• 한국결정성장학회지
• /
• 제19권5호
• /
• pp.237-241
• /
• 2009

Dislocation dipoles were formed in the early stage of deformation of Y-CSZ single crystal at high temperatures. And the dipoles were pinched off to break into dipoles loops by dislocation climb. Dislocation loop annealing was peformed in Y-CSZ single crystal to evaluate the diffusivity of cation which was the rate-controlling ion.

• 대한장애인치과학회지
• /
• 제11권2호
• /
• pp.62-66
• /
• 2015

Temporomandibular joint dislocation causes considerable pain, discomfort, and swelling. The anatomic construction of the articular fossa and the eminentia articularis may predispose to dislocation, and weakness of the connective tissue forming the capsule is believed to be a predisposing factor. The capsule may be stretched and, more rarely, torn. Dislocation may be unilateral or bilateral and may occur spontaneously after stretching of the mouth to its extreme open position, such as during a yawn or during a routine dental operation. Manual reduction with the patient under muscle-relaxing condition or anesthesia is recommended method. After the reduction of an acute dislocation, immobilization of the jaw is recommended to allow the stretched and sometimes torn capsule to heal, thus preventing recurrence. A Barton's bandage may be applied for 2 to 3 weeks to prevent the patient from opening the jaw too wide. But, it results in recurrent dislocation in the neurologically disabled patient, because of loose intermaxillary fixation. This is a case report about management of recurrent temporomandibular joint dislocation by multiple loop wirings and intermaxillary elastics in cerebrovascular accident patient.

• Interaction and multiscale mechanics
• /
• 제6권3호
• /
• pp.301-316
• /
• 2013

The influence of indenter geometry on nanoindentation was studied using a static molecular dynamics simulation. Dislocation nucleation, dislocation locks, and dislocation movements during nanoindentation into Al (001) were studied. Spherical, rectangular, and Berkovich indenters were modeled to study the material behaviors and dislocation activities induced by their different shapes. We found that the elastic responses for the three cases agreed well with those predicted from elastic contact theory. Complicated stress fields were generated by the rectangular and Berkovich indenters, leading to a few uncommon nucleation and dislocation processes. The calculated mean critical resolved shear stresses for the Berkovich and rectangular indenters were lower than the theoretical strength. In the Berkovich indenter case, an amorphous region was observed directly below the indenter tip. In the rectangular indenter case, we observed that some dislocation loops nucleated on the plane. Furthermore, a prismatic loop originating from inside the material glided upward to create a mesa on the indenting surface. We observed an unusual softening phenomenon in the rectangular indenter case and proposed that heterogeneously nucleating dislocations are responsible for this.

• Journal of Magnetics
• /
• 제16권4호
• /
• pp.427-430
• /
• 2011

The rolled steels for welded structure applied tensile stress have been examined by means of magnetic Barkhausen noise (MBN) method and of a physical parameter obtained from a hysteresis loop. The behaviors of MBN parameters and coercive force with tensile stress were discussed in relation to microstructure changes. There is no change in MBN parameters and coercive force below yield strength. The coercive force rises rapidly with tensile stress above yield strength. On the other hand, the rms voltage and the peak in averaged rms voltage take a maximum around yield strength and then decreases. The magnetomotive force at peak in the averaged rms voltage shows a minimum around yield strength. These phenomena are attributed to the combined effects of cell texture and dislocation density. In addition, the behaviors of MBN parameters around yield strength may be reflected by the localized changes in strain field due to the formation of dislocation tangles.

• 한국결정성장학회지
• /
• 제16권2호
• /
• pp.66-70
• /
• 2006

실리콘웨이퍼 표면에 기계적인 손상을 가한 후 산화 열처리 공정을 실시하면 온도와 기계적인 손상의 크기에 따라 여러 가지 결정 결함이 발생된다. 기계적인 손상이 크고 열처리 온도가 증가함에 따라 dislocation loop 등의 대형 결함들이 발생되고 열처리 온도가 낮거나 손상의 크기가 작을수록 OISF(Oxidation Induced Stacking Faults)등의 소형 결함들이 많이 발생된다. Minority carrier lifetime을 측정하여본 결과 결함의 크기가 작을수록 minority carrier lifetime이 높은 것으로 밝혀졌다. 더욱이 dislocation loop 등의 결정 결함보다는 결함 발생 이전 단계인 strained layer등이 금속불순물에 대한 gettering의 효과가 더욱 높음을 알 수 있었다.

• Clinics in Shoulder and Elbow
• /
• 제25권3호
• /
• pp.224-229
• /
• 2022

Background: Most acromioclavicular joint (ACJ) injuries are caused by direct trauma to the shoulders, and various methods and techniques are used to treat them; however, none of the options can be considered the gold standard. This study examines the horizontal stability of the ACJ after a complete dislocation was repaired using one of two Ethibond suture techniques, the loop technique and the two holes in the clavicle technique. Methods: In this single-blind, randomized clinical trial, 104 patients diagnosed with complete ACJ dislocation type V were treated using Ethibond sutures with either the loop technique or the two holes in the clavicle technique. Horizontal changes in the ACJ were radiographically assessed in the lateral axial view, and shoulder function was evaluated by the Constant (CS) and Taft (TS) scores at intervals of 3, 6, and 12 months after surgery. Results: The horizontal stability of the ACJ was better with the two-hole technique than the loop technique at all measurement times. CS and TS changes showed a significant upward trend over time with both techniques. The mean CS and TS at the final visit were 95.2 and 11.6 with the loop technique and 94.0 and 11.9 with the two-hole technique, respectively. The incidence of superficial infections caused by the subcutaneous pins was the same in the two groups. Conclusions: Due to the improved ACJ stability with the two-hole technique, it appears to be a more suitable option than the loop technique for AC joint reduction.

• Nuclear Engineering and Technology
• /
• 제35권5호
• /
• pp.471-481
• /
• 2003

In order to evaluate the microstructural characteristics of irradiated fuel claddings (Zircaloy-4), two irradiated specimens having different burnups (18 GWD/MTU and 42 GWD/MTU) were prepared from the G23-M4 fuel rods, which were loaded in Kori Unit 1 for 4 fuel cycles. The oxide thickness, hydride morphology and hardness change were characterized by an optical microscope and a micro-hardness tester after preparing the irradiated specimens in the PIE (Post Irradiation Examination) facilities. The dislocation loops and the amorphous transformation of precipitates induced by the neutron irradiation in the nuclear plant were also examined by a TEM. As the burnup increased from 18 GWD/MTU to 42 GWD/MTU, the oxide thickness increased from $6.0{\mu}m\;to\;25.3{\mu}m$ and the contents of hydrogen pick-up in the Zr matrix also greatly increased. In the comparison of the hardness of the unirradiated fuel cladding, the amount of hardness increase was nearly $9.3\%\;and\;24.2\%$ for the irradiated samples of 18 and 42 GWD/MTU, respectively. Both -type dislocation loops and -type dislocation components were observed simultaneously in the irradiated specimens and the densities of the dislocation was increased by increasing the burnup. The precipitates in both the irradiated specimens were amorphously transformed by the neutron irradiation and the trend of the amorphous transformation of the precipitates was enhanced at a higher burnup.

• 한국재료학회지
• /
• 제4권3호
• /
• pp.349-356
• /
• 1994

재료의고온소성변형과 수명예측 및 수명향상을 위하여 재료의 변형기구를 규명하는 것이 매우 중요하다. 이를 위하여 전위환모델이 자주 사용되며, 현재 실험적인 결과를 토대로 한 두개의 중요한 전위환모델로서, Orlova등고 Mills등이 제시한 모델들이 있다. 이들은 모두AI-5.5at.%MG을 사용하였으나 상호 상반된 전위환모델을 설명하고 있다. 그러므로 본 연구에서는 상반된 전위환 모델을 확인하기 위하여 AI-5.5at.%MG을 사용하여 573K의 약 30MPa에서 $\varepsilon$=0.03까지 크\ulcorner시험을 하고, 이러한 크\ulcorner시험후 이어서 각각 약 15,10 및 oMPa의 응력감소 시험도 수행하였으며, 동시에 응력감소 시험 전과 후의 전위구조를 관찰하여 전위환모델을 고찰하였다.

• Applied Microscopy
• /
• 제16권2호
• /
• pp.14-24
• /
• 1986

The interrelation of secondary defects, intermediate S' phase and aging condition in Al-2.0 wt% Cu-1.1 wt% Mg alloy is studied by transmission electron microscope. The results obtained in this study are as follows. 1. High density of dislocation loops, helices and stacking faults are observed in this specimen with aging treatment. 2. The number of dislocation loops and the width of loop free zone (LFZ) are increased with aging time. 3. The intermediate S' phase precipitates and grows on the dislocations and secondary defects. 4. The misfit dislocations are formed around intermediate S' phase. 5. It is thought that the helices appear to be produced by the climb of screw dislocations, while the dislocation loops appear to be formed both by condensation of vacancies into collapsed discs and by interaction of helices with screw of opposite sign.

• 한국전기전자재료학회논문지
• /
• 제11권10호
• /
• pp.796-803
• /
• 1998

Intrinsic and proximity gettering are popular processes to get higher cumulative production yield and usually adopt multi-step annealing and high energy ion implantation, respectively. In order to test the combined processed of these, high energy \ulcornerAs\ulcorner ion implantation and 2-step annealing process were adopted. After the ion implantation followed by 2-step annealing, the wafers were cleaved and etched with Wright etchant. The morphology of cross section on samples was inspected by FESEM. The concentration profile of As was measured by SRP. The location and type of secondary defects inspected by HRTEM were dependent on the 1st annealing temperatures. That is, a line of dislocation located at $1.5mutextrm{m}$ apart from the surface at $600^{\circ}C$ lst annealing was changed to some dislocation lines or loops nearby the surface at 100$0^{\circ}C$. The density of dislocation line was reduced but the size of the defects was enlarged as the temperature increased.