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The iBNCT project aims to develop “iBNCT001,” a demonstration device of the linac-based neutron irradiation facility for boron neutron capture therapy (BNCT) application. iBNCT001 generates an epithermal neutron beam by irradiating 8 MeV protons accelerated by a linac onto a beryllium target. Currently, the linac can drive an average proton current of 2.1 mA. Several experiments were performed using a water phantom to confirm the main physical characteristics of the neutron beam produced at the irradiation position. The measurement results demonstrated that the maximum thermal neutron flux achievable in the phantom volume was approximately 1.36 × 10 9 cm − 2 s − 1 when a normal beam collimator with a 120 mm diameter was used. This neutron beam intensity was sufficient to complete the irradiation within 30 min using the BNCT approach. In addition to normal beam collimators, extended collimators that protrude 100 mm from the wall were developed. By using an extended collimator, it is possible to prevent interference of the patient’s body with the wall when irradiating head and neck cancers. The measurement results for the extended collimator demonstrated that irradiation with the collimator could be completed within 1 h when the neutron beam is generated with an average proton current of 2.1 mA.

本研究は、青年期における野菜摂取量と生活習慣や食意識の関係について明らかにすることを目的とした。調査時期は、平成27年から平成29年の4月に実施した。調査対象は、Ｓ大学短期大学部の女子学生283名とした。調査内容は、対象者の身体計測、生活習慣調査、食物摂取頻度調査である。統計における群分けは、本調査における野菜摂取量の平均値137.8g以上を「平均以上群」、平均値未満を「未満群」とした。野菜摂取量と身体状況、食品群別摂取量、栄養素等摂取量の関係については独立したサンプルのｔ検定、食事摂取頻度と共食頻度、食意識および知識、運動習慣と運動への意識との関係についてはχ２検定を行った。統計処理には、SPSS Statictics 22 for Windowsを使用し、有意水準は5％（両側検定）とした。平均以上群は118名（45.7%）、未満群は140名（54.3%）であり、食品摂取量、栄養素摂取量、昼食の摂取頻度、共食頻度、食意識、運動習慣において2群間に有意差が認められた。共食頻度、食意識を高めることは、野菜摂取量を増やす要因になることを示唆した。

本研究は、青年期における食塩摂取に対する意識と生活習慣の関係について明らかにすることを目的とした。調査時期は、平成27年から平成29年の4月毎に実施した。調査対象は、平成27年から平成29年のＳ大学短期大学部に入学した283名とした。調査内容は、対象者の身体計測、生活習慣調査、食物摂取頻度調査である。統計における群分けは、「塩分を控えようと心がけていますか」の問いに対し、「いつも心がけている」、「ときどき心がけている」と回答したグループを減塩意識群、「あまり心がけていない」、「ほとんど心がけていない」と回答したグループを無意識群とした。身体状況、栄養素等摂取量、食品群別摂取量との関係については独立したサンプルのｔ検定、食習慣との関係についてはχ２検定、減塩意識および知識と食塩摂取量の関係については一元配置分散分析を行った。減塩意識群は150名（53.0％）、無意識群は133名（47.0％）であり、減塩意識と嗜好、その他の食品への意識、いも類、緑黄色野菜、種実類、レチノール当量、身体を動かそうとする意識の間に有意差が認められた。これらのことから、減塩意識をもつことは、野菜摂取量の増加に繋がり、高血圧の一次予防となる食行動がとれる要因になると考えられた。食塩摂取量を低下させる要因は、1日当たりの食塩摂取量の基準値や目標値を知っていることであると考えられた。

本研究は、スチームコンベクションオーブンによる加熱モードがおいしさに及ぼす影響とその要因を明らかにするために、食材の大きさと重量および水分量の変化を計測し嗜好との関係性を考察することを目的とした。分析試料は、冷凍真さば(真さば：アイルランド産)を使用した。調理条件は塩焼きとし、試料の重量の1.0％に相当する食塩を添加し、５分間おいた後、中心温度75℃以上１分間加熱した。各加熱モード・加熱時間で調理後、ミキサーにかけ赤外線水分計で水分量を測定し、もう一方で官能評価を行った。各加熱モードにおける大きさの変化は、コンビモードは横、高さ、ホットモードは横、スチームモードも横に有意な差が認められた（p

P-type doping in selected areas of gallium nitride (GaN) using magnesium (Mg)-ion implantation and subsequent ultra-high-pressure annealing (UHPA) are investigated to improve the performance of vertical GaN power devices. UHPA allows a high-temperature process without decomposition of the GaN surface and virtually complete activation of the implanted Mg ions in GaN. In the present paper, we provide an overview of recent challenges in making UHPA more realistic as an industrial process. Instead of UHPA at more than 1400 °C for a short duration, prolonged UHPA at 1300 °C demonstrates a comparable acceptor activation of Mg-ion-implanted GaN. This can reduce the annealing pressure to approximately 300 MPa and enlarge the processable wafer diameter. The second challenge is controlling the doping profiles in the lateral and vertical directions. We demonstrate fine patterning of the p-type regions, which indicates the limited lateral diffusion of Mg through UHPA. However, controlling the vertical doping profile is challenging. The nitrogen vacancies formed by ion implantation reduce the effective acceptor concentration near the surface, which can be compensated for by sequential nitrogen ion implantation. Defect-assisted Mg diffusion to the deeper region causes a redistribution of the Mg atoms and should be considered in the design of a device. Such anisotropic diffusion of Mg to the c-axis has potential applications in the fabrication of unique vertical device structures such as super junctions.

An area selective doping via ion implantation is a key technology to realize gallium nitride (GaN) based energy-efficient power devices; however, conventional annealing leads to the formation of numerous Mg-enriched defects, which result in inefficient p-type activation. The recent invention of ultra-high-pressure annealing (UHPA) has enabled a significant improvement in p-type activation efficiency. In this study, we investigated the formation of Mg-enriched defects in Mg implanted GaN followed by annealing under either conventional atmospheric pressure or ultra-high-pressure. Unlike the conventional annealing, UHPA leads to a much lower number density of Mg-enriched defects. Correlative scanning transmission electron microscopy, atom probe tomography, cathodoluminescence, and secondary ion mass spectrometry analyses have shown that the number density of Mg-enriched defects is substantially suppressed by the UHPA. The dissolved Mg concentrations in the GaN matrix for both the conventional and the UHPA samples are almost of the same value, approximately 2 × 1018 cm−3; however, the UHPA sample shows over one order of magnitude stronger intensity of donor–acceptor-pair emission than the conventional one. Thus, the implanted Mg is effectively activated as acceptors through the UHPA technique.

In this study, we clarify the impact of annealing pressure and temperature of the ultra-high-pressure annealing (UHPA) as a post-implantation-annealing (PIA) on the acceptor activation for Mg-ions-implanted GaN samples. The pressure to prevent the thermal decomposition is absolutely determined by the equilibrium N 2 partial pressure in the phase diagram of GaN-Ga-N 2 system, so that the pressure below the critical pressure always leads to the serious surface decomposition of GaN. In low temperature cathodoluminescence examinations, the samples processed at 1400°C or above exhibited more intense emissions in the near band edge and donor-acceptor pair band with a suppression of green luminescence related to point defects. Temperature dependent Hall-effect measurement was allowed for the UHPA samples annealed at 1400°C or above, whereas free holes were not observed for the 1300°C-UHPA. Moreover, the acceptor concentrations (N a ) for samples annealed at 1400°C or above were close to Mg concentrations. We thus revealed the key process parameters in UHPA, which is at more than 1400°C under the N 2 overpressure exceeding the equilibrium partial pressure. These findings can play as a key role in the selective area doping using UHPA.

It is well known that ion implantation is one of the basic tools for semiconductor device fabrication. The implantation process itself damages, however, the crystallographic lattice of the semiconductor. Such damage can be removed by proper post-implantation annealing of the implanted material. Annealing also allows electrical activation of the dopant and creates areas of different electrical types in a semiconductor. However, such thermal treatment is particularly challenging in the case of gallium nitride since it decomposes at relatively low temperature (~800 °C) at atmospheric pressure. In order to remove the implantation damage in a GaN crystal structure, as well as activate the implanted dopants at ultra-high pressure, annealing process is proposed. It will be described in detail in this paper. P-type GaN implanted with magnesium will be briefly discussed. A possibility to analyze diffusion of any dopant in GaN will be proposed and demonstrated on the example of beryllium.

We performed an isothermal annealing study on Mg-implanted GaN at 1300 °C in an ultra-high-pressure (1 GPa) nitrogen ambient. Annealing for more than 30 min resulted in a high acceptor activation ratio and a low compensation ratio that were comparable to those obtained with annealing at 1400 °C for 5 min. We also performed annealing at 1300 °C in a reduced nitrogen pressure of 300 MPa which makes us possible to expand the inner diameter of annealing equipment in the future. High electrical activation, similar to one obtained by annealing at 1 GPa, was successfully obtained.

2010（平成22）年４月、鈴鹿短期大学（現鈴鹿大学短期大学部）生活学科の生活学専攻内に生活コミュニケーションコースが設置された。 本コースは、養護教諭２種、栄養士、保育士、音楽療法士２種などの資格取得を目指す他専攻・コースとは異なり、コミュニケーションをキーワードに、人と人、人と動物、人と社会・情報といったさまざまな関わりにおいて、総合的人間理解の形成を目指すカリキュラムが検討された。 2011（平成23）年４月、生活学科を生活コミュニケーションに学科名を変更、生活学専攻を生活コミュニケーション学専攻に専攻名が変更された。2012（平成24）年４月に、庄野キャンパスから郡山キャンパスに移転し、鈴鹿国際大学（現鈴鹿大学）と同じキャンパスになり、2015（平成27）年４月には鈴鹿国際大学が鈴鹿大学に名称変更され、鈴鹿短期大学は鈴鹿大学短期大学部として大学とより一体化し、新しいスタートを切った。この時、生活コミュニケーション学専攻のコース名を変更し、養護教諭・福祉コースは養護教諭・音楽療法士コースに、生活コミュニケーションコースはペットコースに名称変更し、より一層の充実をはかった。 2017（平成29）年度に鈴鹿大学こども教育学部が設置され、鈴鹿大学短期大学部生活コミュニケーション学専攻は養護教諭養成を新学部に移し、ペットコースは学生募集停止となった。獣医学部以外でペット動物を専門に学ぶことができる大学は、帝京科学大学、千葉科学大学、ヤマザキ学園大学、日本獣医生命科学大学といずれも関東圏の４年制大学だけである。筆者は、日本で唯一ペット動物を学ぶことができる短大のペットコースが地域に受け入れられ、定着することを期待し努力してきたので、ペットコース学生募集の停止は残念でならない。 大きな教学改革の流れの中で、ペットコースも変化に対応してきた。ペットコース２年生２名が在籍中であるが、ここで一度、ペットコースの7年間を振り返りたい。

近年、ヒトのがん治療において、外科療法、化学療法、放射線療法に次ぐ新たな治療法として免疫療法が注目されている。日本で免疫療法が行われるようになったのは1970年代からであり、以降、免疫学の基礎的研究成果が積み重ねられるにつれて、免疫療法も第１世代から最新の第５世代へ変遷している。犬猫における癌の免疫療法はほとんどのがんに有効であるといわれる。特に乳腺管がん、悪性黒色腫（メラノーマ）、肥満細胞種の再発や転移抑制の効果については多くの症例が報告されている。 筆者は以前1970年代から1980年代前半までの初期免疫療法研究の変遷について、薬剤や生理活性物質による第１、第２世代の免疫療法とリンパ球の活性化による第３世代の免疫療法を簡潔にまとめた。今回、初期の免疫療法の流れをくみ、特に1990年代以降に発展したがんペプチドワクチン療法、樹状細胞療法などの新しい免疫療法について、その作用機序や手法、治療効果等について文献調査を行った。 これらの新しい免疫療法は医学領域においては、いくつかのがんで、すでに実験的に有効性が確認されており、がんの治療に用いられているものがある。獣医領域では未だ大規模な臨床データが示されていないものの、がん患畜のQOLを改善させるといった報告が数多く見受けられる。

For the solution to global energy issues, highly-efficient energy conversion using next-generation power devices is required. Gallium nitride (GaN) having superior properties such as high breakdown electric field (2.8–3.75 MV/cm) is a powerful candidate for next-generation high-power semiconductor devices. [1] , [2] The selective area doping makes it possible to precisely engineer high-power devices with complex structures, allowing formation of low-resistivity region for contacting electrodes and optimization of the electric field configuration in the edge termination represented by the field limiting ring (FLR) and in the junction barrier Schottky (JBS) structures, as used in Si and SiC power devices. [3]

Ion implantation (I/I) and annealing techniques to enable high carrier doping into selected regions are one of important research fields for realization of GaN power devices. However, particularly difficult research challenges are present in Mg-I/I into GaN as p-type doping technique. First problem is related to nitrogen vacancies (VN), crystal defects introduced by Mg-I/I . [1] Second issue is connected to degeneration of GaN surface by pyrolysis reaction during high-temperature annealing process. We examined Mg/N co-implantation into GaN as p-doping in order to compensate of VN defects. Research on ultra-high pressure thermal activation process to maintain equilibrium conditions at high temperature was conducted to avoid degradation of GaN surface. We prepared Mg/N co-implanted GaN-on-GaN samples with 300-nm-deep Mg-box-profile of 1E19 cm-3 and with N-box-profile of various concentrations in the range 0 ~ 1E20 cm-3. The samples were annealed without a protection cap layer at temperature between 1300 °C and 1480 °C under 1 GPa in N2 atmosphere. Samples capped with sputter-AlN were treated by conventional lamp annealing at 1300 °C for a comparison purpose. We obtained the dominant Green Luminescence (GL) emission at 2.3 eV and the recessive Donor Acceptor Pair (DAP) emission at 3.2 eV from a low-temperature cathodoluminescence (LT-CL) spectra in Mg-I/I samples without N co-implantation. This is in good agreement with results published before.[1][2] In addition to this, we found that the Mg/N co-implantation, for optimized N-ion dose, suppresses the GL intensity while maintaining the DAP intensity. Furthermore, in the ultra-high pressure thermal activation process, the DAP intensity markedly increases with anneal temperature and GL intensity suppression is also visible. These results strongly suggest that the origin of GL is related to VN, and the VN defect compensation occurs by N co-implantation. We also compare the AFM images of GaN surface roughness. The ultra-high pressure annealed surfaces were as smooth (RMS = 0.2~0.3 nm) as the as-implanted samples (0.3 nm), whereas surface treated with conventional lamp was rough (1.9 nm). We can, therefore, conclude that Mg/N co-implantation and ultra-high pressure thermal activation process allows activation of the Mg acceptor and recovery of p-GaN crystal quality. Such treatment results in VN defect compensation and a smooth surface of the annealed sample. This work was supported by MEXT “Program for research and development of next-generation semiconductor to realize energy-saving society.” [1] A. Uedono et al., Phys. Status Solidi B 252, No. 12 (2015) [2] K. Kojima et al., Appl. Phys. Express 10, 061002 (2017).

Isochronal annealing was performed on Mg-ion-implanted GaN under 1 GPa N2 ambient pressure for 5 min at temperatures of 1573–1753 K. Secondary ion mass spectrometry showed diffusion of Mg atoms and introduction of H atoms during annealing. Deeper diffusion was observed with increasing temperature. From Hall-effect measurements, p-type conductivity was found even for the sample with the lowest annealing temperature of 1573 K. For this sample, the acceptor activation ratio was 23% and the compensation ratio was 93%. The acceptor activation ratio increased to almost 100% and the compensation ratio decreased to 12% with increasing annealing temperature.

A trench-gate metal-oxide-semiconductor field-effect transistor (T-MOSFET) has great potential for use in gallium nitride (GaN)-based vertical power switching devices owing to its high blocking voltage and high current capability. To form an optimal trench shape that has highly vertical sidewalls and rounded corners, we developed a dry-etching technique using inductively coupled plasma reactive ion etching (ICP-RIE). A highly vertical trench was obtained by including SiCl4 reactive gas mixed with Cl2 gas in the ICP-RIE process, where Si-related byproducts suppressed the etching of the sidewall and allowed selective etching in the vertical direction. We found that the optimization of the bias power was a key to suppress the formation of subtrenches and to avoid an isotropic etching mode. The optimal etching condition leads to natural formation of rounded corners at the trench bottom. In addition, a multistep-bias etching technique was applied to reduce etching-induced damage. Cross-sectional transmission electron microscopy images revealed that lattice distortion on the sidewall surface was eliminated by multistep-bias etching. Based on the rectification properties of the Schottky barrier diodes formed on the trench sidewalls, the Schottky barrier height was comparable to the not-etched surfaces. This indicates that the gap states caused by etching-induced damage can almost be eliminated in the multistep-bias process. The proposed technique is suitable for GaN-based vertical T-MOSFETs.

The effects of ultra-high-pressure annealing (UHPA) on the surface of Mg-ion-implanted GaN were investigated by X-ray photoelectron spectroscopy (XPS). After Mg ion implantation or Mg–N co-implantation, GaN was annealed at 1400 °C for 5 min under a nitrogen pressure of 1 GPa. No deterioration of the surface stoichiometry occurred after UHPA despite the extremely high annealing temperature. The angle-resolved XPS with calibration showed that the surface Fermi level was pinned at 0.5 eV from the conduction band edge after dehydrogenation subsequent to UHPA. However, the absence of pinning at the charge neutrality level showed that surface disorder was absent after UHPA. The surface photovoltaic effect as evidence of the achievement of p-type conduction even in the near-surface region was more remarkable for Mg–N-ion-implanted samples after dehydrogenation subsequent to UHPA. There is the possibility that the density of N-vacancy-related defects was reduced more by Mg–N co-implantation.

Herein, we propose and demonstrate the edge termination for GaN-based one-sided abrupt p–n junctions. The structure is comprised of a combination of a shallow negative bevel mesa and selective-area p-type doping under the mesa. Based on the Technology Computer Aided Design (TCAD) simulation, the maximum electric field at the junction edge is markedly reduced to approximately 1.3 times that of the parallel-plane electric field in the proposed structure, which is almost half of the unimplanted diode. The TCAD simulation also shows that the shallow mesa angle of 6 ° effectively reduces the optimum acceptor concentration (Na) in the implanted region and enhances the breakdown voltage. The optimum Na value can be covered by the proposed technology based on the Mg-ion implantation and subsequent ultra-high-pressure annealing (UHPA). Using the formation of the shallow bevel mesa, the Mg-ion implantation, and the UHPA process, we experimentally demonstrate the p–n diodes with a breakdown voltage over 600 V, which is in good agreement with the TCAD simulation. The proposed method can be applied to a vertical trench-gate metal-oxide-semiconductor field-effect transistor with a high figure-of-merit.

In this work we present quasi-solid state dye-sensitized solar cells obtained employing artificial hydrotalcite nano-clay as electrolyte additive, with a greatly improved photo-energy conversion efficiency of up to 10.9% with respect to the 9.6% obtained for liquid electrolyte ruthenium based reference cell. Through impedance spectroscopy, we have evaluated quantitatively the effects of shifts in the conduction band energy level and variations of electron recombination rates over the photovoltage. We demonstrated that the origin of these changes could be ascribed to the chemical effects induced by the fluctuation of ionic species inside the pores of TiO2 in the presence of nano-clay. These results highlight the dual functionality of clay electrolyte that enables the fabrication of stable solar devices under irradiation tests over 1000 h, and pushes up the photo-energy conversion efficiency up to a record values. We acknowledge fi nancial support from Generalitat Valenciana under Project PROMETEO/2009/058. V.G.-P. acknowledge the fi nancial support of Japan Society for the Promotion of Science (JSPS) through its Post-doctoral fellowship for overseas research- ers.

Defect time-evolution was investigated in Mg ion-implanted GaN after annealing at 1573 K for an unprecedentedly long duration. Transmission electron microscopy directly revealed that annealing for over 30 min reduced defects inhibiting Mg activation, just like annealing at 1753 K for a short duration. The cathodoluminescence intensity of donor–acceptor pair originating from Mg acceptors increased as the duration increased, and the intensity after annealing for 60 min was higher than after short-duration annealing at 1753 K. These show the potential of lowering the annealing temperature by prolonging the duration, which would lead to practical annealing technology for Mg ion-implanted GaN.

Vacancy-type defects in Mg-implanted GaN were probed by using a monoenergetic positron beam. Mg ions were implanted into GaN to obtain 0.3-μm-deep box profiles with Mg concentrations of 1 × 1019 cm−3. The major defect species in an as-implanted sample was determined to be Ga-vacancy related defects such as a complex between Ga and N vacancies. The sample was annealed under a nitrogen pressure of 1 GPa in a temperature range of 1000–1480 °C without a protective capping layer. Compared with the results for Mg-implanted GaN annealed with an AlN capping layer, the defect concentration was decreased by the cap-less annealing, suggesting that the surface of the sample was an effective sink for vacancies migrating toward the surface. Depth distributions of Mg after annealing above 1300 °C were influenced by the presence of residual vacancies at this temperature. Hydrogen atoms were unintentionally incorporated into the sample during annealing, and their diffusion properties were also affected by both vacancies and Mg.

The fabrication processes of p-type regions for vertical GaN power devices are investigated. A p-type body layer in a trench gate metal-oxide-semiconductor field-effect transistor requires precise control of the effective acceptor concentration, which is equal to the difference between the Mg acceptor concentration (Na) and the compensating donor concentration (Nd). The carbon atoms incorporated during growth via metalorganic vapor phase epitaxy substitute nitrogen sites (CN) and function as donor sources in a p-type GaN layer. Since interstitial H atoms ( H i ) also compensate holes, their removal from an Mg-doped layer is crucial. Extended anneals to release H atoms cause the formation of extra hole traps. The p+ capping layer allows effective and rapid removal of H atoms from a p-type body layer owing to the electric field across the p+/p– junction. On the other hand, selective area p-type doping via Mg ion implantation is needed to control the electrical field distribution at the device edge. Ultrahigh-pressure annealing (UHPA) under a nitrogen pressure of 1 GPa enables post-implantation annealing up to 1753 K without thermal decomposition. Cathodoluminescence spectra and Hall-effect measurements suggest that the acceptor activation ratio improves dramatically by annealing above 1673 K as compared to annealing at up to 1573 K. High-temperature UHPA also induces Mg atom diffusion. We demonstrate that vacancy diffusion and the introduction of H atoms from the UHPA ambient play a key role in the redistribution of Mg atoms.

Defects in Mg ion-implanted GaN epitaxial layers formed after annealing at 1573 K and at 1753 K were analyzed by transmission electron microscopy. Degradation of the GaN surface, which occurs at temperatures higher than about 1573 K, was avoided by ultra-high-pressure annealing under a N2 atmosphere at 1 GPa. Annealing for damage recovery in ion-implanted compound semiconductors generally requires temperatures at about two-thirds of their melting point, which is reportedly 2518 K or higher for GaN. Thus, defect analysis in ion-implanted GaN annealed at temperatures higher than 1573 K is necessary to understand the defect recovery. Atomic-resolution transmission electron microscopy analysis showed that interstitial-type extended defects and inversion domains with Mg segregation were formed during the annealing at 1573 K. These defects were not observed in a sample annealed at 1753 K; instead, vacancy-type extended defects were formed. Such evolution of defects can be explained by previous theoretical studies that indicated that the migration energy of vacancy-type defects is higher than that of interstitial-type defects. Moreover, the formation of vacancy-type extended defects implies a reduction in the concentrations of vacancies and their complexes. Since the vacancies and their complexes can compensate for Mg acceptors, their reduced concentration should increase the acceptor activation efficiency. Also, the disappearance of Mg segregation during high-temperature annealing should increase the activation efficiency since the segregated Mg atoms are electrically inactive. It is thus concluded that the evolution of defects caused by high-temperature annealing above 1573 K increases the activation efficiency of acceptors in Mg ion-implanted GaN.

text, 紀要論文 / Departmental Bulletin Paper

Plasma-induced damage was reduced by multistep-bias etching that involved a stepwise decrease of the etching bias power (P bias) and subsequent annealing. The depth of damage at P bias = 60 W was determined to be 60 nm from the capacitance–voltage characteristics of Ni/Al2O3/etched-GaN metal-oxide-semiconductor diodes. The damaged layer was removed by subsequent etching at P bias = 5 W and 2.5 W. The residual and shallow damage induced by the low P bias was then recovered by subsequent annealing at 400 °C. The multistep-bias etching of inductively coupled plasma reactive ion etching was thus confirmed to be effective for achieving a high etching rate with low damage.

To investigate Mg diffusion during ultra-high-pressure annealing, which activates Mg acceptors in GaN, GaN samples with p–n junctions prepared via epitaxial growth were annealed at 1573 K under 1 GPa. The profiles of Mg diffusion toward the underlying n-type layer cannot be explained by a simple diffusion model. We found that H atoms diffused along with Mg atoms. By considering the suppressed diffusion of positively charged interstitial H atoms due to the electric field in the depletion layer, we could better reproduce the Mg–H diffusion profiles, suggesting that H atoms play a key role in the Mg diffusion process.

After the accident at the Fukushima Daiichi Nuclear Power Plant in Japan, it has steadily become more important to ensure the structural integrity of cask systems containing spent fuels or radioactive debris during seismic events. These cask systems are free-standing cylindrical structures and are believed to show rocking and sliding motions at huge seismic excitations. In the worst case, these cask systems can possibly overturn or collide with each other. Therefore, it is very important to reduce the sliding and rocking motions of the cask system in order to avoid subsequent contamination due to radioactive substances. To date, the authors have been studying the response behaviors of these motions, and have developed some types of methods that are effective at mitigating sliding or rocking motions, and confirmed the effectiveness of these methods. A system utilizing coaxial circular cylinders and high-viscosity liquid filled into the annular spaces was developed for the suppression of sliding motion. This system was installed at the bottom end of the rigid body. Previous studies show that liquids with high-viscosity provide a very large added damping effect that causes sliding motion to be suppressed significantly. For the suppression of rocking motion, the authors developed a system that utilizes a gyro system, and confirmed it’s effectiveness both analytically and experimentally. However, the gyro system is slightly complex and requires electric power even during a seismic event. Thus, some passive suppression method is required. On the other hand, the above-mentioned coaxial circular cylindrical system filled with high-viscosity liquid is thought to have a high damping effect on rocking motion, along with suppression of sliding motion. This study investigated the effect of rocking motion suppression due to the above-mentioned coaxial circular cylindrical system that is utilized for the suppression of sliding motion. First, an analytical model that can account for the coupled rocking and sliding motion was established, and then the rocking behavior of a rigid structure coupled with its sliding motion was studied. Next, shaking table tests were conducted by using a fundamental test model. By comparing the analytically obtained rocking motion with that obtained by the test results, the validity of the analytical model was confirmed. Finally, the analytical model was modified for cask systems equipped with a rocking suppression system, and the rocking motion was analyzed to evaluate its effectiveness. The proposed rocking suppression system was found to be very effective in suppressing the rocking motion of the rigid body when subjected to base excitations.

The terminology and notation used here have been introduced in the following articles: [3], [4], [2], [15], [11], [14], [1], [5], [13], [12], [19], [20], [16], [7], [17], [8], [18], [9], and [6]. Let X, Y be non empty normed structures, let x be a point of X, and let y be a point of Y . Then 〈x, y〉 is a point of X × Y. Let X, Y be non empty normed structures, let s1 be a sequence of X, and let s2 be a sequence of Y . Then 〈s1, s2〉 is a sequence of X × Y. We now state several propositions: (1) Let X, Y be real linear spaces and T be a linear operator from X into Y . Suppose T is bijective. Then T−1 is a linear operator from Y into X and rng(T−1) = the carrier of X. (2) Let X, Y be non empty linear topological spaces, T be a linear operator from X into Y , and S be a function from Y into X. Suppose T is bijective

Wurtz coupling of dibutylaminotrimethyl-1,2-dichlorodisilane 1, which is readily available from by-products in the industrially operated direct synthesis of chloromethylsilanes, afforded polymer 2, a partially networked (branched) structure, where the degree of cross-linking depends on the polymerization conditions such as the temperature. Polymer 2, which has a network structure, shows an absorption maximum at about 360 nm that is approximately 30 nm red-shifted relative to the absorption maximum of poly(dialkylsilane)s. In the emission spectra, 2 exhibits a broad emission at 440 and 400 nm, which is ascribed to the network (or branching) silicon units and the linear silicon chains, respectively. The unusual photophysical properties presumably arise from the amino groups on silicon as well as the network structure.

Polysilanes with an optically active alkoxy group, i.e., (S)-(+)-2-butoxy, (R)-(-)-2-butoxy, (S)-(-)-2-methyl-1-butoxy, and (S)-(+)-3,7-dimethyl-1-octoxy, at the terminal positions, the chiral carbon centers of which were located at the α, β, and γ positions relative to the oxygen, respectively, were prepared, and the effect of the position of chiral center of the terminal optically active group on the induction of optical activity in polysilanes was investigated. The circular dichroism (CD) spectra of these polymers showed positive Cotton signals around 340 nm at temperatures below -20 °C, but the intensities were small, indicating that the optically active groups at the terminal positions have some ability, albeit small, to induce optical activity to the polysilanes. Further, the optically active (S)-(+)-2-butoxy and (R)-(-)-2-butoxy groups did not control the helical sense direction of the polymers, despite the different chiral stimuli from the 2-butoxy groups introduced to the terminal positions. To control the helical structure of polysilanes by the use of optically active terminal groups, appropriate optically active groups are required.

Thermolysis of 2,3-benzo-1,4-diphenyl-7-silanorbornadiene derivatives 1 in the presence of 2,3-dimethylbutadienes gave the trapping products of the corresponding bissilylene, disilenylsilylene, and a tetrasila-1,3-butadiene, via a consecutive disilanylsilylene to silyldisilene rearrangement.

再発を繰り返していた小腸gastrointestinal stromal tumor (以下, GIST) に対し, 4回の手術とイマチニブの内服治療にてCT上CRが得られた症例を経験したので報告する. 症例は70歳の男性で, 下腹部痛にて受診した. CTで下腹部に15cm大の境界明瞭で内部は充実部と. 胞部が混在する腫瘍を認めた. 小腸造影およびガストログラフィン内服併用CTで腫瘍と小腸内腔の交通を認め腫瘍を含む小腸部分切除を行った. 病理学的にGISTと診断された. その後, 約3年間に3回の腹腔内再発を認め, 2・3回目は開腹し腫瘍切除を行った. しかし, 4回目の手術時には多発肝転移も認めた. このため, 主病巣のみ切除しその他はイマチニブの治療効果に期待した. 遺伝子解析にてexon11に変異を認め300mgより開始. 投与1か月後で縮小効果を認め, 400mgに増量し投与10か月後にて多発肝転移部・腹腔内再発部ともにCT上CRと判断された. 現在まで副作用なく投与継続中である.

Several polysilane block copolymers have been prepared by the newly developed method, anionic polymerization of masked disilenes. Especially amphiphilic block copolymers of poly(1,1-dimethyl-2,2-dihexyldisilene) and poly methacrylate are focused. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(2-hydroxyethyl methacrylate) (PMHS-b-PHEMA) is the first example of the amphiphilic polysilane copolymer that can form micelles in polar solvents. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(methacrylic acid) (PMHS-b-PMAA) is more polar than (PMHS-b-PHEMA), soluble in water to form micelles. The cross-linking reaction of (PMHS-b-PMAA) with 1,10-diaza-4,7-dioxadecane and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride afforded the first shell cross-linked micelles (SCM) of polysilane. In addition to interesting properties, SCM is indicated to be able to form hollow sphere particles (hollow shell cross-linked micelles, HSCM) by a photochemical process. Reversible encapsulation of guest molecules by SCM and HSCM is demonstrated. Finally, SCM can be used as the template for the synthesis of metal nanoparticles, which may be used as catalysts.

The activation parameters of the dimerization of t-butylmesitylsilylene (2a), dimesitylsilylene (2b) and bis(2,4,6-triisopropylphenyl)silylene (2c) to the corresponding disilenes were estimated by monitoring the time-dependent changes in their UV-Vis absorption spectra. The activation energy increased in the order: 2a < 2b < 2c.

Silole-core dendrimers having benzyl-ether-type dendron units in the periphery are readily synthesized by the Ni-catalyzed reaction of benzyloxy-substituted diphenylacetylenes with 1,1,2,2-tetramethyldisilane.Key words: silole, dendrimer, nickel-catalyzed reaction, convergent synthesis.