Spatial patterns of residents’ daily activity space and its influencing factors based on the CatBoost model: A case study of Nanjing, China

The complexity and fragmentation of people’s activity space are challenging to planners.However,the relevant studies are mostly concerned on the relationship between the social attributes and the activity space of residents in a single or several communities,or the spatiotemporal laws of activity space on a macro scale.The research on the spatial characteristics of residents’activity space still needs to be strengthened.The present study analyses the spatial patterns of residents’activity space based on mobile phone signaling data to fill the gap of previous studies that assessed residents’activity space across small geographic areas.First,according to the spatial scope and direction of an activity space and residents’activity coverage rate,spatial patterns can be divided into three types:compact,extended,and directional extension patterns.The CatBoost method is then used to statistically analyze the influencing variables of spatial patterns,and the order of importance of the following influencing factors is determined:the built environment is more influential than social and economic situations.This study aims to strengthen the understanding of residents’activity space at the spatial level and provide a basis for the optimization of communities with different spatial patterns.

Space Materials Science in China:Ⅱ.Ground-based Researches and Academic Activities

Activities of space materials science research in China have been continuously supported by two main national programs.One is the China Space Station(CSS)program since 1992,and the other is the Strategic Priority Program(SPP)on Space Science since 2011.In CSS plan in 2019,eleven space materials science experimental projects were officially approved for execution during the construction of the space station.In the SPP Phase Ⅱ launched in 2018,seven pre-research projects are deployed as the first batch in 2018,and one concept study project in 2019.These pre-research projects will be cultivated as candidates for future selection as space experiment projects on the recovery of scientific experimental satellites in the future.A new apparatus of electrostatic levitation system for ground-based research of space materials science and rapid solidification research has been developed under the support of the National Natural Science Foundation of China.In order to promote domestic academic activities and to enhance the advancement of space materials science in China,the Space Materials Science and Technology Division belong to the Chinese Materials Research Society was established in 2019.We also organized scientists to write five review papers on space materials science as a special topic published in the journal Scientia Sinica to provide valuable scientific and technical references for Chinese researchers.

Research on Thermal Comfort of Outdoor Space in Summer Urban Park: Take Mianyang Urban Park as an Example

One of the factors for the evaluation of the space environment is the comfort of outdoor activities spaces in urban parks. The space composed of different landscape elements has different microclimate environment. In this paper, in order to evaluate the role of thermal comfort in influencing resident’s assessment of the outdoor space and activities of the park, a thermal comfort survey was conducted on the outdoor open space of Mianyang Urban Park in summer. In this article, meteorological surveys, questionnaire surveys and observation of park attendance are selected to collect data. The physiological equivalent temperature (PET) assessment was selected as the index to evaluate resident’s thermal comfort level, and the comprehensive evaluation and analysis of the spatial thermal environment of different outdoor landscape elements in the park. The overall comfort of current visitors is mainly influenced by their subjective heat perception voting (TSV). In this article, we focus on providing microclimate adjustment considerations for urban park landscape design, and may help people understand the outdoor thermal comfort of Mianyang in summer, increase the using time of outdoor activities, and promote the use of outdoor space.

China Issues White Paper on Space Activities

The Information Office of the State Council published a white paper on China’s space activities in 2016 on December27,2016,setting out China’s vision as a space power for the first time.'China’s Space Activities in 2016'is the fourth white paper on China’s space activities issued by the State Council Information Office.It contains five chapters except Preamble and Conclusion,including Purposes,Vision and Principles of Devel-

Actively Promoting Regional Space Cooperation——Vice Administrator, Loan Enjie headed a delegation to attend the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications

A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications held at Islamabad, the Capital of Pakistan from April 22 to 26, 1995. Following the First AsiaPacific Workshop held in Beijing in December, 1992, and the First Asia-Pacific Conference on Multilateral Cooperation in

A RESEARCH ON URBAN RECREATIONISTS' TRAVELING BEHAVIORS IN SHANGHAI

Urban recreationists consist of those who have used urban recreational facilities, no matter they are local residents or nonlocals. Traveling models will exert impacts not only on the use of urban recreational facilities but also on the development and management of recreational resources. Taking Shanghai as a sample of destinaton and origin of urban recreationists, the author did his study based on data from comprehensive travel measurement and users' survey, including field questionnaire survey, mailing questionnaire survey, home survey, and cordon monitonng. To analyze traveing models of urban recreationists in Shanghai, the author used techniques of Recreational Activity Space (RAS) and the Use Curve (UC) Analysis. Rogarding Shanghai as an origin, the author first discussed types and characteristics of the RASs which are presented by isotourist lines in the proper and outskirts of Shanghai, the Yangtze Delta and the China's Mainland respectively. These RASs reflect the trave directional bias of Shanghainese. Then the author regarded Shanghai as a deshnahon and analyzed the RASs of tounsts from Otier provinces, which demonstrated the attractiveness of and distance decay of Shanghai. He found that a U-shaped UC model existed in the distance decay under the influence of attractiveness and distance. Finally, the author suggested, that the availability, periodicity and attractiveness, besides distance, are the basic mechanisms that affect the urban recreationists' traveling models in a city such as Shanghai.

我国太空活动现代化治理中的若干重大问题

太空活动治理现代化是国家治理现代化的战略支撑,是国家参与全球治理的重要手段,更是实现航天强国目标的基本保障.太空活动治理体系分为制度、协调、全球和技术手段等4个方面.太空活动现代化治理就是在制度、协调、全球和技术手段等几个方面,改革不适应新时代发展的体制机制障碍、法律法规及技术短板,实现太空活动治理系统化、制度化、法治化、科学化.

Electronic States of Some Semiconductor Clusters

Potential surfaces and equilibrium geometries of InAs 2, In 2As, InAs 2 + and In 2As + were studied using the complete active space multi configuration self consistent field (CASMCSCF) technique. Two electronic states, namely 2B 2 and 2B 1, were found to prevail as the ground states for the InAs 2 and In 2As trimers, respectively. The corresponding adiabatic ionization energies were computed and the leading configurations of the ground states were analyzed according to the wavefunctions.

Ethynyl Substitution Effect on the Electronic Excitation Spectra of Aniline

We made an extended study on the structure and properties of the low-lying electronic states of ethynyl substituted aniline and their cations. We performed these calculations using density functional theory method（B3LYP and CAM-B3LYP DFT） and the complete active space self-consistent field（CASSCF） approach in connection with the aug-cc-pVZ Dunning＇s basis sets and concerted ANO-L-VDZP basis sets. Our results included their equilibrium geometries, the vertical excitation spectra and the vertical and adiabatic ionization energies. The effect of ethynyl substitution on the electronic structure and the spectroscopy of aniline was probed.