Search results

This paper aims to improve the device performance from the perspective of reducing ohmic contact resistance; the effects of different electrode structures and alloying parameters on the series resistance and power-current-voltage of laser diodes (LDs) have been investigated in this paper.

Four groups of p-GaAs side metal electrodes with different metal layer arrangements and thicknesses are fabricated for the investigated LDs. The investigated p-GaAs side electrodes are based on Ti/Pt/Au material and the n-GaAs side metal electrodes all have a same structure of Ni/Ge/Ni/Au/Ti/Pt/Au. The LDs with different electrodes were alloyed at 380°C for 60 s and 420°C for 80 s.

The experimental results show that the series resistance decreases by 14%–20%, the output power increases by 2%–2.2% and the conversion efficiency increases by 1.69%–2.16% for the LDs prepared with optimized alloying parameters (420°C for 80 s). The laser diode with p-GaAs side Ti/Pt/Au electrode of 30/70/100 nm has the best device characteristics under both annealing conditions.

The utilization of this improvement on ohmic contact property in electrode is not only very important for upgrading high-power LDs but also helpful for GaAs-based microelectronic devices such as HBT and monolithic microwave integrated circuit.

This study aims to explore how a Chinese lesson study (LS) supports a teacher's learning of transforming curriculum reform ideas into classroom practices.

Data analyzed in this study included lesson plans, three videotaped research lessons, three audio-taped group meetings, interviews, the teacher's reflection journals and other related materials. Clarke and Hollingsworth's interconnected model of professional growth (IMPG) was adopted as the theoretical and analytical framework for examining the teacher's learning process.

This study found that teachers can deepen their understanding of innovative curriculum ideas and implement them through an iterative cycle of planning, enactment and reflection in LS. Involving knowledgeable others in the process and reflecting on evidence-based evaluation of students' learning outcomes is crucial for changing the teacher's knowledge, beliefs, attitudes and teaching practices. Theoretical tools, such as learning trajectory, are useful for transforming curriculum reform ideas that teachers find abstract and overly broad into concrete and actionable lesson designs.

Theoretically, this study can broaden our knowledge about how the under-studied mechanism of Chinese LS can contribute to helping teachers to transform reform ideas into classroom practices. Practically, this study provides suggestions for researchers and educators to reflect on and improve the effectiveness of teachers' professional development programs in a reform context.

The purpose of this paper is to explore what professional knowledge and competence (PKC) that knowledgeable others, namely, mathematics teaching research specialists (MTRS) in China, need to know, and how they may develop their PKC.

This study adopts mixed methods. A survey on PKC with 549 MTRS is utilized to examine MTRS’ perceived held and ideal PKC and perceived effective ways of developing their PKC. The responses to the open-ended questions on the survey were used to identify additional dimensions of PKC and ways of developing PKC. Multiple techniques of quantitative data analysis were employed to feature the characteristics of PKC and structure of the survey, and the relationship between background variables and perception of PKC. Collectively, this study paints a rich and comprehensive picture about Chinese knowledgeable others’ knowledge and competence, and its development.

The data analysis reveals that the participants appreciated the six-dimension model of MTRS’ PKC. They were confident with their PKC in general, but varied in different aspects. The factor analysis showed the six-dimension model could be further clustered into two components: knowledge about mathematics teaching and learning and competence in mentoring and educational leadership, and knowledge about content, assessing student learning, and use of technology. The participants perceived their learning through multiple ways including: learning through reading, attending specific training programs, attending and mentoring teaching research activities both school-based and across regions, observing and debriefing lessons, sharing within online learning communities. All these venues jointly contribute to developing MTRS’ PKC.

This is the first empirical study on MTRS’ PKC and its development in China based on such a large sample. The findings of this study not only contribute to an understanding of knowledgeable others in Chinese lesson study and providing suggestions for support of their development, but also provide implications for studies of practice-based mathematics teacher-educators globally.

This study aimed to explore how an adapted theoretical framework by networking two theories could help document teachers' collective learning through lesson study.

Interconnected Model of Teacher Professional Growth (IMPG) and Documentational Approach to Didactics (DAD) has been used individually to document teachers' professional learning from different aspects. The IMPG captures teachers’ growth through the iterative process and dynamics (i.e. enactment and reflection) among four domains (personal domain, external domain, practice domain and consequence domain). At the same time, the DAD primarily focuses on teacher learning through the interactions between resources and teachers. To deepen understanding of teachers' learning through lesson study, in this study, a networked theoretical framework through which the DAD model is enriched by incorporating some ideas from IMPG is proposed. A lesson study, including five stages of study, plan, enact, reflect and refine, facilitated by a researcher was conducted in Shanghai China. The data sets including all videotaped meetings and research lessons and lesson plans of the lesson study are analyzed based on the adapted framework qualitatively.

The results show that the teachers' document evolved from adopting the traditional teaching materials to adapting both traditional ones and e-resources with careful consideration of student learning through the lesson study process.

This study advances our understanding of networking strategies and their usefulness for deepening teacher professional learning as document development through lesson study. However, the sustainability of this type of professional learning needs to be further explored.

This study expands teacher learning through lesson study as the document development and enriches the DAD theory by illuminating the process of the documentational genesis.

This special issue reveals how lesson study in China continues to serve as a powerful platform to support change in teaching. The papers included in this issue explore how university faculty members and researchers support teachers to cross boundaries resulting from the introduction of key competencies-based (hexin suyang 核心素养) curriculum reform (KCR).

The theme of continuity and change is examined against the backdrop of Chinese lesson study's (CLS's) consistent supporting role in enabling curriculum reform. These analyses make use of concepts involved in understanding boundary crossing, such as using boundary objects and their roles, to help make sense of the new theories, tools, and resources as well as relationships engendered in responding to the reform's demand. While recognizing the continuity at play in Chinese LS, the authors use the lens of learning at the boundary of research-practice partnerships (RPPs) (Farrell et al., 2022) to contemplate the future of CLS.

The papers touch on three major themes: (1) the role of university-school partnerships in meeting the new demands of key competencies reform; (2) resourceful tools, strategies and structures to support boundary crossing for teachers; and (3) roles and relationships for mutual learning in university-school partnerships. Together these three themes, considered across the papers in this issue, point to the need to redefine CLS to engender versatility and hybridity and to enlist mutual learning relationships in future university-school partnerships. Such redefinition positions lesson study to both continue and change.

The papers in this issue are expected to promote mutualist learning in future CLS research-practice partnerships. To do so, research needs to move from focusing on change of a single case teacher to clarifying what experts and teachers each learn from the LS and from each other. Attention also needs to focus on the collaborative discourse and ways such discourse is able to promote mutual learning, emotional support in facing change as well as critical and constructive problem solving.

Practically, to better support boundary crossing, this special issue encourages academics and teachers to identify and work around boundary objects and their enabling features to enhance knowledge and identity of both university and teacher participants for more effective research-practice partnerships.

This special issue offers a pioneering set of studies that contributes to an in-depth understanding of how CLS is supporting the current competencies-based reform in China. It also provides concrete future directions for research and practice to enhance university-school partnerships' response to reform.

Although CLS has been implemented in China for over a century, it is barely known to educators internationally. The purpose of this paper is to synthesize the salient characteristics of Chinese lesson study (CLS), introduce the major themes of this special issue, and invite dialogues about the theories and practices of CLS.

The authors of this editorial paper conducted an extensive literature review on CLS, analyzed the contents and methods of the existing research categorically, compared CLS with other models of LS globally, and present this special issue articles and their major contributions thematically. The theoretical framework of the paper relies mainly on cultural theories and theories on research paradigms such as improvement science, which explain why and how CLS functions in Chinese education system over time.

Existing studies suggest that CLS is a deliberate practice for developing instructional expertise, a research methodology for linking research and practice, and an improvement science for instruction and school improvement system wide. In addition to the theorization of CLS, this special issue also introduces some adaptations of CLS outside of China such as the USA and Italy.

This paper, for the first time, spells out some salient features of CLS, and discusses issues in adapting CLS in other parts of the world. It will enrich the understanding of LS theories and practices in China and promotes trans-cultural development of LS internationally.

With the increasing complexity of public–private partnership (PPP) projects, the amount of data generated during the construction process is massive. This paper aims to develop a new information management method to cope with the risk problems involved in dealing with such data, based on domain ontologies of the construction industry, to help manage PPP risks, share and reuse risk knowledge.

Risk knowledge concepts are acquired and summarized through PPP failure cases and an extensive literature review to establish a domain framework for risk knowledge using ontology technology to help manage PPP risks.

The results indicate that the risk ontology is capable of capturing key concepts and relationships involved in managing PPP risks and can be used to facilitate knowledge reuse and storage beneficial to risk management.

The classes in the risk knowledge ontology model constructed in this research do not yet cover all the information in PPP project risks and need to be further extended. Moreover, only the framework and basic methods needed are developed, while the construction of a working ontology model and the relationship between implicit and explicit knowledge is a complicated process that requires repeated modifications and evaluations before it can be implemented.

The ontology provides a basis for turning PPP risk information into risk knowledge to allow the effective sharing and communication of project risks between different project stakeholders. It can also have the potential to help reduce the dependence on subjectivity by mining, using and storing tacit knowledge in the risk management process.

The apparent suitability of the nine classes of PPP risk knowledge (project model, risk type, risk occurrence stage, risk source, risk consequence, risk likelihood, risk carrier, risk management measures and risk case) is identified, and the proposed construction method and steps for a complete domain ontology for PPP risk management are unique. A combination of criteria- and task-based evaluations is also developed for assessing the PPP risk ontology for the first time.