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Preparation of AlN thin films for film bulk acoustic resonator application by radio frequency sputtering

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 464-470页

作者： Kan LI Hao JIN De-miao WANG yi-fei TANG Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.

关键词： Aluminum nitride (A1N) Piezoelectric thin film Radio frequency (RF) reactive sputtering Preferred orientation,Film bulk acoustic resonator (FBAR)

Driving decision-making analysis of car-following for autonomous vehicle under complex urban environment

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Journal of Central South University 2017年第6期24卷 1476-1482页

作者： CHEN Xue-mei JIN Min miao yi-song ZHANG Qiang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

The decision-making under complex urban environment become one of the key issues that restricts the rapid development of the autonomous vehicles. The difficulty in making timely and accurate decisions like human beings under highly dynamic traffic environment is a major challenge for autonomous driving. Car-following has been regarded as the simplest but essential driving behavior among driving tasks and has received extensive attention from researchers around the world. This work addresses this problem and proposes a novel method RSAN(rough-set artificial neural network) to learn the decisions from excellent human drivers. A virtual urban traffic environment was built by Pre Scan and driving simulation was conducted to obtain a broad set of relevant data such as experienced drivers' behavior data and surrounding vehicles' motion data. Then, rough set was used to preprocess these data to extract the key influential factors on decision and reduce the impact of uncertain data and noise data. And the car-following decision was learned by neural network in which key factor was the input and acceleration was the output. The result shows the better convergence speed and the better decision accuracy of RSAN than ANN. Findings of this work contributes to the empirical understanding of driver's decision-making process and it provides a theoretical basis for the study of car-following decision-making under complex and dynamic environment.

关键词： autonomous vehicle car-following decision-making rough set (RS) artificial neural network (ANN) PreScan

New Members of High-Energy-Density Compounds: YN5 and YN8

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Chinese Physics Letters 2021年第6期38卷 49-53页

作者： Jun-yi miao Zhan-Sheng Lu Feng Peng Cheng Lu School of Physics Henan Normal UniversityXinxiang 453007China College of Physics and Electronic Information Luoyang Normal UniversityLuoyang 471022China School of Mathematics and Physics China University of Geosciences(Wuhan)Wuhan 430074China

Polymeric nitrogen is a promising candidate for a high-energy-density material. Synthesis of energetic compounds with high chemical stability under ambient conditions is still a challenging problem. Here we report a theoretical study on yttrium nitrides by first principles calculations combined with an effective crystal structure search method. It is found that many yttrium nitrides with high nitrogen content can be formed under relatively moderate pressures. The results indicate that the nitrogen-rich YN_(5) and YN_(8) compounds are recoverable as metastable high-energy materials under ambient conditions, and can release enormous energies(2.51 kJ·g^(-1) and 3.18 kJ·g^(-1)) while decomposing to molecular nitrogen and YN. Our findings enrich the family of transition metal nitrides, and open avenues for design and synthesis of novel high-energy-density materials.

关键词： material ambient yttrium

A historical overview of nano-optics:From near-field optics to plasmonics

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Chinese Physics B 2024年第5期33卷 134-145页

作者：邓妙怡朱星 Department of History of Science Technology and MedicineAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China School of Physics Peking UniversityBeijing 100871China

Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer *** early studies of nano-optics,the main concern focus is to obtain higher optical resolution over the diffraction *** researches of near-field imaging and spectroscopy based on scanning near-field optical microscopy(SNOM)are *** exploration of improving SNOM probe for near-field detection leads to the emergence of surface *** the sense of resolution and wider application,there has been a significant transition from seeking higher resolution microscopy to plasmonic near-field modulations in the nano-optics community during the nano-optic ***,studies of nano-optics prefer the investigation of plasmonics in different material *** this article,the history of the development of near-field optics is briefly *** difficulties of conventional SNOM to achieve higher resolution are *** an alternative solution,surface plasmons have shown the advantages of higher resolution,wider application,and flexible nano-optical modulation for new *** typical studies in different periods are introduced and characteristics of nano-optics in each stage are *** this way,the evolution progress from near-field optics to plasmonics of nano-optics research is *** future development of nano-optics is discussed then.

关键词： nano-optics near-field optics surface plasmon plasmonic modulation

Landscape fragmentation associated with the Qingzang Highway and its influencing factors-A comparison study on road sections and buffers

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Geography and Sustainability 2021年第1期2卷 59-67页

作者： yi miao Teqi Dai Xingdou Yang Jinping Song Faculty of Geographical Science Beijing Normal University19th Xinjiekouwai StreetHaidian DistrictBeijing 100875China

Many studies have examined the effect of roads on landscape *** they rarely considered local characteristics of the road and road buffer ***,this study that took place in the Qingzang Highway(QH)examined the variations in road buffers and road sections of landscape *** QH was divided into 32 sections with 23 buffer *** on the indicators of landscape fragmentation from 1980 to 2018,we found significant spatial heterogeneity between sections and ***,landscape fragmentation de-creased with increasing buffer distance to the *** different sections,the coefficients of variation between buffers were rather high and significantly ***,fixed-width buffers may overestimate or underes-timate the spatial scope and influence intensity of a *** impacts of road sections around provincial capitals,prefecture-level cities and main counties on landscape fragmentation were relatively extensive and formed clus-ters of highly fragmented *** results indicated that natural and anthropogenic factors,such as altitude,climate,distance to major settlements and socioeconomic conditions,could well explain the spatiotem-poral characteristics of landscape ***,precipitation and the distance to major settlements had higher explanatory power for landscape fragmentation in permafrost regions,whereas slope and socioeconomic condition had higher explanatory power for non-permafrost regions in Xizang Autonomous Region.

关键词： Qingzang Highway Landscape fragmentation Road section Buffer Geodetector

Relationship between the GH-IGFs axis and the proliferation of bile duct cancer cell line QBC939 in vitro

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Hepatobiliary & Pancreatic Diseases International 2008年第1期7卷 76-81页

作者： Cai, Hui-Hua Sun, Yue-Ming Bai, Jian-Feng Shi, yi Zhao, Han-Lin miao, yi Nanjing Med Univ Affiliated Hosp 1 Dept Minimally Invas Surg Nanjing 210029 Peoples R China

BACKGROUND: In recent years, recombined human growth hormone (rhGH) has been increasingly used in patients to help them recover from operation. But GH, as a mitogen, can promote cell renewal and increase malignant transformation. In the current study, we assessed the proliferation of a bile duct cancer cell line (QBC939) in vitro with GH and explored the possible relationship with the axis of GH-IGFs (insulin-like growth factors). METHODS: QBC939 cells in the exponential growth stage were harvested and divided into an experimental group (GH group) and a control group (NS group). The GH group was divided into four sub-groups according to the dose of GH and culture time (50 mu g/L for 2 hours, 50 mu g/L for 24 hours, 100 mu g/L for 2 hours, 100 mu g/L for 24 hours). The NS group was divided into two sub-groups (NS for 2 hours and NS for 24 hours). After 2 or 24 hours, IGF-1 and IGF-2 were detected using the enzyme-linked immunosorbent assay. The QBC939 cells cultured for 24 hours with two GH concentrations were made into single cell suspensions and samples underwent subsequent cell cycle evaluation. Messenger RNA of IGF-1 and IGF-2 receptor (IGF-1RmRNA and IGF-2RmRNA) were tested with the method of in situ hybridization. RESULTS: There was no statistically significant difference between the GH and NS groups after 2 hours of culture (P>0.05). But after 24 hours of culture, GH stimulated cell growth in vitro and also elevated the percentage in S phase and the proliferation index (P<0.05). IGF-1RmRNA and IGF-2RmRNA were expressed in QBC939 in contrast to the blank group. The expression of IGF-1RmRNA increased with the dose of GH, but IGF-2RmRNA did not. CONCLUSION: GH can stimulate QBC939 cell growth and proliferation in vitro and the mechanism is most likely by the GH-IGF-1-IGF-1R axis.

关键词： growth hormone bile duct cancer cell cycle

Spontaneous expulsion of a duodenal lipoma after endoscopic biopsy: A case report

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World Journal of Gastroenterology 2022年第34期28卷 5086-5092页

作者： Zhi-Hao Chen Li-Hong Lv Wen-Sheng Pan yi-miao Zhu Department of Gastroenterology Zhejiang Provincial People’s HospitalHangzhou 310014Zhejiang ProvinceChina Affiliated Hospital People’s Hospital of Hangzhou Medical CollegeHangzhou 310014Zhejiang ProvinceChina Department of Gastroenterology Xianju County People’s HospitalTaizhou 317300Zhejiang ProvinceChina

BACKGROUND Gastrointestinal(GI)lipomas are benign submucosal tumors of mature adipocytes that arise mainly in the colon and stomach,sometimes in the ileum and jejunum,and rarely in the *** with symptomatic lipomas require endoscopic or surgical *** expulsion of lipomas after biopsy is a rare condition that has limited case *** SUMMARY A 56-year-old man presented to our hospital with intermittent postprandial epigastric ***(EGD)revealed a 10-mm soft yellowish submucosal lesion with the“pillow sign,”located in the second portion of *** ultrasonography(EUS)using a 12-MHz catheter probe showed a hyperechoic,homogenous,and round solid lesion(OLYMPUS EUS EUME2,UM-DP12-25R,12-MHz radial miniprobe,Olympus Corporation,Tokyo,Japan).Deep biopsy was performed using the bite-on-bite technique with *** examination was compatible with submucosal *** lesion spontaneously expelled 12 d after the ***-up EUS performed after 2 mo confirmed this *** Deep biopsy could lead to spontaneous GI lipoma *** might be the first step in lipoma diagnosis and treatment.

关键词： Lipoma Duodenal neoplasms Spontaneous expulsion Endoscopic biopsy Adipose tissue Case report

Roles of Smad3 and Smad7 in rat pancreatic stellate cells activated by transforming growth factor-beta 1

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Hepatobiliary & Pancreatic Diseases International 2010年第5期9卷 531-536页

作者： Qian, Zhu-yin Peng, Quan Zhang, Zheng-Wei Thou, Long-An miao, yi Nanjing Med Univ Affiliated Hosp 1 Dept Gen Surg Nanjing 210029 Peoples R China

BACKGROUND: Pancreatic stellate cells (PSCs) play a major role in promoting pancreatic fibrosis. Transforming growth factor beta 1 (TGF-beta 1) is a critical mediator of this process. This study aimed to determine the expression of the Smad3 and Smad7 genes in the process of PSC activation, and explore the mechanisms of chronic pancreatitis. METHODS: The expressions of Smad3 and Smad7 in PSCs before and after TGF-beta 1 treatment were detected by reverse transcription-polymerase chain reaction and Western blotting analysis. Smad3 expression was detected in PSCs after treatment with 5 ng/ml of TGF-beta 1 for 24 hours. RESULTS: Smad7 expression was decreased in TGF-beta 1 -activated PSCs (P<0.05) in a dose-dependent manner. When TGF-beta 1 concentration reached 10 ng/ml, the expression of p-Smad3, Smad3, and Smad7 was inhibited (P<0.05). CONCLUSIONS: TGF-beta 1 promotes the expression of Smad3 and inhibits the expression of Smad7 during the activation of PSCs. In contrast, high-dose TGF-beta 1 downregulates the expression of Smad3 in completely activated PSCs.

关键词： pancreatic stellate cell transforming growth factor beta 1 chronic pancreatitis Smad3 Smad7

Phylogenetic Analysis and Expression Patterns of the MAPK Gene Family in Wheat (Triticum aestivum L.)

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Journal of Integrative Agriculture 2012年第8期11卷 1227-1235页

作者： LIAN Wei-wei TANG yi-miao GAO Shi-qing ZHANG Zhao ZHAO Xin ZHAO Chang-ping Beijing Engineering and Technique Research Center of Hybrid Wheat Beijing Academy of Agricultural and Forestry Sciences Beijing 100097 P.R.China College of Life Science Capital Normal University Beijing 100048 P.R. China

Mitogen activated protein kinases （MAPK） cascades based on protein phosphorylation play an important role in plant growth and development. In this study, we have identified 15 putative members of the wheat MAPK gene （TaMPK） family through an in silico search of wheat expressed sequence tags （EST） databases based on the presence of amino acid sequence of Arabidopsis and rice MAPKs. Phylogenetic analyses of MAPKs from wheat, rice and Arabidopsis genomes have classified them into seven subgroups （A, B, C, D, E, F, and G）. Using the available EST information as a source of expression data, the MAPK family genes from Triticum aestivum were detected in diverse tissues. Further expression analysis of the MAPKs in NCBI EST database revealed that their transcripts were most abundant in callus （20%）, followed by leaf （12%） and inflorescence （12%）. Most MAPK family genes showed some tissue specificity.

关键词： wheat MAPK EST phylogenetic analysis profile