• Title/Summary/Keyword: 자기 특성

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Study on the Structure of the Korea-Japan Joint Development Zone by Means of Geophysical Data (지구물리 자료를 이용한 한일공동개발구역 일원의 구조 해석)

  • Jeongwon Ha;Sik Huh;Hyoungrea Rim
    • Geophysics and Geophysical Exploration
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    • v.27 no.1
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    • pp.23-36
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    • 2024
  • In this study, we analyze the structure of the Korea-Japan Joint Development Zone (JDZ) using gravity, magnetic, and seismic data. Gravity and magnetic data analysis confirmed that the Jeju Basin exhibits low anomalies compared to adjacent areas. We applied the total gradient to the Bouguer anomaly to identify basin boundaries, and computed the analytic signal from the total magnetic anomaly data to enhance the edges of the magnetic anomalies. The Taiwan-Sinzi Belt, exhibits high magnetic anomalies and crosses the center of the JDZ in the northeast-southwest direction; we presume that intrusive rocks are sporadic in the JDZ. The 3D inversion results of the gravity and magnetic data show a strong correlation between magnetic susceptibility and density (i.e. a low-density zone in the Jeju Basin and the Ho Basin, and a high magnetic susceptibility distribution in the Taiwan-Sinzi Belt). Comparison of the density and seismic profiles of the Jeju Basin shows that high densities are associated with sill, horst, and basement highs, whereas low densities are associated with basement low and grabens. These results suggest that interpretations based on seismic, gravity and magnetic data can effectively reveal the subsurface structure of the JDZ.

Persistent Primitive Olfactory Artery Type 4 with Fusiform Aneurysm: A Case Report (방추형동맥류를 동반한 제4형 잔류 원시 후각동맥의 영상 소견: 증례 보고)

  • Heecheol Park;Jin Wook Baek;Hae Woong Jeong;Young Jin Heo;Suyoung Yun;Ji-Yeon Han
    • Journal of the Korean Society of Radiology
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    • v.84 no.6
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    • pp.1361-1366
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    • 2023
  • The persistent primitive olfactory artery (PPOA) is a rare variant of the anterior cerebral artery, first reported in 1979. It reportedly has a high correlation with the development of aneurysms, owing to the hemodynamic stress induced by the structural characteristics of the hairpin turn. Herein, we present a rare case of PPOA type 4 with a fusiform aneurysm at the hairpin turn segment in a 46-year-old female with occasional headaches. Time-of-flight MR angiography and transfemoral cerebral angiography revealed an unusual branch arising from the left A1 segment, running anteromedially along the ipsilateral olfactory tract, and turning the hairpin posterior to the olfactory bulb. This branch continued into the left accessory middle cerebral artery, and a fusiform aneurysm was observed at the hairpin segment. No further treatment was performed, and follow-up imaging was recommended. Nevertheless, it is essential to recognize and diagnose these rare variations.

Consolidation and magnetic properties of ferromagnetic Fe-MgO powders prepared by ball milling process (볼밀링법으로 제조된 강자성 Fe-MgO 분말의 벌크화 및 자기적 특성)

  • Chung-Hyo Lee
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.34 no.4
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    • pp.125-130
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    • 2024
  • Preparation of ferromagnetic powders for the mixture of hematite and pure Mg powders by ball milling has been investigated. Also, consolidation of the ball-milled powders was performed in a spark plasma sintering machine at 800-1,000℃. It is found that a ferromagnetic Fe-MgO composite powders are obtained by ball milling of hematite and pure Mg powders before 1 hour. The magnetization and coercivity of ball-milled samples change at the results of the solid state reaction of hematite by pure Mg during ball milling. The saturation magnetization of ball-milled samples increases with increasing ball milling time and reaches to a maximum value of 93.4 emu/g after 5 hours of ball milling. Shrinkage change after sintering of ball-milled sample for 5 hours was significant above 300℃ and gradually increased with increasing temperature up to 800℃. X-ray diffraction result shows that the average grain size of Fe in Fe-MgO bulk sample sintered at 900℃ is 50 nm. It can be also seen that the coercivity of bulk sample sintered at 900℃ is still high value of 90 Oe, indicating that the grain growth of magnetic Fe phase during sintering process tend to be suppressed.

Clinical and MR Predictors of Retro-Odontoid Pseudotumor Regression Following Posterior Fixation in Patients with Atlantoaxial Instability (환축 불안정 환자에서 후방 고정술 후 치상돌기 후방 가성종양 퇴행의 임상 및 자기공명영상 예측 인자)

  • Jisu Kim;Youngjune Kim;Eugene Lee;Joon Woo Lee
    • Journal of the Korean Society of Radiology
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    • v.85 no.4
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    • pp.754-768
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    • 2024
  • Purpose To identify clinical and MR predictors of retro-odontoid pseudotumor (ROP) regression after posterior fixation in patients with atlantoaxial instability. Materials and Methods We included patients who had undergone posterior fixation for atlantoaxial instability and preoperative and postoperative MR imaging. Patients were classified into two groups according to the degree of ROP regression after posterior fixation: regression (≥ 10% reduction) and no regression (< 10% reduction). Mann-Whitney and Fisher's exact tests were performed to identify the clinical (age and sex) and MR predictors (preoperative ROP thickness, ROP type, MR signal homogeneity of the ROP, spinal cord signal change, spinal cord atrophy, ossified posterior longitudinal ligament, os odontoideum, and atlantodental interval) associated with ROP regression. Results We retrospectively assessed 11 consecutive patients (7 female; median age, 66 years [range, 31-84 years]). Posterior fixation induced ROP regression in eight (72.7%) patients. Older age and greater preoperative ROP thickness significantly correlated with ROP regression (p = 0.024 and 0.012, respectively). All patients with preoperative ROP thickness > 5 mm exhibited ROP regression. The other variables were not significantly associated with ROP regression. Conclusion Older age and thicker preoperative ROP are associated with ROP regression after posterior fixation in patients with atlantoaxial instability.

The Influence of Sense of Humor and Stress Coping Styles on Adaptation to Clinical Practice among Nursing Students (간호대학생의 유머감각과 스트레스 대처 방식이 임상실습 적응에 미치는 영향)

  • Sook Kang
    • Journal of Industrial Convergence
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    • v.22 no.8
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    • pp.63-72
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    • 2024
  • This study attempted to explore the impact of sense of humor and stress coping styles among nursing students on adaptation to clinical practice. The study included 180 nursing students as participants, and data collection was conducted using self-administered questionnaires from April 15 to 26, 2024. The collected data underwent t-test, one-way ANOVA, Pearson's correlation coefficients, and multiple regression analysis. The research findings revealed that the sense of humor scored 3.52, stress coping styles scored 3.40, and adaptation to clinical practice scored 3.46. Adaptation to clinical practice according to general characteristics showed statistically significant differences based on major satisfaction (F=29.80, p<.001), clinical practice satisfaction (F=40.46, p<.001), relationships with peers in clinical practice (F=5.05, p<.001), and personality (t=-3.41, p<.05). Adaptation to clinical practice showed statistically significant positive correlations with sense of humor (r=.31, p<.001) and stress coping styles (r=.43, p<.001). The factors influencing adaptation to clinical practice were clinical practice satisfaction(β=.34, p<.001), stress coping styles (β=.29, p<.001), and major satisfaction (β=.23, p<.05), explaining 42% of the total variance.

A Study on the Dépaysement of the Animation (애니메이션에 있어서 데페이즈망에 관한 연구)

Analysis on Relevant Factors in Practice of Prevention for Infections in Dental Clinics - (Focusing on Dental Hygienists) (치과 진료실 감염예방 실천도의 관련요인 분석 (치과위생사를 중심으로))

  • Nam, Young-Shin
    • Journal of dental hygiene science
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    • v.8 no.3
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    • pp.189-198
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    • 2008
  • Objective: The study aimed to provide basic data for enhancing dental hygienists' practice of prevention for infections of dental hygienists by examining what factors there were in their preventing the infections in dental clinics. Method: The subjects of study were 168 dental hygienists who participated in continuing medical education of Incheon & Gyeonggi-do association and Seoul city association in October and November 2005. For the data analysis, an SPSS WIN 13.0 program was used and its significance level was 0.05. In terms of analysis methods, frequency analysis and technical statistics analysis were performed for general characteristics, ANOVA was performed for general traits, practice, medical environments for knowledge and practice analysis, correlation analysis was performed for the relation between knowledge & organization-related factors and practice, Chi-Square Tests were performed for the relation between general traits and educational experiences, T-test was performed for practice and knowledge according to the educational experiences for preventing infections and multiple regression analysis was performed for the factors that affect the practice for preventing infections. Result: knowledge showed statistically significant differences by age (F=4.895, p=0.003) and those with the education experiences in preventing infections had higher scores in practice of prevention for infections than those without them (t=3.315, p=0.001). The correlation between knowledge and practice was significant statistically (p<0.05), the factors related to organization showed significant correlation (p<0.01) and the higher the factors related to organizations, knowledge, education experiences, service career, the higher the practice for prevention of infections was ($R^2=0.32$). Conclusions: In order to enhance the dental hygienists' practice for the prevention of infections, it would be necessary to treat the contents of the infection prevention in educational curriculum at schools and enhance dental hygiene students' knowledge on the prevention of infection and to develop the programs, with which continuous education and PRS could be conducted through in-house education and continuing medical education of the hospital after school graduation and it has been believed that it would be the most important for dental hygienists to make efforts and interest in organizations actively so as to build up safe working environments.

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Separation of Ferrous Materials from Municipal Solid waste Incineration Bottom Ash (생활폐기물(生活廢棄物) 소각(燒却) 바닥재의 자력선별(磁力選別)에 따른 ferrous material의 분리(分離) 특성(特性))

  • Um, Nam-Il;Han, Gi-Chun;You, Kwang-Suk;Cho, Hee-Chan;Ahn, Ji-Whan
    • Resources Recycling
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    • v.16 no.3 s.77
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    • pp.19-26
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    • 2007
  • The bottom ash of municipal solid waste incineration generated during incineration of municipal solid waste in metropolitan area consists of ceramics, glasses, ferrous materials, combustible materials and food waste and so on. Although the ferrous material was separated by the magnetic separation before the incineration process, of which content accounts for about $3{\sim}11%$ in bottom ash. The formation of a $Fe_3O_4-Fe_2O_3$ double layer(similar to pure Fe) on the iron surface was found during air-annealing in the incinerator at $1000^{\circ}C$. A strong thermal shock, such as that takes place during water-cooling of bottom ash, leads to the breakdown of this oxidation layer, facilitating the degradation of ferrous metals and the formation of corrosion products and it existed as $Fe_2O_3,\;Fe_3O_4\;and\;FeS_2$. So, many problems could occur in the use of bottom ash as an aggregate substitutes in construction field. Therefore, in this study, the separation of ferrous materials from municipal solid waste incineration bottom ash was investigated. In the result, the ferrous product(such as $Fe_2O_3,\;Fe_3O_4,\;FeS_2$ and iron) by magnetic separator at 3800 gauss per total bottom ash(w/w.%) accounted for about 18.7%, and 87.7% of the ferrous product was in the size over 1.18 mm. Also the iron per total bottom ash accounted for about 3.8% and the majority of it was in the size over 1.18 mm.

The Relationship between Entrepreneurial Education and Entrepreneurial Intentions : Focusing on Moderating Effects of Entrepreneurial Orientation and Environmental Factors (창업교육과 창업의지의 관계: 기업가 지향성과 환경적 요인의 조절효과)

  • Lee, Jae-Seok;Lee, Sang-Myung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.10 no.3
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    • pp.61-74
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    • 2015
  • This study attempts to empirically examine the influence of entrepreneurial education in university on entrepreneurial intentions of undergraduate and graduate students as potential entrepreneur and new moderating factors on the relationship between entrepreneurial education and entrepreneurial intentions. We suggested EO(innovativeness, risk-taking propensity, proactiveness and locus of control) and environmental factors(entrepreneurial family background and resource accessibility) as new moderating factors in the relationship. For this study, the following research questions are raised : First, is there a significant difference in entrepreneurial intentions of enrolled and unenrolled students in entrepreneurial education? Second, does entrepreneurial education affect entrepreneurial intentions positively? Finally, do EO and environmental factors have moderating effects in the relationship between entrepreneurial education and entrepreneurial intentions? In order to test our research model, the current study collected data from 265 undergraduate and graduate students who are majoring in natural sciences or engineering in Seoul National Univ., Hanyang Univ., and KAIST. To investigate our research questions and hypotheses, independent-sample T-test and hierarchical regression analysis were employed. The results of empirical analysis revealed that entrepreneurial education positively related to entrepreneurial intentions and that the relationship between entrepreneurial education and entrepreneurial intentions moderated by EO and environmental factors. First, the result showed the significant difference in entrepreneurial intentions between enrolled and unenrolled students in entrepreneurial education. Entrepreneurial intentions of students who enrolled entrepreneurial education was higher than others. Second, entrepreneurial education affected the entrepreneurial intentions positively. Finally, the moderating effects of innovativeness, risk-taking propensity, proactiveness and entrepreneurial family background among investigated six moderators were significant. entrepreneurial education-entrepreneurial intentions relationship was even stronger under high innovativeness and high proactiveness. But risk-taking propensity and entrepreneurial family background decreased the effect of entrepreneurial education on entrepreneurial intentions.

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The Severity and Variables Influencing Depression in Cancer Patients with Pain (통증이 있는 암환자의 우울 정도 및 우울에 영향을 미치는 요인)

  • Kim, Hyun-Sook;Yun, Young-Ho;Lee, So-Woo;Heo, Dae-Seog;Son, Haeng-Mi;Huh, Bong-Yul
    • Journal of Hospice and Palliative Care
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    • v.2 no.2
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    • pp.125-137
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    • 1999
  • Purpose : Surveying the rates, severity, and variables influencing depression and their correlation between pain and depression in Korean cancer patients, we attempted to provide a basic database for the effective depression management program. Methods : The results of survey were colleted from 10 patients who were hospitalized at Seoul National University Hospital for cancer treatment from February to June of 1999. Factors of depression and the level of pain were examined by self-reported survey employing Korean version of Beck Depression Inventory(BDI) and an abridged version of Brief pain Inventory respectively. The purpose of this study and guidelines for the questionnaires were clearly explained to participating patients by Resgitered Nurses before answering the survey. Demographic and clinical characteristics of patients were compiled by reviewing their medical records in corporation with a family physician. The difference in the level of depression among patient groups was analyzed with the t-test and ANOVA, and the correlation between variables with Pearson correlation coefficient. Results : 1) 142 subjects comprised 79 male and 63 female, and their mean age was 51.86. 2) The mean scores of the worst pain for last 24-hours was 6.08(SD 2.23), the average pain for last 24-hours 4.44(SD 1.85), and the mean scores of pain at the time of survey 3.48(SD 2.25), while the mean scores of the least pain for last 24-hours 2.25(SD 1.83). 3) The mean BDI scores were 23.73(SD 0.99), and 55.6% of patients were evaluated to be in depression(cutting point 21). Scores of depression for cancer patients were higher than normal population. 4) The correlation between worst pain for last 24-hours and depression(r=0.252, P=0.002), average pain for last 24-hours and depression(r=0.225, P=0.007), present pain and depression(r=0.291, P=0.000) were significant. 5) Significant differences were found among groups of cancer patients with pain with respect to gender(t=3.59, p=0.000), level of education(F=4.063, P=0.009), ECOG(F=3.352, P=0.021). There was significant positive correlation between depression and pain(r=0.171, P=0.042). Conclusions : More than 50% of cancer patients with pain are suffering from depression. We have shown that the variables like the degree of pain, gender, level of education, ECOG, and age are significantly related to the depression in cancer patients. The findings of this study may be used for assessing high-risk patients in need of intervention and for planning effective therapeutic strategies for them after the routine assessment. Further study is necessary to investigate the cultural differences and the variables influencing on depression in Korean cancer patients.

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