2000年以来日本行政管理与规划体系修正的评述

区域规划与管理是每一个国家所面临的普遍问题,特别是那些拥有巨大城镇群的新兴工业国家。随着经济的不断发展,日本在东京、近畿等地区出现了若干个大城市的急速扩张——已经超出了地方政府的行政辖区,这给协调不同辖区之间的规划带来了一定的困难。首先讨论首都圈与近畿圈等发展过程中所存在的问题及其内在原因,并评述日本试图通过旨在"增效分权"的平成大合并、部分修正国家和区域规划体系以及"道州制"设想来应对这些问题的经验,最后也论及对中国区域规划与管理的启示。     

由代官山复合建筑群看社会可持续性

代官山复合建筑群规划是从1969年开始、跨越1/4个世纪、阶段性地建造起来的住宅、店铺以及文化设施的复合体。这个规划不仅在日本,在世界上也是广为人知的项目。本文分析了该项目的建筑、空间特征,叙述了它完成建筑上至关重要的社会可持续性的途径,同时指出它与更为广义的可持续性相关。     

Comparative 3D simulation on water absorption and hygroscopic swelling in japonica rice grains under various isothermal soaking conditions

Cracking in rice grains caused by moisture absorption is a major concern among food processors because it has a detrimental effect on the texture. This paper aimed to simulate moisture diffusion three dimensionally (3D) using Fick's diffusion equation, compare the results with an empirical model (Peleg's equation), and simulate in 3D the hygroscopic swelling in rice during soaking at 25, 35, 45 and 55 °C. This study intends to provide preparatory information in understanding the cracking mechanism during soaking. The concept was based on finite element analysis to evaluate both the moisture diffusion and hygroscopic expansion coefficients of milled rice using the reconstructed 3D model of rice geometry. The proposed model was satisfactory for describing the moisture absorption kinetics with root mean square error (RMSE), that ranged from 0.66 to 2.52% dry basis. The results of the 3D simulation of hygroscopic swelling were found to be adequate in representing the swelling characteristics of rice. Analysis of 3D simulation enabled both quantitative and qualitative assessment of the changes in the amount, distribution of moisture, and expansion in the geometry of rice grains.     

Synergetic Exfoliation and Lateral Size Engineering of MoS2 for Enhanced Photocatalytic Hydrogen Generation

Generally, exfoliation is an efficient strategy to create more edge site so as to expose more active sites on molybdenum disulphide (MoS₂). However, the lateral sizes of the resultant MoS₂ monolayers are relatively large (≈50–500 nm), which retain great potential to release more active sites. To further enhance the catalytic performance of MoS₂, a facile cascade centrifugation‐assisted liquid phase exfoliation method is introduced here to fabricate monolayer enriched MoS₂ nanosheets with nanoscale lateral sizes. The as‐prepared MoS₂ revealed a high monolayer yield of 36% and small average lateral sizes ranging from 42 to 9 nm under gradient centrifugations, all exhibiting superior catalytic performances toward photocatalytic H₂ generation. Particularly, the optimized monolayer MoS₂ with an average lateral size of 9 nm achieves an apparent quantum efficiency as high as 77.2% on cadmium sulphide at 420 nm. This work demonstrates that the catalytic performances of MoS₂ could be dramatically enhanced by synergistic exfoliation and lateral size engineering as a result of increased density of active sites and shortened charge diffusion distance, paving a new way for design and fabrication of transition‐metal dichalcogenides‐based materials in the application of hydrogen generation.     

Simulation of slow current transients and current compression in AlGaAs/GaAs HFETs

Two-dimensional transient simulations of AlGaAs/GaAs HFETs are performed in which substrate traps and surface states are considered. When the drain voltage is raised abruptly, the drain current overshoots the steady-state value, and when it is lowered abruptly, the drain current remains at a low value, showing drain-lag behavior. Turn-on characteristics are also calculated when both the gate voltage and the drain voltage are changed abruptly, and quasi-pulsed I-V curves are derived from them. It is shown that the drain lag due to substrate traps could become a cause of so-called current compression of the HFETs. It is also shown that gate lag due to surface states could become a major cause of the current compression.     

Carbon Nitride Loaded with an Ultrafine,Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO₃ and BaLa₄Ti₄O₁₅.     

Six Methodological Findings of a Chemical Engineering Scientist through a Lifelong Odyssey

The historical turning point we are now facing is the biggest since the Industrial Revolution. For sustainable social metabolic system development, a transformative change in industrial processes and systems as well as our lifestyles is required. A firm cornerstone for a constructive life, a clear perspective for science and technology, and open mindedness will help us to tackle the big issue of a transformative redesign of our society. Furthermore, for effective change from centralized to decentralized energy systems, it is necessary to empower regional communities. This article presents six features concerning the above issues that are methodologically valuable for researchers and engineers.     

Chemical engineering for the Anthropocene

The environmental and resource crises that confront human life on earth demand changes to the whole socio-economic metabolic system. The changes will affect all aspects of life, including the practice of chemical engineering. The historical association of the profession with the fossil carbon economy means that the expertise that makes up chemical engineering must be re-examined and repurposed urgently if the discipline is to play a full role in the socio-economic transition. In this article, we review the historical development of chemical engineering to identify its unique features and find ways in which it can change to meet the challenge. A pattern of 30-year cycles in the development of the discipline is revealed, showing the way it has built up by incorporating approaches from other disciplines and also developing a unique set of skills and knowledge. Chemical engineering as taught needs to prepare graduates to operate under the kind of social contract embodied in declarations by professional bodies. We propose ways in which the expertise comprising chemical engineering can be applied in the ‘just transition’ to a less unsustainable society, including new approaches to plant and process design and also applications ‘outside the pipe’ to environmental modelling and industrial ecology. The unsustainability crisis results from a history of poor public and private decisions, so examination of the different types of decisions is timely. Specific roles for chemical engineers in deliberative decision processes are identified, including enhanced emphasis on risk and precaution.