检索结果-南通市图书馆

Chinese Journal of Polymer Science 2020年第11期38卷 1258-1266,I0009页

作者： Xi-Ting Lei li-Fen Tong Ming-Zhen Xu Yong You Xiao-bo liu School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China

Low dielectric in terlayer films have become an important element to ensure the development of the microelectr onics industry.A kind of flexible interlayer dielectrics,polyarylene ether nitrile/bisphenol A cyanate ester(PEN/BADCy)film,with good thermal stability and low frequency dependence,has been developed by solution casting ***,materials were designed to incorporate bisphenol A cyanate ester as a part of blend,contributing to the frequency stability and structural *** morphological study combined with electron microscopy revealed the uniform and flexible microstructure information with controllable morphology through self-polymerization of cyanate esters with different prepolymerization time and curing *** dielectric films could present high thermal stability with Tg>180℃.Significant improvement in the dielectric properties was achieved for the dielectric constant and loss was much stabler than neat PEN over the frequency range from 100 Hz to 5 *** the prepolymerization time was 3h and final curing temperature reached 230℃,the dielectric constant and dielectric loss of the films were 3.36 and 0.013 at 100 kHz,*** dimensional stability(CTE=53.67×10^-6 K^-1)was confirmed and con sidered beneficial to use as an in terlayer dielectrics.

关键词： Polyarylene ether nitrile Bisphenol A cyanate ester Interlayer dielectrics Tunable microstructures

Influence of Annealing on Properties of ZnO Films Grown via Plasma-enhanced MOCVD

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2003年第4期19卷 383-385页

作者： ZHAO Bai-jun DU Guo-tong yanG Hong-jun WANG Jin-zhong ZHANG Yuan-tao yanG Xiao-tian liU bo-yang MA yan yanG Tian-peng liU Da-li li Wan-cheng FANG Xiu-jun College of Electronics and Engineering Jilin UniversityChangchun 130023P.R.China

The structural and the optical properties of ZnO films with high quality grown via plasma-enhanced metal\|organic chemical vapour deposition(MOCVD) on C-plane sapphire substrate were studied. The crystallinity and the optical properties of the films are greatly improved having been annealed in oxygen plasma atmosphere. The structure, the band gap and the binding energy of O 1s electrons, and the molar ratio of O to Zn were determined by X-ray diffraction(XRD), photoluminescence(PL) and X-ray photoelectron scan methods. For both the annealed and the as-grown films, the exciton peak features were observed at room temperature. The band-edge photoluminescence of the annealed film is much stronger than that of the as-grown film, and the exciton peak relating to the deep level at 439 nm disappears. The molar ratio of O to Zn in the annealed film is 0 91, while it is 0 78 for the as-grown film.

关键词： Plasma-enhanced MOCVD Sapphire Substrate

Understanding the surface segregation behavior of bimetallic CoCu toward HMF oxidation reaction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第11期31卷 85-90,I0004页

作者： yanwei Zhu Jianqiao Shi Yingying li Yuxuan Lu bo Zhou Shuangyin Wang Yuqin Zou State Key Laboratory of Chem/Bio-Sensing and Chemometrics Advanced Catalytic Engineering Research Center of the Ministry of EducationCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082HunanChina School of Chemistry and Chemical Engineering Jishou UniversityJishou 416000HunanChina

Surface segregation is ubiquitous in multi-component materials and is of great important for catalysis but little is known on the surface structure under graphene ***,we show that the graphene encapsulated CoCu performs well for the electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)to2,5-furandicarboxylic acid(FDCA)with the onset potential before 1.23 VRHEand a nearly 100%selectivity of FDCA under 1.4 *** the experimental results,the unprecedented catalytic performance was attributed to local structural distortion and sub-nanometer lattice composition of the CoCu *** accurately show the dispersed Cu doped Co_(3)O_(4) nano-islands with a lot of edge sites on the bimetallic Co-Cu ***,the gradient components effectively facilitate the establishment of built-in electric field and accelerate the charge *** and experimental results reveal that the surface Co and neighbouring Cu atoms in sub-nanometer lattice synergistically promote the catalysis of *** work offers new insights into surface segregation in tuning the element spatial distribution for catalysis.

关键词： CoCu alloy Surface segregation Sub-nanometer lattice Electrocatalysis HMF oxidation

A new synthetic route to MgO–MgAl2O4–ZrO2 highly dispersed composite material through formation of Mg5Al2.4Zr1.7O12 metastable phase: synthesis and physical properties

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 332-341页

作者： Peng Jiang Guo-xiang Yin Ming-wei yan Jia-lin Sun Bin li Yong li School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing Beijing 100083 China

Mg_5Al_(2.4)Zr_(1.7)O_(12) metastable phase was successfully synthesized from analytical-grade Mg O,α-Al_2O_3,MgAl_2O_4,and ZrO_2 under an N_2 *** sintering temperature was varied from 1650 to 1780°C,and the highest amount of Mg_5Al_(2.4)Zr_(1.7)O_(12) appeared in the composite material when the sintering temperature was 1760°*** to our research of the formation mechanism of Mg_5Al_(2.4)Zr_(1.7)O_(12),the formation and growth of MgAl_2O_4 dominated when the temperature was not higher than 1650°*** the temperature was higher than 1650°C,MgO and ZrO_2 tended to diffuse into MgAl_2O_4 and the Mg_5Al_(2.4)Zr_(1.7)O_(12) solid solution was *** the temperature reached 1760°C,the formation of Mg_5Al_(2.4)Zr_(1.7)O_(12) was *** effect of Mg Al_2O_4 spinel crystals was also studied,and their introduction into the composite material promoted the formation and growth of Mg_5Al_(2.4)Zr_(1.7)O_(12).A highly dispersed MgO–Mg Al_2O_4–ZrO_2 composite material was prepared through the decomposition of the Mg_5Al_(2.4)Zr_(1.7)O_(12) metastable *** as-prepared composite material showed improved overall physical properties because of the good dispersion of MgO,MgAl_2O_4,and ZrO_2 phases.

关键词： metastable phases formation mechanisms composite materials refractory materials synthesis physical properties

A Distributed Phase Shifter Using Bi_(1.5)Zn_(1.0)Nb_(1.5)O_(7)/Ba_(0.5)Sr_(0.5)TiO_(3) Thin Films

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第7期30卷 251-253页

作者： li Ru-Guan JIANG Shu-Wen GAO li-Bin li yan-Rong State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054

We report the demonstration of a monolithic phase shifter employing Bi_(1.5)Zn_(1.0)Nb_(1.5)O_(7)/Ba_(0.5)Sr_(0.5)TiO_(3)(BST)thin films on sapphire *** BST and BZN thin films are successively deposited by radio-frequency magnetron sputtering.A distributed phase shifter with a coplanar-waveguide transmission line periodically loaded with the BZN/BST capacitors is *** return loss of the circuit is better than-13 dB from 1 to 12 GHz,and it provides 65°phase shift with an insertion loss of-4 dB at 12 *** results show that BZN/BST thin films are promising candidate dielectrics for rf/microwave tunable applications.

关键词： (3) BST phase

Now-and Fore-casting the Secular Epidemiological Trends and Seasonality of the Comeback of Scarlet Fever in China:A 16-year Time Series Analysis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2022年第6期35卷 563-567页

作者： WANG Yong Bin li yan yan LU Hao TAO Ying Jun li Yu Hong WANG Lei liANG Wen Juan Department of Epidemiology and Health Statistics School of Public HealthXinxiang Medical UniversityXinxiang 453003HenanChina National Center for Tuberculosis Control and Prevention China Center for Disease Control and PreventionBeijing 102206China Center for Musculoskeletal Surgery Charité-Universitätsmedizin BerlinCorporate Member of Freie Universität BerlinHumboldt-Universität Zu Berlin and Berlin Institute of HealthBerlinGermany

Scarlet fever(SF)is a common communicable disease that results from group A Streptococcus(GAS)infections[1].SF accounted for the global loss of life among children 5–15 years of age in the 18th and 19th centuries[2].A rapid reduction in SF morbidity and mortality occurred due to the scale-up of effective antibiotics and improvements in sanitation and nutrition[3].The unexpected increase in the incidence of SF has attracted a renewed interest in infectious diseases[3].Because the triggers that cause SF outbreaks are not fully understood and there is a scarcity of available vaccines protecting susceptible populations from GAS infections,effective prevention and control plans are required to stop the continued spread of SF.

关键词： prevention mortality continued

Monolithic tapered Yb‑doped fber chirped pulse amplifer delivering 126μJ and 207 MW femtosecond laser with near difraction‑limited beam quality

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2023年第3期16卷 169-178页

作者： Tao Wang bo Ren Can li Kun Guo Jinyong Leng Pu Zhou College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense TechnologyChangsha 410073China

In this work,a high-energy and high peak power chirped pulse amplifcation system with near difraction-limited beam quality based on tapered confned-doped fber(TCF)is experimentally *** TCF has a core numerical aperture of 0.07 with core/cladding diameter of 35/250µm at the thin end and 56/400μm at the thick *** a backward-pumping confguration,a maximum single pulse energy of 177.9μJ at a repetition rate of 504 kHz is realized,corresponding to an average power of 89.7 *** partially compensating for the accumulated nonlinear phase during the amplifcation process via adjusting the high order dispersion of the stretching chirped fber Bragg grating,the duration of the amplifed pulse is compressed to 401 fs with a pulse energy of 126.3μJ and a peak power of 207 MW,which to the best of our knowledge represents the highest peak power ever reported from a monolithic ultrafast fber *** the highest energy,the polarization extinction ratio and the M2 factor were respectively measured to be~19 dB and *** addition,the corresponding intensity noise properties as well as the short-and long-term stability were also examined,verifying a stable operation of the *** is believed that the demonstrated laser source could fnd important applications in,for example,advanced manufacturing and photomedicine.

关键词： High-energy laser Femtosecond laser Tapered fber Fiber laser Chirped pulse amplifer

R2R3-type Lo MYB21 affects jasmonate-regulated development and dehiscence of anthers in lily(lilium oriental hybrids)

在线全文

学校读者我要写书评

暂无评论

Horticultural Plant Journal 2024年第1期10卷 239-251页

作者： Zheng Tong Tingting Dong Qiuhua li Rui Wang Junna He bo Hong Institute of Tropical Bioscience and Biotechnology Chinese Academy of Tropical Agricultural Sciences&Hainan Institute for Tropical Agricultural ResourcesHaikouHainan 571101China Beijing Key Laboratory of Development and Quality Control of Ornamental Crops Department of Ornamental HorticultureChina Agricultural UniversityBeijing 100193China Beijing Garden Expo Management Center Beijing 100072China

lilies are widely cultivated for cut flowers,but their large anthers carry a considerable amount of colored pollen that is dispersed *** the molecular mechanism of anther development and dehiscence could help solve this ***21,encoding a putative R2R3v-myb avian myeloblastosis viral oncogene homolog(MYB)transcription factor,was identified from oriental lilies(lilium‘Siberia’).Real-time quantitative PCR analysis showed that LoMYB21 was mainly expressed in the anther,filament and stigma and had high expression during the late stages of lily anther ***21 had transactivation activity and was located in the nucleus through yeast one-hybrid assays and transient expression in Nicotiana *** of LoMYB21 by virus-induced gene silencing(VIGS)in lilium‘Siberia’led to anther indehiscence and reduced the expression of genes related to Jasmonate acid(JA)biosynthesis and signal *** of LoMYB21 in DEX::LoMYB21 transgenic Arabidopsis caused procumbent inflorescences that became infertile,accompanied by higher expression of JA biosynthetic and signaling *** results demonstrated that JA content and signaling were abnormal in silenced lily and transgenic LoMYB21 Arabidopsis,which affected anther *** study indicated that LoMYB21 could regulate lily anther dehiscence through JA biosynthesis and signaling during the late stages of anther development.

关键词： lilium LoMYB21 Anther dehiscence Jasmonate acid

Characterization on the formation of porosity and tensile properties prediction in die casting Mg alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第7期10卷 1857-1867页

作者： Zixin li Dejiang li Wenke Zhou bo Hu Xingfeng Zhao Jingya Wang Ming Qin Jiangkun Xu Xiaoqin Zeng National Engineering Research Center of light Alloy Net Forming School of Materials Science and EngineeringShanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China Hitachi(China)Research&Development Corporation Rui Jin BuildingNo.205 Maoming Road(S)Shanghai 200020China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China

The 3D visualization of the porosity in high-pressure die casting(HPDC)Mg alloys AZ91D and Mg4Ce2Al0.5Mn(EA42)was investigated by X-ray computed *** was demonstrated that the volumetric porosity at the near-gate location for alloy EA42 was significantly higher than that far from the gate *** difference resulted from the low valid time during intensified casting pressure *** of alloy EA42 exhibited a narrow pore distribution in the side view(~0.5 mm)compared to the wide distribution(~1.8 mm)of alloy AZ91D,which was mainly attributed to the formation mechanism of the defect *** formation of microporosity in the defect band of alloy EA42 was inhibited because of the significant latent heat released by a large amount of the Al11Ce3phase segregated in the defect band during ***,an effective estimator(Z-Propagation)was introduced,which is proposed to predict the projected area fraction of the porosity(f)involved during tensile failure with better effectiveness compared with traditional methods based on the actual fractured *** coupling the Z-Propagation method with the critical local strain model,the logarithmic fracture strain and true fracture stress of the specimens were predicted within 3.03%and 1.65%of the absolute value of the average relative error(AARE),respectively.

关键词： High-pressure die casting Porosity Tensile property Magnesium alloy X-ray computed tomography

Mixed Aleatory-epistemic Uncertainty Modeling of Wind Power Forecast Errors in Operation Reliability Evaluation of Power Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2022年第5期10卷 1174-1183页

作者： Jinfeng Ding Kaigui Xie bo Hu Changzheng Shao Tao Niu Chunyan li Congcong Pan Powerand Energy Reliability Research Center State Key Laboratory of Power Transmission Equipment&System Security and New TechnologyChongqing UniversityChongqing400044China

As the share of wind power in power systems continues to increase, the limited predictability of wind power generation brings serious potential risks to power system reliability. Previous research works have generally described the uncertainty of wind power forecast errors(WPFEs) based on normal distribution or other standard distribution models, which only characterize the aleatory uncertainty. In fact, epistemic uncertainty in WPFE modeling due to limited data and knowledge should also be addressed. This paper proposes a multi-source information fusion method(MSIFM) to quantify WPFEs when considering both aleatory and epistemic uncertainties. An extended focal element(EFE) selection method based on the adequacy of historical data is developed to consider the characteristics of WPFEs. Two supplementary expert information sources are modeled to improve the accuracy in the case of insufficient historical data. An operation reliability evaluation technique is also developed considering the proposed WPFE model. Finally,a double-layer Monte Carlo simulation method is introduced to generate a time-series output of the wind power. The effectiveness and accuracy of the proposed MSIFM are demonstrated through simulation results.

关键词： Wind power forecast error(WPFE) epistemic uncertainty multi-source information fusion method(MSIFM) operation reliability extended focal element(EFE) double-layer Monte Carlo simulation