• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.539-542
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• 2009

A new gerbera variety "Pink Swan" was released by the National Horticultural Research Institute (NHRI) in 2007. A cross was made between "Royal" with orange and single and 'Himalaya' with white and semi-double in 2004. After investigation of the characteristics for 4 years (from 2004 to 2007), it was selected specially for the use of cut-flower. "Pink Swan" is a vigorous medium-sized cultivar with pink (RHS R48D), yellow green center and semi-double. The average flower diameter is 10.6 cm. And inner ray floret and disc diameter is 5.99cm and 1.83cm, respectively. It produces a large yield with continuous supply of flowers and has adequate peduncle height. We believe that "Pink Swan" has a great potential for expanding cultivated area of domestic gerbera cultivar and increasing farmers-income.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.499-502
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• 2008

A new gerbera variety 'Yellow Wing' was released by the National Horticultural Research Institute (NHRI) in 2007. A cross was made between 'Gold Finger' with yellow and single and 'Yellow Springs' with yellow and spider in 2004. After investigation of the characteristics for 4 years (from 2004 to 2007), it was selected specially for the use of cut-flower. 'Yellow Wing' is a vigorous cultivar with yellow (RHS YO14B), green center and spider type. The flower diameter is 10.6cm. And inner ray floret and disc diameter is 2.83cm and 2.03cm, respectively. It produces a large yield with continuous supply of flowers and has adequate peduncle height and brilliant color. We believe that 'Yellow Wing' has a great potential for expanding cultivated area of domestic gerbera cultivar and increasing farmers-income.

• Journal of Korean Neurosurgical Society
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• v.42 no.5
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• pp.367-370
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• 2007

Objective : There are numerous reports on the primary stabilizing effects of the different cervical cages for cervical radiculopathy. But, little is known about the subsidence which may be clinical problem postoperatively. The goal of this study is to evaluate subsidence of cage and investigate the correlation between radiologic subsidence and clinical outcome. Methods : To assess possible subsidence, the authors investigated clinical and radiological results of the one-hundred patients who underwent anterior cervical fusion by using $AMSLU^{TM}$ cage during the period between January 2003 and June 2005. Preoperative and postoperative lateral radiographs were measured for height of intervertebral disc space where cages were placed intervertebral disc space was measured by dividing the sum of anterior, posterior, and midpoint interbody distance by 3. Follow-up time was 6 to 12 months. Subsidence was defined as any change in at least one of our parameters of at least 3 mm. Results : Subsidence was found in 22 patients (22%). The mean value of subsidence was 2.21 mm, and mean subsidence rate was 22%. There were no cases of the clinical status deterioration during the follow-up period No posterior or anterior migration was observed. Conclusion : The phenomenon of subsidence is seen in substantial number of patients. Nevertheless, clinical and radiological results of the surgery were favorable. An excessive subsidence may result in hardware failure. Endplate preservation may enables us to control subsidence and reduce the number of complications.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.363-369
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• 2011

Objective : We investigated the clinical and radiological advantages of unilateral laminectomy in posterior lumbar interbody fusion (PLIF) procedure comparing with bilateral laminectomy, under the same procedural condition including bilateral instrumentation and insertion of two cages, in patients with degenerative lumbar disease with unilateral leg symptoms. Methods : We retrospectively reviewed 124 consecutive cases of PLIF via unilateral or bilateral approach between January 2006 and April 2010. In 80 cases (bilateral group), two cages were inserted via bilateral laminectomy, and in 44 cases (unilateral group), via unilateral laminectomy. The average follow-up duration was 29.5 months. The clinical outcomes were evaluated with the Visual Analogue Scale (VAS) and the Oswestry disability index (ODI). The fusion rates and disc space heights were determined by dynamic standing radiographs and/or computed tomography. Operative times, intra-operative and post-operative blood losses and hospitalization periods were also evaluated. Results : In clinical evaluation, the VAS and ODI scores showed excellent outcomes in both groups. There were no significant differences in term of fusion rate, but the perioperative blood loss and the operative time of the unilateral group were lower than that of the bilateral group. Conclusion : Unilateral laminectomy can minimize the operative time and perioperative blood loss in PLIF procedure. However, the different preoperative disc height between two groups is a limitation of this study. Despite this limitation, solid fusion and satisfactory symptomatic improvement could be achieved uniquely by our surgical method. This surgical method can be an alternative surgical technique in patients with unilateral leg pain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.92-101
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• 2005

In this paper, the Gunn diode mount is experimentally designed for use in a W-band waveguide voltage controlled oscillator(VCO). The role of the Gunn diode mount is to match the low impedance of the Gunn diode to the high impedance of waveguide. Computer simulations of VCO characteristics such as center frequency, frequency tuning range, and output power are carried out for various values of disc diameter, disc height, post diameter, and utilized in the experimental optimization of the Gunn diode mount. The designed VCO shows excellent characteristics; 93.9 GHz center fiequency, 600 MHz frequency tuning range with $2{\%}$ linearity, 16 dBm output power.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.443-447
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• 1999

To investigate the effect of a shaded apodizer on the read-out signal in an optical disc system, we consider the is apodizer in which the amplitude transmittance decreases gradually from the center of pupil toward its edge and the iH apodizer in which the amplitude transmittance increases gradually from the center of pupil toward its edge, using the scalar diffraction theory. We also consider the bump shapes which are a cylindric, a semi-conic, and a conic bump, and bump height which is given by $\lambda/4$ and occurs to the phase change $(\pi)$). The read-out signal of is apodizer increases from S = 0 upto maximum value, and then decreases for increasingly larger values of bOo While the iH apodizer has two maximum values. When an optical disc system has a spherical aberration $(W_{40}=0.5\lambda)$, the maximum read-OUt signal of is apodizer is higher than that of iv apodizer which has no apodizer.odizer.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.374-378
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• 2016

Objective : A modified surgical technique of posterior cervical foramintomy called posterior cervical inclinatory foraminotomy (PCIF) was introduced in previous preliminary article. PCIF allows better preservation of facet joint and capsule than conventional techniques. The authors conducted a study to investigate long-term outcomes of PCIF. Methods : We retrospectively reviewed demographic, radiologic, and clinical data from the patients who underwent PCIFs at our institution. Criteria included a minimum of 48 month follow-up and PCIFs for patients with radiculopathy from foraminal stenosis (C2-T1; single or multilevel) with persistent or recurrent root symptoms despite conservative treatment for more than 3 months. Patients who had undergone previous cervical operation were excluded. The visual analogue scale (VAS) score was used for clinical follow-up, and radiologic follow-up was performed to compare the changes of cervical sagittal alignment, focal angle and disc-space height of treated segment. Results : The PCIFs were performed between April 2007 and March 2011 on 46 patients (32 males and 14 females) with a total of 73 levels affected. The average duration of follow-up was 74.4 months. Improvements in radiculopathic pain were seen in 39 patients (84.7%), and VAS score decreased from $6.82{\pm}1.9$ to $2.19{\pm}1.9$. Posterior neck pain also improved in 25 patients (71.4%) among 35 patients, and VAS score decreased from $4.97{\pm}2.0$ to $2.71{\pm}1.9$. The mean disc-space heights of treated segment were $5.41{\pm}1.03mm$ preoperatively and decreased to $5.17{\pm}1.12mm$ postoperatively. No statistically significant changes in cervical sagittal alignment, focal angle were seen during the follow-up period (Cox proportional hazards analysis and Student t-test, p>0.05). Conclusion : The PCIF is highly effective in treating patients with cervical spondylotic radiculopathy, leading to long-lasting relief in pain. Long-term radiologic follow-up showed no significant spinal angular imbalance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.3
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• pp.454-464
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• 1987

The objective of this research is to analyze and evaluate the dynamic flow curve of metals under impact loading at both high strain rate (.epsilon.=1/h dh/dt > 10$\^$3/m/s/m) and large strain (.epsilon.=In h/h$\_$0/ > 1.0). A test method for dynamic compression of metal disc is described. The velocity of the striker face and the force on the anvil are measured during the impact period. From these primitive data the axial stress, strain, and strain rate of the disc are obtained. The Strain rate is determined by the striker velocity divided by the specimen height. This gives a slightly increasing strain rate over most of the deformation period. Strain rates of 100 to 10,000 per second are achieved. Attainable final strains are 150%. A discussion of several problem areas is presented. The friction on the specimen surfaces, the determination of the frictional coefficient, the influence of the specimen geometry (h$\_$0//d$\_$0/ ratio) on the friction effect, the lock-up condition for a given configuration, the friction correction factor, and the evaluation of several lubricants are given. The flow function(stress verus strain) is dependent on the material condition(e.g., prior cold work), specimen geometry, strain rate, and temperature.

• Journal of Korean Neurosurgical Society
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• v.56 no.3
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• pp.224-229
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• 2014

Objective : To report long-term clinical and radiological outcomes of minimally invasive posterior cervical foraminotomy (MI-PCF) performed in patients with unilateral single-level cervical radiculopathy. Methods : Of forty-six patients who underwent MI-PCF for unilateral single-level radiculopathy between 2005 and 2013, 33 patients were included in the study, with a mean follow-up of 32.7 months. Patients were regularly followed for clinical and radiological assessment. Clinical outcome was measured by visual analogue scale (VAS) for the neck/shoulder and arm, and the neck disability index (NDI). Radiological outcome was measured by focal/global angulation and disc height index (DHI). Outcomes after MI-PCF were evaluated as changes of clinical and radiological parameters from the baseline. Mixed effect model with random patients' effect was used to test for differences in the clinical and radiological parameters repeat measures. Results : There were no complications and all patients had an uneventful recovery during the early postoperative period. VAS scores for neck/shoulder and arm improved significantly in the early postoperative period (3 months) and were maintained with time (p<0.001). NDI improved significantly post-operatively and tended to decrease gradually during the follow-up period (p<0.001). There were no statistically significant changes in focal and global angulation at follow-up. Percent DHIs of the upper adjacent or operated disc were maintained without significant changes with time. During the follow-up, same site recurrence was not noted and adjacent segment disease requiring additional surgery occurred in two patients (6%) on the contra-lateral side. Conclusion : MI-PCF provides long-term pain relief and functional restoration, accompanied by good long-term radiological outcome.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.572-575
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• 2011

A new gerbera cultivar 'Whiteny' was released by the National Institute of Horticultural & Herbal Science in 2009. A cross was made between 'Wonder King' with white semi-double and 'Ever Green' with pale greenish white and semi-double in 2007. After evaluation of the characteristics for four years (from 2007 to 2010), it was selected specially for the use of cut flower. The 'Whiteny' cultivar has pure white color (RHS W155D) with black disc center and semi-double flower. The average flower diameter is 11.5 cm, large-sized flower. And inner ray floret and disc diameter are 7.8 cm and 2.2 cm, respectively. It has a long peduncle height, 52.2 cm, and longer vase life, 12.1 days. And it is also adaptable to the local cultural environment of Korea. It is expected that if the 'Whiteny' cultivar is planted, the royalty paid to foreign varieties can be saved. And the local growers will also be benefitted since the cost of cultivars will be lower than the imported ones.