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Finite-q antiferrotoroidal and ferritoroidal order in a distorted kagome structure
No full textA highly geometrically frustrated lattice structure such as a distorted kagome (or quasikagome) structure enriches physical phenomena through coupling with the electronic structure, topology, and magnetism. Recently, it has been reported that an intermetallic HoAgGe exhibits two distinct magnetic structures with the finite magnetic vector q = (1/3, 1/3, 0): One is the partially ordered state in the intermediate-temperature region, and the other is the kagome spin ice state in the lowest-temperature region. We theoretically elucidate that the former is characterized by antiferrotoroidal ordering, while the latter is characterized by ferritoroidal ordering based on the multipole representation theory, which provides an opposite interpretation to previous studies. We also show how antiferrotoroidal and ferritoroidal orderings are microscopically formed by quantifying the magnetic toroidal moment activated in a multiorbital system. As a result, we find that the degree of distortion for the kagome structure plays a significant role in determining the nature of antiferrotoroidal and ferritoroidal orderings, which brings about the crossover between the antiferro-type and the ferri-type distributions of the magnetic toroidal dipole. We confirm such a tendency by evaluating the linear magnetoelectric effect. Our analysis can be applied irrespective of lattice structures and magnetic vectors without annoying the cluster origin
Anomalous proximity effect of a spin-singlet superconductor with a spin-orbit interaction
No full textThe anomalous proximity effect of a spin-triplet p-wave superconductor has been known as apart of Majorana physics, and is explained by the penetration of zero-energy states from a surface of a superconductor to a dirty normal metal. We demonstrate that a spin-singlet d-wave superconductor without any surface zero-energy states exhibits the anomalous proximity effect in the presence of a specific spin-orbit interaction. The results show the quantization of the zero-bias conductance in a dirty normal-metal/superconductor junction. We also discuss a relation between our findings and results in an experiment on a CoSi2/TiSi2 junction
大学における教育支援の公平性の確保 : 合理的配慮を必要とする学生への支援に基づく検討
No full textIn Japan, based on the Act for the Eliminating Discrimination against Persons with Disabilities in 2006, all business operators have been obliged to provide reasonable accommodation from April 2024 onwards.
Universities have been working to develop support systems including the physical environment, but it is difficult to share information about reasonable accommodation due to the need to protect personal information, and there is not much research on the subject. In particular many aspects of activities in the classroom are left to the judgement of the lecturers, and in Japanese language classes, which often include collaborative activities, there are many lecturers who struggle to respond to students who have difficulty participating in these activities. In this paper, based on interviews to relevant staff conducted at universities in Canada, Australia and South Korea, we will clarify that the number of students with learning disabilities and other characteristics that are not easily apparent from appearances is increasing worldwide, and that this is leading to a fundamental shift in teaching and learning.
We will then consider the environment and particularly the role of lecturers necessary for creating inclusive classroom settings, using Japanese language lessons at Hokkaido University as a reference in future classroom activities.日本では，「障害者差別解消法」に基づき，2024年4月以後，すべての事業者に合理的配慮の提供が義務化された。各大学は，物理的環境をはじめとする支援体制の構築・整備に取り組んでいるが，合理的配慮にかんしては，個人情報保護の観点からもその共有が難しく，研究の蓄積も多くはない。特に教室内での活動では教員の判断に任されている部分が多く，協働活動を多く含む日本語の授業では，それらの活動への参加に困難を感じている学生への対応に苦慮している教員も少なくない。本稿では，カナダ，オーストラリア，韓国の大学における聞き取り調査をもとに，世界的に発達・学習障害など外見からはわかりにくい障害・特性を抱える学生が増えていること，そのために抜本的な教授・学びの転換が求められていることを明らかにする。その上で，北海道大学における日本語の授業実践を手掛かりに，インクルーシブな授業作りに必要な環境や教員の役割を考える
A Systematic Review of the Dynamic Assessment for Early Identification and Intervention of Children with Reading Difficulties
No full text単語レベルの読みに困難を示す児童を早期に発見し，適切な介入を行うことを目指し，音韻意識とデコーディングのダイナミックアセスメント（DA）に関する研究について，システマティックレビューを行った。特に，Response to intervention（RTI）モデルの中で，DAを活用している研究に着目し，本邦でDAを実施する際に，特に重要な点を検討した。2024年5月までに発表された論文のうち19本が該当し，7本にRTIモデルとの併用が確認された。何をアウトカムにするかによって，用いるDA課題が異なっており，本邦で実施する場合には，仮名文字の特徴と読みの発達過程を考慮して，課題作成を行うことが重要と思
われた。また，RTIとの併用には，全ての参加者を対象として行う場合と，一部のみに行う場合があり，対象とする子どもと実施上の課題を考慮して実施方法を検討する必要がある。A systematic review was conducted to explore research on the Dynamic assessments (DA) of phonological awareness and decoding, aimed at early identification and intervention for children with reading difficulties. We focused on studies utilizing DA within the Response to intervention (RTI) model and examined key considerations for implementing DA in Japan.
We collected 19 studies published by May 2024, of which seven integrated the RTI model.
The results showed that tasks differed depending on the outcome, and it seems essential to create tasks in Japan considering the characteristics of kana letters and the developmental process of reading. Furthermore, regarding combining RTI and DA, DA was conducted for all participants or only some of the participants in others. Consequently, when implementing DA at Japanese schools, it is imperative to consider the children to be targeted and the issues involved in implementation
海成粘土における除荷挙動の実験研究とモデル化
No full textThere is a rising demand for land reclamation in coastal cities with economic and demographic growth in East and Southeast Asia. Marine clays play a critical role in these projects, as their deformation characteristics significantly impact subsoil quality. The long-term loading behavior of marine clays has been studied by many researchers.However, there are relatively few existing studies focusing on the unloading behavior after preloading, and strain rate dependency on the unloading behavior of marine clays remains unclear.
This study aims to accumulate experimental data on the unloading behavior of marine clays and develop a strain rate-based model for improving the prediction accuracy for marine clays’ unloading behavior. The authors conducted a series of constant rate of strain (CRS) consolidation tests from loading to unloading, and long-term unloading oedometer tests for marine clays to observe the unloading behavior. Controlling the preloading duration corresponding to different strain rates at the end of preloading to elucidate the stress history’s effect.
Moreover, instead of a parameter σ'p (preconsolidation pressure) for normal consolidation visco-plastic behavior, the authors develop and propose a new visco-plastic model by introducing a concept of plastic rebound boundary and a new parameter R for swelling behavior in unloading. This parameter R represents the normalized distance from the current stress state to the plastic rebound boundary in logarithmic effective consolidation stress. Therefore, the visco-plastic model for behavior in the loading stage has been developed into the swelling visco-plastic behavior in the unloading stage of marine clay. Comparing the simulation and test results, the simplified visco-plastic swelling model shows great agreement with the test results.
This thesis provides a novel perspective on the unloading behavior of marine clays and experimentally validates the efficacy of a strain rate-based model in describing their swelling behavior. The new model offers significant theoretical support for optimizing foundation design and prediction in future coastal land reclamation projects.
The thesis is composed of 8 chapters. Chapter 1 introduces the study’s background, objectives, and the need for improving the accuracy of prediction for unloading behavior of marine clay. Chapter 2 provides a literature review of experimental research, such as incremental loading (IL) oedometer tests, constant rate of strain (CRS) consolidation tests and inter-connected consolidation tests, on the loading and unloading behavior of marine clays, as well as some recent constitutive models developed to simulate unloading behavior. Chapter 3 introduces the physical properties of Ariake clay, Louiseville clay and Onsøy clay, respectively. The consolidation characteristics of the three marine clays are compared based on their compression curves. Chapter 4 describes two types of CRS consolidation test methodologies: constant unloading strain rate consolidation test and multi-stepwise unloading strain rate consolidation test. The experimental results demonstrate the direct influence of unloading strain rate on the unloading behavior. In addition, the strain rate dependency is compared between loading and unloading stages.Chapter 5 presents two types of incremental loading oedometer test methodologies: fourstage unloading oedometer test and long-term unloading oedometer test. The influence of overconsolidation ratio (OCR) and preloading duration on the unloading behavior is investigated, and the strain rate dependency during unloading is quantitatively evaluated.Chapter 6 describes the proposed model's development process in detail and presents its simulation results based on the experimental data. First, the loading behavior of the new model adopts the formulation proposed by Watabe et al. (2008; 2012). Then, a new strain rate-based swelling model for unloading is developed by incorporating the concept of a plastic unloading boundary (Amerasinghe and Kraft, 1983; Tachibana et al., 2020) and reference overconsolidation ratio (OCRref). Finally, numerical simulations are conducted to evaluate the model's performance. The simulated results show good agreement with the observed unloading behavior of marine clays. Chapter 7 further discusses the new visco-plastic model, including a comparison between the swelling behavior during unloading and loading behavior. The advantages of introducing the reference overconsolidation ratio OCRref are elaborated, and the proposed model is systematically compared with some existing models. Finally, Chapter 8 summarizes the study's findings and provides some recommendations for further research
