For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions.Much attention has been paid to gC_(3)N_(4)as a...For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions.Much attention has been paid to gC_(3)N_(4)as a promising photocatalyst for the generation of hydrogen.To improve the separation of photogenerated charge,porous nanosheet g-C_(3)N_(4)was modified with Pt nanoclusters(Pt/g-C_(3)N_(4))through impregnation and following photo-induced reduction.This catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)N_(4).The strong interactions of Pt-N in Pt/g-C_(3)N_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes effectively.In addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into H_(2)and CO_(2)via formaldehyde and formate.This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.展开更多
Test anxiety, which means individuals show excessive worry, nervousness and anxiety in examination contexts, is becoming a more and more common phenomenon. A moderate level of test anxiety will motivate students while...Test anxiety, which means individuals show excessive worry, nervousness and anxiety in examination contexts, is becoming a more and more common phenomenon. A moderate level of test anxiety will motivate students while a too high or too low level of test anxiety will influence students’ academic performance and their cognitive abilities. Most present researches are focused on secondary school students or on the final exam of a specific school. Few researches on college students and standard tests can be found. Therefore, the researcher took 255 college students as samples to investigate the test anxiety level of non-English majors, their attitudes towards different test tasks (ATDTT) and the correlation between them. The results of the research are as follows: Firstly, the students from non-English majors are at the lower of a moderate test anxiety level in CET-4 and there is no significant gender difference. Secondly, among the four sections in CET-4, students are most positive in writing, less positive in translation and reading, and the least positive in listening. Thirdly, students’ ATDTT in CET-4 are negatively correlated with total test anxiety, cognitive anxiety and emotional anxiety. The researcher hopes this research can offer some help to teachers and students in need.展开更多
This research made a comprehensive comparison on the listening test of the new CET-4 with the old one. Besides, by applying the schema theory, it also provides a series of new teaching methods which can be used to imp...This research made a comprehensive comparison on the listening test of the new CET-4 with the old one. Besides, by applying the schema theory, it also provides a series of new teaching methods which can be used to improve the quality of the college English listening courses' teaching and help students solve the problem in the news report section of the new CET-4.展开更多
基金supported by the National Natural Science Foundation of China(51672081)the Program of Tri-three Talents Project of Hebei Province(China,A202110002)+1 种基金the Young Top Talents Fund Program of Higher Education Institutions of Heibei Province(BJ2020009)the Project of Science and Technology Innovation Team,Tangshan(20130203D)。
文摘For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions.Much attention has been paid to gC_(3)N_(4)as a promising photocatalyst for the generation of hydrogen.To improve the separation of photogenerated charge,porous nanosheet g-C_(3)N_(4)was modified with Pt nanoclusters(Pt/g-C_(3)N_(4))through impregnation and following photo-induced reduction.This catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)N_(4).The strong interactions of Pt-N in Pt/g-C_(3)N_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes effectively.In addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into H_(2)and CO_(2)via formaldehyde and formate.This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.
文摘Test anxiety, which means individuals show excessive worry, nervousness and anxiety in examination contexts, is becoming a more and more common phenomenon. A moderate level of test anxiety will motivate students while a too high or too low level of test anxiety will influence students’ academic performance and their cognitive abilities. Most present researches are focused on secondary school students or on the final exam of a specific school. Few researches on college students and standard tests can be found. Therefore, the researcher took 255 college students as samples to investigate the test anxiety level of non-English majors, their attitudes towards different test tasks (ATDTT) and the correlation between them. The results of the research are as follows: Firstly, the students from non-English majors are at the lower of a moderate test anxiety level in CET-4 and there is no significant gender difference. Secondly, among the four sections in CET-4, students are most positive in writing, less positive in translation and reading, and the least positive in listening. Thirdly, students’ ATDTT in CET-4 are negatively correlated with total test anxiety, cognitive anxiety and emotional anxiety. The researcher hopes this research can offer some help to teachers and students in need.
文摘This research made a comprehensive comparison on the listening test of the new CET-4 with the old one. Besides, by applying the schema theory, it also provides a series of new teaching methods which can be used to improve the quality of the college English listening courses' teaching and help students solve the problem in the news report section of the new CET-4.
