Possible recipe for building a ＂football＂ with boron

If you look carefully at a football, you will notice that its surface is composed of hexagons andpentagons. Hexagons lie side by side while any pentagon is surrounded by five hexagons. How many corners and edges are there？ Football players do not have to know that as long asthey do pass and shoot right; an architect or structural physicist, however, could readily give the answer.     

A powder method for the high-efficacy evaluation of electro-optic crystals

The electro-optic crystal holds great promise for extensive applications in optoelectronics and optical communication. However, the discovery of novel electro-optic crystals is sporadic due to the difficulties of large-sized crystal growth for electro-optic coefficient measurement. Herein, to address this issue, a high-efficacy evaluation method using accessible powder samples is proposed in which the second-harmonic-generation effect, infrared reflectance spectrum and Raman spectrum are introduced to predict the magnitude of the electro-optic coefficient. The calculated electro-optic coefficients of numerous reported electro-optic crystals through this approach give universal agreement to the experimental values, evidencing the validity of the strategy. Based on this method, CsLiMoO₄ is screened as a novel potential electro-optic crystal and a high-quality crystal is grown by the Czochralski technique for electro-optic coefficient measurement using the half-wave voltage method, the result of which is also comparable to the calculated value. Consequently, the evaluation strategy presented here will pave a new way to explore promising electro-optic crystals efficiently.     

一种添加剂改性氯化亚锡晶体的研究

为了满足工业化制备高主成份氯化亚锡的需求,主成份大于等于99.50%的氯化亚锡产品。单纯提高氯化亚锡浓缩液Sn2＋,会造成在甩干过程中晶体结块,且硬度大,无法破碎包装的问题。文章介绍了添加一种添加剂分散氯化亚锡关联结晶,形成均匀、光泽度高的晶体的研究。     

A growing trend toward knowledge work in Canada

This paper answers three questions related to the growing trend toward knowledge occupations in Canada: (i) What was the magnitude of the trend between 1971 and 1996? (ii) Was the trend a widespread phenomenon or was it restricted to specific industries? (iii) What are the proximate causes of the trends? Using five censuses—1971, 1981, 1986, 1991, 1996—and the input/output (I/O) data, the paper provides evidence that the Canadian economy is becoming increasingly knowledge-based, although the upgrading trends differ across knowledge occupations. Moreover, we find that this phenomenon is spread across all industrial sectors. Finally, using a decomposition analysis borrowed from Wolff and Baumol, three factors—the substitution effect, the productivity-lag effect and the demand effect—have been examined in order to shed some light on these trends. We find that these effects vary according to the nature of the knowledge involved in these different groups of occupations, thus reflecting not only the importance of the technological change ‘skill bias’ but also the increasing complexity of controlling and managing the new economic activities.     

林芝福建公园冷季型草坪的建植管理技术

近几年，西藏林芝开始草坪的试种工作。在林芝地区福建公园草坪建植过程中，重视和加强建植技术和苗期管理，是取得成功的关键性因素。     

Investigating and predicting online food recipe upload behavior

Studying online food behavior has recently become an active field of research. While there is a growing body of studies that investigate, for example, how online recipes are consumed, in the form of views or ratings, little effort has been devoted yet to understand how they are created. In order to contribute to this lack of knowledge in the area, we present in this paper the results of a large-scale study of nearly 200k users posting over 400k recipes in the online recipe platform Kochbar.de. The main objective of this study is (i) to reveal to what extent recipe upload patterns can be explained by socio-demographic features and (ii) to what extent they can be predicted. To do so, we investigate the utility of several features such as user history, social connections of the users, temporal aspects as well as geographic embedding of the users. Statistical analysis confirms that recipe uploads can be explained by socio-demographic features. Extensive simulations show that among all features investigated, the social signal, in the form of friendship connections to other users, appears to be the strongest one and henceforth is the best to predict what type of recipe will be uploaded and what ingredients will be used in the future. The research conducted in this work contributes to a better understanding in online food behavior and is relevant for researchers working on online social information systems and engineers interested in predictive modeling and recommender systems.     

中小型高科技企业成长环境评价体系构建研究

本文在明确中小型高科技企业成长环境概念的基础上,重新审视其成长环境构成要素并对其进行划分,从八个子环境遴选评价指标组成我国中小型高科技企业成长环境理论评价体系。并运用隶属度分析、相关性分析、鉴别力分析和反馈检验等方法对理论指标进行实证筛选,构建了一个由直接环境与间接环境相耦合而成的中小型高科技企业成长环境评价体系。     

Understanding and predicting cross-cultural food preferences with online recipe images

Predicting food preferences is challenging due to the numerous factors that can influence individual taste. Cultural influences are one such factor that can significantly impact food preferences. Irrespective of culture, however, food visual aesthetics drive food choice. With this in mind, we study 15,000 images of food from prominent recipe portals in China, the US and Germany with the aim of identifying common visual trends related to food choice. We report that distinguishing between appreciated and less appreciated recipes based on visual features through multiple machine learning experiments is possible, with a maximum accuracy of 67%. The classifiers trained on one culture, when applied to other cultures, reveal that appreciated recipes from US and German portals share visual similarities, while the visual aspects making recipes attractive for Chinese users differ. Complementing our machine learning experiments, we conducted a user study with 450 participants from the three cultures. Participants are asked to rank recipes based on their appeal and provide justification through answering 19 questions. The results reveal significant predictors of preference, including perceived appearance and taste across all countries, and negative perception of perceived healthiness for US and German participants. Analysis of 77 consistently labelled appealing/non-appealing images reveal significant variations in low-level visual features such as colourfulness, sharpness, and contrast. These findings suggest that these low-level visual features may play a critical role in determining whether an image is perceived as appealing or not across different cultures. Our results offer promising insights into the development of cross-culture food recommender systems. By demonstrating common ground across food cultures, we believe that these systems can provide personalised meal suggestions that reflect user’s preferences while incorporating ideals such as healthfulness and sustainability.     

实现中部崛起的人才战略研究

人才对于中部崛起具有非常重要的战略意义,根据中部六省人才的统计资料,对人才的现状及存在问题进行分析研究,并提出了解决问题的对策和措施。     

企业家人力资本成长环境分析

经济的发展在很大程度上取决于企业的发展状况,而企业的发展必然与企业家的经营管理密不可分。企业家的健康成长需要根治于良好的环境,良好的文化环境、舆论环境、体制环境等对企业家的培育和成长具有重要的现实意义。     

American postdoctoral salaries do not account for growing disparities in cost of living

The National Institute of Health (NIH) sets postdoctoral (postdoc) trainee stipend levels that many American institutions and investigators use as a basis for postdoc salaries. Although salary standards are held constant across universities, the cost of living in those universities’ cities and towns vary widely. Across non-postdoc jobs, more expensive cities pay workers higher wages that scale with an increased cost of living. This work investigates the extent to which postdoc wages account for cost of living differences. More than 27,000 postdoc salaries across all US universities are analyzed alongside measures of regional differences in cost of living. We find that postdoc salaries do not account for cost of living differences, in contrast with the broader labor market in the same cities and towns. Despite a modest increase in income in high cost of living areas, real (cost of living adjusted) postdoc salaries differ by 29% ($15k 2021 USD) between the least and most expensive areas. Cities that produce greater numbers of tenure-track faculty relative to students such as Boston, New York, and San Francisco are among the most impacted by this pay disparity. The postdoc pay gap is growing and is well-positioned to incur a greater financial burden on economically disadvantaged groups and contribute to faculty hiring disparities in women and racial minorities.