• Korean Journal of Materials Research
• /
• v.18 no.6
• /
• pp.326-333
• /
• 2008

Since the 1990s, the second generation of Zirconium alloys containing main alloy compositions of Nb, Sn and Fe have been used as a replacement of Zircaloy-4 (Zr-Sn-Fe-Cr), a first-generation Zirconium alloy, to meet severe and rigorous reactor operating conditions characterized by high-burn-up, high-power and high-pH operations. In this study, the mechanical properties and creep behaviors of Zr-Sn-Fe-Cr and Zr-Nb-Sn-Fe alloys were investigated in a temperature range of $450{\sim}500^{\circ}C$ and in a stress range of $80{\sim}150\;MPa$. The mechanical testing results indicate that the yield and tensile strengths of the Zr-Nb-Sn-Fe alloy are slightly higher compared to those of Zr-Sn-Fe-Cr. This can be explained by the second phase strengthening of the $\beta$-Nb precipitates. The creep test results indicate that the stress exponent for the steady-state creep rate decreases with the increase in the applied stress. However, the stress exponent of the Zr-Sn-Fe-Cr alloy is lower than that of the Zr-Nb-Sn-Fe alloy in a relatively high stress range, whereas the creep activation energy of the former is slightly higher than that of the latter. This can be explained by the dynamic deformation aging effect caused by the interaction of dislocations with Sn substitutional atoms. A higher Sn content leads to a lower stress exponent value and higher creep activation energy.

• Child Health Nursing Research
• /
• v.8 no.2
• /
• pp.174-182
• /
• 2002

The purpose of this study was to investigate the experiences of accident and visiting emergency center, and the experiences of education about emergency care for parents. The subjects of this study were 117 mothers whose children are attending 9 different nursery schools or kindergartens. The instrument used in this study was developed by researchers and validated by nursing professor, first aid doctor and the president of nursery school, and consisted of 'most important thing in child rearing' ,'experiences of accident and visiting emergency center', 'type of trauma' and 'need for parent education program' the result of this study were as followed ; 1.There were 70.09％ of the experience of visiting emergency center among the subjects. The cause of visiting emergency center were high fever and convulsion(42.86％), and trauma by accident(28.04％) 2. The most common type of the indoor accident were fall down and slipping(76.92％), the common type of trauma were contusion (76.92％), abrasion(47.01％), laceration(29.06％), dislocation or fracture(12.82％), burn(10.26％), piercing(8.55％). 3.47.01％ of subjects had the experience of education about emergency care for parents. They were educated by child rearing journals (32.72％), small books which were published by hospitals or community health center (25.45％), mass media(21.8％), parent seminar (12.72％), nursery school or kindergarten (5.45％). In conclusion, the need of emergency care for children was strongly found. Therefore, on the basis of above results, the parent education program which fits their cognitive level and their health care needs So, it must be directed on the further study of parents' knowledge about emergency care for children. To enhance the effectiveness of program and accomplish the children's health promotion, advanced instructional media and demonstration must be included.

• Journal of Welding and Joining
• /
• v.31 no.6
• /
• pp.112-118
• /
• 2013

In this study, constant loading test (CLT) was performed to evaluate the hydrogen embrittlement resistance for multipass FCA weld metals of 600MPa tensile strength grade. The microstructures of weld metal-2 having the smallest carbon equivalent (Ceq=0.37) consisted of grain boundary ferrite and widmanstatten ferrite in the acicular ferrite matrix. The weld metal-1 having the largest Ceq=0.47, showed the microstructures of grain boundary ferrite, widmanstatten ferrite and the large amount of bainite (vol.%=19%) in the acicular ferrite matrix. The weld metal-3 having the Ceq=0.41, which was composed of grain boundary ferrite, widmanstatten ferrite, and the small amount of bainite (vol.%=9%) in the acicular ferrite matrix. Hydrogen desorption spectrometry (TDS) used to analyze the amount of diffusible hydrogen and trapping site for the hydrogen pre-charged specimens electrochemically for 24 hours. With increasing the current density of hydrogen pre-charging, the released amount of diffusible hydrogen was increased. Furthermore, as increasing carbon equivalent of weld metals, the released diffusible hydrogen was increased. The main trapping sites of diffusible hydrogen for the weld metal having a low carbon equivalent (Ceq=0.37) were grain boundaries and those of weld metals having a relatively high carbon equivalent (Ceq: 0.41~0.47) were grain boundaries and dislocation. The fracture time for the hydrogen pre-charged specimens in the constant loading test was decreased as the carbon equivalent increased from 0.37 to 0.47. This result is mainly due to the increment of bainite that is vulnerable to hydrogen embrittlement.

• Archives of Craniofacial Surgery
• /
• v.12 no.1
• /
• pp.33-36
• /
• 2011

Background: In a frontal sinus reconstruction, the literature primarily recommends a surgical approach for definite treatment with the exception of for anterior wall fractures with no dislocation. Many studies have assessed a range of methods for the reduction of frontal sinus fractures. This paper presents a case, in whom the anterior wall of the frontal sinus was reconstructed using an outer table calvarial bone graft in an en bloc manner. Patient and methods: A 36-year-old male visited the emergency room with a heavy injury to the forehead. He was diagnosed with fractures of the anterior and posterior wall of the frontal sinus. The neurosurgeon removed the fractured area and repaired the meninges. Afterwards, cranialization was performed and the opening of the nasofrontal duct was obstructed. After fixing the removed bone to its original location, all fragments of fractured anterior wall were purged out and the anterior wall reconstructed using an en bloc calvarial bone graft. Results: In the post-operative 8 months period, there were no complications, the round contour of the forehead was expressed well and the patient was satisfied with the result. Conclusion: There are many methods for reconstructing the anterior wall of the frontal sinus. On the other hand, in cases of large fracture sites with many fractured bone fragments, en bloc harvesting of the outer table calvarial bone could be a better choice than making use of only plates and screws because this method shows a good results in terms of aesthetics with a low complication rate.

• Metals and materials international
• /
• v.24 no.6
• /
• pp.1359-1368
• /
• 2018

The mechanical properties and microstructure evolution of Mg-8Li-3Al-1Y alloy undergoing different rolling processes were systematically investigated. X-ray diffraction, optical microscope, scanning electron microscopy, transmission electron microscopy as well as electron backscattered diffraction were used for tracking the microstructure evolution. Tensile testing was employed to characterize the mechanical properties. After hot rolling, the $MgLi_2Al$ precipitated in ${\beta}-Li$ matrix due to the transformation reaction: ${\beta}-Li{\rightarrow}{\beta}-Li+MgLi_2Al+{\alpha}-Mg$. As for the alloy subjected to annealed hot rolling, ${\beta}-Li$ phase was clearly recrystallized while recrystallization rarely occurred in ${\alpha}-Mg$ phase. With regard to the microstructure undergoing cold rolling, plenty of dislocations and dislocation walls were easily observed. In addition, the microstructure of alloys subjected to annealed cold rolling revealed the formation of new fresh ${\alpha}-Mg$ grains in ${\beta}-Li$ phase due to the precipitation reaction. The mechanical properties and fracture modes of Mg-8Li-3Al-1Y alloys can be effectively tuned by different rolling processes.

• Korean Journal of Metals and Materials
• /
• v.46 no.9
• /
• pp.545-553
• /
• 2008

Dynamic deformation behavior of ultra-fine-grained pure coppers fabricated by equal channel angular pressing (ECAP) was investigated in this study. Dynamic torsional tests were conducted on four copper specimens using a torsional Kolsky bar, and then the test data were analyzed by their microstructures and tensile properties. The 1-pass ECAP'ed specimen consisted of fine dislocation cell structures elongated along the ECAP direction, which were changed to very fine, equiaxed subgrains of 300~400 nm in size as the pass number increased. The dynamic torsional test results indicated that maximum shear stress increased with increasing ECAP pass number. Adiabatic shear bands were not found at the gage center of the dynamically deformed torsional specimen of the 1- or 4-pass ECAP'ed specimen, while some weak bands were observed in the 8-pass ECAP'ed specimen. These findings suggested that the grain refinement according to the ECAP was very effective in strengthening of pure coppers, and that ECAP'ed coppers could be used without serious reduction in fracture resistance under dynamic torsional loading as adiabatic shear bands were hardly formed.

• Clinics in Shoulder and Elbow
• /
• v.25 no.3
• /
• pp.210-216
• /
• 2022

Background: Reverse shoulder arthroplasty (RSA), first introduced as a management option for cuff tear arthropathy, is now an accepted treatment for complex proximal humeral fractures. Few studies have identified whether the outcomes of RSA for shoulder trauma are comparable to those of RSA for shoulder arthritis. Methods: This is a retrospective, single-institution cohort study of all patients who underwent RSA at our institution between January 2013 and December 2019. In total, 49 patients met the inclusion criteria. As outcomes, we evaluated the 1-year American Shoulder and Elbow Surgeons (ASES) and Constant shoulder scores, postoperative shoulder range of motion, intra- and postoperative complications, and cumulative revision rate. The patients were grouped based on preoperative diagnosis to compare postoperative outcomes across two broad groups. Results: The median follow-up period was 32.8 months (interquartile range, 12.6-66.6 months). The 1-year visual analog scale, range of motion, and Constant and ASES functional scores were comparable between RSAs performed to treat shoulder trauma and that performed for arthritis. The overall complication rate was 20.4%, with patients with a preoperative diagnosis of arthritis having significantly more complications than those with a preoperative diagnosis of trauma (34.8% vs. 7.7%). Conclusions: Patients who underwent RSA due to a proximal humeral fracture or dislocation did not fare worse than those who underwent RSA for arthritis at 1 year, in terms of both functional and radiological outcomes.

• Hip & pelvis
• /
• v.35 no.1
• /
• pp.54-61
• /
• 2023

Purpose: The purpose was to examine the clinical and radiological outcomes after surgical treatment of acetabular fractures with total hip arthroplasty with a dual mobility cup cemented into a porous multihole cup in the population of frail elderly patients. Materials and Methods: A retrospective review of 16 patients who underwent surgery (mean age, 76.7 years) with a mean follow-up period of 36.9 months was conducted. Following surgery, patients underwent postoperative follow-up at six weeks, three, six, and 12 months and clinical and radiological examinations were performed. Results: Classification of fractures was based on the Letournel classification. Following surgery, all patients were allowed weight-bearing as tolerated immediately postoperative. Fourteen patients showed maintenance of preoperative mobility status at one year. The mean Harris hip score was 64.8 (range, 34.7-82.8) and 80.0 (range, 60.8-93.8) at three months and one year, respectively. The mortality rate was 12.5% at one year (2/16). Complications included heterotopic ossification (2/16), deep venous thrombosis (1/16), heamatoma (1/16), and femoral revision due to a Vancouver B2 fracture (1/16). No case of deep infection, dislocation, or implant loosening was reported. Conclusion: Total hip arthroplasty using a dual mobility cup cemented into a porous multihole cup with locking screws resulted in a stable construct with a capacity for immediate weight-bearing as tolerated with rapid relief of pain. The findings of this study suggest that this procedure can be regarded as a safe method that has shown promising clinical and radiological outcomes for treatment of patients with medical frailty.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.747-754
• /
• 2012

The purpose of this study was to compare inter-regional accident modes using the National Hospital Discharge Patient Injury Survey. In order to determine economic status of each region, 234 cities and counties were categorized as 5 groups according to their financial self-reliance ratio. The main results are as follows. First, transport accidents had increased by the age group of 25 to 44 but decreased thereafter. Second, the frequency of car accidents was the highest among several types of transport accidents. Most common site of transport accidents was roads and highways. Third, there was significant difference in the modes of transport accident among regions. Fourth, emergency admission rate was quite different according to regional groups but it was no significant difference by economic status. Lastly, there was significant difference in injury patterns by region groups. In regions which were high economic status, there were relatively less serious injury patterns such as sprain, strain, dislocation while regions which were in low economic status had experienced serious injury including fracture, stab wound, and open fracture. We could find the difference in accident modes by regional economic status. Therefore, health authority should consider different accident prevention strategies by regional groups.

• Journal of Haehwa Medicine
• /
• v.15 no.1
• /
• pp.125-140
• /
• 2006

Study of east & west medical science documentary records of Hip joint pain lead to following conclusions. 1. Easten medicine classify hip joint pain with terms "Bi-chu-tong", "Bi chu in tong" "Bi-chu-choong-tong". 2. Easten medicine asorts cause of hip joint pain with external factor, such as exogenous energy, six yin evil energy and intrinsic factor, which are weakness caused by prolonged deasease, warm-heat evil. 3. In western medicine, causes that trigger hip joint pain are trauma, fracture, dislocation,and bacterial infection. 4. Treatment of hip joint disorder in western medicine, physiotherapy concerning conservative treatment, and pain control with drug treatment, kinesitherapy are used, and concernig fracture, operation is used. 5. In Eastern medicine, principle of treating hip joint pain, sung-juk-sa-ji(盛則寫之), hu-juk-bo-ji(虛則補之), yul-juk-jil-ji(熱則疾之), han-juk-yu-ji(寒則留之), ham-ha-juk-chim-ji(陷下則沈之), bul-sung-bul-hu(不盛不虛), yi-kyong-chui-ji(以經取之) is presented. This priciple of treatment was descended through ages and is now applied to treatments such as Acupuncture, Herbal, physical treatment based on so-san-eo-hyul(消散瘀血), seo-kun-tong-rak(舒筋通絡), so-ri-kwan-jul(疏利關節) principle. 6. In Eastern medicine, meridians used to treat hip joint pain are The Chok yangmyung wi Kyong(足陽明胃經), Chok taeum bi Kyong(足太陰脾經), Chock soyang dam Kyong(足少陽膽經), Chock guelum gan Kyong(足厥陰肝經). In conclusion, hip joint pain should be considered in relationship with internal organs and whole body system. Western & Eastern point of view should be carefully inspected and connected and intensive study of nervous system and meridian is required, in order to adopt best treatment for the patients.