• Journal of Korean Neurosurgical Society
• /
• v.30 no.7
• /
• pp.883-890
• /
• 2001

Objectives : An in vitro biomechanical study of posterior lumbar interbody fusion(PLIF) with threaded cage using two different approaches was performed on eighteen functional spinal units of bovine lumbar spines. The purpose of this study was to compare the segmental stiffnesses among PLIF with one long posterolateral cage, PLIF with one long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages. Methods : Eighteen bovine lumbar functional spinal units were divided into three groups. All specimens were tested intact and with cage insertion. Group 1(n=12) had a long threaded cage($15{\times}36mm$) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2(n=6) had two regular length cages($15{\times}24mm$) inserted posteriorly with bilateral facetectomy. Six specimens from group 1 were then retested after unilateral facet joint screw fixation in neutral(group 3). Likewise, the other six specimens from group 1 were retested after fixation with a facet joint screw in an extended position(group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion. Results : PLIF with a single cage, group 1, had a significantly higher stiffnesses than PLIF with two cages, group 2, in left and right torsion(p<0.05). Group 1 showed higher stiffness values than group 2 in pure compression, flexion, left and right bending but were not significantly different. Group 3 showed a significant increase in stiffness in comparison to group 1 for pure compression, extension, left bending and right torsion(p<0.05). For group 4, the stiffness significantly increased in comparison to group 1 for extension, flexion and right torsion(p<0.05). Although there was no significant difference between groups 3 and 4, group 4 had increased stiffness in extension, flexion, right bending and torsion. Conclusion : Posterior lumbar interbody fusion with a single long threaded cage inserted posterolaterally with unilateral facetectomy enables sufficient decompression while maintaining a majority of the posterior elements. In combination with a facet joint screw fixation, adequate postoperative stability can be achieved. We suggest that posterolateral insertion of a long threaded cage is biomechanically an ideal alternative to PLIF.

• Journal of the Korean Arthroscopy Society
• /
• v.13 no.3
• /
• pp.249-253
• /
• 2009

Purpose: We evaluated the clinical and radiographic results of arthroscopic ankle arthrodesis using 3 cannulated screws for the treatment of arthritis of ankle. Materials and Methods: From May 2006 to February 2009, 17 cases of arthritis of ankle were treated by ankle arthrodesis using 3 cannulated screws under arthroscopy. There were 8 male and 7 female and the average age was 62.2 years. We evaluated them clinically using AOFAS ankle-hindfoot functional scale, VAS pain score and patient’s satisfaction. For the radiographic evaluation, we checked them by simple AP, lateral and mortise view. The average follow-up period was 24.2 months. Results: The ankle-hindfoot functional scale was improved from an average of 47.4 points preoperatively to an average of 82.5 points at the last follow-up. The visual analogue scale pain score was decreased from an average of 8.6 to 2.4. Patient's satisfaction had favorable results with excellent in 7 cases(41.2%), good in 8 cases(47.0%), fair in 1 case(5.9%) and poor in1 case(5.9%). All ankles were successfully fused and the mean period of fusion was 9.1 weeks. Conclusion: Arthroscopic ankle arthrodesis using 3 cannulated screws was good modality of ankle arthrodesis with good clinical results and high union rate in the case of advanced ankle arthritis.

• Journal of Korean Society of Forest Science
• /
• v.22 no.1
• /
• pp.49-62
• /
• 1974

1. In the comparison of survival ratio among three different methods(bark graft, veneer graft, root graft), bark graft showed the highest survival ratio and root graft was the lowest. It was shown to be significant at the level of 5% in the analysis of variance for the results. It was able to be supposed that one of the main causes for the results was the different amounts of ferric tannic acid which was formated owing to the reaction of grafting knife with tannic acid oozing from cutting faces of the tree. In juvenile tissue graft, the survival ratio of inverted radicle graft was a little higher than that of juvenile stem graft, but there was no significant difference between two methods in analysis of variance. 2. The most hairs of chestnut tree leaves were recognized as stellates on the most part of leaves except for venation. The number of rays in the stellates was ranged from 4 to 8 generally. It was shown to be highly significant differences at the level of 1% among the each race growing at the similar environmental condition in the length of ray and the distributed ratio of the stellates having different ray number. 3. Excepting for the basal width of serration there were no significant differences between $Imakita_1$, $Imakita_2$ as well as between $Teteuchi_1$, $Teteuchi_2$ at the each point of experimental items in this study. Such results made this study more useful. 4. Among the races that were growing in the similar environmental condition, there were highly significant differences at the level of 1% in the length and the width of serration. 5. The rolling of hair, the angle of serration from the leaf margin, the existence of lateral vein in the serration, the intrusion of main vein into the serration and the width of main vein were observed to be somewhat useful as the subsidiary methods for the identification of chestnut races.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.1
• /
• pp.25-32
• /
• 1998

To characterize the growth environment, inorganic composition and morphological chracteristics of leaves of Korean tea plant, soil and tea leaf samples were collected from 15 locations and analyzed. The chemical characteristics of soils were in range of pH 4.09~6.15, OM 23.9~72.6g/kg, available phosphate less than 300mg/kg, K $0.8{\sim}2.5cmol^+/kg$, Na $tr{\sim}0.17cmol^+/kg$, Ca $1.0{\sim}6.2cmol^+/kg$, and Mg $0.3{\sim}2.1cmol^+/kg$. The contents of Ni. Cr, Zn. Cu, Pb, and Cd were at the level less than natural content in upland soil. Most of the sample soils were sandy loamy and loamy texture. The native tea plants were mainly grown in bamboo thicket or in forest. The leaf sizes of tea plants were $6.85{\pm}1.75{\times}2.6{\pm}0.5cm$, lateral vein number $14.2{\pm}2.7$, and crenated number $58.5{\pm}11.2$, and the leaf color was thin to dark green. The contents of $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$ and $Ca^{2+}$ in tea leaves were in range of 30.5~47.7, 45.5~164.5, 16,998~25,431, 1.590~2,392 and 1,085~1,958mg/kg, respectively. The contents of $F^-$, $Cl^-$, $NO_3{^-}$, $PO_4{^{3-}}$ and $SO_4{^{2-}}$ were in range of 21.2~63.2, 126.4~257.9, 108.5~185.9, 1,270~1.819, and $954{\sim}1,670mg/kg$, respectively. The leaf size of native tea plant grown widlly in Shunchun Changchun-ri, Hwasun Ssangbongsa, Kuryoi Chonunsa, Bosong Daewonsa and Namhae Boriam was as large as those of Yabukita. Japan cultiver, grown at Kangjin Jangwon tea field.

• Publications of The Korean Astronomical Society
• /
• v.36 no.3
• /
• pp.65-78
• /
• 2021

Jagyeokru, an automatic striking water clock described in the Sejong Sillok (Veritable Records of King Sejong) is essentially composed of a water quantity control device and a time-signal device, with the former controlling the amount or the flow rate of water and the latter automatically informing the time based on the former. What connects these two parts is a signal generating device or a power transmission device called the 'Jujeon' system, which includes a copper rod on the float and ball-racked scheduled plates. The copper products excavated under Gongpyeong-dong in Seoul include a lot of broken plate pieces and cylinder-like devices. If some plate pieces are put together, a large square plate with circular holes located in a zigzag can be completed, and at the upper right of it is carved 'the first scheduled plate (一箭).' Cylinder-like devices generally 3.8 cm in diameter are able to release a ball, and have a ginkgo leaf-like screen fixed on the inner axis and a bird-shaped hook of which the leg fixes another axis and the beak attaches to the leaf side. The lateral view of this cylinder-like device appears like a trapezoid and mounts an iron ball. The function of releasing a ball agrees with the description of Borugak Pavilion, where Jagyeokru was installed, written by Kim Don (1385 ~ 1440). The other accounts of Borugak Pavilion's and Heumgyeonggak Pavilion's water clocks describe these copper plates and ball releasing devices as the 'Jujeon' system. According to the description of Borugak Pavilion, a square wooden column has copper plates on the left and right sides the same height as the column, and the left copper plate has 12 drilled holes to keep the time of a 12 double-hours. Meanwhile, the right plate has 25 holes which represent seasonal night 5-hours (Kyeong) and their 5-subhours (Jeom), not 12 hours. There are 11 scheduled plates for seasonal night 5-hours made with copper, which are made to be attached or detached as the season. In accordance with Nujutongui (manual for the operation of the yardstick for the clepsydra), the first scheduled plate for the night is used from the winter solstice (冬至) to 2 days after Daehan (大寒), and from 4 days before Soseol (小雪) to a day before the winter solstice. Besides the first scheduled plate, we confirm discovering a third scheduled plate and a sixth scheduled plate among the excavated copper materials based on the spacing between holes. On the other hand, the width of the scheduled plate is different for these artifacts, measured as 144 mm compared to the description of the Borugak Pavilion, which is recorded as 51 mm. From this perspective, they may be the scheduled plates for the Heumgyeonggak Ongru made in 1438 (or 1554) or for the new Fortress Pavilion installed in Changdeokgung palace completed in 1536 (the 31^st year of the reign of King Jungjong) in the early Joseon dynasty. This study presents the concept of the scheduled plates described in the literature, including their new operating mechanism. In addition, a detailed model of 11 scheduled plates is designed from the records and on the excavated relics. It is expected that this study will aid in efforts to restore and reconstruct the automatic water clocks of the early Joseon dynasty.

• The Journal of Korean Academy of Prosthodontics
• /
• v.59 no.3
• /
• pp.271-280
• /
• 2021

Purpose. The aim of this study was to evaluate the relationship between the patient's occlusion and a cracked tooth by using T-scan occlusal analysis and a quantitative light-induced fluorescence (QLF) technology. Materials and methods. This study was carried out on 51 patients having cracked teeth between January, 2019 and December, 2020. The tooth crack was determined with a Q-ray pen and QLF parameters (ΔF_max and ΔR_max) were obtained by a Q-ray software. T-scan tests were conducted to all subjects and then, the occlusal force and disclosing time were analyzed. Mann-Whitney U test was performed to compare the occlusal force and disclosing time between cracked teeth groups and contra-lateral normal teeth groups (α = .05). Mann-Whitney U test was performed to compare ΔF_max and ΔR_max according to the results of cold/bite tests (α = .05). A Spearman correlation analysis was run to determine the relationship between ΔF_max or ΔR_max and occlusal force or disclosing time (α=.05). Results. The mean occlusal force and disclosing time were significantly higher on cracked teeth than on normal teeth (P < .05). The ΔF_max or ΔR_max were not significantly different according to the results of cold/bite tests (P > .05). There was no correlation between ΔF_max or ΔR_max and occlusal force or disclosing time (P > .05). Conclusion. There was a significant relationship between occlusion and cracked tooth syndrome. QLF has the potential to be a valuable tool for the diagnosis of tooth crack in clinical practice.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.2
• /
• pp.387-393
• /
• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.

• Korean Journal of Heritage: History & Science
• /
• v.52 no.1
• /
• pp.120-147
• /
• 2019

In this study, we divided the portraits in the reign of King Seonjo into those which were created before and after the Japanese invasion. We then examined various aspect of costumes expressed in the portraits of meritorious vassals. To analyze official uniforms (Heuk-Danryeung), we examined the Samo height; the side wings' type and pattern; the Danryeung pattern; the Mu style; the processing method of lateral lines in Danryeung the rank badge and rank belt, the color of Dabho and Cheolrik, which were undergarment of Danryeung and Heuk-wa. The meritorious vassals' portraits, prior to Imran, were analyzed with a portrait of Han Eung-in, a Gwang-kuk Pyeong-nan meritorious vassals. The Samo was the highest of the Choson dynasties, and the cloud and treasure pattern was identified on the side wings. The Heuk-Danryeung was a dark blue(acheongsaeg) Danryeung of manja-shaped cloud patterns with a large outward wrinkled Mu, and it had a wild goose badge (second rank) and a Sabgeumdae. It did not coincide with the Pumgye(Jaheondaebu) recorded in Gugjo-inmulgo. Reddish Dabho for Dangsang-kwan, green Cheolrik which was undergarment of Danryeung, and Heuk-wa. were identified. After the invasion of Japan, portraits of Hoseong, Seonmu, and Cheong-nan meritorious vassals were analyzed through eighteen portraits, including Lee Hyeon-bok. After the invasion of the Japanese, the height of the Samo's top was much lower and the width of the side wings was wider than before the invasion of Japanese. The Heuk-Danryeung was a dark blue (acheongsaeg) Danryeung of manja-shaped cloud patterns with a stretching backward Mu. Rank badge and rank belts were almost identical with the record, but there were two exceptions (Sin-jab and Kim, Sae-sin). Therefore, it was reaffirmed that the meritorious vassals' portraits were drawn by the Pumgye at the time of appointment. Among the undergarments of Heuk-Danryeung, green Dabho(11), blue Dabho(4), reddish Dabho(3), and blue Cheolrik(10), green Cheolrik(6), reddish Cheolrik(1), and yucheongsaeg Cheolrik(1) were identified, However, it is suggested that the Dabho of Hoseong, Seonmu, and Cheong-nan meritorious vassals should be the reddish Dabho of Dangsang-kwan, which is the same as the previous Imran, and a green Cheolrik.

• Journal of the Korean Orthopaedic Association
• /
• v.53 no.6
• /
• pp.498-504
• /
• 2018

Purpose: To evaluate the clinical and radiological outcomes, and the complications of unicompartmental knee arthroplasty (UKA) using a fixed bearing prosthesis after 5-year follow-up. Materials and Methods: Twenty-six knees (25 patients) that underwent fixed bearing UKA between May 2003 and August 2011 were included. The subjects were 3 males (3 knees) and 22 females (23 knees), and the average age was 63.5 years. The preoperative diagnosis was osteoarthritis (23 knees) and osteonecrosis (3 knees). The mean follow-up duration was 67 months (from 60 to 149 months). The clinical evaluation included pre- and postoperative American knee society knee and function score, and range of motion. The radiology evaluation included standing antero-posterior, lateral view, and fluoroscopic film to analyze the postoperative alignment and osteolysis. Results: The mean American Knee Society knee score and function score were improved from 42.0 and 57.5 to 87.9 and 85.0, respectively (p<0.001). The mean preoperative and postoperative range of motion was $132.9^{\circ}$ and $132.5^{\circ}$, respectively. The mean femorotibial angle were varus $0.5^{\circ}$ preoperatively and valgus $2.2^{\circ}$ postoperatively. A radiolucent line was observed in 2 knees; one knee had a stable implant, while in the other knee, patellofemoral arthritis was identified during UKA. Diffuse pain of the knee joint with tenderness of the medial joint line was identified at the follow-up, so conversion to total knee arthroplasty was recommended. No other complications, such as osteolysis, infections, postoperative stiffness, and dislocation, were encountered. Conclusion: The midterm results of fixed bearing UKA were clinically and radiologically satisfactory.

• Korean Journal of Heritage: History & Science
• /
• v.45 no.2
• /
• pp.4-19
• /
• 2012

There remain many royal tombs of the Goryeo Dynasty in Gaeseong and Ganghwa. During the Goryeo Dynasty, these royal tombs were taken over tradition of tomb construction style from previous generation, and they completed their own inventive style. Furthermore they handed down those style to the Joseon Dynasty. The area of tomb was divided into 3 or 4 steps, and stone figures and T-shaped houses for sacrifice were arranged on each steps. It was the stone chamber of lateral opening style which had an entrance to southward, and it was formed as a rectangular box-shaped with a pile of stone walls and a flat ceiling. There was a coffin stand in the middle of floor, and traditional bricks were around them. The wall side and ceiling had been whitewashed and painted pictures. These are general characteristics for the tomb construction style of the Goryeo Dynasty. By the way, we can notice a number of features except those general things with inspection in detail. In early days, we confirmed 1step-parallel fulcrum ceiling, coffin stand of all in one stone, bier of burial artifact, and mural of plant material as a set, but they were changed as flat ceiling, Red-stone wall with rectangular stone, coffin stand set as stone pillar through the period of transitional form as of in the late 12th century. In case of several royal tombs, the fragments of king's epitaph which were confirmed from tombs could be defined owners clearly, and there were considerable timing difference between the large numbers of celadons which were excavated with the fragments of king's epitaph and recording chronologically of stone chamber structure. The reason for timing difference is that posterity artifacts were buried through repairing courses by occasion of destruction caused by robbing of the royal tombs. Meanwhile I inferred the existing hypothesis about owners of royal tombs and autonym ones in comparison the burial spot direction of hypothesis ones and outcomes of excavation. Therethrough, some hypothesis about owners of royal tombs such as Myung-neung which was assumed as tomb of the King Choongmok were not correct.