期刊文献+
共找到17篇文章
< 1 >
每页显示 20 50 100
The IDD Transcription Factors:Their Functions in Plant Development and Environmental Response
1
作者 Jing Liu Defeng Shu +5 位作者 Zilong Tan Mei Ma huanhuan yang Ning Guo Shipeng Li Dayong Cui 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第1期63-79,共17页
INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversi... INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversity of physiological processes and functions in plant growth and development,including floral transition,plant architecture,seed and root development,and hormone signaling.In this review,we especially summarized the latest knowledge on the functions and working models of IDD members in Arabidopsis,rice,and maize,particularly focusing on their role in the regulatory network of biotic and abiotic environmental responses,such as gravity,temperature,water,and pathogens.Understanding these mechanisms underlying the function of IDD proteins in these processes is important for improving crop yields by manipulating their activity.Overall,the review offers valuable insights into the functions and mechanisms of IDD proteins in plants,providing a foundation for further research and potential applications in agriculture. 展开更多
关键词 INDETERMINATE DOMAIN flowering time root development shoot gravitropism plant immunity hormonal signaling environmental responses
下载PDF
Research on Training Needs,Training Transfer,and Training Effectiveness of In-Service Teachers in Local Normal Colleges
2
作者 huanhuan yang 《Journal of Contemporary Educational Research》 2024年第5期254-257,共4页
This study aims to understand the in-service training needs,training transfer,and training effectiveness of teachers in local normal universities in China,while also proposing a continuous professional development pla... This study aims to understand the in-service training needs,training transfer,and training effectiveness of teachers in local normal universities in China,while also proposing a continuous professional development plan for teachers.Descriptive research methods were employed,with questionnaires serving as the primary data collection tool.The survey revealed that the educational background of teachers in local normal universities is characterized by an unreasonable distribution of academic qualifications,with a shortage of teachers holding postgraduate and higher degrees.Additionally,the training effectiveness for female teachers was found to be lower than that of male teachers.There is a lack of personalization in training needs,which tends to be more generalized.The transfer effect of training is moderate,and there is a need for further enhancement at the behavioral level of training effectiveness.A continuous professional development plan for teachers has been formulated to improve training effectiveness and promote professional development. 展开更多
关键词 Training needs Training transfer Training effectiveness Continuous professional development for teachers
下载PDF
铜基催化剂电催化高效还原CO_(2)制备C_(2+)产物的调控策略 被引量:2
3
作者 杨焕焕 李诗颖 许群 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第5期32-65,共34页
电催化CO_(2)还原,可利用太阳能、风能等可再生能源产生的清洁电能驱动CO_(2)在常温常压下绿色高效地转化为甲烷,甲醇、乙烯和乙醇等化学品.其中,多碳产物(C_(2+)产物)因能量密度大、附加值高而备受关注.Cu可以有效吸附中间体CO,促进C-... 电催化CO_(2)还原,可利用太阳能、风能等可再生能源产生的清洁电能驱动CO_(2)在常温常压下绿色高效地转化为甲烷,甲醇、乙烯和乙醇等化学品.其中,多碳产物(C_(2+)产物)因能量密度大、附加值高而备受关注.Cu可以有效吸附中间体CO,促进C-C键偶联,是目前公认的可以有效催化CO_(2)转化为C_(2+)还原产物的金属,但反应涉及多电子转移、质子耦合、路径复杂,加之水相体系中析氢副反应的影响,C_(2+)产物选择性差.本文以CO_(2)还原过程中的四个关键步骤为主线,综述了Cu基催化剂表面结构的改性策略,以提高CO_(2)还原制备C_(2+)产物性能,并深入分析了催化剂表面结构与性能之间的构效关系.(1)抑制析氢:通过有机层修饰及形貌调控对催化剂表面进行疏水改性,抑制H2O传输,同时促进CO_(2)扩散.(2)促进CO_(2)吸附活化:Cu与CO_(2)捕获材料复合,可以有效促进CO_(2)吸附;卤素离子可以提供孤对电子给CO_(2),形成X-C键(X=F^(-),Cl^(-),Br^(-),I^(-)),促进CO_(2)的吸附及活化.(3)调控CO中间体的生成及吸附性能:Cu与CO高选择性催化剂复合构建双功能串联催化剂,可以有效提高催化剂表面CO浓度及覆盖度;催化剂表面增强的局部热-电场效应可促进CO中间体的吸附及耦合;线性吸附的CO和桥式吸附的CO共存,以及低频线性吸附的CO可以有效进行耦合,促进C_(2+)产物生成.(4)促进C-C耦合成键:C-C耦合是生成C_(2+)产物最关键的一步,限域形貌结构,可以有效提高中间产物在催化剂表面的浓度及保留时间,提高C-C耦合几率;氧化物衍生铜、杂原子掺杂和有机分子修饰等可以调控催化剂表面铜物种价态,Cu^(δ+)和Cu^(0)协同,可以促进CO_(2)活化,增强CO中间体吸附,降低C-C耦合能垒;空位、晶界和台阶等缺陷可以改变C1中间体在催化剂表面的吸附性能,降低C-C耦合能垒;Cu单原子催化剂较高的原子利用率以及Cu原子与配位原子协同可有效促进C-C耦合,调节单一C_(2+)产物选择性;异质界面可以改变本征电导率,提高电荷转移速率,调节催化剂表面电子结构,进一步调控对中间体的吸附,促进C-C耦合几率.催化剂表面结构重组、化学态变化、积碳、Fe/Ni等杂质沉积和微量有机杂质吸附等会影响催化反应稳定性.构建Cu-载体相互作用及限域结构,引入缺陷位点、原子掺杂、有机分子修饰和纯化电解质溶液等方法可以有效缓解催化剂失活.此外,本文指出了CO_(2)还原制C_(2+)产物领域未来潜在的研究方向:(1)开发时间及空间分辨的原位谱学技术,结合理论计算研究催化剂的动态变化及中间体的演变过程,揭示催化反应机理,为实现单一C_(2+)产物高选择性,设计高效率及高稳定性催化剂提供理论指导;(2)深入认识催化反应失活机理,设计新型催化剂及反应器,提高整个体系反应稳定性;(3)关注阳极反应,尝试新的氧化反应替代能耗较高的析氧反应;、设计高稳定的阳极反应催化剂;开发化学及机械稳定的离子交换膜,减少CO_(2)向阳极的扩散,提高整体反应能效及经济性等. 展开更多
关键词 铜基催化剂 二氧化碳电还原 表面工程 C_(2+)产物 改性策略
下载PDF
Understanding the mechanisms of resistance to tomato leaf mold:A review 被引量:7
4
作者 Tingting Zhao Tong Pei +4 位作者 Jingbin Jiang huanhuan yang He Zhang Jingfu Li Xiangyang Xu 《Horticultural Plant Journal》 SCIE CAS CSCD 2022年第6期667-675,共9页
Tomato leaf mold is a common disease in tomato production and severely impacts the growth,fruit quality and yield of tomato plants.Research on tomato leaf mold has a long history and has focused mainly on the differen... Tomato leaf mold is a common disease in tomato production and severely impacts the growth,fruit quality and yield of tomato plants.Research on tomato leaf mold has a long history and has focused mainly on the differentiation of pathogen races,the structure and function of pathogen Avr gene products,the cloning of Cf resistance genes and the analysis of disease resistance mechanisms.Interactions between Cf and Avr are in accordance with the"gene-for-gene"hypothesis and typical Cf/Avr interactions are part of effector-triggered immunity(ETI).However,an increasing number of studies have proven that pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)is involved in the disease resistance response system mediated by Cf genes.In addition,different Cf genes have both similar and different roles in the disease resistance response,indicating that the disease resistance mechanism of Cf genes is complex.In this paper,progress in tomato leaf mold research was reviewed,and the regulatory mechanism underlying the Cf-mediated disease resistance response was thoroughly explored.We hope this summary will lay a foundation for research on tomato leaf mold disease resistance mechanisms and is applicable to breeding for disease resistance. 展开更多
关键词 Tomato leaf mold Cf genes Disease resistance Cf/Avr interactions
下载PDF
Virus-induced gene silencing of SlPYL4 decreases the drought tolerance of tomato 被引量:4
5
作者 Yue Li Xiaochun Zhang +4 位作者 Jingbin Jiang Tingting Zhao Xiangyang Xu huanhuan yang Jingfu Li 《Horticultural Plant Journal》 SCIE CSCD 2022年第3期361-368,共8页
The abscisic acid(ABA)receptor PYR/PYL/RCAR,located upstream of the ABA signaling pathway,recognizes ABA signals and initiates the primary process of signal transduction.In our previous study,we found that the PYL4 ge... The abscisic acid(ABA)receptor PYR/PYL/RCAR,located upstream of the ABA signaling pathway,recognizes ABA signals and initiates the primary process of signal transduction.In our previous study,we found that the PYL4 gene in tomato plants was significantly upregulated after exogenous treatment with the hormone ABA.The present study used virus-induced gene silencing(VIGS)to further elucidate the role of the PYL4 gene in response to drought in tomato(Solanum lycopersicum)plants.Under the drought treatment,the SlPYL4-silenced plants wilted faster than the control plants did.Physiological indicators showed that the total reactive oxygen species(ROS)content and superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)activities of the SlPYL4-silenced plants were lower than those of the control plants after 3 and 6 h of drought stress treatment.After 3 h of drought treatment,hydrogen peroxide(H_(2)O_(2)) and superoxide anion(O_(2)^(−).)accumulatedmuch more in the leaves of the SlPYL4-silenced plants than in the leaves of the control plants.These results indicated that PYL4 plays a positive role in drought tolerance in tomato plants.Our results also suggest that SlPYL4 is located upstream of the ABA pathway to regulate the expression of PP2C,SnRK,and AREB/ABF genes. 展开更多
关键词 PYL4 Drought resistance VIGS TOMATO
下载PDF
Green and selective hydrogenation of aromatic diamines over the nanosheet Ru/g-C_(3)N_(4)-H_(2) catalyst prepared by ultrasonic assisted impregnation-deposition method 被引量:3
6
作者 huanhuan yang Liguo Wang +5 位作者 Shuang Xu Yan Cao Peng He Jiaqiang Chen Zheng Zheng Huiquan Li 《Green Energy & Environment》 SCIE EI CSCD 2022年第6期1361-1376,共16页
In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_... In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_(2) were synthesized via ultrasonic assisted impregnation-deposition method.Ultrafine Ru nanoparticles(<2 nm)were highly dispersed on nanosheet g-C_(3)N_(4)-H_(2).Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species.Meanwhile,the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring,i.e.,almost complete 4,40-diaminodiphenylmethane(MDA)conversion and>99%4,40-diaminodicyclohexylmethane selectivity,corresponding to a reaction activity of 35.7 mol_(MDA) mol_(Ru)^(-1) h^(-1).Moreover,the reaction activity of catalyst in the fifth run was 36.5 mol_(MDA) mol_(Ru)^(-1) h^(-1),which was comparable with that of the fresh one.The computational results showed that g-C_(3)N_(4) as support was favorable for adsorption and dissociation of H_(2) molecules.Moreover,the substrate scope can be successfully expanded to a variety of other aromatic diamines.Therefore,this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines. 展开更多
关键词 Nanosheet carbon nitride Ultrafine Ru species Selective hydrogenation Aromatic diamine Alicyclic diamine
下载PDF
Aperture efficiency and mode constituent analysis for OAM vortex beam generated by digital metasurface 被引量:1
7
作者 Di Zhang Xiangyu Cao +2 位作者 huanhuan yang Jun Gao Shiqi Lv 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第3期185-191,共7页
A systematic study of the aperture efficiency and mode constituent for orbital angular momentum(OAM) vortex beam generated by digital metasurface is presented. The aperture efficiency and OAM spectrum are computed for... A systematic study of the aperture efficiency and mode constituent for orbital angular momentum(OAM) vortex beam generated by digital metasurface is presented. The aperture efficiency and OAM spectrum are computed for different bit numbers. It is found that the aperture efficiency declines for digital metasurface due to the phase quantization error,especially for 1-bit device. Fortunately, the OAM spectrum is barely affected by phase quantization and the designated main mode keeps dominant for different bit numbers, indicating that high purity OAM vortex beam can be generated by digital metasurface. Besides, the influence of topological charge l is also investigated. For a fixed metasurface, the radiation performance deteriorates sharply with the growing of l and the parasitic OAM mode becomes dominant at certain angle.At last, a prototype of 1-bit metasurface was simulated, fabricated and measured in anechoic chamber. The simulation and experiment results verify the correctness of the numerical analysis. 展开更多
关键词 ORBITAL ANGULAR momentum(OAM) efficiency MODE CONSTITUENT metasurface
下载PDF
Manipulating single oxygen at Cu_(2)O-island surfaces through thermomechanical coupling
8
作者 huanhuan yang Xiao Jiang +3 位作者 Zhihao Wang Hanpu Liang Xie Zhang Pengfei Guan 《Science China Materials》 SCIE EI CAS CSCD 2024年第10期3288-3297,共10页
Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation ... Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation rules of oxygen defects remain unclear,preventing the realization of controllable oxygen defects on oxide-island surfaces.Here,we utilize the first-principles method to investigate the formation rules of intrinsic oxygen defects in the surface layers of prototypical metal-oxide(Cu_(2)O)surfaces under thermomechanical coupling effects.We establish the thermodynamic phase diagram for oxygen-defect-modulated Cu_(2)O surfaces,enabling the prediction of the growth of oxide islands during Cu oxidation,which aligns closely with in-situ environmental transmission electron microscopy(ETEM)experiment observations.By exploring the strain-modulated phase diagrams,we propose a potential strategy for controlling the type and concentration of oxygen defects on oxide-island surfaces.Our findings provide an effective approach to theoretically understanding the oxidation process of metal surfaces,thus enabling the computational design of high-performance corrosion-resistant surfaces. 展开更多
关键词 first-principles calculations Cu_(2)O-island surfaces oxygen defects biaxial strains thermodynamic phase diagram
原文传递
An anti-collision algorithm for robotic search-and-rescue tasks in unknown dynamic environments
9
作者 yang CHEN Dianxi SHI +2 位作者 huanhuan yang Tongyue LI Zhen WANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2024年第4期569-584,共16页
This paper deals with the search-and-rescue tasks of a mobile robot with multiple interesting targets in an unknown dynamic environment.The problem is challenging because the mobile robot needs to search for multiple ... This paper deals with the search-and-rescue tasks of a mobile robot with multiple interesting targets in an unknown dynamic environment.The problem is challenging because the mobile robot needs to search for multiple targets while avoiding obstacles simultaneously.To ensure that the mobile robot avoids obstacles properly,we propose a mixed-strategy Nash equilibrium based Dyna-Q(MNDQ)algorithm.First,a multi-objective layered structure is introduced to simplify the representation of multiple objectives and reduce computational complexity.This structure divides the overall task into subtasks,including searching for targets and avoiding obstacles.Second,a risk-monitoring mechanism is proposed based on the relative positions of dynamic risks.This mechanism helps the robot avoid potential collisions and unnecessary detours.Then,to improve sampling efficiency,MNDQ is presented,which combines Dyna-Q and mixed-strategy Nash equilibrium.By using mixed-strategy Nash equilibrium,the agent makes decisions in the form of probabilities,maximizing the expected rewards and improving the overall performance of the Dyna-Q algorithm.Furthermore,a series of simulations are conducted to verify the effectiveness of the proposed method.The results show that MNDQ performs well and exhibits robustness,providing a competitive solution for future autonomous robot navigation tasks. 展开更多
关键词 Search and rescue Reinforcement learning Game theory Collision avoidance DECISION-MAKING
原文传递
基于靶点和活性成分的筛选探讨连翘抗病毒作用机制
10
作者 孙娜 马烁 +9 位作者 靳琳萱 张新 周苗 杨欢欢 李文倩 吴欣茹 侯艳艳 袁宇涵 张玉 舒朋华 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2024年第6期543-558,共16页
连翘作为传统中药,具有显著的抗病毒作用,尤其是在治疗新冠肺炎方面。然而,其抗病毒有效化合物及其靶点尚不清楚。本论文利用网络药理学技术筛选连翘中的抗病毒成分和靶标,并利用分子对接技术分析了它们之间的相互作用。最终,从连翘中... 连翘作为传统中药,具有显著的抗病毒作用,尤其是在治疗新冠肺炎方面。然而,其抗病毒有效化合物及其靶点尚不清楚。本论文利用网络药理学技术筛选连翘中的抗病毒成分和靶标,并利用分子对接技术分析了它们之间的相互作用。最终,从连翘中筛选出11个活性化合物(1–11)和7个抗病毒靶标(AKT1、TP53、MYC、PTEN、CASP8、MMP9和VEGFA),并利用基因本体论分析预测了潜在靶标可能的生物信号通路。基于分子对接结果,我们讨论了活性化合物的构效关系。此外,对活性化合物的吸收、分布、代谢、排泄和毒性(ADMET)特性进行了预测和分析。本研究阐明了连翘多个靶点和途径在治疗病毒性疾病中的协同作用,以及活性化合物的可药用性。本研究为开发和设计新型抗病毒药物提供了依据。 展开更多
关键词 连翘 抗病毒 中药靶点 活性成分
原文传递
非缠结缔合高分子的熔体拉伸性能 被引量:1
11
作者 杨欢欢 吴世龙 +2 位作者 陈红兵 张志杰 陈全 《中国科学:化学》 CAS CSCD 北大核心 2023年第4期580-593,共14页
缔合高分子是指链间具有吸引作用(如离子键、氢键作用)的高分子.理解缔合高分子的熔体拉伸性能对于缔合高分子材料的开发和加工成型具有重要的指导意义.本综述聚焦本课题组在非缠结缔合高分子熔体拉伸行为研究中的最新进展,对熔体拉伸... 缔合高分子是指链间具有吸引作用(如离子键、氢键作用)的高分子.理解缔合高分子的熔体拉伸性能对于缔合高分子材料的开发和加工成型具有重要的指导意义.本综述聚焦本课题组在非缠结缔合高分子熔体拉伸行为研究中的最新进展,对熔体拉伸行为进行分类(如脆性行为、韧性行为和超韧性行为),并进一步总结了熔体拉伸行为对于缔合程度、缔合强度和缔合种类的依赖性.研究表明,脆韧行为不仅取决于拉伸流场下缔合网络结构的破坏,而且取决于网络结构破坏后的重整行为. 展开更多
关键词 缔合高分子 熔体拉伸 网络结构 破坏与重组
原文传递
蛋白质N-糖基化在拟南芥生长周期中的变化规律及去糖基化对根发育的影响 被引量:1
12
作者 王婷 羊欢欢 +2 位作者 赵弘巍 Josef Voglmeir 刘丽 《植物学报》 CAS CSCD 北大核心 2021年第3期262-274,共13页
蛋白质N-糖基化修饰在植物生长发育中发挥重要作用。为探究蛋白质N-糖基化在拟南芥(Arabidopsis thaliana)整个生长周期中的变化规律以及去N-糖基化对拟南芥生根发育的影响,通过N-糖链酶解和HPLC与MALDI-TOF-MS分析解析了不同生长时期... 蛋白质N-糖基化修饰在植物生长发育中发挥重要作用。为探究蛋白质N-糖基化在拟南芥(Arabidopsis thaliana)整个生长周期中的变化规律以及去N-糖基化对拟南芥生根发育的影响,通过N-糖链酶解和HPLC与MALDI-TOF-MS分析解析了不同生长时期的拟南芥Col-0植株的N-糖链组成(结构和含量)变化。以BSA溶液为阴性对照,无菌去离子水为空白对照,用N-糖酰胺酶(PNGase Rz)溶液处理拟南芥幼苗8小时;然后继续在MS培养基中培养5天、10天,测量主根长度并检测N-糖链组成的变化。结果显示,从拟南芥中解析出12种N-糖链结构,其中包括4个高甘露糖型和8个复杂型。在拟南芥整个生长周期中,复杂型N-糖链含量始终高于高甘露糖型,其中含木糖和岩藻糖的复杂型结构是N-糖链的主要组成,而Man3XylFucGlcNAc2含量最高。高甘露糖型N-糖链含量由幼苗期的13.87%缓慢上升至抽薹期的19.02%,盛花期回落至17.98%,而在长角果成熟期快速下降至最低点2.36%,衰老期再度小幅回升至5.23%。用高浓度糖酰胺酶液PNGase Rz处理后,可观察到幼苗主根生长受到显著抑制,且培养10天后仍然无法恢复正常;而低浓度酶液处理组与阴性对照组差异不显著,根长和生长状态基本正常。糖链分析结果显示,与对照组相比,高、低浓度酶液处理组的N-糖链组成均发生显著变化,主要表现为高甘露糖型含量显著低于空白对照组,同时随生长时间的延长该差异逐渐减小,最终消失。研究表明,拟南芥N-糖基化组成随着生长发育发生周期性变化,且去糖基化酶处理能够瞬时影响拟南芥蛋白质N-糖基化修饰,进而抑制根的发育。 展开更多
关键词 拟南芥 N-糖链 根发育 去糖基化
原文传递
Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty 被引量:19
13
作者 Yue Zhao Wenjun Long +4 位作者 Caiqi Du huanhuan yang Shimin Wu Qin Ning Xiaoping Luo 《Frontiers of Medicine》 SCIE CAS CSCD 2018年第2期174-181,共8页
The relationship between vitamin D deficiency and idiopathic central precocious puberty (ICPP) has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of simil... The relationship between vitamin D deficiency and idiopathic central precocious puberty (ICPP) has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of similar ages were enrolled and retrospectively studied. The ICPP group had significantly lower serum 25- hydroxyvitamin D (25[OH]D) levels than the control group. Furthermore, a nonlinear relationship was found between serum 25[OH]D and ICPP, and a cut-offpoint for serum 25[OH]D was found at 31.8 ng/ml for ICPP with and without adjusting the different confounding factors. Girls with serum 25[OH]D 〉~ 31.8 ng/ml had a lower odds ratio (unadjusted: OR 0.36, 95% CI 0.15 to 0.83, P 〈 0.05; height and weight adjusted: OR 0.44, 95~0 CI 0.18 to 1.08, P = 0.072; BMI adjusted: OR 0.36, 95% CI 0.16 to 0.84, P 〈 0.05). The ICPP subjects with 25[OH]D deficiency had a higher body mass index (BMI) than the subjects from the two other subgroups. Correlation analysis showed that vitamin D level is correlated with BMI and some metabolic parameters in the ICPP group. Our study suggested that vitamin D status may be associated with ICPP risk and may have a threshold effect on ICPP. 展开更多
关键词 idiopathic central precocious puberty threshold effects vitamin D status
原文传递
Assessment of commutation failure in HVDC systems considering spatial-temporal discreteness of AC system faults 被引量:6
14
作者 huanhuan yang Zexiang CAI +1 位作者 Xiaohua LI Chaoyun YU 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2018年第5期1055-1065,共11页
This paper presents a novel commutation failure(CF) assessment method considering the influences of voltage magnitude drop, phase shift, and spatial-temporal discreteness of AC system faults. The commutating voltage-t... This paper presents a novel commutation failure(CF) assessment method considering the influences of voltage magnitude drop, phase shift, and spatial-temporal discreteness of AC system faults. The commutating voltage-time area is employed to analyze the spatial-temporal discreteness of AC system faults causing CF in high-voltage direct current systems, and the influences of fault position and fault time on CF are revealed. Based on this, a novel CF criterion is proposed, further considering the influence of voltage phase shift and the spatial-temporal discreteness. Then this research develops a new CF assessment method, which does not rely on electromagnetic transient simulations. A real case from the China Southern Power Grid is used to verify the practicability of the proposed method by comparing with simulation results obtained using PSCAD/EMTDC. 展开更多
关键词 COMMUTATION FAILURE Spatial-temporal DISCRETENESS Phase SHIFT ASSESSMENT method
原文传递
Ultrawideband metamaterial absorber for oblique incidence using characteristic mode analysis 被引量:1
15
作者 KUN GAO XIANGYU CAO +3 位作者 JUN GAO TONG LI huanhuan yang SIJIA LI 《Photonics Research》 SCIE EI CAS CSCD 2022年第12期2751-2759,共9页
An ultrawideband,polarization-insensitive,metamaterial absorber for oblique angle of incidence is presented using characteristic mode analysis.The absorber consists of conductive meander square loops and symmetric ben... An ultrawideband,polarization-insensitive,metamaterial absorber for oblique angle of incidence is presented using characteristic mode analysis.The absorber consists of conductive meander square loops and symmetric bent metallic strips,which are embedded with lumped resistors.With the aid of modal currents and modal weighting coefficients,the positions of the lumped resistors are determined.After that,the equivalent circuit(EC)model and admittance formula are proposed and analyzed to further understand the working principle and ultrawide bandwidth.The proposed absorber measures an absorption bandwidth of 4.3–26.5 GHz(144.1%in fractional bandwidth)for 90%absorptivity under normal incidence.At the oblique angle of incidence of 45°,the bandwidth of 90%absorptivity is still 5.1–21.3 GHz(122.72%)for transverse electric(TE)polarization,and 6.8–29.5 GHz(125.07%)for transverse magnetic(TM)polarization.The good agreement among simulation,measurement,and EC calculation demonstrates the validity of the proposed method and indicates that the method can be applied to other microwave and optical frequency bands.The proposed metamaterial absorber can be widely applied in electromagnetic compatibility,electromagnetic interference,radar stealth,and biomedical detection. 展开更多
关键词 POLARIZATION ABSORBER MODE
原文传递
Is sodium percarbonate a good deltamethrin choice in situ remediation of pollution? 被引量:1
16
作者 Xu Zhang Baigang Ren +6 位作者 Shangge Li Xiaodi Qu huanhuan yang Shiguo Xu Zongming Ren Qiang Kong Cheng Wang 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2017年第3期45-52,共8页
In this research, the toxic effects of deltamethrin (DM) on the behavior responses of Zebra fish (Damo rerio) in the characteristic of behavior strength were investigated followed by an assessment of an in situ re... In this research, the toxic effects of deltamethrin (DM) on the behavior responses of Zebra fish (Damo rerio) in the characteristic of behavior strength were investigated followed by an assessment of an in situ remediation of the DM pollution using sodium percarbonate. Behavior strength ofDanio rerio was approximately 0.83 in the control group and was slightly higher than 0.83 in the sublethal treatment (0.1 TU (toxic unit)), which suggested that sublethal DM exposure could induce a stimulation effect in 48 h of exposure. In lower DM concentration treatments (0.5 and 1.0 TU), behavior strength could be inhibited significantly. Behavior responses of Danio rerio showed a gradually increased tendency when they were exposed to higher concentration of DM, and the declining amplitudes of behavior strength changed with the increase of DM concentrations. These results suggested that DM had evident acute toxicity effects on the behavior responses of Danio rerio with a good dose-effect relationship. The in situ remediation of the DM pollution using sodium percarhonate showed that the toxic effect of DM on behavior responses ofDanio rerio could be eliminated even in the highest concentration of DM (5.0 TU). Meanwhile, the behavior response of Danio rerio in the treatment of sodium percarbonate was the same as in the control, which indicated that sodium percarbonate had no evident toxic effects on the behavior of Daniu rerio in the current concentration. This study suggested that adding sodium percarbonate in situ might be a good way to eliminate the DM toxic effects. 展开更多
关键词 Behavior strength Sublethal treatment Detoxification Accidental pollution
原文传递
An extraction-assay system: Evaluation on flavonols in plant resistance to Pb and Cd by supercritical extraction-gas chromatography
17
作者 Xu Zhang huanhuan yang +2 位作者 Xinlei Wang Wen Song Zhaojie Cui 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2018年第4期55-62,共8页
In this research, supercritical carbon dioxide extraction (SFE) showed better extraction etlect when compared with Solid- liquid extraction (SLE), Soxhlet extraction (SEt and Ultrasonic extraction (UE), not onl... In this research, supercritical carbon dioxide extraction (SFE) showed better extraction etlect when compared with Solid- liquid extraction (SLE), Soxhlet extraction (SEt and Ultrasonic extraction (UE), not only in the rate but also the time. The comparison among these three extraction modifiers, including acetone, ethanol and methanol demonstrated that ethanol was preferred to SFE due to its high extraction effect and low toxicology. In addition, parameter of SFE, influence of temperature and pressure were investigated, and the best extraction effect was achieved at the optima conditions, temperature of 40℃ and the pressure of 35 MPa. Thus, SFE is a highly effective method for flavonols extraction, requiring minimum energy and producing non-toxic byproduct. SFE-GC system is applied for the evaluation on flavonols that plays a key role in plant resistance to heavy metal, with its content and synthetase gene expression significantly increasing in plant when threatened by heavy metal. Besides, results indicated that flavonols can improve plant resistance to oxidative stress by quenching the redundant ROS in matrix. 展开更多
关键词 FLAVONOLS Heavy metal Supercritical carbon dioxide extraction (SEE)GC Plant resistance
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部