• Journal of Korean Neurosurgical Society
• /
• 제64권4호
• /
• pp.575-584
• /
• 2021

Objective : Cervical expansive laminoplasty is an effective surgical method to address multilevel cervical spinal stenosis. During surgery, the spinous processes of C2 and C7 are usually preserved to keep the insertion points of the cervical musculature and nuchal ligament intact. In this regard, dome-like laminectomy (undercutting of C7 lamina) instead of laminoplasty is performed on C7 in selected cases. However, resection of the lamina can weaken the C7 lamina, and stress fractures may occur, but this complication has not been characterized in the literature. The objective of the present study was to investigate the incidence and risk factors for C7 laminar fracture after C7 dome-like laminectomy and its impact on clinical and radiological outcomes. Methods : Patients who underwent cervical open-door laminoplasty combined with C7 dome-like laminectomy (n=123) were classified according to the presence of C7 laminar fracture. Clinical parameters (neck/arm pain score and neck disability index) and radiologic parameters (C2-7 angle, C2-7 sagittal vertical axis, and C7-T1 angle) were compared between the groups preoperatively and at postoperatively at 3, 6, 12, and 24 months. Risk factors for complications were evaluated, and a formula estimating C7 fracture risk was suggested. Results : C7 lamina fracture occurred in 32/123 (26%) patients and occurred at the bilateral isthmus in 29 patients and at the spinolaminar junction in three patients. All fractures appeared on X-ray within 3 months postoperatively, but patients did not present any neurological deterioration. The fracture spontaneously healed in 27/32 (84%) patients at 1 year and in 29/32 (91%) at 2 years. During follow-up, clinical outcomes were not significantly different between the groups. However, patients with C7 fractures showed a more lordotic C2-7 angle and kyphotic C7-T1 angle than patients without C7 fractures. C7 fracture was significantly associated with the extent of bone removal. By incorporating significant factors, the probability of C7 laminar fracture could be assessed with the formula 'Risk score = 1.08 × depth (%) + 1.03 × length (%, of the posterior height of C7 vertebral body)', and a cut-off value of 167.9% demonstrated a sensitivity of 90.3% and a specificity of 65.1% (area under the curve, 0.81). Conclusion : C7 laminar fracture can occur after C7 dome-like laminectomy when a substantial amount of lamina is resected. Although C7 fractures may not cause deleterious clinical outcomes, they can lead to an unharmonized cervical curvature. The chance of C7 fracture should be discussed in the shared decision-making process.

• Steel and Composite Structures
• /
• 제34권5호
• /
• pp.681-698
• /
• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• 대한기계학회논문집
• /
• 제16권6호
• /
• pp.1121-1140
• /
• 1992

본 연구에서는 부착형 칩절단구의 경사면 대신에 원고면으로 형성한 형태 칩 절단구를 고찰하고, 재래형과 비교하여 더 효과적인 칩절단구를 개발 실용화하고자 한 다. 가공법으로서는 연속칩의 처리가 가장 곤란한 선삭을, 공작물로서는 연속칩이 가장 잘 생성되는 SM 20 C의 연강을, 공구재료로서는 P계열의 초경합금을 써서 저속에 서 고속절삭속도까지 시험하였다.

• 한국산림과학회지
• /
• 제20권1호
• /
• pp.45-50
• /
• 1973

싸리류(類)에 대(對)한 선발된 우량개체 및 앞으로 육성(育成)될 신품종(新品種)에 대(對)하여 무성번식의 방법을 구명(究明)코져 조록싸리, 참싸리, 늦싸리, 싸리, 털근록싸리, 풀싸리를 공시재료로 하여 4월(月) 상순(上旬) 삽목직전 1년지(年枝)를 채취하여 삽수길이 15~20cm, 삽수굵기 3~4mm, 삽수상하단을 동일하게 타원형으로 조제하여 1,000배액의 "우수프론"으로 소독한 삽상길이 150cm의 모래상에 삽목하였으며 삽목후 해가림 관수를 하였다. 그 결과 교배에 의한 신품종 및 선발개체(選拔個體)에 대(對)한 무성번식이 가능함을 인정할 수 있었으며 아래와 같은 결과를 얻었다. 1. 싸리류(類)의 삽목발근율은 50.3~69% 로 품종간 차이를 인정할 수 있었으며 털조록싸리, 조록싸리의 발근율이 제일 높고 풀싸리가 제일 낮았다(유의 수준 1%). 2. 생육상황(生育狀況)은 조록싸리, 싸리가 좋았으며 풀싸리가 가장 불량했다. 3. 본당(本當) 뿌리수는 길이 5cm 이상만을 측정하였으며 털조록싸리가 6.4개로 제일 많고 풀싸리가 1.3개로 제일 적었다(유의수준 1%). 4. 본당(本當) 뿌리의 총연장은 털조록싸리 279.8cm, 조록싸리 200.1cm로 가장 길고 풀싸리는 41.1cm로 가장 짧았다(유의 수준 1%). 5. 본당(本當) 근류착생수는 직경 1mm 이상만을 조사하였으며 털조록싸리 34.4개, 조록싸리 27.1개로 제일 많고 풀싸리는 4.6개로 제일 적었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제13권5호
• /
• pp.580-586
• /
• 2000

Data collected between 1981 and 1991 at the Philippine Carabao Center at Central Luzon State University (PCC-CLSU) were used for the comparison of growth, milk yield and draughtability of Murrah-Philippine crossbred and Philippine native buffaloes. Body weights and body measurements were available at 3-month intervals from birth to 36 months of age for a total of 34 $Murrah{\times}Philippine$ native buffalo F1 crossbreds (CBB; 21 cows, 13 bulls) and 32 Philippine native buffaloes (PNB; 16 cows, 16 bulls). Lactation records were available for 14 CBB and 19 PNB cows. Data for draughtability under wet and dry ploughing conditions were available for 4 CBB and 4 PNB steers. The results indicate that crossbreds grow faster (0-9 months of age: cows $442{\pm}19$ vs. $301{\pm}21g/day$, bulls $305{\pm}23$ vs. $296{\pm}21g/day$; 9-36 months of age: cows $227{\pm}10$ vs. $147{\pm}12g/day$, bulls $282{\pm}13$ vs. $138{\pm}12g/day$), mature earlier and produce more milk (1st lactation: $1139{\pm}153$ vs. $450{\pm}112kg$; 2nd lactation: $1115{\pm}132$ vs. $488{\pm}136kg$) than native buffaloes, but have a poorer draughtability (wet ploughing; force as % of body weight $8.8{\pm}0.2$ vs. $12.2{\pm}0.6$; dry ploughing: cut depth $10.98{\pm}0.25$ vs. $11.92{\pm}0.13cm$, velocity $0.50{\pm}0.03$ vs. $0.60{\pm}0.02m/sec$, force as % of body weight $9.0{\pm}0.6$ vs. $11.3{\pm}0.7$). The correlation coefficients between body weight and body measurements at birth and at 3-month intervals indicate that heart girth has a relatively high correlation with body weight, especially in crossbreds. It is concluded that in Philippine smallholder farming systems in which meat and milk production are secondary to draught power, the native buffalo is preferable from the point of view of input needed to maintain the number of animals kept for a required draught force.

• 산경연구논집
• /
• 제13권6호
• /
• pp.39-49
• /
• 2022

Purpose: As part of these efforts, in-depth research is needed on efficient and practical utilization of underground spaces and underground shopping malls. In addition, efforts are being made to find effective alternatives to various problems currently occurring in underground shopping malls, but it is not easy. In addition, the development entity and the maintenance entity are different from each other, and the management is not unified, making it difficult to maintain underground shopping malls. From this point of view, it can be said that it is time to actively and specifically discuss ways to revitalize underground shopping malls. Data and methodology: In the domestic distribution environment, traditional markets and shops are stagnating due to rapid changes in consumption patterns, such as the spread of large companies with advanced distribution techniques such as hypermarkets, shopping malls, and SCM, the rapid increase in Internet and home shopping, and the importance of convenience for young consumers. In order to revitalize underground shopping malls, it is necessary to strengthen the organization and self-rescue efforts of merchants' associations, change consciousness through merchant education, change to specialized markets, find nuclear stores and representative restaurants, and support the hardware sector. Results: The connection of underground shopping malls in each region of the country, where commercial districts are separated from each other, will also play an important role in reviving the function of the city in the future. To do this, it is first necessary to connect underground shopping malls that have been cut off. In other words, connection between connectable underground shopping malls should be promoted. Of course, long-term projects should be promoted step by step, and many consultations should be made on how to connect with the ground for each local government. Conclusion: This is because in the future, the underground space cannot just be a walking place, but another space of the Korean Wave where you can experience satisfying the five senses. K-shopping Hallyu content can be created by creating a characteristic story for each underground shopping mall in the city, permanently this story-oriented event, and creating a safe and elegant environment. If there is a story, so-called "Senomi Shopping" will be possible. A new Korean Wave will be created that can satisfy "the fun of writing, the fun of seeing, and the fun of feeling" at the same time.

• 대한공업교육학회지
• /
• 제32권2호
• /
• pp.23-46
• /
• 2007

이 연구는 지금까지 출제된 공업계열 과목의 수능 문항을 대상으로 하여, 내용 영역 및 행동 영역 별로 문항을 분류 추출하고 각 영역 별로 고루 출제되고 있는지를 분석하여, 출제 경향 및 문제점을 파악하고 참신한 문항 개발 사례를 분석하여 공업계열 문항 개발에의 시사점을 제시하는데 그 목적이 있다. 이 연구의 목적을 달성하기 위하여 내용 영역 별로 문항을 분류하여 분석하고, 행동 영역 별로 예시 문항을 추출하여 분석하였으며, 참신한 문항 개발 사례를 선정하였다. 이를 통하여 얻은 주요 결론은 다음과 같다. 첫째, 내용 영역별 문항 분류를 통하여 출제 경향을 분석한 결과 비교적 중영역 별로 고르게 출제되었다. 둘째, 공업 입문은 입문적 성격이 강한 이론 과목의 특성이 있고 공업의 전반적인 내용을 포괄하고 있어 다른 과목에 비하여 비교적 시사적인 내용이 많이 출제되었는데, 교육과정과 관련된 시사적인 문항을 출제하였어도 당초 의도와는 전혀 다르게 문항에 제시된 정보만으로도 문제를 해결할 수 있는 문항이 많이 출제되었다. 셋째, 행동 영역의 하위 영역별로 예시 문항을 추출하여 분석한 결과 다양한 소재를 활용한 타당하고 참신한 문항이 많이 출제되었다. 이 연구를 수행하면서 나타난 문제점과 연구 결과를 토대로 앞으로 공업계열 수능 문항을 개발하는데 있어서 몇 가지 제언을 하면 다음과 같다. 첫째, 이 연구에서는 공업계열 모든 과목을 대상으로 하지 않고 공업 입문 과목에 한정하여 분석하였기 때문에, 기초 제도, 정보 기술 기초, 프로그래밍 등의 과목에 대한 후속 분석이 필요하다. 둘째, 행동 영역 별로 하위 영역을 통합하여 새로운 하위 영역을 지속적으로 개발하고, 하위 영역 분류 및 내용에 대한 타당성 검증 연구가 수행된다면 보다 참신하고 좋은 문항을 개발하는데 도움이 될 것이다.

• 트랜스-
• /
• 제7권
• /
• pp.81-101
• /
• 2019

인터뷰는 다큐멘터리의 심장이라는 말이 있을 정도로 중요한 의미와 비중을 지닌다. 내러티브 극영화에서는 이야기적 서술이 중심이 되는데 반해 다큐멘터리는 담화적 성격이 강하고, 담화는 내레이션과 인터뷰로 구성된다. TV 다큐멘터리에서는 인터뷰가 관습적인 쇼트를 반복적으로 활용하는 데 반해, 상대적으로 큰 스크린을 대상으로 하는 다큐멘터리 영화에서는 인터뷰의 미쟝센은 미학적 심도를 깊게 고려해야한다. 2017년 개봉하여 다큐멘터리 영화사상 세 번째로 관객을 동원한 <노무현입니다>는 본편 분량의 40퍼센트가 같은 앵글과 같은 사이즈로 구성하는 시도를 한다. TV 다큐멘터리에서는 인터뷰 컷이 30초를 넘어가는 경우는 드물 뿐 아니라, 1분을 넘는 경우 몰입도가 현저히 낮아지는 만큼 인터뷰 담화의 분량과 압축은 연출자와 수용자 모두에게 중요한 요소다. <노무현입니다>의 인터뷰 시퀀스의 경우 최소 8분30초에서 최대 11분이라는 상대적으로 긴 담화 중심의 서브 플롯을 관객들에게 소통 가능한 방식으로 전달하는 것이 관건이었다. 나아가 주인공인 노무현의 서거 후 제작된 만큼 주인공의 음성을 배제하고 주변인물을 통해 노무현의 음성을 간접적으로 재현한다는 한계를 안고 제작이 진행되었다. 본 연구에서는 다큐멘터리 연출에 있어서 인터뷰의 의미와 범위, 미쟝센을 미학적으로 응용한 사례들을 고찰하여 <노무현입니다>의 인터뷰 시퀀스를 도출하는 과정을 복기한다.

• 대한치과보철학회지
• /
• 제44권1호
• /
• pp.1-9
• /
• 2006

Purpose: The purpose of this study was to evaluate the efficacy and substitute possibility of a newly developed flowable composite resins as a luting cement for translucent fiber post. Material & Method: Two kinds of 12 mm translucent fiber Post (D.T. Light-Post (Bisco, USA) and FRC Postec (Ivoclar vivadent, Liechtenstein) was inserted into the teflon mold (7 mm diameter, 9 mm long) and Filtek-Flow (3M ESPE. USA), a light activated flowable composite resin, was polymerized for 60 seconds through the post. Also, the post was cut from the tip to 9 mm, 6 mm, 3 mm, and Filtek-Flow was light cured according to each length. For comparison, 60 seconds light-cured and 24 hours self-cured two dual cured resin cement (Duo-cement (Bisco, USA) and 2 Panavia-F (Kuraray, Japan)) samples were prepared as control group. Also cavities (1 mm in width, 1 mm in depth and 12 mm in length) were prepared using acrylic plate and aluminum bar, and flowable composite resin was flied and light cured by the diffused light from the fiber post's side wall. The degree of polymerization was measured according to the distance from curing light using Vickers' hardness test. Result: Within the limitation of this study, the following conclusions were drawn: 1. Vickers' hardness of light cured dual cured resin cement and flowable composite resin decreased from Panavia-F, Filtek-Flow and Duo-cement accordingly (p<0.05). In the dual curing resin cement, light curing performed group showed higher surface hardness value than self cured only group (p<0.05). 2. Surface hardness ratio (light cured through fiber post /directly light cured) of D.T. Light-Post using Filtek-Flow showed about 70% in the 6 mm deep and about 50% in the 12 mm deep FRC Postec showed only 40% of surface hardness ratio. 3. Surface hardness ratio by diffused light from the post's side wall showed about 50% at 6 mm and 9 mm deep, and about 40% at 12 mm deep in D.T. Light-Post. However, FRC Postec showed about 40% at 6 mm deep, and almost no polymerization in 9 mm and 12 mm deep.

• 치과방사선
• /
• 제20권2호
• /
• pp.299-313
• /
• 1990

The author analysed tomographic and cephalometric radiographs of 82 temporomandibular joints from 41 symptomatic patients and 40 temporomandibular joints from 20 asymptomatic young adults. The results were as follows; 1. The mean condylar angulation in control group and patient group was 21.72±6.48° 20.13±9.14° respectively and there was no significant difference between two groups. 2. The mean depth of cut was 6.63±0.38㎝ in control group and 6.57±0.46㎝ in patient group. 3. Mean height and width of condylar head were 6.66±1.83㎜, 12.42±0.49㎜ in control group and 6.22±1.36㎜, 11.93±l.92㎜ in patient group. 4. The mean height of articular fossa was 10.20±2.04㎜ in control group and 9.89±1.98㎜ in patient group. The mean width of articular fossa was 21.08±2.08㎜ in control group and 21.24±3.03㎜ in patient group. 5. In centric occlusion the superior joint space was largest (4.15±0.93㎜), followed by the posterior joint space (2.99±0.97㎜) and the anterior joint space (2.70±0.73㎜) in control group. The superior joint space (3.47±1.31㎜) and posterior joint space (3.47±7.07㎜) were same in patient group. There was significant difference in left superior joint spaces between two groups (p<0.05). 6. The condylar position in articular fossa was displaced anteroinferiorly (0.99±3.65㎜ anteriorly, 1.75±1.01㎜ inferiorly) in control group and posteroinferiorly (3.20±4.69㎜ posteriorly, 1.25±1.87㎜ inferiorly) in patient group with 1 inch opening. In maximum opening, it was displaced anteroinferiorly (6.09±3.55㎜ anteriorly, 1.38±2.47㎜ inferiorly) in control group and anteroinferiorly (1.70±5.96㎜ anteriorly, 1.37±1.85㎜ inferiorly) in patient group. There was significant difference in anteroposterior position of both condyles with 1 inch opening and maximum opening between two groups (p<0.01). 7. The mean inclination of upper central incisor and the posterior inclination of articular eminence in control group was 65.60±6.04° 58.88±9.18° in control group, and 67.14±8.41°, 59.70±9.08° in patient group respectively. There was no significant correlation between two groups.