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BIVARIATE FRACTAL INTERPOLATION FUNCTIONS ON RECTANGULAR DOMAINS

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Journal of Computational Mathematics 2002年第4期20卷 349-362页

作者： xiao-yuan Qian (Department of Applied Mathematics, Dalian University of Technology, Dalian 116024, China) Department of Applied Mathematics Dalian University of Technology Dalian 116024

Non-tensor product bivariate fractal interpolation functions defined on gridded rectangular domains are constructed. Linear spaces consisting of these functions are introduced. The relevant Lagrange interpolation problem is discussed. A negative result about the existence of affine fractal interpolation functions defined on such domains is obtained.

关键词： fractal bivariate functions interpolation

A universal Wi-Fi fingerprint localization method based on machine learning and sample differences

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Satellite Navigation 2021年第1期2卷 385-399页

作者： xiaoxiang Cao yuan Zhuang Xiansheng Yang xiao Sun Xuan Wang State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430072China

Wi-Fi technology has become an important candidate for localization due to its low cost and no need of additional *** Wi-Fi fingerprint-based positioning is widely used because of its ready hardware and acceptable accuracy,especially with the current fingerprint localization algorithms based on Machine Learning(ML)and Deep Learning(DL).However,there exists two ***,the traditional ML methods train a specific classification model for each scene;therefore,it is hard to deploy and manage it on the ***,it is difficult to train an effective multi-classification model by using a small number of fingerprint *** solve these two problems,a novel binary classification model based on the samples’differences is proposed in this *** divide the raw fingerprint pairs into positive and negative samples based on each pair’s *** relative features(e.g.,sort features)are introduced to replace the traditional pair features which use the Media Access Control(MAC)address and Received Signal Strength(RSS).Finally,the boosting algorithm is used to train the classification *** UJIndoorLoc dataset including the data from three different buildings is used to evaluate our proposed *** preliminary results show that the floor success detection rate of the proposed method can reach 99.54%(eXtreme Gradient Boosting,XGBoost)and 99.22%(Gradient Boosting Decision Tree,GBDT),and the positioning error can reach 3.460 m(XGBoost)and 4.022 m(GBDT).Another important advantage of the proposed algorithm is that the model trained by one building’s data can be well applied to another building,which shows strong generalizable ability.

关键词： Fingerprint-based positioning Sample difference Binary-classification Boosting Machine learning Wi-Fi positioning

High-timing-precision detection of single X-ray photons by superconducting nanowires

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National Science Review 2024年第1期11卷 194-203页

作者： Shuya Guo Jingrou Tan Hengbin Zhang Jinguang Wang Tianhao Ji Labao Zhang xiaolong Hu Jian Chen Jun Xie Kai Zou Yun Meng xiaomin Bei Ling-An Wu Qi Chen Hao Wang xuecou Tu xiaoqing Jia Qing-yuan Zhao Lin Kang Peiheng Wu Research Institute of Superconductor Electronics Nanjing University Qian xuesen Laboratory of Space Technology Beijing National Laboratory of Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Hefei National Laboratory School of Precision Instrument and Optoelectronic Engineering Tianjin University Key Laboratory of Optoelectronic Information Science and Technology Ministry of Education

Precisely acquiring the timing information of individual X-ray photons is important in both fundamental research and practical applications. The timing precision of commonly used X-ray single-photon detectors remains in the range of one hundred picoseconds to microseconds. In this work, we report on high-timing-precision detection of single X-ray photons through the fast transition to the normal state from the superconductive state of superconducting nanowires. We successfully demonstrate a free-running X-ray single-photon detector with a timing resolution of 20.1 ps made of 100-nm-thick niobium nitride film with an active area of 50 μm by 50 μm. By using a repeated differential timing measurement on two adjacent X-ray single-photon detectors, we demonstrate a precision of 0.87 ps in the arrival-time difference of X-ray photon measurements. Therefore, our work significantly enhances the timing precision in X-ray photon counting, opening a new niche for ultrafast X-ray photonics and many associated applications.

关键词： single-photon detection timing precision superconductor ultrafast phenomenon pulsar X-ray navigation

All-trans retinoic acid promotes smooth muscle cell differentiation of rabbit bone marrow-derived mesenchymal stem cells

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第7期11卷 489-496页

作者： Zhong-yuan SU Ying LI xiao-li ZHAO Ming ZHANG College of Life Sciences Zhejiang University Hangzhou 310058 China Zhejiang Academy of Medical Science Hangzhou 310058 China

Bone marrow-derived mesenchymal stem cells are multipotent stem cells, an attractive resource for regenerative medicine. Accumulating evidence suggests that all-trans retinoic acid plays a key role in the devel- opment and differentiation of smooth muscle cells. In the present study, we demonstrate, for the first time, that rabbit bone marrow-derived mesenchymal stem cells differentiate into smooth muscle cells upon the treatment with all-trans retinoic acid. AII-trans retinoic acid increased the expression of myocardin, caldesmon, 22-kDa smooth muscle cell- specific protein （SM22Q）, and SM-myosin heavy chains in rabbit bone marrow-derived mesenchymal stem cells, as detected by reverse transcription polymerase chain reaction （PCR）. Immunostaining of SM22a and SM-myosin heavy chains using monoclonal antibodies also indicated smooth muscle cell differentiation of rabbit bone marrow- derived mesenchymal stem cells following the treatment with all-trans retinoic acid. In addition, more than 47% of bone marrow-derived mesenchymal stem cells demonstrated the contractile phenotype of smooth muscle cells. Western blot results showed that SM-1 and SM-2 were highly expressed in the differentiated cells. These results suggest that all-trans retinoic acid may serve as a potent agent for functional smooth muscle cell differentiation in tissue engineering.

关键词： Bone marrow-derived mesenchymal stem cells Smooth muscle cells AII-trans retinoic acid Rabbit

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桩端采空区对嵌岩桩承载力的影响

科学技术与工程 2024年第18期24卷 7821-7832页

作者：王开源孙增奎沈宇鹏赵晓林徐金翠中交公路规划设计院有限公司北京100010 北京交通大学土木建筑工程学院北京100044

针对桩端采空区对嵌岩桩的设计(如承载性能和长期服役性能)提出的挑战,以杜家山特大桥采空区嵌岩桩为原型,进行缩尺模型试验,研究采空区到桩端不同距离以及采空区是否注浆的单桩承载力。计算比例参数,并选择合适的试验材料进行模型构建... 详细信息

针对桩端采空区对嵌岩桩的设计(如承载性能和长期服役性能)提出的挑战,以杜家山特大桥采空区嵌岩桩为原型,进行缩尺模型试验,研究采空区到桩端不同距离以及采空区是否注浆的单桩承载力。计算比例参数,并选择合适的试验材料进行模型构建;通过多级荷载试验,获得采空区到桩端不同距离以及注浆后桩顶沉降、桩基础轴力、桩端阻力和桩侧摩阻力的变化特征;并对比分析了无采空区嵌岩桩的承载特征。结果表明,随着采空区到桩端距离的减小,桩端持力层的承载能力减小,不利于模型桩的承载力;注浆后,桩端持力层的承载能力明显增加,导致模型桩的桩顶沉降显著减少,承载能力显著提高。

关键词：嵌岩桩采空区模型试验桩顶沉降桩基础轴力桩端阻力桩侧摩阻力

Improving the Softness of BOPP Films： From Laboratory Investigation to Industrial Processing

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Chinese Journal of Polymer Science 2017年第9期35卷 1122-1131页

作者： ling-pu meng xiao-wei chen yuan-fei lin 李良彬 National Synchrotron Radiation Lab Key Laboratory of Soft Matter Chemistry Chinese Academy of Sciences University of Science and Technology of China Hefei 230026 China

Young＇s modulus of biaxially oriented polypropylene （BOPP） films prepared with homemade film stretcher was investigated, which can be used to indicate the softness of films. It was found that the modulus of films was decreased by about 69% as the content of polyethylene （PE） added into polypropylene （PP） reached 30%. Also, increasing draw temperature can induce lower stress level during stretching, which may lead to the formation of crystals with low orientation level and thus decreased modulus of films. Based on laboratory study, BOPP films produced on commercial line were studied by differential scanning calorimetry （DSC）, wide and small-angle X-ray scattering （WAXS, SAXS） with varying contents of PE. SAXS results show that the crystals are oriented in both machine direction （MD） and transverse direction （TD）, and the crystals are more oriented in TD than MD according to the WAXS results for all films. Also, the orientation parameter of crystal along TD increases from 0.68 to 0.83 as the contents of PE increase from 0% to 25%. Meanwhile, the modulus of films in MD declines with increase of PE contents generally, improving the film softness. Orientation of crystals is thus an effective structure parameter to adjust the film softness. The relationship of processing-structure-property is also established.

关键词： Polymer films Stretching processing Processing-structure-property relationship Crystal orientation

Development and Application of Detection Methods for Capture and Transcription Elongation Rate of Bacterial Nascent RNA

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生物化学与生物物理进展 2024年第9期51卷 2249-2260页

作者： LI yuan-yuan WANG Yu-Ting WU Zi-Chun LI Hao-Xuan FEI Ming-Yue SUN Dong-Chang GUALERZI O.Claudio FABBRETTI Attilio GIULIODORI Anna Maria MA Hong-Xia HE Cheng-Guang Engineering Research Center of the Chinese Ministry of Education for Bioreactor and Pharmaceutical Development College of Life SciencesJilin Agricultural UniversityChangchun 130118China School of Biosciences and Veterinary Medicine University of CamerinoCamerino(MC)62032Italy College of Biotechnology and Bioengineering Zhejiang University of TechnologyHangzhou 310014China

Objective Detection and quantification of RNA synthesis in cells is a widely used technique for monitoring cell viability,health,and metabolic *** exposure to environmental stimuli,both the internal reference gene and target gene would be *** a result,it is imperative to consider the accurate capture of nascent RNA and the detection of transcriptional levels of RNA following environmental *** study aims to create a Click Chemistry method that utilizes its property to capture nascent RNA from total RNA that was stimulated by the *** The new RNA was labeled with 5-ethyluridine(5-EU)instead of uracil,and the azido-biotin medium ligand was connected to the magnetic sphere using a combination of“Click Chemistry”and magnetic bead *** the new RNA was captured and the transcription rate of 16S rRNA was detected by fluorescence molecular beacon(M.B.)and quantitative reverse transcription PCR(qRT-PCR).Results The bacterial nascent RNA captured by“Click Chemistry”screening can be used as a reverse transcription template to form *** with the fluorescent molecular beacon M.B.1,the synthesis rate of rRNA at 37℃is 1.2 times higher than that at 15℃.The 16S rRNA gene and cspI gene can be detected by fluorescent quantitative PCR,it was found that the measured relative gene expression changes were significantly enhanced at 25℃and 16℃when analyzed with nascent RNA rather than total RNA,enabling accurate detection of RNA transcription *** Compared to other article reported experimental methods that utilize screening magnetic columns,the technical scheme employed in this study is more suitable for bacteria,and the operation steps are simple and easy to implement,making it an effective RNA capture method for researchers.

关键词： nascent RNA selection Click Chemistry fluorescence molecular beacon

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大学物理实验课线上线下混合式教学改革探索

湖北第二师范学院学报 2024年第8期41卷 52-58页

作者：王筠祁红艳杨辉冯国强吉紫娟王艺吴肖媛薛聪湖北第二师范学院物理与机电工程学院武汉430205 湖北第二师范学院太赫兹技术与新能源材料及器件专家工作站武汉430205 湖北第二师范学院光电材料与元器件研究所武汉430205

分析研究一个学期湖北第二师范学院理工科本科专业大学物理实验课线上线下混合式教学改革,这项改革既有利于学生随时随地在线预习实验、按时在线提交实验报告,也有利于教师随时随地在线批阅实验报告,从根本上杜绝了学生交错或者没交实... 详细信息

分析研究一个学期湖北第二师范学院理工科本科专业大学物理实验课线上线下混合式教学改革,这项改革既有利于学生随时随地在线预习实验、按时在线提交实验报告,也有利于教师随时随地在线批阅实验报告,从根本上杜绝了学生交错或者没交实验报告事情的发生。通过分析学生在线学习的大量数据发现,个别实验课由于实验装置老旧、仪器调节困难费时,极大影响学生实验测量精度,实验教学效果大打折扣;进一步分析还发现学生普遍的实验误差分析存在的问题较多,误差理论的掌握不够扎实,这也为今后本课程教学改革指明方向。

关键词：大学物理实验课线上线下混合式教学教学改革

Trichostatin A Extends the Lifespan of Drosophila melanogaster by Elevating hsp22 Expression

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Acta Biochimica et Biophysica Sinica 2004年第9期36卷 618-622页

作者： Dan TAO#, Jun LU#, Hui SUN, Yan-Mei ZHAO, Zhi-Gen yuan, xiao-xue LI, and Bai-Qu HUANG* Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China Institute of Genetics and Cytology Northeast Normal UniversityChangchun 130024China

The level of acetylation of histones in nucleosomes is related to the longevity of yeast and animals. However, the mechanisms by which acetylation and deacetylation affect longevity remain unclear. In present study, we investigated the influence of histone acetylation modification on the expression of hsp22 gene and the lifespan in Drosophila melanogaster using histone deacetylase (HDAC) inhibitor Trichostatin A (TSA). The results showed that TSA could extend the lifespan of Drosophila melanogaster. Furthermore, TSA significantly promoted the hsp22 gene transcription, and affected the chromatin morphology at the locus of hsp22 gene along the polytene chromosome. Present data implicate that TSA may affect the lifespan of Drosophila through changing the level of histone acetylation and influencing the expression of hsp22 gene that is related to aging.

关键词： histone acetylation histone deacetylase inhibitor Drosophila melanogaster hsp22 lifespan