ALUMINA POWDER PREPARED BY THE HYDROLYSIS OF AL-PROPOXIDE IN THE SUPERCRITICAL FLUID OF PROPANOL

Nakagawa, Nakagawa, Z.,Enomoto, Enomoto, N.,Nomura, Nomura, S.,Kim, Kim, D.W.,Lim, Lim, D.Y. 한국재료학회 1995 Fabrication and Characterization of Advanced Mater Vol.2 No.4

Al-isopropoxide dispersed into isopropanol was heated in an autoclave above the critical point of propanol(23$5^{\circ}C$, 4.7MPa). Propanol coexisting Al-isopropoxide produced some water during the condensation reaction to isopropul ether, while only propanol did not change under that conditions. This water hydrolyzed Al-isopropoxide to form an alumina at 30$5^{\circ}C$ and 11.0MPa. This alumina had a similar X-ray diffraction pattern of $\chi$-alumina. The heating treatment showed the aluminal transformed directly to ${\alpha}$-alumina around 110$0^{\circ}C$, not to pass via any other intermediate aluminas. The aluminal was named pseudo $\chi$-alumina as a new phase. As-prepared alumina was fine powder of about 20nm, and had about 5% weight loss in the temperature range from 30$0^{\circ}C$ to 65$0^{\circ}C$, and the IR spectral showed no constitutional water.

ASIA SPINE: The Past, Present, and Future

신동아,김영수,Hiroshi Nakagawa,서정근,김세훈 대한척추신경외과학회 2018 Neurospine Vol.15 No.1

The sharing of international academic accomplishment and friendship is important; furthermore, to better understand and anticipate the future, we should look back and remember where we started. Regarding ASIA SPINE, the authors aimed to record how the pioneers of Asian spinal surgery started this spine meeting series more than 20 years ago and that later developed into the present state of the conference. The authors will also explore the possible future of this conference. In June 1996, when Professor Hiroshi Nakagawa organized the 11th Annual Meeting of the Japanese Society of Spinal Surgery, spinal neurosurgeons from Korea and Japan including Professor Young Soo Kim, Professor Jung Keun Suh, and Professor Nakagawa discussed the establishment of a multinational conference on spinal surgery via a partnership between the 2 countries. Finally, from September 18 to 20, 1997, the First Biennial Meeting of the Japan-Korea Conference on Spinal Surgery was held in Nagoya, Japan, with Professor Hiroshi Nakagawa as the first organizing President. From then, a biennial meeting was held every other year in Korea or Japan until 2009. In September 2010, the next generation of spinal neurosurgeons decided to organize the first meeting of ASIA SPINE in Incheon, Korea, in order to represent all Asian spine specialists. This meeting has been since held annually around the region including in Taiwan. Remembering the pioneers in the field of spinal surgery is invaluable and extremely important. The authors hope that interest in ASIA SPINE will further expand to other nations in Asia who have advanced philosophies and refined technologies. We wish ASIA SPINE continued success and the ability to promote prolonged international friendship among the Asian countries.

ASTROMETRIC OBSERVATION OF MIRA VARIABLES WITH VERA

NAKAGAWA, AKIHARU,OMODAKA, TOSHIHIRO,HANDA, TOSHIHIRO,KAMEZAKI, TATSUYA,PROJECT, VERA The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

The calibration of the period luminosity relation (PLR) for Galactic Mira variables is one of the principle aims of the VERA project. We observe $H_2O$ maser emission at 22 GHz associated with Mira variables in order to determine their distances based on annual parallaxes. We conduct multi-epoch VLBI observations over 1-2 years with a typical interval of one month using VERA in order to obtain annual parallaxes with an accuracy of better than than 10%. Recently, the annnual parallax of T Lep was determined to be $3.06{\pm}0.04$ mas corresponding to a distance of $327{\pm}4pc$ (Nakagawa et al., 2014). The circumstellar distribution and kinematics of $H_2O$ masers was also revealed. With accurate distances to the sources, calibrations of K-band absolute magnitudes ($M_K$) can be improved compared to conventional studies. By compiling Mira variables whose distances were determined with astrometric VLBI, we obtained a PLR of $M_K=3.51logP+1.37{\pm}0.07$.

The novel function of Oct3/4 in mouse tooth development

Nakagawa, Eizo,Zhang, Li,Kim, Eun-Jung,Shin, Jeong-Oh,Cho, Sung-Won,Ohshima, Hayato,Jung, Han-Sung Springer-Verlag 2012 Histochemistry and cell biology Vol.137 No.3

The novel expression of Oct3/4 and Bmi1 in the root development of mouse molars.

Nakagawa, Eizo,Zhang, Li,Shin, Jeong-Oh,Kim, Eun-Jung,Cho, Sung-Won,Ohshima, Hayato,Chen, Zhi,Jung, Han-Sung Springer 2012 Cell and tissue research Vol.347 No.2

<P>The root apex of the tooth elongates until the completion of root development. Although the signaling molecules inducing root elongation have been studied, the characteristic of the cells having the ability to maintain the root elongation remains unclear. This study aimed to investigate the characteristics of the cells involved in the root elongation. Octamer-binding factor 3/4 (Oct3/4) is known as one of the key regulators in maintaining the pluripotency and self-renewal properties of embryonic stem cells. Bmi1, the polycomb-group transcriptional repressor, has emerged as a key regulator in several cellular processes including stem cell self-renewal and cancer cell proliferation. At the beginning of root formation, ameloblasts expressed Oct3/4 in the nucleus, except in the apex of the cervical loop, in which Bmi1and cyclinD were expressed. At PN6, the expression of Oct3/4 in the ameloblasts shifted from the nucleus to the cytoplasm, whereas ameloblastin-negative Hertwig's epithelial root sheath (HERS) cells expressed Bmi1 and cyclinD. By PN10, the cells in the apex of HERS began to express Oct3/4 in their nucleus, whereas Bmi1 and cyclinD began to decrease in their expressions. The odontoblasts consistently expressed Oct3/4 in their cytoplasm. Our results suggest that (1) Oct3/4 creates the border between the ameloblasts from the proliferative region of HERS, (2) Bmi1-positive cells would be one of the candidates resulting in root elongation and (3) the Oct3/4 expression in the cytoplasm of odontoblasts may be related to maintain the odontoblastic characteristics.</P>

Skill Transferability and Migration: A Theoretical Analysis of Skilled Migration Under Frictional Skill Transfer

Nakagawa Mariko 한국국제경제학회 2020 International Economic Journal Vol.34 No.2

In this study, we analyze how skill transferability from an origin country to a destination country characterized by lower productivity, affects skilled worker migration, by using a multi-country new economic geography model proposed by Gasper et al. (2018). Specifically, we explain how countries that are less frictional in terms of skill transfer attract more high-skilled international migrants. The analysis, which is based on asymmetric skill transferability among countries that can be divided into two groups – those with smooth skill transferability for migrants and those with less smooth skill transferability – finds that countries with smooth skill transferability are more likely to be the industrial core attracting all skilled workers. We also find that lower frictional migration costs from a country with less smooth skill transferability to a country with smooth skill transferability always accelerates industrial agglomeration in the smooth skill transferability core country, while lower frictional migration costs between smooth skill transferability countries does not necessarily accelerate industrial agglomeration in a country with smooth skill transferability due to market crowding effects.

Make-up of a Simulator having the Same Brake Characteristics as Actual Elevator Emergency Stop Device

Nakagawa, Toshiko,Suzuki, Kazuo,Haga, Akira,Hayakawa, Naoya Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.4

The authors study a novel type of elevator emergency stop device which enables to soften impact force at an emergency halt. A new structure of emergency stop devices has been already proposed by our laboratory and also its characteristics has been already proposed by our laboratory and also its characteristics has been shown by digital simulations[1]. In order to confirm the actual effects of our proposed emergency stop device, we have made up a simulator having the same characteristics as the conventional emergency stop device to accomplish the experiments from now on. In this paper, this process is introduced.

Danger Estimation with HIC and Risk Curve in Passengers Falls from Running Rail Cars

Nakagawa, Toshiko The Korean Society of Safety 2011 International Journal of Safety Vol.10 No.2

In 2001, an independent official board was constituted in Japan to investigate aircraft and railway accidents. In the past 10 years, many accidents and serious incidents have been investigated and these official reports were published by the board, on which the author had sat for 9 years as boarding member. In the interim, there were several train disasters which mocked our trust in railways and also many apparent trivial incidents. In recent years, serious incidents, which a door of running rail cars opens suddenly with some trouble, happen 2 or 3 times in a year. For the past 10 years, such incidents have happened 14 times and 13 cases of them were closed by the board mentioned above. In these 13 cases, no one fell off the rail car, so that the death toll was none luckily. In this paper, these 13 serious incidents are picked up among all the reports published by the board and outlined using some tables. Especially, fall accidents of passengers are discussed mainly from the view point of impact force and duration time. Then, the equation of HIC (Head Injury Criteria) and the risk curves in terms of the HIC are dealt with properly.

Long-period surface structure stabilized by Fermi surface nesting:Cu(001)−(20×20)R26.6°−In

Nakagawa, T.,Yeom, H. W.,Rotenberg, E.,Krenzer, B.,Kevan, S. D.,Okuyama, H.,Nishijima, M.,Aruga, T. American Physical Society 2006 Physical review. B, Condensed matter and materials Vol.73 No.7

일본에서의 기체분리막의 현황 및 응용

Nakagawa Tsutomu 한국막학회 1994 멤브레인 Vol.4 No.1

The development of separation technology is an important research subject as is clear from its role in the Japanese government's research and development program for basic technology for the next generation(1981~1990). Japan is poor not only in mineral resources but also in energy resources and if a sudden change occurs in oil producing facility or an accident occurs in a nuclear power plant, then energy policy must undergo changes and economic foundations may collapse. Japan has already experienced this. Although, oil prices are stable at present and Japan can import oil at low cost due to the yen appreciation, Japan needs to promote development work for any new energy crisis that may come in the future. This has been the motive for gas separation membrane development in Japan. The study of gas permeation through polymer membranes, which is the basis for membranes for gas separation, at Japanese universities began many years ago, but interest in membranes for gas separation was aroused mainly by the Government. The development of gas separation membranes in Japan started with membranes for oxygen separation on an industrial scale.