To solve the problems of high rebound rate and strength reversion of shotcrete,a non-fluorine and non-alkaline liquid flash setting admixture(FSN)with low rebound and high early strength was synthesized under 60-65℃w...To solve the problems of high rebound rate and strength reversion of shotcrete,a non-fluorine and non-alkaline liquid flash setting admixture(FSN)with low rebound and high early strength was synthesized under 60-65℃water bath environment through orthogonal test design and taking setting time and compressive strength as indicators.The experimental results show that the optimum mass ratio of FSN is aluminum sulfate:diethanolamine:triethanolamine:pseudo-boehmite:lithium carbonate:water=57%:8%:0.05%:2%:2%:31%.When FSN is added with 7%of the mass of portland cement,the cement paste can be initially set in 3 min and finally set in 5 min.The compressive strength of mortar is 1.2 MPa at 6 h,18.0 MPa at 1 d,and more than 100%at 28 days;The microscopic analysis shows that the rapid release of Li^(+),NH^(4+),and CO_(3)^(2-)ions by FSN in the paste solution effectively shortens the induction period of high C_(3)S content in Portland cement,directly forms early coagulation AFt crystals in FSN and CH dominated by Al_(2)(SO_(4))_(3),and forms a large number of C-S-H gels in the later stage,so that the cement can quickly coagulate and harden,and the strength in the later stage is not retracted.展开更多
On an early autumn afternoon, Wang Fuchun sits at his desk looking through a heavy picture album adorned with a dozen pale-green sticky notes. Titled The Chinese and Their Lives, it is another of Wang’s documentary p...On an early autumn afternoon, Wang Fuchun sits at his desk looking through a heavy picture album adorned with a dozen pale-green sticky notes. Titled The Chinese and Their Lives, it is another of Wang’s documentary photography albums almost ready for publication.展开更多
Upon arriving back in Urumqi after a 500-kilometer trek across Xinjiang from Hami,Wang Jiangjiang immediately began sorting the materials he collected on the trip:audio and video recordings from more than 30 Muqam art...Upon arriving back in Urumqi after a 500-kilometer trek across Xinjiang from Hami,Wang Jiangjiang immediately began sorting the materials he collected on the trip:audio and video recordings from more than 30 Muqam artists.He also created a spreadsheet to catalogue information about their lives and careers.展开更多
“Our joint nomination for the Ong Chun ceremony to be inscribed on UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity(ICH)has succeeded,”declared Gan Yong Hoe,president of the Baba Nyonya ...“Our joint nomination for the Ong Chun ceremony to be inscribed on UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity(ICH)has succeeded,”declared Gan Yong Hoe,president of the Baba Nyonya Association of Malaysia,after traveling from Malacca to Kuala Lumpur to join Dato’Sri Hajah Nancy Shukri,Minister of Tourism,Arts and Culture of Malaysia,at the 15th session of the UNESCO Intergovernmental Committee for the Safeguarding of the Intangible Cultural Heritage via video on December 17,2020.Gan excitedly sent video footage of the event to Chen Geng,former president of the Xiamen Minnan Culture Research Association,an old friend who became an important participant in the joint effort after learning about the ceremony from Gan.展开更多
Long after the lights have gone out in dormitories of Peking University,it’s not uncommon to find Wang Yipeng still at her desk sending pictures to journalists to cover the 11th China-ASEAN Youth Camp and 4th China-A...Long after the lights have gone out in dormitories of Peking University,it’s not uncommon to find Wang Yipeng still at her desk sending pictures to journalists to cover the 11th China-ASEAN Youth Camp and 4th China-ASEAN Youth Summit.As the event approaches,it has become normal for her to stay up late.“During preparations,my colleagues in the organizing committee are all very busy because we want to make sure that everything is ready for the summit,”Wang grins in the autumn sunshine.“My job is media relations for the event.”A student in the Department of Southeast Asian Studies,School of Foreign Languages at Peking University,Wang has never previously participated in a China-ASEAN Youth Summit,and her studies are far from journalism or communication.However,Wang has handled the intimidating job as director of public relations well so far.Knowing that her performance exerts a direct influence on the process and public image of the summit,she pursues excellence in every detail of her work.展开更多
基金Funded by the National Key Research and Development Program of China(No.2021YFB2601200)the Natural Science Foundations of Hebei Province(No.E2022210103)。
文摘To solve the problems of high rebound rate and strength reversion of shotcrete,a non-fluorine and non-alkaline liquid flash setting admixture(FSN)with low rebound and high early strength was synthesized under 60-65℃water bath environment through orthogonal test design and taking setting time and compressive strength as indicators.The experimental results show that the optimum mass ratio of FSN is aluminum sulfate:diethanolamine:triethanolamine:pseudo-boehmite:lithium carbonate:water=57%:8%:0.05%:2%:2%:31%.When FSN is added with 7%of the mass of portland cement,the cement paste can be initially set in 3 min and finally set in 5 min.The compressive strength of mortar is 1.2 MPa at 6 h,18.0 MPa at 1 d,and more than 100%at 28 days;The microscopic analysis shows that the rapid release of Li^(+),NH^(4+),and CO_(3)^(2-)ions by FSN in the paste solution effectively shortens the induction period of high C_(3)S content in Portland cement,directly forms early coagulation AFt crystals in FSN and CH dominated by Al_(2)(SO_(4))_(3),and forms a large number of C-S-H gels in the later stage,so that the cement can quickly coagulate and harden,and the strength in the later stage is not retracted.
文摘On an early autumn afternoon, Wang Fuchun sits at his desk looking through a heavy picture album adorned with a dozen pale-green sticky notes. Titled The Chinese and Their Lives, it is another of Wang’s documentary photography albums almost ready for publication.
文摘Upon arriving back in Urumqi after a 500-kilometer trek across Xinjiang from Hami,Wang Jiangjiang immediately began sorting the materials he collected on the trip:audio and video recordings from more than 30 Muqam artists.He also created a spreadsheet to catalogue information about their lives and careers.
文摘“Our joint nomination for the Ong Chun ceremony to be inscribed on UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity(ICH)has succeeded,”declared Gan Yong Hoe,president of the Baba Nyonya Association of Malaysia,after traveling from Malacca to Kuala Lumpur to join Dato’Sri Hajah Nancy Shukri,Minister of Tourism,Arts and Culture of Malaysia,at the 15th session of the UNESCO Intergovernmental Committee for the Safeguarding of the Intangible Cultural Heritage via video on December 17,2020.Gan excitedly sent video footage of the event to Chen Geng,former president of the Xiamen Minnan Culture Research Association,an old friend who became an important participant in the joint effort after learning about the ceremony from Gan.
文摘Long after the lights have gone out in dormitories of Peking University,it’s not uncommon to find Wang Yipeng still at her desk sending pictures to journalists to cover the 11th China-ASEAN Youth Camp and 4th China-ASEAN Youth Summit.As the event approaches,it has become normal for her to stay up late.“During preparations,my colleagues in the organizing committee are all very busy because we want to make sure that everything is ready for the summit,”Wang grins in the autumn sunshine.“My job is media relations for the event.”A student in the Department of Southeast Asian Studies,School of Foreign Languages at Peking University,Wang has never previously participated in a China-ASEAN Youth Summit,and her studies are far from journalism or communication.However,Wang has handled the intimidating job as director of public relations well so far.Knowing that her performance exerts a direct influence on the process and public image of the summit,she pursues excellence in every detail of her work.
