• Korean Journal of Environment and Ecology
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• 제32권5호
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• pp.507-512
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• 2018

Three natural Pinus thunbergii stands in southern Korea were studied to investigate stem density, biomass expansion factors, allometric equations and stand biomass. Stand ages of stand 1, 2 and 3 were 15, 29 and 45 years old, respectively. Three $10m{\times}10m$ plots were set up, five sample trees were cut and roots of three sample trees were excavated for dimension analysis in each stand. Stem density of stand 1, 2 and 3 were $0.450g/cm^3$, $0.440/cm^3$ and $0.457g/cm^3$, respectively, and there was no significant difference among the three stands. Biomass expansion factors of above-ground and total tree decreased with increasing stand age. Above-ground biomass expansion factor of stand 1 was significantly higher than those of stand 2 and 3, and total tree biomass expansion factor of stand 1 was significantly higher than that of stand 3. Allometric equations were developed for the 15 sample trees of the three stands based on D or $D^2H$. Above-ground biomass of stand 1, 2 and 3 were 50.72t/ha, 89.92t/ha, 194.07t/ha, respectively, and total tree biomass of stand 1, 2 and 3 were 61.62t/ha, 113.12t/ha, 248.36t/ha, respetively.

• Journal of Korean Society of Forest Science
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• 제98권6호
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• pp.772-779
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• 2009

This study was conducted to estimate the carbon (C) contents in pure and mixed stands of pine (Pinus densiflora) and oak (Quercus spp.) trees for establishing the C inventory of forest ecosystems. A total of fifteen 20 m${\times}$20 m pure and mixed stands of pine and oak trees were chosen in natural forests in Hoengseong, Kangwon based on the basal area of all trees ${\geq}$ 5 cm DBH: three of 95% of pine and 5% oak trees [pine stand], three of 100% of oak trees [oak stand], and nine of 20 to 70% of pine and 80 to 30% of oak trees [mixed stand]. To estimate C contents in the study stands, biomass in vegetation, forest floor and coarse woody debris (CWD) were calculated and C concentrations in vegetation, forest floor, CWD and soil (0-30 cm) were analyzed. There was no significant difference in vegetation C contents among the stands; 147.6 Mg C/ha for the oak stand, 141.4 Mg C/ha for the pine stand and 115.8 Mg C/ha for the mixed stand. Forest floor C contents were significantly different among the stands (p<0.05); 12.7 Mg/ha for the pine stand, 9.9 Mg/ha for the oak stand, and 8.4 Mg/ha for the mixed stand. However, CWD C contents were not significantly different among the stands (p>0.05); 2.2 Mg/ha for the mixed stand, 1.7 Mg/ha for the oak stand, and 1.1 Mg/ha for the pine stand. Soil C contents up to 30 cm depth were not significantly different among the study stands; 44.4 Mg C/ha for the pine stand, 41.6 Mg C/ha for the mixed stand, and 33.3 Mg C/ha for the oak stand. Total ecosystem C contents were lower in the mixed stand than those in the pure stands, because vegetation C contents which occupied almost total ecosystem C contents were lower in the mixed stand than those in the pure stands; 199.6 Mg C/ha for the pine stand, 192.5 Mg C/ha for the oak stand and 169.1 Mg C/ha for the mixed stand. Lower vegetation C contents in the mixed stand might be influenced by interspecific competition between pine and oak trees and intraspecific competition among the oak trees resulted from high stand density. We suggest that forest management such as thinning to enhance C storage is indispensible for minimizing the competition in forest ecosystems.

• Journal of Forest and Environmental Science
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• 제35권3호
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• pp.197-204
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• 2019

A tree-length harvesting system using the HAM300, which is mounted on a farm tractor prototype machine, have been recently introduced in South Korea for thinning old (>30 years) forests. However, no research has previously been conducted on the characteristics of residual stand damage associated with cable yarding systems on thinning treatment stands in South Korea. Therefore, there were assessed on the degree and quantity of residual stand damage caused by felling and yarding process to broaden the knowledge of residual stand damage on semi-mechanized skyline thinning operations. This study investigated scar size, direction, area, shape type and their distribution on the residual stand damage caused by felling and yarding operations. Damage to residual trees was generated for 7.4% and 6.9% of residual trees in felling and yarding operations, respectively. Damaged direction of scars was located in front-side (38.9%) and up-side (34.7%) for felling operations while the highest scar damage was found on down-side (44.6%) for yarding operations. Scar heights of felling damage were higher than those of yarding damage. In yarding operation, the most of the scars was located within l0m from the center of the skyline corridor. These results should be useful information for forest managers and landowners to reduce residual stand damages and retain valuable timber volume from thinning treatments.

• The monthly packaging world
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• 통권317호
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• pp.74-79
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• 2019

• Journal of the Korean Vacuum Society
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• 제15권3호
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• pp.325-330
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• 2006

In order to verify the integrity of the first wall (FW) of the International Thermonuclear Experimental Reactor (ITER), the fabricated Cu/SS mock-up is tested in the JAEA Electron Beam Irradiation Test Stand (JEBIS). To fabricate the Cu/SS mock-up, CuCrZr and 316L authentic stainless steel (SS316L) are used for Cu alloy and steel, respectively The hot isostatic pressing (HIP) is used as a manufacturing method with a $1050^{\circ}C$ and 150 MPa. The high heat flux (HHF) test is performed using an electron beam with a heat flux of $5MW/m^2$ and a cycle of 15-sec on time and 30-sec off time. The temperature measurement in the HHF test shows good agreement with the results obtained from ANSYS code analysis, which is used for determining the HHF test conditions.

• Journal of Korean Neurosurgical Society
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• 제47권5호
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• pp.352-357
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• 2010

Objective : This retrospective study was performed to evaluate the clinical and radiological results of anterior lumbar interbody fusion (ALIF) using two different stand-alone cages in the treatment of lumbar intervertebral foraminal stenosis (IFS). Methods : A total of 28 patients who underwent ALIF at L5-S1 using stand-alone cage were studied [Stabilis$^{(R)}$ (Stryker, Kalamazoo, MI, USA); 13, SynFix-LR$^{(R)}$ (Synthes Bettlach, Switzerland); 15]. Mean follow-up period was 27.3 ${\pm}$ 4.9 months. Visual analogue pain scale (VAS) and Oswestry disability index (ODI) were assessed. Radiologically, the change of disc height, intervertebral foraminal (IVF) height and width at the operated segment were measured, and fusion status was defined. Results : Final mean VAS (back and leg) and ODI scores were significantly decreased from preoperative values (5.6 ${\pm}$ 2.3 ${\rightarrow}$ 2.3 ${\pm}$ 2.2, 6.3 ${\pm}$ 3.2 ${\rightarrow}$1.6 ${\pm}$ 1.6, and 53.7 ${\pm}$ 18.6 ${\rightarrow}$ 28.3 ${\pm}$ 13.1, respectively), which were not different between the two devices groups. In Stabilis$^{(R)}$ group, postoperative immediately increased disc and IVF heights (10.09 ${\pm}$ 4.15 mm ${\rightarrow}$ 14.99 ${\pm}$ 1.73 mm, 13.00 ${\pm}$ 2.44 mm ${\rightarrow}$ 16.28 ${\pm}$ 2.23 mm, respectively) were gradually decreased, and finally returned to preoperative value (11.29 ${\pm}$ 1.67 mm, 13.59 ${\pm}$ 2.01 mm, respectively). In SynFix-LR$^{(R)}$ group, immediately increased disc and IVF heights (9.60 ${\pm}$ 2.82 mm ${\rightarrow}$ 15.61 ${\pm}$ 0.62 mm, 14.01 ${\pm}$ 2.53 mm ${\rightarrow}$ 21.27 ${\pm}$ 1.93 mm, respectively) were maintained until the last follow up (13.72 ${\pm}$ 1.21 mm, 17.87 ${\pm}$ 2.02 mm, respectively). The changes of IVF width of each group was minimal pre- and postoperatively. Solid arthrodesis was observed in 11 patients in Stabilis group (11/13, 84.6%) and 13 in SynFix-LR$^{(R)}$ group (13/15, 86.7%). Conclusion : ALIF using stand-alone cage could assure good clinical results in the treatment of symptomatic lumbar IFS in the mid-term follow up. A degree of subsidence at the operated segment was different depending on the device type, which was higher in Stabilis$^{(R)}$ group.

• Journal of Korean Neurosurgical Society
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• 제58권2호
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• pp.119-124
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• 2015

Objective : We compared the clinical and radiographic outcomes of stand-alone polyetheretherketone (PEEK) cage and Zero-Profile anchored spacer (Zero-P) for single level anterior cervical discectomy and fusion (ACDF). Methods : We retrospectively reviewed 121 patients who underwent single level ACDF within 2 years (Jan 2011-Jan 2013) in a single institute. Total 50 patients were included for the analysis who were evaluated more than 2-year follow-up. Twenty-nine patients were allocated to the cage group (m : f=19 : 10) and 21 for Zero-P group (m : f=12 : 9). Clinical (neck disability index, visual analogue scale arm and neck) and radiographic (Cobb angle-segmental and global cervical, disc height, vertebral height) assessments were followed at pre-operative, immediate post-operative, post-3, 6, 12, and 24 month periods. Results : Demographic features and the clinical outcome showed no difference between two groups. The change between final follow-up (24 months) and immediate post-op of Cobb-segmental angle (p=0.027), disc height (p=0.002), vertebral body height (p=0.033) showed statistically better outcome for the Zero-P group than the cage group, respectively. Conclusion : The Zero-Profile anchored spacer has some advantage after cage for maintaining segmental lordosis and lowering subsidence rate after single level anterior cervical discectomy and fusion.

• PNF and Movement
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• 제15권1호
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• pp.77-84
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• 2017

Purpose: This study aimed to investigate the effect of visual feedback training-for gradual weight shift in sit-to-stand training-on the balance and walking abilities of chronic hemiplegia patients. Methods: Twenty patients with chronic hemiplegia volunteered to participate in this study. The experimental group received visual feedback for gradual weight shift in the sit-to-stand training, while the contrast group followed the standard process for the sit-to-stand training. The evaluation of the balance and walking ability was conducted with the functional reach test (FRT), Berg balance scale (BBS), five time sit-to-stand (FTSTS) test, timed up and go (TUG) test, 10 m walk test (10MWT), balancia, activities-specific balance confidence (ABC) scale, and falls efficacy scale (FES). Results: In the results before and after intervention, there was a significant difference in TUG, 10MWT, ABC, and FES in the visual feedback training group (p < 0.05). In the control group, there was a significant difference in the 10MWT and ABC (p < 0.05). Also, in the evaluation of the postural fluctuations, the control group data showed a significant increase in Covar. The visual feedback group showed a significant difference in the W average. Conclusion: The visual feedback training group showed some improvement in terms balance and walking ability and on the ABC scale and FES. Therefore, if the diagonal progressive weight bearing exercise is combined with the various patterns and basic principles of PNF, it may be a more efficient intervention method.

• Journal of Korean Society of Forest Science
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• 제99권4호
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• pp.553-558
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• 2010

This study was conducted to clarify the differences in rodents population densities between natural restored and red pine silvicultured forests after forest fire in Samcheok, Gangwon Province, Korea from March to December 2008. One ha size of 3 study plots were set up in each natural restored and silvicultured stand. We trapped the small rodents during 4 consecutive nights every 2 months in each stand. Understory coverage and number of shrub stems were higher in silvicultured stand than in natural restored stand. Coverage of overstory, suboverstory and midstory, number of tree stem, woody seedling stems and dead wood, and amount of coarse woody debris were higher in natural restored stand than in silvicultured stand. Six hundred eighty eight individuals of four species, such as Apodemus agrarius, A. peninsulae, Eothenomys regulus and Tamias sibiricus were captured in our study. Number of captured small rodents were higher in natural restored stand than in silvicultured stand. Also, species compositions were differed in both stands. The captured number of A. agrarius and A. peninsulae were most highest in April and December. E. regulus were shown higher number of captured in April and June, and T. sibiricus were in June and October. Removal of coarse woody debris and silvicultural practice would not be good for the inhabitation of small rodents. For the conservation of small rodents diversity, management of understory and canopy would be needed in forest fired area.

• Journal of the Ergonomics Society of Korea
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• 제35권6호
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• pp.493-501
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• 2016

Objective: This study analyzes the effect of angle conditions of rehabilitation equipment used for supporting hemiplegic patients on their rehabilitation training for standing action. The study was performed by adjusting the rear angle of seat inclination through a motion analysis. Background: Owing to a loss of muscle rigidity and degradation of muscle control ability, hemiplegic stroke patients suffer from asymmetrical posture, abnormal body balance, and degraded balance abilities due to poor weight-shifting capacity. The ability to shift and maintain one's weight is extremely essential for mobility, which plays an important role in our daily life. Thus, to improve patients' ability to maintain weight evenly and move normally, they need to undergo orthostatic and ambulatory training. Method: Using a motion analysis system, knee movements on both hemiplegic side and non-hemiplegic side were measured and analyzed in five angles ($0^{\circ}$, $10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$) while supported by the sit-to-stand rehabilitation equipment. Results: The knee movements on both sides increased as the angle increased in angle support interval to support a hemiplegic patient's standing up position. In standing up interval, a hemiplegic patient's knee movement deviations on both sides decreased, and the movement differences between hemiplegic and non-hemiplegic legs also decreased as the angle increased. Conclusion: The results of this study showed that the rehabilitation effectiveness increases as the angle increases, leading to a balanced standing posture through the decrease of movement difference between hemiplegic and non-hemiplegic sides and an improved standing up ability through the increase of knee movement on both sides. However, angles higher than $50^{\circ}$ didn't provide a significant effect. Therefore, a support angle under $50^{\circ}$ was proposed in this study. Application: The results of this study are expected to be applicable to the design of sit-to-stand support equipment to improve the effectiveness of the rehabilitation process of hemiplegic patients.