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金淳郁 고려대학교 의과대학 1964 고려대 의대 잡지 Vol.1 No.1
Ligation of carotid arteries has been a desirable method of treatment of intracranial aneurysms. The primary problem, however, is to determine the range in which severe insufficiency is avoided while adequate pressure reduction is achieved in the aneurysm. No clear criteria have been reported in this regard. It is not known what pressure changes occur in the circle of Wills, in the aneurysmal sac, or segments distal or proximal to the aneurysms following ligation of the carotid artery. Neither is the relationship between intraarterial pressure and aneurysmal rupture, collapse or thrombus formation known. In order to clarify such problems, an investigation was carried out on 23 dog's carotid aneurysms which were experimentally produced by means of the demudation method previously described and of vein pouch graft invented by German and Black. To measure carotid artery pressure, a 17 gauge needle was inserted into the carotid artery which was connected to Sanborn eletromanometer, or, in some occasions, to U tube pressure manometer. Pressures were determined in normal carotid out in the proximal and distal carotid on which an aneurysm was produced, or beneath the aneurysmal orifice. The size of aneurysm was measured in diameter and/or circumference under induced systemic hyper or hyopotension, by proximal ligation or trapping procedure. On the vein pouch successfully maintaining its patency, thrombus formation in the aneurysmal sac was observed after ligating the proximal carotid. Results obtained are as follows: 1. Pressure in common carotid artery was reduced to 21.6∼40.7% in systolic and to 50∼31.8% in pulse presssure by proximal occlusion, and 3.9% more reduction was obtained by bilateral carotid ligation. Distal occlusion made increase of systolic pressure in the segment to 17∼18% and pulse pressure to 18%. Occlusion of the opposite common carotid elevated the systolic pressure to 2.9% of the original level. 2. The intraarterial pressure in distal to the aneurysms was 5.5∼6.3% lower than that of proximal part. 3. Drug induced hypertension in systemic blood pressure made the experimental aneurysm expand and hypotension collapsed it significantly. During the hypertension to as much as 250 mmHg, blood infiltrated into the tunica media around the artificial muscular defect and a little amount of serum seeped out through the internal layer at the denuded part. 4. The diameter of the experimental aneurysm was reduced from 5.7mm. to 5.5mm. by proximal ligation and to 5.0mm. by' trapping procedure. 5 . Intra-aneurysmal thrombus formation was begun a t the 1/2 reduction of the cross sectional area of the proximal lumen, then increased the thickness of the thrombus by graded occlusion. The aneuyrsm was found as a solid mass 2 days following complete closure. 6. In 4 out of 7 denudations, the internal layer was ruptured by increase of the intraarterial pressure ranged around 250,260, 440 and 640 mmHg. There was no definite relationship between the occurrence of the rupture and the width of the denudation.
김순욱 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.9
The observed features of typical, symmetric outbursts in the neutron star X-ray transient Aquila X-1 such as the rise, the plateau in the maximum, and the decay, are reproduced with a timedependent disk instability model. No external effect such as irradiation is necessary to account for the observation. In the model, a truncated inner disk radius that is more than ten times larger than the magnetically truncated one and that is plausibly appropriate to the scale proposed by hot flow models must be adopted. The model shows that such symmetric outbursts in Aql X-1 may be inside-out outbursts, while outside-in outbursts have been conjectured based on observations. The implication of the presented model, with observations, is discussed together.
Critical Temperature and Accretion Rate of Outbursts in Long-period Dwarf Novae
김순욱 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.9
Dwarf nova outbursts are nonlinear phenomena, and a time-dependent disk model is necessary to account for observations in detail. However, it is also necessary to elaborate a simpler steady-state fit to interpret observations. To know in what condition the outburst is initiated, understanding of the dwarf nova outburst is important. The parameterized, steady-state fitting formulae are suggested by Smak (Acta Astron. 52, 429 (2002); ibid 60, 83 (2010)) for the critical disk temperature and mass accretion rate above which the disk becomes thermally unstable. The fits give a single-valued temperature and accretion rate and are radius-independent whereas the observations show that the outbursts are radius-dependent phenomena of the ionizaton propagating in the disk. The fits have been tested to account for the observed outbursts only for systems with orbital periods shorter than a half day. Therefore, we examine the fits for orbital period as long as 2 days and compare the fits to the time-dependent model of a long-period dwarf nova GK Per. The fits are not much different from the time-dependent result for the critical temperature. However, the fits for the critical mass accretion rate above which the disk enters the hot state overestimate the time-dependent model for a long-period system like GK Per. The critical mass accretion rate in the intermediate state is consistent with that from the time-dependent disk model. However, the fit value should be treated as a maximum possible value below which the disk maintains the intermediate state, which is consistent with an interpretation for the observations of the Z Cam stars.