후기구석기시대 돌날석기문화 경질ㆍ연질망치제작기법의 고고학적 증거와 기술변화 연구

이헌종,이상석 한국문화유산협회 2016 야외고고학 Vol.0 No.27

1기(40∼30ka)에 해당하는 유적을 관찰한 결과 대체로 경질망치를 사용하여 돌날을 제작한 것으로 생각된다. 주로 수양개 Ⅵ지구, 덕소, 갈산리, 호평동유적 등에서 돌날몸돌과 돌날, 기술격지 등을 통해 경질망치떼기의 증거를 확인할 수 있었다. 대체로 40∼30ka 시기에 확인되는 돌날몸돌들에서는 독특한 특징들이 확인된다. 돌날제작양상은 작업면이 모서리나 측면을 이용하거나 넓은 면을 이용하는 양상을 보인다. 제작과정에서는 주로 경질망치를 이용하여 수직박리로 돌날을 생산한 것으로 추정된다. 그리고 이 시기의 대부분 몸돌에서는 타격면과 박리면 상에서 자연면이 많이 확인된다. 이는 최소한의 성형을 통해 돌날박리를 시도한 것으로 추정된다. 돌날 역시 그 형태가 불규칙하여 정형성이 떨어진다. 몸돌 뿐 아니라 돌날 상에 경질망치떼기의 흔적이 잘 남아있다. 2기(30∼15ka)는 대체로 대형의 돌날몸돌보다 중·소형의 돌날이 주로 확인된다. 연질망치떼기의 흔적은 입암리, 용산동, 오지리, 진그늘유적에서 확인된다. 경질망치 떼기의 증거는 용산동, 오지리, 진그늘, 고례리, 입암리유적에서 돌날몸돌과 돌날에서 확인된다. 이 시기의 돌날몸돌은 넓은 작업면을 이용하여 돌날을 박리한 몸돌과, 몸돌을 삼각형으로 성형하여 좁은 측면을 이용하여 돌날을 제작한 몸돌이 주를 이룬다. 넓은 작업면을 이용한 몸돌의 경우 몸돌 성형과정에 있어서는 대체로 경질망치를 이용하였으며, 돌날 박리과정에서는 연질망치와 경질망치를 모두 사용된 것으로 확인되었다. 이는 상황에 따라 돌날을 제작하는 과정에서 연질과 경질망치를 동시에 사용하여 효과적으로 돌날을 생산하려는 시도를 확인 할 수 있다. 측면을 이용하는 돌날몸돌이 특징적인데, 이는 전체 몸돌성형을 통하여 돌날몸돌을 삼각형 모양으로 성형한다. 하단부 조정이 정교하게 이루어지는 과정에서 작업면의 능조정이 다른 형태의 돌날몸돌이 비해 정형성을 띠게 된다. 연속적인 박리작업을 용이하게 하는 중요한 요인 중 하나이다. 대체로 수직박리를 통해서 hinging기법의 돌날과 대각선 박리를 통해서 Plunging기법의 돌날이 박리된 양상을 파악할 수 있다. 1기에 비해 규칙적인 돌날제작이 있었던 것을 알 수 있다. The results of the experimental work and observation of stone artifacts, at the 1st Stage(40~30ka) show that large blade technique, which used hard hammer percussion, was the most frequent. Blades were made by using hard hammers identified at the Suyanggae Loc. 6, Galsan-ri sites. Both blades and cores were found at the Hopyeong-dong site. However, evidence of the hard hammer percussion was also found on the technical flakes at the site. Moreover, two different traits of blade cores of the 1st stage(40~30ka) were discovered. The trait is that the corner and lateral part of core for detaching blades was used, while narrow and wide striking platform was used for the second trait. Generally, these traits often used hard hammer technique. Since the natural cortex shapes leave much of the pebble surface in tact, limited core shaping process allows us to approximate the detaching of blades. The 2nd Stage(30~15ka) is characterized as using middle and small blade techniques. Several features of soft hammer percussion appeared on the blade cores at the Ibam-ri, Yongsan-dong, Oji-ri, and Jinguneul sites. Moreover, the evidence of hard hammer percussion were found on both blade cores and blades at the Yongsan-dong, Oji-ri, Jinguneul, koreri, Juknae-ri, and Ibam-ri sites. In general, the main types of cores are the sub-wedge-shaped core and wide working surface core. Mainly, the wide working surface core is treated as hard hammer percussion for shaping core but both hard and soft hammer percussion for the making of detaching blades. It is very effective for the reduction strategy. The sub-wedge -shaped core also existed in this stage and mainly soft hammer technique was used. It is easy to get a series of regular-type blades based on the sub-inverted triangle core shape and treatment of lower part of the core. It held whole length blades such as not only straight (hinging) blades through perpendicular flaking but curved-type(plunging) blades through diagonal flaking as well.

Ca와 Zr을 소량 첨가한 나노결정 Fe-Si-B-Cu계 합금의 미세조직변화와 자기적특성

안수봉,장수환,박원욱,손근용 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.3

Nanocrystalline Fe-Si-B-Nb-Cu Finemet alloys show low saturation magnetic flux density compared to amorphous Fe-Si-B alloys. In the Fe-Si-B-Cu base amorphous alloys, Cu atoms form clusters which act as heterogeneous nucleation sites for α-Fe crystals. The addition of Ca element atoms, distributed along grain boundaries, helps inhibit grain growth and increase resistivity. These alloys can be crystallized into fine nanograins through proper heat treatment, with increased saturated flux density and decreased core loss. According to previous studies, the addition of Zr element can also reduce nanograin size and suppress grain growth by its distribution mainly along the grain boundaries. In this experiment, the effects of added Ca and Zr on the microstructural changes and magnetic properties of Fe-Si-B-Cu were evaluated in detail. Fe-Si-B-Cu alloys containing Ca, and Zr elements were melt-spun to make rapidly solidified ribbons ~20 μm in thickness. The ribbons were then wound into toroidal shaped ribbon cores and heat treated to obtain the nanocrystalline soft magnetic ribbon cores. The microstructure was observed using TEM, and the magnetic characteristics were evaluated using an B-H meter and impedance analyzer. Based on the results, the Fe- Si-B-Cu ribbon core containing 0.037 wt.% Ca and 1.68 wt.% Zr was determined to have the lowest core loss among the alloys, when annealed at 440 oC for 30 min. It was also confirmed that the added Ca and Zr elements were distributed along the grain boundary, and suppress the growth of crystals. In conclusion, the addition of minor elements Ca and Zr to the nanocrystalline ribbon core was very effective at reducing core loss, and the saturated flux density of the core also increased pronouncedly compared to the Fe-Si-B-Nb-Cu Finemet alloys.

Fe계 나노결정 분말코아의 연자성특성에 미치는 입도제어 및 바인더 첨가의 영향

조은경,조현정,권훈태,조은민,류혁현,손근용,박원욱,Cho E.K.,Cho H.J.,Kwon H.T.,Cho E.M.,Ryu H.H.,Sohn K.Y.,Park W.W. 한국분말야금학회 2006 한국분말재료학회지 (KPMI) Vol.13 No.4

The amorphous $Fe_{73}Si_{16}B_7Nb_3Cu_1$ alloy strip was pulverized to get a flake-shaped powder after annealing at $425^{\circ}C$ for 90 min and subsequently ground to obtain finer flake-shaped powder by using a ball mill. The powder was mixed with polyimide-based binder of $0.5{\sim}3wt%$, and then the mixture was cold compacted to make a toroidal powder core. After crystallization treatment for 1 hour at $380{\sim}600^{\circ}C$, the powder was transformed from amorphous to nanocrystalline with the grain size of $10{\sim}15nm$. Soft magnetic characteristics of the powder core was optimized at $550{\sim}600^{\circ}C$ with the insulating binder of 3wt%. As a result, the powder core showed the outstanding magnetic properties in terms of core loss and permeability, which were originated from the optimization of the grain size and distribution of the insulating binder.

Evaluation of DC Brush-less Motors Using Powder Magnetic Cores

Mori Katsuhiko,Nakayama Ryoji,Kanagawa Kinji 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

We made a high-speed motor and a DC brush-less motor for factory automation (FA) to investigate applicability of powder magnetic core to motor application, and compared those performances with the similar motors having conventional electro magnetic steel core. Permeability and saturated magnetization of powder magnetic core are less than those of elect romagnetic steel core, however output performances of each core motor are almost the same. The FA motor with powder magnetic core using three-dimensional magnetic circuit showed higher torque than the same volume motor with electromag netic steel core.

신소재 분말코어 적용 ISG시스템용 오일펌프모터개발

이재령(Jaeryung Lee),김성진(Seong Jin Kim),박현달(Hyundal Park) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

This paper describes the weight reduction technology of brushless DC (BLDC) motor with both advanced magnetic powder core instead of Si sheet steel core and copper cladding aluminum (CCA) instead of copper winding. In order to apply the high-density magnetic core for BLDC motor, the warm compaction process with die wall lubrication was used in this work. In general, the density of magnetic core is strongly associated with the core loss. The motor efficiency was improved as the magnetic core density was increased. Results showed that the oil pump motor using the advanced magnetic powder core was decreased about 10% in size and reduced about 10% in weight comparing to the convention motor with Si sheet steel core. Consequently, the motor and oil pump system containing the advanced powder core was satisfied the requirements during the performance and durability test.

실리카로 코팅된 철 나노분말을 이용한 나노구조 연자석 코어의 제조 연구

김진권 ( Jin Kwon Kim ),홍종순 ( Jong Soon Hong ),이기선 ( Kee Sun Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 ELECTRONIC MATERIALS LETTERS Vol.3 No.3

Fe@SiO2 nanoparticles with average size of 30 nm have been prepared and their magnetic properties have been investigated. The SiO2 coating layer has been formed by hydrolysis and polycondensation of tetra-ethoxysilane(TEOS). The existence of Fe and Si atoms were characterized by energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) and the core-shell structure was determined by high resolution transmission electron microscopy (HRPTEM). Fe nano-particle are stabilized by SiO2 thin layer with about 2 nm thickness. Magnetic measurements done by a superconducting quantum interference device (SQUID) magnetometer show the Fe@SiO2 nano-particles are in ferromagnetic state. Thermal treatment has been done to increase crystalinity of the particles. With the particles, toroidal cores were made using a hydraulic press. The core has a dimension with outer-diameter of 10mm, inner-diameter of 5mm and height of 5mm. The apparent density of the core is measured as about 50% determined by Archimedes-method. The permeability of the core was measured by B-H meter within frequency of 1 MHz.

Loss-Separation Study on Silica-insulated Gas-atomized Fe-Si-Al Soft Magnetic Composites

T. T. Xu,B. W. Zhang,Z. Shi,W. W. Guan,K. Wan,X. Y. Shi,W. Liu,H. L. Su,Z. Q. Zou,Y. W. Du 한국자기학회 2020 Journal of Magnetics Vol.25 No.2

Fe-Si-Al soft magnetic composites were composed of gas-atomized Fe-9.6wt.%Si-5.4wt.%Al alloy powders insulated with silica nanoparticles. The influence of silica insulation content on the core’s magnetic properties was studied. It was found that increasing the silica mass ratio deteriorated the effective permeability and core loss in the frequency range of 40-120 kHz, while improved the quality factor at 100 kHz and DC-bias performance. The effective demagnetizing field reflected by density and the core’s volume resistivity may cause the variations of these magnetic parameters. Loss separation fitting was performed using the Bertotti formula, indicating that silica insulation increased the hysteresis loss and reduced the eddy-current loss. The hysteresis loss took over at the frequency lower than 120 kHz in this work. With increasing the frequency, the eddy-current loss grew more quickly than the hysteresis loss. Therefore, different methods should be adopted to reduce the core loss according to the core’s application frequency.

Test Results of SMC Cores as Some Types of Motor Cores

Asaka Kazuo,Ishihara Chio,Enomoto Yuuji,Ito Motoya 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

SMC(Soft Magnetic Composite) materials which we have newly developed were studied for their applying effects. It shows almost the same motor output power as the laminated Si-steels of 0.35mm in thickness, although core loss of SMC is about 1.5 times that of the laminations. As shown in the results, the SMC motor core is sufficient for real use as a motor core. Furthermore, a 3-D shaped motor core made of SMC can improve approximately 20% of the output compared with the same size motor made of laminations.

Improvement in the Super Low Core-loss Soft Magnetic Materials

Maeda Toru,Sato Atsushi,Mochida Yasushi,Toyoda Haruhisa,Mimura Koji,Nishioka Takao 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

We reported a P/M soft magnetic material with core loss value of , which is lower than that of 0.35mm-thick laminated material, by using high purity gas-atomized iron powder. Lack of mechanical strength and high cost of powder production are significant issues for industrial use. In order to achieve both low core loss and high strength by using inexpencive powder, the improvement of powder shape and surface morphology and binder strength was conducted. As the result, the material based on water-atomized powder with 80 MPa of TRS and 108 W/kg of core loss (W10/1k) was achieved.

Practical Guidelines for Ultrasound-Guided Core Needle Biopsy of Soft-Tissue Lesions: Transformation from Beginner to Specialist

김상윤,정혜원,오탁선,이종석 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.2

Ultrasound-guided core needle biopsy (US-CNB) is an important step in the diagnosis of musculoskeletal soft-tissue lesions. To maximize efficacy and minimize the complications of US-CNB, it is critical to collaborate with a multidisciplinary team and to understand the particular considerations of US-CNB for these lesions. The purpose of this article is to provide a systematic review and step-by-step tips for using US-CNB to diagnose musculoskeletal soft-tissue lesions.