We have developed a spherical FCT code in order to simulate the interaction of supernova remnants with stellar wind bubbles. We assume that the density profile of the supernova ejecta follows the Chevalier mode1(1982) where the outer portion has a power-law density distribution(ρ∝γ−n ρ∝γ−n ) and the SN ejecta has a kinetic energy of 1051 1051 ergs. The structure of wind bubble has been calculated with the stellar mass loss rate ˙ M=5×10−6M⊙/yr M˙=5×10−6M⊙/yr and the wind velocity υ=2×103 υ=2×103 km/s We have simulated seven models with different initial conditions In the first two models we computed the evolution of SNRs with n=7 and n=14 in the uniform medium The numerical results agree with the Chevalier's similarity solution at early times. When all of the power-law portion of the ejecta is swept up by the reverse shock, the evolution slowly converges to the Sedov-Taylor stage. There is not much difference between the two cases with different n's The other five models simulate SNRs produced inside wind bubbles. In model III, we consider the SN ejecta of 1.4 M⊙ M⊙ and the radius of bubble ~2.76 pc so that ratio of the mass α(=MW.S/Mej α(=MW.S/Mej is 2. We follow the complex hydrodynamic flows produced by the interaction of SN shocks with stellar shocks and with the contact discontinuities, In the model III, the time scale for the SN shock to cross the wind shell τcross τcross is similar to the time scale for the reverse shock to sweep the power-law density profile τbend τbend . Hence the SN shock crosses the wind shell. At late times SN shock produces another shell in the ambient medium so that we have a SNR with double shell structure. From the numerical results of the remaining models, we have found that when τcross/τbend≤2 τcross/τbend≤2 , or equivalently when α≤50 α≤50 , the SNRs produced inside wind bubbles have double shell structure. Otherwise, either the SN shock does not cross the wind shell or even if it crosses at one time, the reverse shock reflected at the center accelerates the wind shell to merge into the SN shock Our results confirm the conclusion of Tenorio-Tagle et a1(1990).

We carried out high-resolution(FWHM=3' .3) HI 21 cm observations of the supernova remnant(SNR) PKS0607+17 and HII region S261 using Arecibo 305-m telescope. The observation was to investigate whether the high-velocity(HV) gas detected in the southern area of PKS0607+17 by Koo & Heiles(1991) is physically associated with the SNR or not. The velocity of the HV gas ranges from +64 km/s to +87 km/s, which is difficult to result from the Galactic rotation. The HV gas could be the gas accelerated by supernova blast wave. However, because the observation of Koo and Heiles(1991) was carried out using Hat Creek radio telescope(FWHM ≃ ≃ 36'), the association of the HV gas with the SNR could not be investigated. Using the Arecibo HI 21cm data, we have found that the HV gas appears m the southern part of the SNR and its velocity ranges from +61 km/s to +77 km/s. But the HV gas is scattered m the whole field, not only toward PKS0607+17 but also outside the SNR Accordingly the HV gas is probably not associated with the SNR, but is accidentally aligned along the same line of sight toward the SNR. Instead we have found that HI clouds at low velocities could be possibly associated with the SNR. In Arecibo HI 21cm channel maps the HI gas seems to surround the southern boundary of the SNR at VLSR VLSR = +19.6 ~ +40.2 km/s. But because the region of the Arecibo HI 21cm observation is not wide enough to examine the HI gas distribution, we investigated this area using the Berkely low-latitude HI survey data(Weaver & Williams 1974) too. There we found HI gas surrounding the radio continuum boundary of PKS0607+17 at VLSR VLSR = +21.6 ~ +258 km/s. It is possible that this HI gas is associated with the SNR, in which case, the velocity of the SNR Vo Vo ≃ ≃ +26 km/s, its distance d ≃ ≃ 12.5 kpc and its radius R ≃ ≃ 145 pc. If we assume that the expansion velocity is ~10 km/s, then the age of the SNR is ∼4.4×106 ∼4.4×106 years. PKS0607+17 could be one of the oldest SNRs in the Galaxy. We also studied HI propertities of the HII region S261, which is ∼1∘ ∼1∘ away from PKS0607+17. There has been no high-resolution m 21 cm observational study on S261. We discovered HI cloud located at the north-eastern part of S261 at VLSR VLSR = +5 km/s ~ +10 km/s, which is possibly associated with the HII region. The central velocity of the HI cloud VLSR VLSR = +7.2 km/s and the corresponding distance d = 1.5 kpc. This velocity is comparable to the radio recombination line velocities.

We have performed the high resolution computer simulation with 1D spherical hydrodynamic code in order to study the dynamical evolution of supernova ejecta interacting with a pre-existing fast wind structure. The fast wind structure has been calculated with Min=3×10−6M⊙yr−1 Min=3×10−6M⊙yr−1 and υin=1000km/sec υin=1000km/sec , which velocity is higher than the critical velocity relating to the initial radiative cooling. The fast wind becomes initially adiabatic. After a shell formation time of ∼4000yrs ∼4000yrs , the wind becomes radiative cooling at the shell zone, forming a thin dense radiative shell and an adiabatic wind bubble afterward. When supernova explodes in the wind center at 20,000yrs after the wind evolves, the supernova ejecta, which has a dense distribution of ρ∝r−n ρ∝r−n (here we have n = 9), interacts initially with, the understood wind zone, producing forward and reverse shocks. The reverse shock heats the supernova ejecta and its temperature increases. In this study, as the mass of the supernova ejecta is larger than that of the wind shell (Mej=5M⊙ Mej=5M⊙ , Msw=2M⊙ Msw=2M⊙ ), we can conform two shell structures: an outer shell by the supernova ejecta and a secondarily shocked wind shell by it. The secondarily shocked wind shell should accelerates in this case to be R-T unstable, consequently producing the knots

It has been recognized that the morphologies of the SNRs from the radio observation are "barrel shaped". To interpret the mechanism of the radiation and the physical state of the environments, we have analytically calculated the dynamical structure of the interacting region in the case where the ejectum has a steep power-law density profile(ρ∼r−n ρ∼r−n ) and the ambient medium has a shallow power-law density profile(ρ∼r−s ρ∼r−s ), assuming that the cosmic rays are isotropically accelerated in the shock wave and the magnetic fields are very weak. The calculated synchrotron radio maps show that the emission from the equator is intense and the emissions from the central and polar regions are less intense. Also the thicknesses of the shell are strongly dependent on s and weakly on n. The azimuthal intensity ratio α α increases as the efficiency of the cosmic ray acceleration increases and s decreases. We compared the results with the morphology of the SNR A. D. 1006(type I SNR). It does agree with the case of s = 0, w = 0.3 - 0.5. This value for w is consistent with the results by Eichler(1979). It provides us the evidence of the cosmic ray acceleration in the shock wave.

분말야금 또는 분말재료공정은 금속과 세라믹에 기초를 둔 신소재 가공기술로서 점차 그 역할이 증대되고 있다. 분말 공정은 합금의 신축성이라는 고유 잇점을 비롯하여, 조성적 균질성, 미세한 조직특성, 그리고 완성 또는 준 완성형태의 성형가능성 등을 제공하는 것으로 특징지워지는데 이러한 모든 것들은 첨단 재료의 제조가공을 위해서 요구되는 특징들이다. 본 강연의 전반부에서는 분말야금공정의 일반적 특징과 이제까지 개발된 첨단 재료들을 분류하고 그 현황을 살펴보았

최근 일본에서는 되살아난 군국주의 망령들이 영토 팽창의 야망에 들떠 미쳐 날뛰고 있다. 이미 오래 전부터 조선의 신성불가침의 영토인 독도를 빼앗아 내려고 온갖 권모술수를 다해 온 일본 반동들은 오늘 독도 침탈책동을 그 어느 때보다 노골적으로 감행하고 있으며, 그들의 해외 팽창야망은 무모한 단계에로 치닫고 있다. 일본 반동들은 최근 8년 동안에만도 일본 국회와 시마네현(島根縣) 의회에서 무려 150여 차에 걸쳐 독도 문제를 논의하였으며, 일본 외무성은 독도를 일본 고유의 영토라고 밝힌 ≪2000년 외교청서i(外交淸書)≫라는 것까지 내돌리었고, 2001년 2 월 일본 시네마현 지사 스미타(澄田)는 현 의회(縣議會)에서 ≪다케시 마(竹島: 독도를 가리킴.)는 역사적으로 보나 국제법에 비추어 보나 일본의 고유한 영토≫라고 떠벌리었다. 지어1) 그들은 무력에 의한 ≪죽도(독도) 탈취≫설까지 고창(高唱)하면서, ≪자위대(自衛隊)≫무력을 동원하여 독도 침탈을 위한 상륙 훈련까지 감행하였다. 역사적으로 일본 통치배들이 들고 나온 ≪죽도(竹島) 영유권≫이란 그 어떤 타당한 근거도 없는 파렴치한 날조이고 왜곡이며 억지였다. 지금까지 알려진 조선과 일본의 옛 문헌들에 독도를 일본의 영토로 규정한 것은 없고, 오히려 그것이 조선의 영토라는 것을 확증해 주는 것뿐이다. 그럼에도 불구하고 그들은 오늘도 저들에게 불리한 것은 ≪의문스럽다.≫, ≪편자의 오해≫라고 부정해 나서면서 파산된 지 오랜 낡은 넉두리2)를 되뇌고 있다. 40여 년 간의 악독한 식민지 통치로 조선 인민에게 헤아릴 수 없는 재난과 불행을 들씌운 일본이 자기의 죄악에 찬 과거에 대하여 성실히 사죄하고 보상할 대신, 침략적인 ≪죽도 영유권≫을 운운하는 것은 우리 민족의 존엄과 자주권에 대한 난폭한 침해이며 인류 양심과 정의에 대한 참을 수 없는 우롱이다. 조선 민주주의 인민공화국 역사학학회는 이런 실정에서 독도가 역사적으로 조선의 불가분의 영토임을 다시 한번 논술하고 일본의 독도 침탈 죄행(罪行)을 단죄하며 일본 반동들의 파렴치한 역사왜곡 행위를 규탄하고자 이 글을 낸다.