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Full blended blade and endwall design of a compressor cascade

Chinese Journal of Aeronautics 2021年第11期34卷 79-93页

作者： Tongtong MENG Guang YANG Ling ZHOU Lucheng JI School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Poly Technologies inc. Beijing 100010China institute for Aero Engine Tsinghua UniversityBeijing 100084China

In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor ***,the control of endwall corner separation in compressor blade rows is important to *** on the previous research of the Blended Blade and End Wall(BBEW)technique,which can significantly reduce corner separation,in combination with a nonaxisymmetric endwall,the full-BBEW technique is proposed in this study to further reduce the separation in endwall *** princ.ple of the unchanged axial passage area is considered to derive the geometric method for this *** models are further classified based on different geometric characteristics of this technique:the BBEW model,inc.ining-Only End Wall(IOEW)model,and full-BBEW *** most effective design of each model is then found by performing several optimizations at the design point and related numerical investigations over the entire operational *** with the prototype,the total pressure loss coefficient decreases by 7%–9%in the optimized full-BBEW at the design ***,the aerodynamic blockage coefficient over the entire operational range decreases more than the other models,which shows its positive effect for *** approach has a larger decrease at negative inc.dence angles where the intersection of the boundary layer plays an important role in corner *** analysis shows that the blended blade profile enlarges the dihedral angle and creates a span-wise pressure gradient to move low momentum fluid towards the ***,the inc.ining hub geometry accelerates the accumulated flow in the corner downstream by inc.easing the pressure ***,though losses in the mainstream grow,especially for large inc.dences,the full-BBEW technique effectively reduces the separation in corners.

关键词： Aerodynamics Blended Blade and End Wall(BBEW) Corner separation Endwall profiling Flow control Turbomachinery

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Multi-coefficient eigenmode operation—breaking through 10°/h open-loop bias instability in wideband aluminum nitride piezoelectric BAW gyroscopes

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Microsystems & Nanoengineering 2023年第1期9卷 149-159页

作者： Zhenming Liu Haoran Wen Farrokh Ayazi School of Electrical and Computer Engineering Georgia Institute of TechnologyAtlantaGA30308USA StethX Microsystems inc. AtlantaGA30308USA

In this paper,a modification to the eigenmode operation of resonant gyroscopes is *** multi-coefficient eigenmode operation can improve cross-mode isolation due to electrode misalignments and imperfections,which is one of the causes of residual quadrature errors in conventional eigenmode operations.A 1400µm annulus aluminum nitride(AlN)on a silicon bulk acoustic wave(BAW)resonator with gyroscopic in-plane bending modes at 2.98 MHz achieves a nearly 60 dB cross-mode isolation when operated as a gyroscope using a multi-coefficient eigenmode *** as-born frequency mismatches in multiple devices are compensated by physical laser *** demonstrated AlN piezoelectric BAW gyroscope shows a large open-loop bandwidth of 150 Hz and a high scale factor of 9.5 nA/°/s on a test board with a vacuum *** measured angle random walk is 0.145°/√h,and the bias instability is 8.6°/h,showing significant improvement compared to the previous eigenmode AlN BAW *** results from this paper prove that with multi-coefficient eigenmode operations,piezoelectric AlN BAW gyroscopes can achieve a noise performance comparable to that of their capacitive counterpart while having the unique advantage of a large open-loop bandwidth and not requiring large DC polarization voltages.

关键词： mode loop operations

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Targeting stem cell signaling pathways for drug discovery:advances in the Notch and Wnt pathways

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Science China(Life Sciences) 2014年第6期57卷 575-580页

作者： AN Songzhu Michael DING Qiang ZHANG Jie XIE JingYi LI LingSong Curegenix inc. Center for Stem Cell and NanoMedicine Shanghai Advanced Research InstituteChinese Academy of Sciences

Signaling pathways transduce extracellular stimuli into cells through molecular cascades to regulate cellular *** stem cells,a small number of pathways,notably those of TGF-?/BMP,Hedgehog,Notch,and Wnt,are responsible for the regulation of pluripotency and *** embryonic development,these pathways govern cell fate specifications as well as the formation of tissues and *** adulthood,their normal functions are important for tissue homeostasis and regeneration,whereas aberrations result in diseases,such as cancer and degenerative *** complex biological systems,stem cell signaling pathways work in concert as a network and exhibit crosstalk,such as the negative crosstalk between Wnt and *** the past decade,genetic and genomic studies have identified a number of potential drug targets that are involved in stem cell signaling ***,discovery of new targets and drugs for these pathways has become one of the most active areas in both the research community and pharmaceutical *** progress has been made and several promising drug candidates have entered into clinical *** review focuses on recent advances in the discovery of novel drugs which target the Notch and Wnt pathways.

关键词： stem cell drug discovery signaling pathways Notch Wnt cancer

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Improvement of decentralized random decrement technique for data processing in wireless sensor network

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Earthquake Engineering and Engineering Vibration 2016年第3期15卷 627-635页

作者： Liu Chengyin Xu Chunchuan Teng Jun School of Civil and Environmental Engineering Harbin Institute of Technology Shenzhen Graduate School Underground Systems Inc. 84 Business Park DriveArmonk

The Random Decrement Technique （RDT）, based on decentralized computing approaches implemented in wireless sensor networks （WSNs）, has shown advantages for modal parameter and data aggregation identification. However, previous studies of RDT-based approaches from ambient vibration data are based on the assumption of a broad-band stochastic process input excitation. The process normally is modeled by filtered white or white noise. In addition, the choice of the triggering condition in RDT is closely related to data communication. In this project, research has been conducted to study the nonstationary white noise excitations as the input to verify the random decrement technique. A local extremum triggering condition is chosen and implemented for the purpose of minimum data communication in a RDT-based distributed computing strategy. Numerical simulation results show that the proposed technique is capable of minimizing the amount of data transmitted over the network with accuracy in modal parameters identification.

关键词： RDT decentralized computing wireless sensor networks nonstationary

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Learning to assess visual aesthetics of food images

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Computational Visual Media 2021年第1期7卷 139-152页

作者： Kekai Sheng Weiming Dong Haibin Huang Menglei Chai Yong Zhang Chongyang Ma Bao-Gang Hu Youtu Lab TencentShanghai 200233China NLPR Institute of AutomationChinese Academy of SciencesBeijing 100190China Kuaishou Technology Beijing 100085China Snap inc. Santa Monica90405USA AI Lab Tencent Inc.Shenzhen 518000China

Distinguishing aesthetically pleasing food photos from others is an important visual analysis task for social media and ranking systems related to ***,aesthetic assessment of food images remains a challenging and relatively unexplored task,largely due to the lack of related food image datasets and practical ***,we present the Gourmet Photography Dataset(GPD),the first largescale dataset for aesthetic assessment of food *** contains 24,000 images with corresponding binary aesthetic labels,covering a large variety of foods and *** also provide a non-stationary regularization method to combat over-fitting and enhance the ability of tuned models to *** results from extensive experiments,inc.uding a generalization ability test,verify that neural networks trained on the GPD achieve comparable performance to human experts on the task of aesthetic *** reveal several valuable findings to support further research and applications related to visual aesthetic analysis of food *** encourage further research,we have made the GPD publicly available at https://***/Openning07/GPA.

关键词： image aesthetic assessment food image analysis dataset regularization

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Load forecasting using 24 solar terms

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Journal of Modern Power Systems and Clean Energy 2018年第2期6卷 208-214页

作者： Jingrui XIE Tao HONG Forecasting R&D SAS Institute Inc. Department of Systems Engineering and Engineering Management University of North Carolina at Charlotte

Calendar is an important driving factor of electricity demand. Therefore, many load forecasting models would inc.rporate calendar information. Frequently used calendar variables inc.ude hours of a day, days of a week,months of a year, and so forth. During the past several decades, a widely-used calendar in load forecasting is the Gregorian calendar from the ancient Rome, which dissects a year into 12 months based on the Moon's orbit around the Earth. The applications of alternative calendars have rarely been reported in the load forecasting literature. This paper aims at discovering better means than Gregorian calendar to categorize days of a year for load *** alternative is the solar-term calendar, which divides the days of a year into 24 terms based on the Sun's position in the zodiac. It was originally from the ancient China to guide people for their agriculture activities. This paper proposes a novel method to model the seasonal change for load forecasting by inc.rporating the 24 solar terms in regression analysis. The case study is conducted for the eight load zones and the system total of ISO New *** from both cross-validation and sliding simulationshow that the forecast based on the 24 solar terms is more accurate than its counterpart based on the Gregorian calendar.

关键词： 24 solar terms Calendar Load forecasting Multiple linear regression

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Evaluation of Simulated CO_2 Concentrations from the CarbonTracker-Asia Model Using In-situ Observations over East Asia for 2009–2013

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Advances in Atmospheric Sciences 2019年第6期36卷 603-613页

作者： Samuel Takele KENEA Young-Suk OH Jae-Sang RHEE Tae-Young GOO Young-Hwa BYUN Shanlan LI Lev D.LABZOVSKII Haeyoung LEE Robert F.BANKS Climate Research Division National Institute of Meteorological Sciences Environmental Meteorology Research Division National Institute of Meteorological Sciences Meteorology Department Delta Air LinesInc.

The CarbonTracker(CT) model has been used in previous studies for understanding and predicting the sources, sinks, and dynamics that govern the distribution of atmospheric CO_2 at varying ranges of spatial and temporal scales. However, there are still challenges for reproducing accurate model-simulated CO_2 concentrations close to the surface, typically associated with high spatial heterogeneity and land cover. In the present study, we evaluated the performance of nested-grid CT model simulations of CO_2 based on the CT2016 version through comparison with in-situ observations over East Asia covering the period 2009–13. We selected sites located in coastal, remote, inland, and mountain areas. The results are presented at diurnal and seasonal time periods. At target stations, model agreement with in-situ observations was varied in capturing the diurnal cycle. Overall, biases were less than 6.3 ppm on an all-hourly mean basis, and this was further reduced to a maximum of 4.6 ppm when considering only the daytime. For instance, at Anmyeondo, a small bias was obtained in winter, on the order of 0.2 ppm. The model revealed a diurnal amplitude of CO_2 that was nearly flat in winter at Gosan and Anmyeondo stations, while slightly overestimated in the summertime. The model's performance in reproducing the diurnal cycle remains a challenge and requires improvement. The model showed better agreement with the observations in capturing the seasonal variations of CO_2 during daytime at most sites, with a correlation coefficient ranging from 0.70 to 0.99. Also, model biases were within-0.3 and 1.3 ppm, except for inland stations(7.7 ppm).

关键词： model evaluation in-situ observations CarbonTracker East Asia

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Accuracy and safety of partial thickness femtosecond laser radial and arcuate keratotomy inc.sions in porcine eyes

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Eye and Vision 2021年第1期8卷 412-421页

作者： E.Valas Teuma Frank A.Bucci Jr Raman Bedi Gary Gray Mark Packer LENSAR Inc.OrlandoFLUSA Bucci Laser Vision Institute Wilkes-BarreWilkes‑BarrePAUSA IrisARC ChandigarhIndia Packer Research Associates Inc.1400 Bluebell Ave.BoulderCO 80302USA

Background:To evaluate the accuracy and safety of micro radial and arcuate keratotomy inc.sions constructed by a femtosecond laser system with a curved contact patient interface in porcine ***:Partial thickness micro radial and arcuate keratotomy inc.sions were constructed in porcine eyes with a femtosecond laser system and evaluated for precision of depth,quality,and *** coherence tomography was used to determine the accuracy and precision of inc.sion *** endothelial safety was assessed by a fluorescent live/dead cell viability assay to demonstrate laser-induced endothelial cell *** was evaluated by ease of opening and examination of ***:In two micro radial inc.sion groups,intended inc.sion depths of 50%and 80%resulted in mean achieved depths of 50.01%and 77.69%,*** three arcuate inc.sion groups,intended inc.sion depths of 80%,600μm or 100μm residual uncut bed thickness resulted in mean achieved depths of 80.16%,603.03μm and residual bed of 115μm,*** loss of endothelial cell density occurred when the residual corneal bed was maintained at a minimum of 85-116μ*** inc.sions were easy to open,and interfaces were ***:A femtosecond laser system with curved contact interface created precise and reproducible micro radial and arcuate keratotomy *** and precision of the inc.sion depth and preservation of endothelial cell density demonstrated the effectiveness and safety of the system.

关键词： Partial thickness micro radial and arcuate keratotomy inc.sions Curved contact patient interface Micro radial keratotomy Arcuate keratotomy Femtosecond laser system with curved contact interface LENSAR femtosecond laser system

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Optimal SOC Headroom of Pump Storage Hydropower for Maximizing Joint Revenue from Day-ahead and Real-time Markets Under Regional Transmission Organization Dispatch

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 238-250页

作者： Yikui Liu Bing Huang Yang Lin Yonghong Chen Lei Wu Electrical and Computer Engineering Department Stevens Institute of TechnologyHobokenNJ 07030USA Midcontinent Independent System Operator Inc.CarmelIN 46032USA

In response to the inc.easing penetration of volatile and uncertain renewable energy,the regional transmission organizations(RTOs)have been recently focusing on enhancing the models of pump storage hydropower(PSH)plants,which are one of the key flexibility assets in the day-ahead(DA)and real-time(RT)markets,to further boost their flexibility provision *** by the recent research works that explored the potential benefits of excluding PSHs’cost-related terms from the objective functions of the DA market clearing model,this paper completes a rolling RT market scheme that is compatible with the DA ***,with the vision that PSHs could be permitted to submit state-of-charge(SOC)headrooms in the DA market and to release them in the RT market,this paper uncovers that PSHs could inc.ease the total revenues from the two markets by optimizing their SOC headrooms,assisted by the proposed tri-level optimal SOC headroom ***,in the proposed tri-level model,the middle and lower levels respectively mimic the DA and RT scheduling processes of PSHs,and the upper level determines the optimal headrooms to be submitted to the RTO for maximizing the total revenue from the two *** case studies quantify the profitability of the optimal SOC headroom submissions as well as the associated financial risks.

关键词： Pump storage hydropower energy market state-of-charge(SOC) headroom market revenue tri-level problem

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Modeling of a Multiple Digital Automatic Gain Control System

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Tsinghua Science and Technology 2008年第6期13卷 807-811页

作者：王经典陆秀洪张利 institute of Microelectronics Tsinghua University Analog Devices (China) inc. Department of Electronic Engineering Tsinghua University

Automatic gain control （AGC） has been used in many applications. The key features of AGC, inc.uding a steady state output and static/dynamic timing response, depend mainly on key parameters such as the reference and the filter coefficients. A simple model developed to describe AGC systems based on several simple assumptions shows that AGC always converges to the reference and that the timing constant depends on the filter coefficients. Measures are given to prevent oscillations and limit cycle effects. The simple AGC system is adapted to a multiple AGC system for a TV tuner in a much more efficient model. Simulations using the C language are 16 times faster than those with MATLAB, and 10 times faster than those with a mixed register transfer level （RTL）-simulation program with integrated circuit emphasis （SPICE） model.

关键词： digital automatic gain control power detection loop filter oscillations limit cycle effect

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