• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.4
• /
• pp.61-69
• /
• 2019

Accelerated aging test for the double base propellant was carried out at three different temperatures (60, 70, and $75^{\circ}C$) for over a year. To evaluate the aging characteristics of the double base propellant, the stabilizer contents and thermal decomposition kinetics were analyzed by using high performance liquid chromatography (HPLC) and AKTS-Thermokinetics software. As a result, stabilizer contents in the double base propellant gradually decreased according to the aging temperature and aging duration. The consumption rate of 2-NDPA in the accelerated aged propellants showed that it was two times faster at $75^{\circ}C$ in compared with ther rate at $70^{\circ}C$. These experimental values were simulated by the SB kinetic model, and it was shown that the two-step model with constant reaction orders n1=1 and n2=0 best describes the process of the stabilizer depletion for the double base propellant.

• 한국노년학
• /
• v.41 no.4
• /
• pp.527-546
• /
• 2021

This study examined the effect of past acceptance on suicidal ideation in older adults and verified double mediation effects of attitude to aging and depression. The responses of 329 aged 65 years or older who participate in senior welfare centers in Seoul and Gyeonggi-do were used. As an analysis method, the double mediation effect was confirmed through serial multiple mediation model verification using the SPSS PROCESS macro program. The followings are the results of the study. First, the past acceptance had a significant effect on the aging attitude, the aging attitude on the depression, and the depression on the suicidal ideation, but the direct effect of past acceptance on the suicidal ideation was not significant. Second, double mediation effects of attitude to aging and depression were significant in the relationship between past acceptance and suicidal ideation. Based on these results, practical and policy interventions to prevent suicide in old age were suggested.

• Archives of Plastic Surgery
• /
• v.47 no.4
• /
• pp.290-296
• /
• 2020

In many aging individuals, dermatochalasis and involutional ptosis appear together. Therefore, for functional and aesthetic purposes, ptosis correction and upper blepharoplasty are performed together. The aim of this article is to investigate factors that should be considered in order to achieve good results when simultaneously performing involutional ptosis correction and upper blepharoplasty in aging patients. Involutional ptosis is usually corrected through aponeurosis advancement in mild cases. In moderate or severe ptosis, the Muller muscle and aponeurosis are used together to correct ptosis. Using the two muscles together has the advantages of reducing lagophthalmos and increasing the predictability of outcomes after surgery. Broadly speaking, the surgical method used for involutional ptosis varies depending on the specific case, but unlike congenital ptosis, it is often not necessary to perform overcorrection. In particular, if there are problems such as severe dry-eye symptoms or risk of lagophthalmos, undercorrection should be considered. When performing ptosis correction, the surgeon should be careful not to overdo skin excision; instead, limited excision should be performed. After ptosis surgery, the brow may descend and the double fold may look too small. However, in order to make the double eyelids look larger, the surgeon should consider making the double eyelid design high rather than excising an excessive amount of skin. In some cases, to obtain more natural double eyelids and favorable results, it may be necessary to perform a sub-brow lift or forehead lift before or after involutional ptosis surgery.

• Phonetics and Speech Sciences
• /
• v.13 no.1
• /
• pp.73-79
• /
• 2021

This study investigated the change in lip movement during speech according to aging. For the study, 15 elderly women with an average of 69 years and 15 young women with an average of 22 years were selected. To measure the movement of the lips, the ratio between the minimum point and the maximum point of movement when pronouncing a double vowel was analyzed in pixel units using image analysis software. For clinical utility, the software was produced by applying an automated algorithm and compared with the results of handwork. This study found that the range of the width and length of lips in double vowel tasks was smaller for the elderly than that of the young. A strong positive correlation was found between manual and automated methods, indicating that both methods are useful for extracting lip contours. Based on the above results, it was found that the range of the lips decreased when ignited as aging progressed. Therefore, monitoring the condition of lip performance by simply measuring the movement of lips before aging progresses, and performing exercises to maintain lip range, will prevent pronunciation problems caused by aging.

• Journal of the Korean Society for Heat Treatment
• /
• v.33 no.5
• /
• pp.226-231
• /
• 2020

The Cu-Co-Si alloy shows high strength by forming precipitates by aging precipitation heat treatment of supersaturated solid solution treated with solution treatment such as Cu-Ni-Si alloy, and the Co₂Si precipitated phase is dispersed in the copper matrix. The effect of aging treatment on the microstructure, mechanical and electrical properties of Cu-Co-Si alloys for electronic devices was investigated. As a results of SEM/EDS analysis, it was found that Co₂Si precipitates of 30~300 nm size were distributed in grains. By performing the double aging treatment, it was possible to improve the strength and electrical conductivity by dispersing the fine precipitate evenly.

• Asian Journal of Atmospheric Environment
• /
• v.4 no.2
• /
• pp.106-114
• /
• 2010

By the application of novel double detector system of micro-PIXE that can detect light elements (Z<14), we made an attempt to provide a thorough discussion on the aging processes of Asian dust (hereafter called "AD") particle by reaction with sea-slat. The elemental spectra and maps obtained from the microbeam radiation of micro-PIXE to individual AD particles were useful for fractionating AD particles into both internally and externally mixed particles. A spatial distribution of elements in a minute domain of single particle obtained by scanning the microbeam irradiation enabled us not only to estimate the chemical mixing state of individual AD particles but also to presume their aging processes in both ambient air and cloud. By calculating the normalized micro-PIXE net count of elements, it was possible to classify individual AD particles into three distinct groups (i.e., (1) Aging type 1: AD particle coated by the gaseous Cl evaporated by the reaction between artificial acids and sea salt; (2) Aging type 2: AD particle mixed with sea salt but no additional reaction with artificial acids; and (3) Non-aged type) A relatively high transformation rate (63.3-75.9%) was shown in large particles (greater than $5.1\;{\mu}m$ in diameter).

• Journal of Digital Convergence
• /
• v.19 no.10
• /
• pp.357-365
• /
• 2021

This study is a descriptive survey research for identifing double mediating effect of ego-integrity and cultural competency and the moderated mediation effect of Wisdom on the relationship between basic pychological needs and successful aging. The participants were 211 elderly people aged at least 60 from June 2020 to March 2021. Data were collection by self-report questionnaire. Data was analyzed by Hayes' number 6 and 91 models using the SPSS/25.0 program and SPSS PROCESS MACRO. According to the study, the ego-integration and cultural competence were effected to double mediated in successful aging, and the ego-integration and cultural competence were effected to successful aging through moderated mediation by wisdom. Therefore, it is needed to develop welfare policy and strategy for the elderly to enhance ego-integration and cultural competence by effort to satisfy basic pychological needs and wisdom.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.150-153
• /
• 2002

Solar UV light is a well-known carcinogen. UVA radiation is probably carcinogenic to humans. In addition, recent investigations point to the importance of UVA irradiation in the photoaging. We investigated the mechanism of sequence- specific DNA damage using $\^$32/P-Iabeled DNA fragments in relation to carcinogenesis and aging. Furthermore, we investigated whether UVA accelerates the telomere shortening in human WI-38 fibroblasts. The exposure of double- stranded DNA fragments to 365 nm light in the presence of endogenous sensitizers produced sequence-specific cleavage at the 5' site of 5'-GG-3' and 5'-GGG-3' sequences. In addition, HPLC analysis revealed that sensitizers plus 365 nm light increased the 8-oxodG content of double-stranded DNA. We discuss the mechanisms of guanine-specific DNA damagecaused by excited photosensitizers in relation to carcinogenesis and aging.

• Molecules and Cells
• /
• v.20 no.2
• /
• pp.297-302
• /
• 2005

The integrity and proper functioning of telomeres require association of telomeric DNA sequences with specific binding proteins. We have characterized PLP-1, a $PUR{\alpha}$ homolog encoded by F45E4.2, which we previously identified as a candidate double stranded telomere binding protein, by affinity chromatography followed by mass spectrometry. PLP-1 bound double-stranded telomeric DNA in vitro as shown by competition assays. Core binding was provided by the third and fourth nucleotides of the TTAGGC telomeric repeat. This is quite different from the binding sequence of CEH-37, another C. elegans telomere binding protein, suggesting that multiple proteins may bind nematode telomeric DNA simultaneously in vivo.

• Archives of Plastic Surgery
• /
• v.40 no.5
• /
• pp.486-491
• /
• 2013

In performing upper blepharoplasty in the elderly, looking younger and keeping the eyelids harmonious with the rest of the face have to be achieved at the same time. The most important goal in upper blepharoplasty for aging is correcting the drooping upper eyelid skin, and in this process, the surgeon may or may not create a double eyelid fold. The pros and cons have to be fully discussed with the patient, but the author personally prefers creating a double fold unless the patient refuses, because it is efficient in correcting and preventing further drooping of the skin. In most patients, the brow is elevated to compensate for the drooping eyelid, and when the drooping is corrected, brow ptosis may ensue. The surgeon has to prepare for these consequences before performing the procedure, and estimate the exact amount of skin to be excised. In the elderly, the skin and the orbicularis oculi muscle is thin, with a decreased amount of subcutaneous fat and retro-orbicularis oculi fat, and in most cases, excision of the skin alone is enough to correct the deformity. Removing large portions of soft tissue may also prolong the recovery period. Unlike younger patients, the lower skin flap should not be stretched too much in the elderly, as it may create an aggressive looking appearance. A few wrinkles in the lower flap should remain untouched to create a natural look. In this article, the author's own methods of performing an aging blepharoplasty are described specifically, with a step-by-step guide and surgical tips.