• 설비공학논문집
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• 제18권9호
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• pp.687-697
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• 2006

The air and water flow distribution are experimentally studied for a heat exchanger composed of round headers and 10 flat tubes. The effects of tube protrusion depth as well as mass flux, and quality are investigated, and the results are compared with the previous 30 channel results. The flow at the header inlet is annular. For the downward flow configuration, the water flow distribution is significantly affected by the tube protrusion depth. For flush-mounted geometry, significant portion of the water flows through frontal part of the header. As the protrusion depth increases, more water is forced to the rear part of the header. The effect of mass flux or quality is qualitatively the same as that of the protrusion depth. Increase of the mass flux or quality forces the water to rear part of the header. For the upward flow configuration, different from the downward configuration, significant portion of the water flows through the rear part of the header. The effect of the protrusion depth is the same as that of the downward flow. As the protrusion depth increases, more water is forced to the rear part of the header. However, the effect of mass flux or quality is opposite to the downward flow case. As the mass flux or quality increases, more water flows through the frontal part of the header. Compared with the previous thirty channel configuration, the present ten channel configuration yields better flow distribution. Possible explanation is provided from the flow visualization results.

• 한국임상수의학회지
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• 제34권6호
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• pp.467-469
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• 2017

Signalment: A 7-month-old, female domestic shorthaired cat was presented for acute pelvic limb paraparesis. Results: There was no abnormality on survey radiographs and blood analysis, however neurological examination revealed proprioception positioning and hopping was absent in the pelvic limbs. Also, anal tone and perineal sensation were reduced. Magnetic resonance (MR) imaging showed nucleus pulposus dehydration and disc protrusion at T12-T13. Ill-defined diffuse lesion was found at T10-L2 level and it showed isointense on T1-weighted images and hyperintense on T2-weighted and FLAIR images. This lesion was considered as edematous lesion secondary to disc protrusion. The presumptive diagnosis was focal spinal cord edema associated with intervertebral disc protrusion. A traumatic aetiology was suspected. The cat was treated corticosteroids and analgesic and clinical sign improved following 9 days of treatment. Clinical relevance : Intervertebral disc protrusion is rare disease in a cat. However, it could be considered as a cause of paraparesis in cats.

• 설비공학논문집
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• 제23권12호
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• pp.805-814
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• 2011

In the present study, the detailed flow structure and heat transfer characteristics in the newly-designed heat transfer surface geometry were investigated. The surface geometry proposed in the present study is a traditional dimple structure combining with a protrusion inside the dimple, which is named a protrusion-in-dimple in this study. The basic idea underlying the present surface geometry is to enhance the flow mixing and the corresponding heat transfer in the flow re-circulating region generated by a conventional dimple cavity. The present study was performed by the direct numerical simulation at a Reynolds number of 2800 based on mean velocity and channel height and Prandtl number of 0.71. Three different protrusion heights for protrusion-in-dimples were considered as the main design parameter of the present study. The calculated pressure drop and heat transfer capacity were assessed in terms of the Fanning friction factor and Colburn j factor. The overall performances estimated in terms of the volume and area goodness factor for protrusion-in-dimple cases were higher than the conventional dimple case.

• Clinics in Shoulder and Elbow
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• 제24권2호
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• pp.66-71
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• 2021

Background: Extra-articular distal humerus locking plates (EADHPs) are precontoured anatomical plates widely used to repair distal humeral extra-articular diaphyseal fractures. However, EADHPs frequently cause distal protrusion and resulting skin discomfort. The purpose of this study was to predict the occurrence of anatomic fit mismatch. We hypothesized that the smaller the humerus size, the greater the anatomic fit mismatch with EADHP. Methods: Twenty humeri were analyzed in this study. Humeral length and distal humeral width were used as parameters of humeral size. Plate protrusion was measured between the EADHP distal tip and the distal humerus. We set the level of unacceptable EADHP anatomic fit mismatch as ≥10 mm plate protrusion. Results: A significant negative linear correlation was also confirmed between humeral size and plate protrusion, with a coefficient of determination of 0.477 for humeral length and 0.814 for distal humeral width. The cutoff value of humeral length to avoid ≥10 mm plate protrusion was 293.6 mm (sensitivity, 88.9%; specificity, 81.8%) and for distal humeral width was 60.5 mm (sensitivity, 100%; specificity, 81.8%). Conclusions: Anatomic fit mismatch in distal humeral fractures after EADHP fixation has a negative linear correlation with humeral length and distal humeral width. For patients with a distal humeral width <60.5 mm, ≥10 mm plate protrusion will occur when an EADHP is used, and an alternative implant or approach should be considered.

• 대한치과교정학회지
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• 제36권1호
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• pp.45-54
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• 2006

최근 안모의 심미성이 중요시되면서 구순 돌출로 인한 비심미성을 해소하고자 내원하는 양악 치조골 전돌자의 수가 증가하는 추세이다. 그러나 이러한 환자에 대한 연구는 많지 않으며 특히 모형을 이용한 연구는 극히 적다. 모형을 이용하는 연구는 주로 손으로 직접 계측하거나 2차원 평면에서 컴퓨터를 이용하여 측정하였으나 근래에 3차원 레이저 스캐너가 도입되면서 모형을 이용한 연구를 좀 더 빠르고 간편하면서도 정확하게 할 수 있게 되었다. 이 연구는 3차원 디지털 모형을 이용하여 양악 치조골 전돌자의 치열궁 특성을 알아보기 위한 것이다. 양악 치조골 전돌자 20명과 정상교합자 20명을 대상으로 치아 크기, 치열궁 폭경 및 치열궁 길이, 치열궁과 구개의 형태를 비교하여 본 결과 양악 치조골 전돌자는 정상교합자보다 치아 크기가 크고, 하악 견치간 폭경 및 제1소구치간 폭경이 크며 치열궁 길이가 길었다. 그리고 치열궁 형태와 구개 형태에서 정상교합자와 차이를 보였다.

• 대한치과교정학회지
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• 제13권2호
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• pp.131-146
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• 1983

Faces of normal occlusion, open bite and class III malocclusion were measured using cephalogram in 190 male and female subjects. Using M.K.G., types of mandibular movement, amount of horizontal and vertical movement were studied in relation to occlusal types, and were compared with each other. The following conclusions were obtained. 1. Movement of protrusion was most different in relation to occlusal type. 2. In normal occlusion, maximal protrusion were horizontal 7.66mm, vertical 3.01mm in male, 6.41, 2.92mm respectively in female and maximal inferior position were -24.32, 33.63mm in male,-23.48, 32.27mm respectively in female. 3. Angle between maximal inferior position and horizontal plane were $53.51^{\circ}$ in male, $53.84^{\circ}$ in female. 4. Generally, amount of mandibular movement was greater in male than female. 5. In open bite, path of protrusion was nearly straight without curve $69.2\%$ in male, $70.2\%$ in female. 6. In class III malocclusion, angle and amount of protrusion were smaller than normal occlusion and path was directed anterior-superiorly in $22.7\%$. 7. There was no correlation coefficient between measurement of face and mandibular movement.

• The Korean Journal of Pain
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• 제21권3호
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• pp.233-236
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• 2008

There are many causes of chronic abdominal pain and abdominal protrusion. But, they are likely to be confused with diabetic thoracic polyradiculopathy. Differentiation between this self-limiting complication and abdominal herniation is important to avoid unnecessary procedure. We describe the case of 77-years-old man with 10 years history of non-insulin dependent diabetes mellitus, who was suffering from postherpetic neuralgia for 10 months and presented with a abdominal segmental paresis and protrusion. The paraspinal electromyography showed bilateral lower thoracic radiculopathy.

• Structural Engineering and Mechanics
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• 제66권6호
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• pp.783-792
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• 2018

This paper presents a detailed theoretical study of the sleeved compression members based on a mechanical model. In the mechanical model, the core protrusion above sleeve and the contact force between the core and sleeve are specially taken into account. Via the theoretical analyses, load-displacement relationships of the sleeved compression members are obtained and verified by the experimental results. On the basis of the core moment distribution changing with the increase of the applied axial load, failure mechanism of the sleeved compression members is assumed and proved to be consistent with the experimental results in terms of the failure modes and the ultimate bearing capacities. A parametric study is conducted to quantify how essential factors including the core protrusion length above sleeve, stiffness ratio of the core to sleeve, core slenderness ratio and gap between the core and sleeve affect the mechanical behaviors of the sleeved compression members, and it is concluded that the constrained effect of the sleeve is overestimated neglecting the core protrusion; the improvement of ultimate bearing capacity for the sleeved compression member is considered to be decreasing with the decrease of the core slenderness ratio and for the sleeved compression member with core of small slenderness ratio, small gap and small stiffness ratio are preferred to obtain larger ultimate bearing capacity and stiffness.

• 대한치과교정학회지
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• 제17권1호
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• pp.33-45
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• 1987

This study was designed to examine relations between posture and size of the tongue and dentoalveolar pattern. The sample was consisted of three groups, the 34 subjects of Normal occlusion, the 31 subjects of Bimaxillary protrusion and the 31 subjects of Class III malocclusion. On the cephalograms, lengths, heights and areas of the tongue and intermaxillary space and on the study model, arch length, intercanine width, intermolar width and palatal height were measured. These data from measuring cephalograms and models were statistically analyzed. The results of the study were as follows; 1. Length of the tongue was the greatest in Bimaxillary protrusion and in order of Normal occlusion and Class III malocclusion. 2. Posture of the tongue was the lowest in Class III malocclusion and in order of Bimaxillary protrusion and Normal occlusion. 3. There were a tendency to be larger area of tongue and intermaxillary space in Class III malocclusion compared to Normal occlusion and Bimaxillary protrusion. 4. Size of the tongue and intermaxillary space showed low correlations with the dentoalveolar pattern.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.101-104
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• 2008

The sailfish is the fastest sea animal, reaching its maximum speed of 110km/h. On its skin, a number of V-shaped protrusions pointing downstream exist. Thus, in the present study, the possibility of reducing the skin friction using its shape is investigated in a turbulent boundary layer. We perform a parametric study by varying the height and width of the protrusion, the spanwise and streamwise spacings between adjacent ones, and their overall distribution pattern, respectively. Each protrusion induces a pair of streamwsie vortices, producing low and high shear stresses at its center and side locations, respectively. These vortices also interact with those induced from adjacent protrusions. As a result, the drag is either increased or unchanged for all the cases considered. In some cases, the skin friction itself is reduced but total drag including the form drag on the protrusions is larger than that of a smooth surface. Since the shape of present protrusions is similar to that used by Sirovich and Karlsson [Nature 388, 753 (1997)] where V-shaped protrusions pointing upstream were considered, we perform another set of experiments following their study. However, we do not obtain any drag reduction even with random distribution of those V-shaped protrusion.