High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is...High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.展开更多
Coordination between the sporophytic tissue and the gametic pollen within anthers is tightly controlled to achieve the optimal pollen fitness. Glucose-6-phosphate/phosphate translocator(GPT) transports glucose-6-phosp...Coordination between the sporophytic tissue and the gametic pollen within anthers is tightly controlled to achieve the optimal pollen fitness. Glucose-6-phosphate/phosphate translocator(GPT) transports glucose-6-phosphate, a key precursor of starch and/or fatty acid biosynthesis, into plastids. Here, we report the functional characterization of Os GPT1 in the rice anther development and pollen fertility. Pollen grains from homozygous osgpt1 mutant plants fail to accumulate starch granules, resulting in pollen sterility. Genetic analyses reveal a sporophytic effect for this mutation. Os GPT1 is highly expressed in the tapetal layer of rice anther. Degeneration of the tapetum, an important process to provide cellular contents to support pollen development, is impeded in osgpt1 plants. In addition, defective intine and exine are observed in the pollen from osgpt1 plants. Expression levels of multiple genes that are important to tapetum degeneration or pollen wall formation are significantly decreased in osgpt1 anthers. Previously, we reported that At GPT1 plays a gametic function in the accumulation of lipid bodies in Arabidopsis pollen. This report highlights a sporophytic role of Os GPT1 in the tapetum degeneration and pollen development. The divergent functions of Os GPT1 and At GPT1 in pollen development might be a result of their independent evolution after monocots and dicots diverged.展开更多
This study presents comparisons regarding current elementary foreign language programs in China and the USA.The design features a comparative analysis approach combined with deductive thematic analysis to collect,anal...This study presents comparisons regarding current elementary foreign language programs in China and the USA.The design features a comparative analysis approach combined with deductive thematic analysis to collect,analyze,and compare relevant data.Data were collected from samples such as governmental documents,organizational guidelines,national statistical reports,published scholarly works,audiovisual materials,and textbooks.Preceding the research,primary categories were identified,used to group data,and then look for similarities and differences.Categories for comparison were:(a)program types,(b)curriculum standards,(c)instructional methods,and(d)assessments.Results indicated US programs could benefit from consistency,widespread support and demand,state-to-state organization and/or alignment,equitable teaching materials,and attention to all student populations.China's program,while organized,could benefit from more authentic,real-life-context,other-culture-oriented practices,flexibility,and deeper,genuine information about English-speaking countries’cultures.This research contributes to scholarly conversations regarding comparisons of elementary foreign language teaching in China and the USA,while also supporting worldwide comparisons and exchange of ideas.展开更多
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2682023CX019National Natural Science Foundation of China under Grant U23B6007 and Grant 52307141Sichuan Science and Technology Program under Grant 2024NSFSC0115。
文摘High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.
基金supported by the grants from National Natural Science Foundation of China (31922005)Zhejiang Provincial Natural Science Foundation of China (LR18C020001)+2 种基金Zhejiang University K.P.Chao’s High Technology Development Foundation (2018RC016)the Young Elite Scientist Sponsorship Program by CAST (2018QNRC001)111 Project (B14027) to J.X。
文摘Coordination between the sporophytic tissue and the gametic pollen within anthers is tightly controlled to achieve the optimal pollen fitness. Glucose-6-phosphate/phosphate translocator(GPT) transports glucose-6-phosphate, a key precursor of starch and/or fatty acid biosynthesis, into plastids. Here, we report the functional characterization of Os GPT1 in the rice anther development and pollen fertility. Pollen grains from homozygous osgpt1 mutant plants fail to accumulate starch granules, resulting in pollen sterility. Genetic analyses reveal a sporophytic effect for this mutation. Os GPT1 is highly expressed in the tapetal layer of rice anther. Degeneration of the tapetum, an important process to provide cellular contents to support pollen development, is impeded in osgpt1 plants. In addition, defective intine and exine are observed in the pollen from osgpt1 plants. Expression levels of multiple genes that are important to tapetum degeneration or pollen wall formation are significantly decreased in osgpt1 anthers. Previously, we reported that At GPT1 plays a gametic function in the accumulation of lipid bodies in Arabidopsis pollen. This report highlights a sporophytic role of Os GPT1 in the tapetum degeneration and pollen development. The divergent functions of Os GPT1 and At GPT1 in pollen development might be a result of their independent evolution after monocots and dicots diverged.
文摘This study presents comparisons regarding current elementary foreign language programs in China and the USA.The design features a comparative analysis approach combined with deductive thematic analysis to collect,analyze,and compare relevant data.Data were collected from samples such as governmental documents,organizational guidelines,national statistical reports,published scholarly works,audiovisual materials,and textbooks.Preceding the research,primary categories were identified,used to group data,and then look for similarities and differences.Categories for comparison were:(a)program types,(b)curriculum standards,(c)instructional methods,and(d)assessments.Results indicated US programs could benefit from consistency,widespread support and demand,state-to-state organization and/or alignment,equitable teaching materials,and attention to all student populations.China's program,while organized,could benefit from more authentic,real-life-context,other-culture-oriented practices,flexibility,and deeper,genuine information about English-speaking countries’cultures.This research contributes to scholarly conversations regarding comparisons of elementary foreign language teaching in China and the USA,while also supporting worldwide comparisons and exchange of ideas.
