• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.108-113
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• 1999

In this study, CT specimens were prepared from ASTM A516 Gr. 65 which was used for pressure vessel plates for moderate and lower temperature service. Fatigue crack growth test was carried out in the environment of low temperature of $10^{circ}C, -10^{circ}C, -30${circ}C\;and\;-50^{circ}C$ and in the range of stress ratio of R=0.05 and 0.3 by means of opening mode displacement. Based on these test results, the characteristics from temperature and stress ration were shown as follows. 1) As the stress ratio, R increased da/dN and ${Delta}K$ of 2nd stage gradually decreased. And as R decreased, the effect of temperature became greater and greater. 2) As the temperature descended, da/dN decreased on a certain ${Delta}K$, and ${Delta}K$ did in a same da/dN. And the stress ratio, R exerted greater influence at the lower temperature. 3) The fatigue crack growth constant, m increased at $10^{circ}C$ and $-10^{circ}C$, snd decreased at $-30^{circ}C$ and $-50^{circ}C$ following the increment of stress ratio R. And m increased along with the reduction of temperature greatly decreased at $-30^{circ}C$ to come close to two(2).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.594-601
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• 2008

Cervical lymph node metastasis is one of the most important predicting factors that influence the prognosis of oral squamous cell carcinoma. Correct diagnosis on cervical lymph node metastasis is essential in determining the extent of operation and treatment modality. So we investigated a clinico-statistical evaluation on cervical lymph node metastasis in 183 patients who were diagnosed with oral squamous cell carcinoma at the Department of Oral and Maxillofacial Surgery in Kyungpook National University Hospital, from January 1st, 1999 to December 31st, 2007. The following results were obtained : 1. Among 183 patients who were diagnosed with oral squamous cell carcinoma, 149 were male and 49 were female. The average age of the patients was 61.8 years old. 2. Patients with advanced T classification showed higher incidence of cervical lymph node metastasis than those with lower T classification. 3. Patients with less differentiated tumors had higher tendency of manifesting cervical lymph node metastasis than those with more differentiated tumors. 4. Sensitivity and specificity on PET/CT was 87.5% and 58.3% respectively. PET/CT showed higher sensitivity and lower false-negative values than those of CT or USG. 5. The 5 - year survival rate of all the oral squamous cell carcinoma patients appeared to be 63.2% By N classification, patients in N0 stage showed a higher survival rate than patients in N1 or N2. 5 - year survival rates according to the modality of neck dissection were as follows in increasing order: no neck dissection group, MRND group, SND group, and RND group.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1422-1432
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• 2014

Convergent all-electron multi-reference configuration-interaction (MRCI) calculations are performed for a lithium dimer with Kaufmann's Rydberg basis functions. A comparison of the results of these calculations with those of the effective core potential/core polarization potential (ECP/CPP) method and experimental data reveals the deficiency of the all-electron ab initio method. The deficiency is related to the mere 51.9% attainment of electron correlation for the ground state. The percent attainment of electron correlation for the first excited state is slightly better than that for the ground state, preventing us from obtaining better agreements with experimental data by means of increasing the size of basis sets. The Kaufmann basis functions are then used with the ECP/CPP method to obtain the accurate convergent potential energy curves for the $^1\prod_u$ states correlated to Li(2p) + Li(2p) and Li(2s) + Li(n = 2, 3, 4). Quantum defect curves (QDCs) calculated for both the $X^2\sum_g$ and 1 $^2\prod_u$ states of the $Li{_2}^+$ ion and the Lu-Fano plot reveal a strong series-series interaction between the two $2snp{\pi}$ and $2pnp{\pi}$ Rydberg series. The QDCs are then used to resolve assignment problems in the literature. The reassignments, performed by Jedrzejewski-Szemek et al., of the dissociation product of the D $^1\prod$ state from (2s+3d) to (2s+3p) and that of the 6 $^1\prod_u$ from (2s+4d) to (2s+4p) are found to be incorrect. It may be more natural to assign their $2snp{\pi}$ Rydberg series as a $2snd{\pi}$ series. The state, assigned as 5p $^1\prod_u$ by Ross et al. and 4d $^1\prod$ by Jedrzejewski-Szemek et al., is assigned as the 7 $^1\prod_u$ state, correlated to the Li(2s) + Li(4f) limit.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.82-92
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• 2013

The Intermittent Aeration MBR systems have the advantage of controlling reaction time by changing aeration period and are one of economic BNR systems since these processes do not require MLSS recirculation that demands capital and operation costs. In this study, two intermittent aeration MBR systems were studied by computer simulation: an intermittent aeration MBR system that had both 1hr/1hr and 4hr/4hr aeration/unaeration periods at intermittent reactor and NEW INTERMITTENT-process that was an energy saving process and certified as a new process by Korean government. Since DO concentration reached only at 0.23mg/L at intermittent reactor when it was aerated, the Intermittent aeration MBR system having 1hr/1hr aeration/unaeration period showed simultaneous nitrification/denitrification and had the highest nitrogen and phosphorus removal efficiencies that were 57% and 55%, respectively. Since this study was based on the constant influent flow and characteristics, more studies are needed to define the operational characteristics of intermittent aeration MBR systems under dynamic influent conditions.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.220-228
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• 2007

In this study, effective simultaneous nitrification and denitrification reaction was accomplished in a completely mixed single bioreactor. As the important factors on the reaction, optimal DO concentration and effective range of influent C/N ratio was investigated with the synthetic wastewater. Experimental results show that stable nitrogen removals were accomplished with 0.5 mg/L DO concentration and over 7 C/N ratio. Nitrogen removal efficiency of the real municipal wastewater was low with 0.5 mg/L DO concentration because of its low C/N ratio. The increment of the C/N ratio at the inflow of the municipal wastewater with addition of external carbon source (glucose) over 7(up to 14) shows over 70% nitrogen removal in the single bioreactor.

• Korean Journal of Head & Neck Oncology
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• v.12 no.2
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• pp.147-152
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• 1996

For advanced head and neck cancers that originate in midline structures, bilateral neck dissection should be considered even if the lymph nodes were negative clinically. But, many complications and mortalities may occur in synchronous bilateral neck dissection at sacrifing of both internal jugular vein. Therefore several types of bilateral neck dissection have been proposed, but the effective and safe methods were not determined yet. So, we have prefered the method of synchronous bilateral neck dissection with preserving one internal jugular vein at least. We operated 21 patients who might be expected high incidences of bilateral neck metastases with above type of neck dissection. We analyzed the data of 21 cases(42 sides) retrospectively. The results were as follows: 1) The primary sites were transglottic(33%), supraglottic(29%), hypopharynx(29%) and tongue base(9%). 2) Types of neck dissection were RND(4 sides), MND(7 sides), FND(16 sides), and SND (15 sides). 3) Postoperative complications were minimal and did not influenced morbidity. 4) Mean interval time of neck recurrence was 21 months. Overall neck recurrent rate after bilateral neck dissecton was 19%. In 19%, neck recurrence from positive lymph nodes was 63% and from negative lymph nodes was 37%. As a results, synchronous bilateral neck dissection with preservation of one internal jugular vein minimally should be done in cases which were suspected high incidence of bilateral lymph node metastases for cure and prevention of neck recurrence.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.17-23
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• 2000

The spatial distribution of allelic frequencies was studied in the natural population of three species (Ligustrum obtusiflolium, Alnus japonica, and Pinus densflora). The distributional patterns of the crown-cover centers were compared between two populations in forests. L. obtusifolium and p. densiflora showed a significantly positive spatial autocorrelation as measured by Moran's I. In P densiflora, the genetic similarity was shown by individuals within up to a scale of 18 m distance and this is partly due to combination of pollen dispersal and long distance seed dispersal by wind or men. In L. obtusifolium, population structure in the distribution of allelic frequencies is related to mating systems and is consisted of a scale of 12.5 m intervals. No spatial structuring of allele frequencies was found for polymorphic enzyme loci within a natural population of Alnus japonica. The results also in- dicate that positive associations between L. obtusifolium and P densiflora can occur when both select the same habitat or have the same environmental requirements.

• The Korean Journal of Physiology
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• v.26 no.1
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• pp.75-88
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• 1992

It is well established that neurons in ventrolateral medulla play a key role in determining the vasomotor tone. The purpose of present study is to identify sympathetic related, medullospinal tract neurons in ventrolateral medulla and to show that these mediate somato-sympathetic reflex. Medullospinal tract cells were identified by antidromic stimulation to intermediolateral nucleus (IML) of the second thoracic ($T_2$) spinal cord in anesthetized cats. Peripheral nerves were stimulated for orthodromic activation of these cells and peripheral receptive fields were determined. Post R wave histogram of unit and spike triggered averaging of sympathetic nerve discharge (SND) were used to define sympathetic related cell. A total of 113 neurons was recorded in ventrolateral medulla that had the axonal projections to $T_2$ spinal cord. Thirty four of these medullospinal cells showed spontaneous discharges and the others not. Between these two groups, rostro-caudal coordinate of the distribution from obex [$4.7{\pm}0.2\;$ (mean S.E.) mm, 4.1 0.1 mm], depth from dorsal surface ($5.5{\pm}0.2mm,\;4.9{\pm}0.1mm$ and conduction velocity ($9.9{\pm}1.7m/sec,\;16.7{\pm}1.9\;m/sec$) were significantly different (p<0.05). In spontaneously discharging group, characteristics of rostral and caudal groups were significantly different and we demonstrated that cells in rostral group mediate somatosympathetic reflex. From these results, we conclude that a certain portion of spontaneously discharging medullospinal tract cells in rostral ventrolateral medulla comprise the efferent outputs of somatosympathetic reflex to sympathetic preganglion neurons.

• Journal of Veterinary Clinics
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• v.27 no.4
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• pp.445-449
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• 2010

A dog with a history of long-term phenobarbital administration presented to Seoul National University Hospital for Animals with clinical signs of footpad ulceration and facial ulcerative dermatitis. Skin lesions (facial/footpad dermatitis), histopathologic signs (parakeratotic hyperkeratosis, edema and hyperplasia of the epidermis), and liver involvement (increased plasma liver enzymes and nodular lesions) suggested a diagnosis of superficial necrolytic dermatitis (SND). The patient died suddenly at home of unknown cause after 8 months medical treatment, but intravenous amino acid supplementation and supportive hepatic medication proved as effective for the skin conditions.

• Journal of Veterinary Clinics
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• v.25 no.5
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• pp.391-395
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• 2008

An 8-year-old intact male Yorkshire cross dog (7.5 kg of body weight) was referred with the primary complaint of exercise intolerance and occasional syncope. Initial cardiological examination could not identify any abnormalities except mild mitral regurgitation. Exercise stress test revealed chronotrophic incompetence. Furthermore the 1 hr-digital event recording found the sudden onset of paroxysmal sinus tachycaridas (156-172 bpm) lasting few minutes and stopping abruptly. In addition, the tachycardia terminated by vagal maneuver and verapamil administration. Based on this finding, the case was diagnosed as sinoatrial reentrant tachycardia (SART). The dog was treated with diltiazem and enalapril. Although the dog still has exercise intolerance, no syncope has been observed after medication.