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A Novel Nano/Micro-Fibrous Scaffold by Melt-Spinning Method for Bone Tissue Engineering

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Journal of Bionic Engineering 2015年第1期12卷 117-128页

作者： Liguo cui Ning Zhang WeiWei Cui Peibiao Zhang Xuesi Chen Key Laboratory of Polymer Ecobiomaterials Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China University of Chinese Academy of Sciences Beijing 100039 China Department of Bone and Joint Surgery First Hospital of Jilin University Changchun 130021 China School of Public Health Jilin University Changchun 130021 China

In order to architecturally and functionally mimic native Extracellular Matrix （ECM）, a novel micro/nano-fibrous scaffold of hydroxyapetite/poly（lactide-co-glycolide）（HA/PLGA） composite was successfully prepared by melt-spinning method. A porous three-dimensional scaffold fabricated by melt-molding particulate-leaching method was used as control. This kind of scaffold comprising both nanofiber and microfiber had an original structure including a nano-network favorable for cell adhe- sion, and a micro-fiber providing a strong skeleton for support. The microfibers and nanofibers were blended homogeneously in scaffold and the compression strength reached to 6.27 MPa, which was close to human trabecular bone. The typical mi- cro/nano-fibrous structure was more benefcial for the proliferation and differentiation of Bone Mesenehymal Stem Cells （BMSCs）. The calcium deposition and Alkaline Phosphatase （ALP） activity were evaluated by the differentiation of BMSCs, and the results indicated that the temporary ECM was very beneficial for the differentiation of BMSCs into maturing osteoblasts. For repairing rabbit radius defects in vivo, micro/nano-fibrous scaffold was used for the purpose of rapid bone remodeling in the defect area. The results showed that a distinct bony callus of bridging was observed at 12 weeks post-surgery and the expression of osteogenesis-related genes （bone-morphogenetic protein-2, Osteonectin, collagen-I） increased because of the ECM-like structure. Based on the results, the novel micro/nano-fibrous scaffold might be a promising candidate for bone tissue engi- neering.

关键词： PLGA-based scaffold melt-spinning nano/micro-fibers bone tissue engineering

Theoretical and experimental characterizations of gigahertz acoustic streaming in microscale fluids

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Nanotechnology and Precision Engineering 2019年第1期2卷 15-22页

作者： WeiWei Cui Wei Pang Yang Yang Tiechuan Li Xuexin Duan State Key Laboratory of Precision Measuring Technology & Instruments College of Precision Precision Instrument and Optoelectronics Engineering Tianjin University

Even as gigahertz(GHz) acoustic streaming has developed into a multi-functional platform technology for biochemical applications, including ultrafast microfluidic mixing, microparticle operations, and cellar or vesicle surgery, its theoretical principles have yet to be established. This is because few studies have been conducted on the use of such high frequency acoustics in microscale fluids. Another difficulty is the lack of velocimetry methods for microscale and nanoscale fluidic streaming. In this work, we focus on the basic aspects of GHz acoustic streaming,including its micro-vortex generation principles, theoretical model, and experimental characterization technologies. We present details of a weak-coupled finite simulation that represents our current understanding of the GHz-acoustic-streaming phenomenon. Both our simulation and experimental results show that the GHzacoustic-induced interfacial body force plays a determinative role in vortex generation. We carefully studied changes in the formation of GHz acoustic streaming at different acoustic powers and flow rates. In particular,we developed a microfluidic-particle-image velocimetry method that enables the quantification of streaming at the microscale and even nanoscale. This work provides a full map of GHz acoustofluidics and highlights the way to further theoretical study of this topic.

关键词： Acoustic streaming Gigahertz Body force Microfluidic PIV

Pyrolyzing soft template-containing poly(ionic liquid)into hierarchical N-doped porous carbon for electroreduction of carbon dioxide

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Chinese Journal of Chemical Engineering 2022年第3期35卷 192-201页

作者： Mingdong Sun Zhengyun Bian WeiWei Cui Xiaolong Zhao Shu Dong Xuebin Ke Yu Zhou Jun Wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China Department of Chemical Engineering University of HullHull HU67RXUnited Kingdom

Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO_(2)(CO_(2)RR)due to their versatile structure and function.However,rational structure control remains one challenge.In this work,we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid)(PIL)that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route.Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species.Significantly,the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor.In CO_(2)RR to CO,the champion catalyst gave a Faraday efficiency of 83.0%and a current density of 1.79 mA·cm^(-2)at-0.9 V vs.reversible hydrogen electrode(vs.RHE).The abundant graphite N species and hierarchical pore structure,especially the unique hierarchical small-/ultramicropores were revealed to enable better CO_(2)RR performance.

关键词： CO_(2)RR Poly(ionic liquid) N-doped carbon materials Pore diameter Hierarchical pore

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平台运作逻辑的政治伦理风险

河南社会科学 2022年第12期30卷 42-50页

作者：崔维维陕西师范大学马克思主义学院陕西西安710119 河南警察学院河南郑州450046

平台通过数据垄断、资本加持已经成为新型“非国家权力体”,其背后隐藏的平台资本主义在双边网络效应的支持下无序扩张,容易带来政治伦理风险。互联网平台依靠技术理性、技术价值遮蔽资本本性,通过资本与技术的合谋俘获公共权力,侵害公... 详细信息

平台通过数据垄断、资本加持已经成为新型“非国家权力体”,其背后隐藏的平台资本主义在双边网络效应的支持下无序扩张,容易带来政治伦理风险。互联网平台依靠技术理性、技术价值遮蔽资本本性,通过资本与技术的合谋俘获公共权力,侵害公共利益。互联网平台的资本遮蔽性、负外部性以及“技术黑箱”导致网络空间政治民主偏离,互联网平台存在的“数据鸿沟”“马太效应”“数据孤岛”带来政治正义解体风险。党和政府应发挥主体治理监管作用,通过建构责任治理、规范治理、底线治理的三维框架,化解互联网平台产生的政治伦理风险,实现平台良性发展和规范并重的目标。

关键词：互联网平台数字经济风险网络治理

An Improved Path Delay Variability Model via Multi-Level Fan-Out-of-4 Metric for Wide-Voltage-Range Digital CMOS Circuits

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Chinese Journal of Electronics 2023年第2期32卷 375-388页

作者： cui Yuqiang SHAN weiwei DAI Wentao LIU Xinning GUO Jingjing CAO Peng National ASIC System Engineering Research Center Southeast University Cadence Design Systems Inc. Nanjing University of Posts and Telecommunications

In advanced CMOS technology, process,voltage, and temperature(PVT) variations increase the paths’ latency in digital circuits, especially when operating at a low supply voltage. The fan-out-of-4 inverter chain(FO4 chain) metric has been proven to be a good metric to estimate the path’s delay variability, whereas the previous work ignored the non-independent characteristic between the adjacent cells in a path. In this study,an improved model of path delay variability is established to describe the relationship between the paths’ max-delay variability and an FO4 chain, which is based on multilevel FO4 metric and circuit-level parameters knobs(i.e., cell topology and driving strength) of the first few cells. We take the slew and load into account to improve the accuracy of this framework. Examples of 28 nm and40 nm digital circuits show that our model conforms with Monte Carlo simulations as well as fabricated chips’ measurements. It is able to model the delay variability effectively to speed up the design process with limited accuracy loss. It also provides a deeper understanding and quick estimation of the path delay variability from the near-threshold to nominal voltages.

关键词： Modeling Process voltage and temperature (PVT) variations Delay variability Digital integrated circuit and FO4 inverter chain

Single-cell RNA sequencing reveals the landscape of maize root tips and assists in identification of cell type-specific nitrate-response genes

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The Crop Journal 2022年第6期10卷 1589-1600页

作者： Xuhui Li Xiangbo Zhang Shuai Gao Fangqing cui weiwei Chen Lina Fan Yongwen Qi Institute of Nanfan&Seed Industry Guangdong Academy of ScienceGuangzhou 510316GuangdongChina College of Agriculture and Biology Zhongkai University of Agriculture and EngineeringGuangzhou 510325GuangdongChina

The root system is fundamental for maize growth and yield.Characterizing its heterogeneity and cell type-specific response to nitrate at the single-cell level will shed light on root development and nutrient uptake.We profiled the transcriptomes of>7000 cells derived from root tips of maize seedlings grown on media with or without nitrate,and identified 11 major cell types or tissues and 85 cell type-specific nitrate-response genes,including several known nitrate metabolic genes.A pseudotime analysis showed a continuous pseudotime series with the beginning at meristematic zone cells and showed that the root hair cell was derived by differentiation of a subset of epidermal cells.Interspecies comparison of root cells between maize and rice revealed the conservation and divergence of the root cell types and identified 57,216,and 80 conserved orthologous genes in root hair,endodermis,and phloem cells respectively.This study provides a global view of maize root tip developmental processes and responses to nitrate at the single-cell level.The genes described in the present work could serve as targets for further genetic analyses and accurate regulation of gene expression and phenotypic variation in specific cell types or tissues.

关键词： Maize Single-cell RNA sequencing Root Nitrate

A comprehensive review of recent advancements and developments in heat exchanger network synthesis techniques

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Science China(Technological Sciences) 2024年第2期67卷 335-356页

作者： XU Yue LIU weiwei ZHANG Lu cui Guo Min XIAO Yuan ZHANG GuanHua YANG QiGuo School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China

The rapid development of computational technology and the increasing energy demand have improved heat exchanger network(HEN)synthesis.The HEN synthesis involves several optimizations of matches,distributions of heat loads,and stream splitting of heat units.Thus,obtaining good results at high efficiency has been the main standard for evaluating the techniques in the research area of HEN synthesis.This paper first summarizes and analyzes the main contributions of the existing HEN synthesis techniques.To compare related data quantitively,information on ten typical cases is presented in this paper.Furthermore,recently improved solutions for commonly encountered existing literature cases demonstrate the evolution and competition trends in the field of HEN synthesis.The comparison data presented in this paper not only provide a useful reference for future research but also present the optimization directions.Based on the findings of this study,it is noted that there is still a large room for improvement,and current approaches are incapable of dealing with all HEN cases.Moreover,it is still difficult to escape a local optimum and overcome structural constraints when seeking the global optimum.As a follow-up to the current work,the parallel computing mode and adaptively coordinating the ratio of global and local searching abilities are major development trends for future investigation.

关键词： heat integration heat exchanger network synthesis sequential synthesis method simultaneous synthesis method optimization techniques development optimization quality

Effects of Width Variation of Pressure-Side Winglet on Tip Flow Structure in a Transonic Rotor

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Journal of Thermal Science 2022年第1期31卷 141-150页

作者： cui weiwei WANG Xinglu YAO Fei ZHAO Qingjun LIU Yuqiang LIU Leinan WANG cuiping YANG Laishun College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Light-duty Gas-turbine Chinese Academy of SciencesBeijing 100190China Key Laboratory of Civil Engineering Disaster Prevention and Mitigation of Shandong Province Qingdao 266590China Clean Energy Laboratory Shandong University of Science and TechnologyQingdao 266590China

Tip leakage flow has become one of the major triggers for rotating stall in tip region of high loading transonic compressor rotors.Comparing with active flow control method,it’s wise to use blade tip modification to enlarge the stable operating range of rotor.Therefore,three pressure-side winglets with the maximum width of 2.0,2.5 and 3.0 times of the baseline rotor,are designed and surrounded the blade tip of NASA rotor 37,and the three new rotors are named as RPW1,RPW2,and RPW3 respectively.The numerical results show that the width of pressure-side winglet has significant influence on the stall margin and the minimum throttling massflow of rotor,while it produces less effect on the choking massflow and the peak efficiency of new rotors.As the width of the pressure-side winglet increases from new rotor RPW1 to RPW3,the strength of leakage massflow has been attenuated dramatically and a reduction of 20%in leakage massflow rate has appeared in the new rotor RPW3.By contrast,the extended blade tip caused by winglet has not introduced much more aerodynamic losses in tip region of rotor,and the new rotors with different width of pressure-side winglet have the similar peak efficiency to the baseline.The new shape of the leakage channel over blade tip which replaces of the static pressure difference near blade tip has dominated the behavior of the leakage flow in tip gap.As both the new aerodynamic boundary and throat in tip gap have reshaped by the low-velocity flow near the solid wall of extended blade tip,the discharging velocity and massflow rate of leakage flow have been suppressed obviously in new rotors.In addition,the increasing inlet axial velocity at the entrance of new rotor has increased slightly as well,which is attributed to the less blockage in the tip region of new rotor.In consideration of the increased inlet axial velocity and the weakened leakage flow,the new rotor presents an appropriately linear increase of the stall margin when the width of pressure-side winglet increases,and has a nearly 15%incre

关键词： pressure-side winglet blade tip aerodynamic losses leakage channel stall margin

Effect of Geometric Variation of Root Fillet on the Flow Characteristic of a Transonic Compressor Rotor

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Journal of Thermal Science 2023年第4期32卷 1407-1420页

作者： cui weiwei LIU Yuqiang LIU Fusong YANG Laishun LI Longting YAO Fei WANG Xinglu WANG cuiping College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao266590China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China Clean energy laboratory Shandong University of Science and TechnologyQingdao266590China

The effects of root fillet on the flow behavior of high loading compressor rotor tends to be much more crucial in practice,and it’s necessary to explore the internal relations between the geometric effects of root fillet and the flow behaviors of rotor blade.Therefore,eight types of root fillet with different radius were designed and installed around the blade root of NASA Rotor67.With the aids of fillet,the corner separation near suction side of blade root has been suppressed significantly in that the root fillet reconstructs the circumferential bending distributon of the suction-side curve from leading edge to trailing edge,and reduces the genmetric turning angle in the latter part of root section near trailing edge.However,apart from the improvement of corner flow characteristic caused by root fillet,both the tip flow deterioration and the decrease of stall margin occur in the new rotors,which indicates an indirect correlation between tip flow characteristic and root fillet exists indeed in the three-dimensional flowfields of transonic rotor.Actually,by means of the new radial pressure equilibrium affected by root fillet,a larger radius of root fillet contributes to much larger blade loading and stronger leakage flow in tip region of compressor rotor.As a result,a monotonic decrease of stall margin was present in the transonic rotor with increase of the root fillet radius.Subsequently,the positive bending of blade tip was introduced to deal with the negative effect caused by the root fillet indirectly.Combined with the effects of root fillet and positive tip-bending on the radial pressure equilibrium existing in channels,both the radial and streamwise loading distributions tend to be much more reasonable in new rotors,and the static pressure difference in former 1/3 chord of blade tip has decreased clearly which benefits to reduce the strength of leakage flow in tip region.Therefore,the flow deterioration in tip region of transonic rotor induced by root fillet has been well suppressed,with an obvious improveme

关键词： root fillet variation corner separation radial pressure equilibrium stall margin positive tip-bending