Robotic Surgery Towards the 21st Century

Kitajima,Masaki 인제대학교 1999 仁濟醫學 Vol.20 No.1

Novel Challenges in Minimally Invasive Surgery for Gastrointestinal Cancers

Kitajima Masaki 대한외과학회 1999 대한외과학회 학술대회 초록집 Vol.1999 No.11

Robotic Surgery Towards the 21st Century

Kitajima, Masaki 인제대학교 1999 仁濟醫學 Vol.20 No.1S

Laparoscopic surgery has been developed rapidly in recent years all over the world. Its indication has been enlarged with the rapid advancement and development of optical system, disposable devices and other operative. instruments. For example, in our institute, we have performed more than 2,600 laparoscopic curative surgery for more than 30 different procedures since 1990. Even lapatoscopic curative surgery for malignancy have been performed for more than 350 patients with early gastric cancer. colo-rectal cancer, esophageal cancer and liver malignancy with satisfactory results. However, complicated procedure in laparoscopic surgery such as suturing and knot tying is still difficult for general surgeons, and this fact prevents its further popularization and the further extension of its indication. In the 21st century, a variety of high-technologies such as robotics, high definition imaging with 3-D, virtual reality system for training and tele-educational system, are expected to assist and support endoscopic surgery to make it much easier and safer.

Cosmological abundance of the QCD axion coupled to hidden photons

Kitajima, Naoya,Sekiguchi, Toyokazu,Takahashi, Fuminobu North-Holland Pub. Co 2018 Physics letters. Section B Vol.781 No.-

<P><B>Abstract</B></P> <P>We study the cosmological evolution of the QCD axion coupled to hidden photons. For a moderately strong coupling, the motion of the axion field leads to an explosive production of hidden photons by tachyonic instability. We use lattice simulations to evaluate the cosmological abundance of the QCD axion. In doing so, we incorporate the backreaction of the produced hidden photons on the axion dynamics, which becomes significant in the non-linear regime. We find that the axion abundance is suppressed by at most O ( <SUP> 10 2 </SUP> ) for the decay constant <SUB> f a </SUB> = <SUP> 10 16 </SUP> GeV , compared to the case without the coupling. For a sufficiently large coupling, the motion of the QCD axion becomes strongly damped, and as a result, the axion abundance is enhanced. Our results show that the cosmological upper bound on the axion decay constant can be relaxed by a few hundred for a certain range of the coupling to hidden photons.</P>

Detection Limit of a NaI(Tl) Survey Meter to Measure 131I Accumulation in Thyroid Glands of Children after a Nuclear Power Plant Accident

Takahiro Kitajima,Michiaki Kai 대한방사선방어학회 2023 방사선방어학회지 Vol.48 No.3

Background: This study examined the detection limit of thyroid screening monitoring conducted at the time of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 using a Monte Carlo simulation. Materials and Methods: We calculated the detection limit of a NaI(Tl) survey meter to measure 131I accumulation in the thyroid gland of children. Mathematical phantoms of 1- and 5-year-old children were developed in the simulation of the Particle and Heavy Ion Transport code System code. Contamination of the body surface with eight radionuclides found after the FDNPP accident was assumed to have been deposited on the neck and shoulder area. Results and Discussion: The detection limit was calculated as a function of ambient dose rate. In the case of 40 Bq/cm2 contamination on the body surface of the neck, the present simulations showed that residual thyroid radioactivity corresponding to thyroid dose of 100 mSv can be detected within 21 days after intake at the ambient dose rate of 0.2 μSv/hr and within 11 days in the case of 2.0 μSv/hr. When a time constant of 10 seconds was used at the dose rate of 0.2 μSv/hr, the estimated survey meter output error was 5%. Evaluation of the effect of individual differences in the location of the thyroid gland confirmed that the measured value would decrease by approximately 6% for a height difference of ±1 cm and increase by approximately 65% for a depth of 1 cm. Conclusion: In the event of a nuclear disaster, simple measurements carried out using a NaI(Tl) scintillation survey meter remain effective for assessing 131I intake. However, it should be noted that the presence of short-half-life radioactive materials on the body surface affects the detection limit.

Oscillatory modes generated by Hopf bifurcations in coupled four oscillators

Hiroyuki Kitajima,Hiroshi Kawakami 대한전자공학회 2002 ITC-CSCC :International Technical Conference on Ci Vol.2002 No.7

A new compound sensor for optical, electrical and ultrasonic measurements in the liquid

Takayuki Kitajima,Akira Kimoto 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper, a compound sensor is proposed for the measurement of ingredient concentration in liquid. In the proposed sensor, the optical property is measured by a light emitting diode (LED) and a phototransistor. In addition, the electrical and ultrasonic properties are measured by PVDF(Polyvinylidene Fluoride) films, which each electrode is constructed by the transparent conductive electrode (ITO electrode), arranged on the surfaces of the LED and phototransistor. In the experiment, the liquid with yellow color, ethanol and NaCl concentrations in distilled water was prepared, and the optical, electrical and ultrasonic properties of the liquid were measured by the proposed sensor. The result suggested that it was possible to measure three kinds of concentrations in the liquid by using the proposed sensor.

Minimal Invasion Surgery and Current Chemotherapy for Gastric Cancer in Japan

Masaki Kitajima 대한종양외과학회 2006 대한임상종양학회 학술대회지 Vol.2006 No.4

日本近代新宗教の思潮と公共性

北島義信(Kitajima Gishin) 원광대학교 종교문제연구소 2015 한국종교 Vol.38 No.-

19세기 중기 동아시아에 위치한 일본과 한국은 공통적으로 역사의 전환기에 직면한다. 이 전환기에 민중의 세상 바꾸기에 대한 갈망은 두 나라에 공통적으로 존재하지만, 기성 종교에는 기본적으로 이러한 갈망에 대한 적절한 대응이나 전망이 존재하지 않았다. 이 과제에 부응한 것은 한국과 일본의 신종교(민중종교)였다. 이들 신종교는 구미의 근대사상에 기초하지 않고, 서민 생활과 밀접히 결합된 토착 종교문화에 의거하면서 이를 근대세계에 합치할 수 있는 것으로 발전시키는 방향성을 가지고 있었다. 거기에는 세속권력의 상대화, 인간주의와 남녀평등, 현세주의, 인류애, 인간의 주체성과 상생의 시점이 존재한다. 여기서 ‘나’를 말살하지 않고, ‘나’의 세계를 넘어, 공공의 세계로 전개되는 공공철학을 볼 수 있다. 일본 신종교(민중종교)의 가장 큰 공헌은 민중의 입장에서 진기사상(神祇 思想)을 발전시키고 인간평등을 드높여, 식민지를 합리화하고 민중을 억압하는 국가신도와 종교적으로 정면대결을 벌였다는 점이다. 국가신도는 자신의 내부에 스스로를 무너뜨릴 신도적 종교를 안고 있었던 것이다. Aspirations of the people to reform the world are commonly found in both Korea and Japan in the middle of the 19th century, but existing religions did not provide proper perspectives to respond to those aspirations. It was new religions which answered people"s demands in both countries. New Religions based on indigenous cultures of religions which were closely related to people"s lives, not on modern ideas of the West, showed new orientation to adapt to the modern world. It also suggested new perspectives such as relativizing secular power, humanism, gender equality, emphasizing this world, personal independence, public concern, etc. We can find public philosophy in it which goes beyond "self" without annihilating "self," and furthermore develops toward the public sphere. As new religions enhanced the value of human equality and developed Jingi thought (神祇思想) from the peoples’ perspective, it could have confronted national Shintoism which coerced people and rationalized colonialism, which might be the biggest contribution of new Japanese religions. We can say that national Shintoism embraced Shintoistic religions which had enough power to demolish national Shintoism itself.

COMPUTER SIMULATION OF MAGNETIC PROPERTIES OF SPRING MAGNETS

N. Kitajima,H. Inoue,Y. Kanai,H. Fukunaga 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5

Magnetic properties of model exchange-spring magnets, which are composed of magnetically soft and hard grains, were calculated by means of computer simulation. The dependence of the magnetic properties on the strength of intergrain exchange interaction and the amount of soft grains was studied. The existence of soft grains enhanced the remanence remarkably, and the remanence over 0.8Ms was obtained in the model magnets containing 25% or more soft grains by volume. The calculated coercivity vs. the strength of the exchange interaction curves showed a peak at a critical strength of the exchange interaction, although the remanence increased monotonously with increase in the strength of the exchange interaction. Thus the maximum energy product also reached a peak around the same critical strength. The calculated maximum energy product exceeded 300kJ/㎥ when the magnet is assumed to be composed of Fe₃B and Nd₂Fe₁₄B.