• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.341-350
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• 2023

The templated grain growth (TGG) method has gained significant attention for its ability to produce highly textured piezoelectric ceramics with significantly enhanced performance, making it a promising method for transducer and actuator applications. However, the texturing process using the TGG method requires the optimization of multiple steps, which can be challenging for beginners in this field. Therefore, in this tutorial, we provide an overview of the TGG method mainly based on our previous published works, including its various processing steps such as synthesizing anisotropic-shaped templates with size and size distribution control using the molten salt synthesis technique, tape casting, and identifying key factors for proper alignment of the templates in the target matrix system. Our goal is to provide a resource that can serve as a basic reference for researchers and engineers looking to improve their understanding and utilization of the TGG method for producing textured piezoelectric ceramics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.362-368
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• 2023

Multilayered actuators using Pb(Mg_1/3Nb_2/3)O₃-Pb(In_1/2Nb_1/2)O₃-PbTiO₃ (PMN-PIN-PT) crystals have demonstrated excellent properties, but are costly and lack mechanical strength. Textured PMN-PIN-PT ceramics exhibit robust mechanical strength and comparable properties to their single crystals form. However, the development of multilayered actuators using textured PMN-PIN-PT ceramics has not been achieved until now. This study presents the development of a multilayered actuator using textured 0.37PMN-0.29PIN-0.34PT ceramics with an Ag_0.9/Pd_0.1 inner electrode, co-fired at 950℃. A random 0.37PMN-0.29PIN-0.34PT ceramics multilayered actuator was also developed for comparison. The multilayered actuator consisted of 9 ceramic layers (36 ㎛ thickness) with an overall actuator thickness of 0.401 mm. The textured and random 0.37PMN-0.29PIN-0.34PT ceramics-based multilayered actuators achieved displacements of 0.61 ㎛ (0.15% strain) and 0.23 ㎛ (0.057% strain) at a low applied peak voltage of 100 V. These results suggest that the developed multilayered actuator using high-performance textured 0.37PMN-0.29PIN-0.34PT ceramics has the potential to replace expensive single crystal-based actuators cost-effectively.

• The Journal of Korean Obstetrics and Gynecology
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• v.36 no.4
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• pp.96-120
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• 2023

Objectives: This study reports the findings that support the efficacy of herbal medicine (HM) for premenstrual syndrome (PMS). Methods: We conducted meta-analysis of findings from randomized controlled trials (RCTs) for PMS treated with HM. The articles were published before July 2022, located using 9 databases (Pubmed, EMBASE, Cochrane Library, CINAHL, CNKI, CiNii, SCIENCE ON, KoreaMed, OASIS). Results: We observed 2,034 studies, of which 23 RCTs met our inclusion criteria. The risk of bias in the included studies was relatively unclear or high. Meta-analysis of 3 RCTs showed that HM group had a significantly higher total effective rate than the western medicine group (RR 1.20 [95% CI 1.06, 1.36, p=0.004]). Meta-analysis of 1 RCT showed that HM group had a significantly lower symptom score (MD -3.04 [95% CI -5.36, -0.72, p=0.01]), while there was no significant difference in daily record of severity of problems scale (MD -20.52 [95% CI -49.33, 8.29, p=0.16]). Conclusions: HM significantly improved PMS symptoms than general treatment and no serious adverse events were reported. However, the evidence on the effectiveness and safety of HM for PMS was not enough to provide reliable results due to the small number and low quality of included studies. We believe that rigorous RCTs will lead to more reliable evidence of the intervention.

• Women's Health Nursing
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• v.5 no.3
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• pp.313-326
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• 1999

This study sought to find out the level of perception of postpartal care and the meaning and opinion of traditional postpartal care (Sanhujori) from health professional. The subjects were 188 health professionals who work at University hospital, clinics, Oriented clinics, and midwifery clinics in Seoul and Chung-Buk, Korea. Data were collected from 8th April, 1999 to 6th May, 1999. The data were analyzed through the SPSS program by use of frequency, percentage, t-test, ANOVA and Scheffe test as a post hoc contrast, $x^2$-test, and stepwise multiple regression. The results of the study were as follows: mean age of the subject was 33.0 years and female was 58.0%. Occupation of the subject was nurse 28.7%, doctor 22.3%, midwife 21.3 Korean Oriental doctor 27.0%. Mean period of career was 7.6 years and the subject who experienced Sanhujori was 54.3%. The subject who did not know 6 principles of Sanhujori was 73.9%. In the opinion on traditional Sanhujori method 68.1% of respondents expressed that Sanhujori is scientific postpartal care which fits Korean people's physical constitution and culture. On the opinion of effective postpartal care in 97.9% of respondents expressed that it is to in hospital postpartal care and traditional Sanhujori perform it according to Korean culture constitution. On the opinion of Sanhujori, 96.6% of respondents expressed that it is necessary to understand Sanhujori with consideration which was adapted to Oriental culture and to verify it through continual study. On the opinion of the effect of the level of performance of Sanhujori upon women's health life, 43.2% of respondents expressed that the level of performance of Sanhujori has great effect on women's general health, including postpartal recovery, Sanhujori prevention, and so on. On the opinion of Sanhujori of women who undergo Caesarean operation, 57.7% of respondents expressed that women who undergo Caesarean operation perform Sanhujori with more attention. On the opinion of Sanhujori center (sanhujorwon), 56.3% of respondents expressed that the center is necessary for women's health and health professional are required to manage the center scientifically. On considering the level of importance of post care according to occupation, midwife showed highest level of importance of traditional Sanhujori doctor the lowest level. Midwife showed the hi level of importance of postpartal care and K Oriental doctor showed the lowest level of importance of women's postpartal care. On considering the relationship between the level of importance of postpartal care and general characteristics, sex, career, clinical department and whether they know 6 principles of Sanhujori or not were statistically significant at the level of 5%. In the stepwise multiple regression analysis, the main influencing variables on the level of importance of postpartal care were occupation, sex, and clinical department. In conclusion, this finding confirmed that professionals were considering the traditional Sa importantly for women's health. Above all things necessary for health professional to integrate concept of traditional Sanhujori into practical nu intervention program, to apply it to profes practices in order to reestablish effective integrative postpartal caring system, and to Sanhujori scientific through performing continual research.

• Clean Technology
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• v.19 no.3
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• pp.300-305
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• 2013

Zinc oxide (ZnO) and reduced graphite oxide (rGO) composites were synthesized and tested as adsorbents for the hydrogen sulfide ($H_2S$) adsorption at mid-to-high (300 to $500^{\circ}C$) temperatures. In order to investigate the critical roles of oxygen containing functional groups, such as hydroxyl, epoxy and carboxyl groups, attached on rGO surface for the $H_2S$ adsorption, various characterization methods (TGA, XRD, FT-IR, SEM and XPS) were conducted. For the reduction process for graphite oxide (GO) to rGO, a microwave irradiation method was used, and it provided a mild reduction environment which can remain substantial amount of oxygen functional groups on rGO surface. Those functional groups were anchoring and holding nano-sized ZnO onto the 2D rGO surface; and it prevented the aggregation effect on the ZnO particles even at high temperature ranges. Therefore, the $H_2S$ adsorption capacity had been increased about 3.5 times than the pure ZnO.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.383-389
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• 2020

Mesoporous silica solid catalysts modified with sulfonic acid were prepared for cationic ring-opening polymerization of octamethylcyclotetrasiloxane (D₄). Two sets of MCM-41 (1.7 and 2.8 nm) and SBA-15 (8.1 and 15.9 nm) with different pore sizes were used as catalyst supports. The surface of silica materials was modified with (3-mercaptopropyl)trimethoxysilane by silylation reaction and oxidized to sulfonic acid. The structures of the prepared catalysts were examined by X-ray diffraction and nitrogen adsorption-desorption. The pore size, specific surface area, and pore volume of the modified solid catalysts decreased slightly. In addition, the modification of the sulfonic acid on the silica surface was confirmed by using infrared spectroscopy and nuclear magnetic resonance spectroscopy. To observe the effect of the particle size on the catalytic activity, it was observed with a scanning electron microscope. The catalysts were used to synthesize PDMS through a ring-opening polymerization of D₄, and the conversion and polymerization rate of the polymerization reaction depended on the pore size, specific surface area, particle size, and particle agglomeration of the catalysts. In order for the polymerization rate, the catalyst prepared with SBA-15 of 8.1 nm pore size had the fastest reaction rate and showed the best catalytic activity.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.299-305
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• 2015

The production performance and egg quality traits among five strains of Korean native chickens (KNC) were evaluated in conventional cages. A total of 240 KNC were housed in a controlled environment. Each strain had 12 replicates with 4 chickens per cage. Feed intake, body weights, egg production and egg quality were measured at 24, 28 and 32 of weeks. Egg quality parameters were analyzed using 150 eggs. Results indicated significant (P<0.05) difference in average body weights, egg production and egg weight among five strains of KNC. In contrast, KNC strains effect was non-significant (P>0.05) for feed efficiency. The difference among those KNC strains on egg shell color, egg shell strength and egg shell density were not different (P>0.05) at the age of week 24 while it was significant (P<0.05) at the age of week 28 and 32. There was no effect (P>0.05) on egg length and egg shape index from five strains of KNC. The significant difference (P<0.05) was observed in egg width with KNC strains during early ages (week 24 and 28) and it was not significant (P>0.05) at the age of 32 weeks. Regarding internal quality parameters, albumen height and Haugh unit were significantly (P<0.05) affected with KNC strains while the effect on yolk color was not significant (P>0.05). Based on the egg weight and the production performance, GS-10 KNC strain was superior when compared with the other strains.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.51-59
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• 2010

We developed an analysis software that automatically detects incoming isotopes for multi-purpose gamma-ray detectors. The software is divided into three major parts; Network Interface Module (NIM), Spectrum Analysis Module (SAM), and Graphic User Interface Module (GUIM). The main part is SAM that extracts peak information of energy spectrum from the collected data through network and identifies the isotopes by comparing the peaks with pre-calibrated libraries. The proposed peak detection algorithm was utilized to construct libraries of standard isotopes with two peaks and to identify the unknown isotope with the constructed libraries. We tested the software by using GammaPro1410 detector developed by NuCare Medical Systems. The results showed that NIM performed 200K counts per seconds and the most isotopes tested were correctly recognized within 1% error range when only a single unknown isotope was used for detection test. The software is expected to be used for radiation monitoring in various applications such as hospitals, power plants, and research facilities etc.

• Solar Energy
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• v.13 no.1
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• pp.22-30
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• 1993

This Paper deals with the experimental study of the axisymmetric air jet impinging vertically on the flat heating surface with and without swirl. The purpose of this study is to investigate the characteristics of flow, augmentation of heat transfer rate, turbulent intensity, and the comparison of heat transfer rate, the optimal swirling condition about the swirl and nonswirl axisymmetric air jet. In order to augment the heat transfer on the flat heating surface without introducing any additional power, the technique used in the present work was placement of twisted tape inserted pipe in front of the nozzle exit in order to make a swirl. The effect of swirl degree is investigated in case of S=0., 0.056, 0.111, 0.222 and the velocity of the jet was 14, 20, 26, 32, 38, 44m/s. The distance between the nozle exit and the stagnation point on the impinging plate was the H/D=$1{\sim}14$. In order to analyze of the flow structure which increase heat transfer, the velocity and the turbulent intensity of the axisymmetric jet was measured by a hot wire anemometer according to the swirl number and H/D.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.110-127
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• 2016

This floristic study was conducted from April to September, 2014 in 12 days. The investigated area was Mt. Segeolsan (1,261 m) which is the part of Chirisan National Park and its neighbor region, Goan-ri, Sandeuk-ri. Based on voucher specimens, flora of this area consisted of 108 families, 376 genera, 584 species, 5 subspecies, 73 varieties, and 16 forma, totally 679 taxa. 17 taxa were endemic to Korea such as Carex okamotoi Ohwi, Cimicifuga austrokoreana H.W. Lee & C.W. Park., Thalictrum rochebrunianum var. grandisepalum (H.Lév.) Nakai, Fallopia koreana B.U. Oh & J.G. Kim, Asarum patens (Yamaki) Yamaki ex Y.N. Lee, and Stewartia pseudocamellia Maxim. etc. Among these species, C. austrokoreana, T. rochebrunianum var. grandisepalum, F. koreana, A. patens are considered having a southern boundary line of distribution in the Chirisan National Park region. And so Carex okamotoi has main distribution center in the Chirisan National Park region, this study region is assumed important in phytogeography. The useful plants were 633 taxa, ethonobotanic plants were 359 taxa in this area. Invasive alien species were 61 taxa, which were naturalized rate (9.0%) and urbanized index (17.4%).