传统套装软件(shrink-wrap software,SWS)和软件即服务(software as a service,SaaS)是两种常见的软件交付模式,SWS交付模式下软件可在通用基础上二次开发并部署安装在用户本地服务器上,SaaS交付模式下软件提供商通过互联网将软件应用...传统套装软件(shrink-wrap software,SWS)和软件即服务(software as a service,SaaS)是两种常见的软件交付模式,SWS交付模式下软件可在通用基础上二次开发并部署安装在用户本地服务器上,SaaS交付模式下软件提供商通过互联网将软件应用程序交付给远程的企业用户。本文考虑一个由两家软件提供商和企业用户构成的市场,每个软件提供商都可以选择采用SWS或者SaaS模式向市场提供软件产品,分别研究不考虑软件质量提升(短期视角下)和考虑软件质量提升(长期视角下)时软件提供商的交付模式选择。研究发现,无论在短期视角下还是长期视角下,企业用户需求越统一、SWS模式二次开发成本越高时,提供商越倾向于选择SaaS模式。在长期视角下,当质量提升成本系数适中或较高时,可形成一家提供商独占市场类型均衡或两家提供商都获得正利润的均衡。最后,我们分析了质量提升对提供商、顾客和社会福利的影响。质量提升在大部分参数范围内损害提供商的利润,对顾客和社会福利有利。展开更多
Mg2Sn04 exhibits green photoluminescence and persistent luminescence, which originate from oxygen vacancies. When Ti4＋ ions were doped, an interesting Mg2SnO4：Ti4＋ phosphor with bluish white photoluminescence under...Mg2Sn04 exhibits green photoluminescence and persistent luminescence, which originate from oxygen vacancies. When Ti4＋ ions were doped, an interesting Mg2SnO4：Ti4＋ phosphor with bluish white photoluminescence under ultraviolet irradiation and with green persistent luminescence was first obtained. Our investigation reveals that two emission centres exist in Mg2SnO4：Ti4＋. The centres responsible for the green emission are considered to be the F centres （oxygen vacancies） and the blue centres are the TiO6 complex. Trap clusters in the band gap with different [Snmg-oi],[snmg-VO], [SnMg-VO ] and mgsn,correspond to the components at 85 °C, 146 213 °C of the thermoluminescence curve.展开更多
We report the first observation of up-conversion photostimulated luminescence in non-doped Mg_(2)SnO_(4).Stimulated by 980 nm infrared laser(reading)after ultraviolet irradiation(writing),the phosphor shows photostimu...We report the first observation of up-conversion photostimulated luminescence in non-doped Mg_(2)SnO_(4).Stimulated by 980 nm infrared laser(reading)after ultraviolet irradiation(writing),the phosphor shows photostimulated emission band covering 470-550nm,which is due to the recombination of F centers with holes.After ceasing ultraviolet irradiation,the storage intensity would rapidly decrease to 59%of its original storage intensity in 2.5h and then would not degrade anymore.It is suggested that the Mg_(2)SnO_(4)has potential applications for optical storage.Accordingly,the possible photostimulated luminescence mechanisms of Mg_(2)SnO_(4)are proposed.展开更多
文摘传统套装软件(shrink-wrap software,SWS)和软件即服务(software as a service,SaaS)是两种常见的软件交付模式,SWS交付模式下软件可在通用基础上二次开发并部署安装在用户本地服务器上,SaaS交付模式下软件提供商通过互联网将软件应用程序交付给远程的企业用户。本文考虑一个由两家软件提供商和企业用户构成的市场,每个软件提供商都可以选择采用SWS或者SaaS模式向市场提供软件产品,分别研究不考虑软件质量提升(短期视角下)和考虑软件质量提升(长期视角下)时软件提供商的交付模式选择。研究发现,无论在短期视角下还是长期视角下,企业用户需求越统一、SWS模式二次开发成本越高时,提供商越倾向于选择SaaS模式。在长期视角下,当质量提升成本系数适中或较高时,可形成一家提供商独占市场类型均衡或两家提供商都获得正利润的均衡。最后,我们分析了质量提升对提供商、顾客和社会福利的影响。质量提升在大部分参数范围内损害提供商的利润,对顾客和社会福利有利。
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 502041032)the Fundamental Research Funds for the Central Universities, China (Grant No. lzujbky-2011-125)the National Innovation Experiment Program for University Students, China (Grant No. 101073005)
文摘Mg2Sn04 exhibits green photoluminescence and persistent luminescence, which originate from oxygen vacancies. When Ti4＋ ions were doped, an interesting Mg2SnO4：Ti4＋ phosphor with bluish white photoluminescence under ultraviolet irradiation and with green persistent luminescence was first obtained. Our investigation reveals that two emission centres exist in Mg2SnO4：Ti4＋. The centres responsible for the green emission are considered to be the F centres （oxygen vacancies） and the blue centres are the TiO6 complex. Trap clusters in the band gap with different [Snmg-oi],[snmg-VO], [SnMg-VO ] and mgsn,correspond to the components at 85 °C, 146 213 °C of the thermoluminescence curve.
基金Supported by the National Natural Science Young Foundation of China(502041032)the Innovation and Entrepreneurship Foundation of Lanzhou University.
文摘We report the first observation of up-conversion photostimulated luminescence in non-doped Mg_(2)SnO_(4).Stimulated by 980 nm infrared laser(reading)after ultraviolet irradiation(writing),the phosphor shows photostimulated emission band covering 470-550nm,which is due to the recombination of F centers with holes.After ceasing ultraviolet irradiation,the storage intensity would rapidly decrease to 59%of its original storage intensity in 2.5h and then would not degrade anymore.It is suggested that the Mg_(2)SnO_(4)has potential applications for optical storage.Accordingly,the possible photostimulated luminescence mechanisms of Mg_(2)SnO_(4)are proposed.
