes that the U. S. government has to focus more on developing the programs that improve work propensity and labor productivity among the currently working-age population rather than continuing to implement the programs that sustain the recent reversal in retirement ages.ment ages.

• Journal of the Korean Institute of Rural Architecture
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• v.8 no.2
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• pp.72-79
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• 2006

This study is to find out formation and development process of urban area in modern ages(1870-1949) focused Yanji city in the east-northern area in china. After the discharge of confinement in the late 19 century, the settlements were formed around east area, that is, the present Yanji urban area. The japanese consular office had been moved in east area since the beginning of the early 20 century, and so, the existing residents moved to west area. And the military and administrative facilities were located on the urban outskirts. After the September 18th Incident on 1932, Yanji had been constructed with the strategic center area under the urban planning. The administrative facilities of those days had been altered to he functional branches and educational facilities, and become the basis of development of Yanji city.

• International Journal of Reliability and Applications
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• v.3 no.1
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• pp.17-23
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• 2002

The class of “new better than used of a specified age” is a large and practical class of life distributions. Its properties, applicability, and testing was discussed by Hollander, Park and Proschan (1986). Their test, while remaining the yardstick for this class, suffers from weak efficiency and weak power, especially for specified ages below the average age. Thus, it is beneficial to have an alternative testing procedure that would work better for early ages and still work well for later ages. This is exactly the subject of the current note. The test developed here is also simpler than that of Hollander, et. al. (1986).

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.103-110
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• 2009

Since the mechanical properties of cement-based materials are time-dependent due to the prolonged cement hydration process, those of fiber reinforced concrete(FRC) may also be time-dependent. Toughness is one of important properties of FRC. Therefore, it should be investigated toughness development of FRCs with curing ages to fully understand the time-dependent characteristics of FRCs. To this end, the effect of curing ages on flexural toughness development of steel fiber reinforced concrete is studied. Three point bending test with notched beam specimen was adapted for this study. Hooked-end steel fiber(DRAMIX 40/30) was used as a fiber ingredient to investigate w/c ratio and fiber volume fraction effect on toughness development during curing. Three different water-cement ratios(0.44, 0.5 and 0.6) and fiber volume fractions(0%, 0.5% and 1%) were used as influence factors. Each mixture specimens were tested at five different ages, 0.5, 1, 3, 7 and 28 days. The study shows that flexure toughness development with age is quite different than other concrete material properties such as compressive strength. The study also shows that the toughness development trend correlates more closely to water/cement ratio than to fiber volume fraction.

• Korean Institute of Interior Design Journal
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• no.13
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• pp.238-248
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• 1997

The spatial form of architecture in the same era has its own common characteristic spatial form. This study is based on this proposition and is focused on how architectural spatial forms have been changed up to now after modern ages(from the beinging of 1900s to the early days of 1990s ; from early modern age, golden modern age, post modern, late modern architecture to recent experimental trend) and how architectural theories of spatial forms will be changed in the future is predicted.

• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.83-115
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• 2013

Erroneous fission-track (FT) ages caused by an inappropriate calibration in the initial stage of FT dating were redefined by re-experiments and zeta calibration using duplicate samples. Revised FT zircon ages newly define the formation ages of Yucheon Group rhyolitic-dacitic tuffs as Late Cretaceous to Early Paleocene ($78{\pm}4$ Ma to $65{\pm}2$ Ma) and Gokgangdong rhyolitic tuff as Early Eocene ($52.1{\pm}2.3$ Ma). In case of the Early Miocene volcanics, FT zircon ages from a dacitic tuff of the upper Hyodongri Volcanics ($21.6{\pm}1.4$ Ma) and a dacitic lava of the uppermost Beomgokri Volcanics ($21.3{\pm}2.0$ Ma) define chronostratigraphies of the upper Beomgokri Group, respectively in the southern Eoil Basin and in the Waeup Basin. A FT zircon age ($19.8{\pm}1.6$ Ma) from the Geumori dacitic tuff defines the time of later dacitic eruption in the Janggi Basin. Based on FT zircon ages for dacitic rocks and previous age data (mostly K-Ar whole-rock, partly Ar-Ar) for basaltic-andesitic rocks, reference ages are recommended as guides for stratigraphic correlations of the Miocene volcanics and basements in SE Korea. The times of accumulation of basin-fill sediments are also deduced from ages of related volcanics. Recommended reference ages are well matched to the whole stratigraphic sequences despite complicated basin structures and a relative short time-span. The Beomgokri Group evidently predates the Janggi Group in the Eoil-Waeup basins, while it is placed at an overlapped time-level along with the earlier Janggi Group in the Janggi Basin. Therefore, the two groups cannot be uniformly defined in a sequential order. The Janggi Group of the Janggi Basin can be evidently subdivided by ca. 20 Ma-basis into two parts, i.e., the earlier (23-20 Ma) andesitic-dacitic and later (20-18 Ma) basaltic strata.