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Biomimetic 3D printing of composite structures with decreased cracking

NANOTECHNOLOGY AND PRECISION ENGINEERING 2024年第3期7卷 24-34页

作者： du, fan Li, Kai Li, Mingzhen fang, Junyang Sun, Long Wang, Chao Wang, Yexin Liu, Maiqi Li, Jinbang Wang, Xiaoying Ningbo Univ Sch Mech Engn & Mech Ningbo 315211 Peoples R China China Univ Min & Technol Sch Mech & Elect Engn Xuzhou 221116 Peoples R China Ningbo Univ Inst Adv Energy Storage Technol & Equipment Ningbo 315211 Peoples R China Ningbo Univ Sch Civil & Environm Engn & Geog Sci Ningbo Peoples R China

The development of tissue engineering and regeneration research has created new platforms for bone transplantation. However, the preparation of scaffolds with good fiber integrity is challenging, because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation. Human skin has an excellent natural heat-management system, which helps to maintain a constant body temperature through perspiration or blood-vessel constriction. In this work, an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed. In this system, the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity. To investigate the solvent evaporation and the interlayer bonding of the fibers, finite-element analysis simulations of a three-layer microscale structure were carried out. The results show that the solvent-evaporation path is from bottom to top, and the strain in the printed structure becomes smaller with a smaller temperature-change rate. Experimental results verified the accuracy of these simulation results, and a variety of complex 3D structures with high aspect ratios were printed. Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5 degree celsius s(-1). Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity. It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration. This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro- and nanostructured sensors and actuators. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://***/licenses/by/4.0/).

关键词： 3D printing Electrohydrodynamic jet Biomimetic Structural integrity Composite scaffold SCAFFOLDS OSTEOPOROSIS

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跨学科视角下的博物馆地理研学课程设计——以中华农业文明博物馆为例

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地理教学 2024年第15期 60-64页

作者：杜凡郭文南京农业大学人文与社会发展学院江苏南京210095 南京农业大学中华农业文明研究院江苏南京210095

目前以单一学科为主的博物馆研学课程内容丰富,但多学科融合教学的博物馆研学课程稀缺。本文从跨学科视角出发,以南京农业大学中华农业文明博物馆为案例,充分挖掘农史专题博物馆所蕴含的地理教学资源,围绕“探秘中国农业的起源与发展”... 详细信息

目前以单一学科为主的博物馆研学课程内容丰富,但多学科融合教学的博物馆研学课程稀缺。本文从跨学科视角出发,以南京农业大学中华农业文明博物馆为案例,充分挖掘农史专题博物馆所蕴含的地理教学资源,围绕“探秘中国农业的起源与发展”“见证中国农业技术体系的创立和发展”“助推现代生态农业的建设”“传承优秀农业文化”四大主题,设计融合地理和历史学科的项目式研学课程,实现历史和地理学科的深度融合,同时创新评价体系,助推跨学科主题学习的博物馆地理研学新发展。

关键词：跨学科地理研学核心素养中华农业文明博物馆

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中美研究生教育对经济增长及创新的贡献分析

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现代大学教育 2024年第3期40卷 96-102页

作者：杜帆李立国中国高等教育学会北京100191 中国人民大学教育学院教育部教育发展与公共政策研究中心北京100872

研究生教育在培养创新人才、提高创新能力以及服务经济社会发展方面具有重要作用。中美两国都是经济大国和研究生教育大国。对比中美两国研究生教育对于创新驱动发展的现状可以发现,美国的研究生教育累积规模对创新驱动经济增长的总效... 详细信息

研究生教育在培养创新人才、提高创新能力以及服务经济社会发展方面具有重要作用。中美两国都是经济大国和研究生教育大国。对比中美两国研究生教育对于创新驱动发展的现状可以发现,美国的研究生教育累积规模对创新驱动经济增长的总效应与直接效应为0.55%与0.44%,中国研究生教育累积规模对创新驱动经济增长的总效应与直接效应为0.13%与0.03%。中国需加快研究生教育发展,积极扩大研究生教育规模,使研究生教育更好地适应经济增长要求,促进创新驱动发展。

关键词：研究生教育创新驱动中美比较经济增长累积规模

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民族村落地方情感空间结构研究——以中国云南双廊为例

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大理大学学报 2024年第3期9卷 8-16页

作者：杜凡南京农业大学人文与社会发展学院南京210095

随着我国经济的发展,民族村落原有的地方景观不断瓦解的同时,村落传统空间和地方居民的生活方式也发生了改变。从情感地理学的视角切入,通过田野民族志探究双廊居民地方的记忆、情感等形成的情感结构对地方空间再生产的意义,将列斐伏尔... 详细信息

随着我国经济的发展,民族村落原有的地方景观不断瓦解的同时,村落传统空间和地方居民的生活方式也发生了改变。从情感地理学的视角切入,通过田野民族志探究双廊居民地方的记忆、情感等形成的情感结构对地方空间再生产的意义,将列斐伏尔的历史-精神-社会的空间三元辩证法应用到地方情感空间结构研究之中,并用部落绘图法绘制出其情感空间图式和理想空间图式。从而对本地居民的日常生活空间、情感空间和地方情感特质进行全面研究。民族村落情感空间结构的研究能够分析在旅游推动下双廊居民的地方情感需求,有助于寻找地方对人的意义和价值,协调社会经济发展和保护传统文化之间的关系以及更好地体现地方本质和特征。

关键词：民族村落地方空间生产情感结构双廊

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基于研学场所“认知—情感—意动”形象三维结构的课程设计——以沙溪古镇为例

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地理教学 2024年第5期 56-60页

作者：钱镜帆陈亚颦杜凡云南师范大学地理学部云南昆明650500 云南师范大学少数民族文化与旅游发展研究院云南昆明650500 南京农业大学人文与社会发展学院江苏南京210095

本文从研学场所旅游地属性的视角出发,基于其认知形象、情感形象和意动形象,整合《普通高中地理课程标准(2017年版2020年修订)》中关于知识与技能,情感、态度和价值观,过程与方法的教学目标任务,以大理州沙溪古镇为例,设计三维结构的研... 详细信息

本文从研学场所旅游地属性的视角出发,基于其认知形象、情感形象和意动形象,整合《普通高中地理课程标准(2017年版2020年修订)》中关于知识与技能,情感、态度和价值观,过程与方法的教学目标任务,以大理州沙溪古镇为例,设计三维结构的研学课程目标和内容。

关键词：认知—情感—意动三维结构研学课程沙溪古镇

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超声内镜引导下穿刺诊断胰腺结核14例

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中华消化内镜杂志 2024年第8期41卷 654-657页

作者：曹卉王晓林邓伊杜凡华中科技大学同济医学院附属梨园医院消化内科武汉430066 华中科技大学同济医学院附属协和医院消化内科武汉430022

总结胰腺结核的临床特点,分析其超声内镜下表现、穿刺组织病理学及病原学结果。回顾性分析2018年1月至2022年1月在武汉协和医院收治的14例胰腺结核患者的病史、临床表现、实验室检查、影像学检查、超声内镜检查(endoscopic ultrasonogra... 详细信息

总结胰腺结核的临床特点,分析其超声内镜下表现、穿刺组织病理学及病原学结果。回顾性分析2018年1月至2022年1月在武汉协和医院收治的14例胰腺结核患者的病史、临床表现、实验室检查、影像学检查、超声内镜检查(endoscopic ultrasonography,EUS)下的表现、超声内镜引导细针穿刺抽吸术(endoscopic ultrasound‑guided fine needle aspiration,EUS‑FNA)获得的组织病理及病原学结果。胰腺结核患者中,男、女各7例,年龄(39.7±16.0)岁,临床表现主要为腹胀、腹痛、食欲下降、体重减轻、腹部包块、梗阻性黄疸、皮肤瘙痒、无症状等。7例患者合并其他器官结核,其中3例合并肺结核。实验室检查示贫血7例,血淀粉酶升高3例,胆红素升高2例,结核抗体阳性10例,结核T‑SPOT阳性12例,患者CA19‑9水平均正常。影像学检查示实性肿块9例,囊实性肿块4例,囊性占位1例,胰周淋巴结增大4例,胆管扩张2例。EUS示胰腺结核好发于胰头部。病灶EUS下均呈低回声,无血管侵犯,其中均匀低回声8例,不均匀低回声6例;病灶内部见高回声钙化灶2例,见无回声液化坏死区1例;病灶肿块长径(3.9±1.6)cm,其中肿块长径<3 cm者5例,肿块长径≥3 cm者9例。组织学检查示干酪样肉芽肿12例。病原学检查结果显示结核杆菌聚合酶链式反应检测阳性11例,抗酸染色找到阳性分枝杆菌3例,培养出结核分枝杆菌1例。全部患者确诊后给予正规药物抗结核治疗,3例黄疸患者行内镜逆行胰胆管造影术及胆道支架置入术。随访期间患者显示预后良好。对于胰腺占位性病变患者,应考虑胰腺结核的可能,胰腺结核的诊断依靠组织活检及病原学检查,EUS‑FNA是获取胰腺组织首选的方法,可避免不必要的手术,并提供及时、准确的诊断。正规抗结核治疗是胰腺结核的主要治疗方法。

关键词：胰腺疾病结核分枝杆菌结核菌素试验超声检查活组织检查,细针

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The measure and characteristics of spatial-temporal evolution of China＇s science and technology resource allocation efficiency

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Journal of Geographical Sciences 2014年第3期24卷 492-508页

作者： fan Fei du Debin WANG Xinzhu Center for Innovation Strategic Studies East China Normal University Shanghai 200241 China

According to the connotation and structure of science and technology resources and some relevant data of more than 286 cities at prefecture level and above during 2001-2010, using modified method--Data Envelopment Analysis （DEA）, science and tech- nology （S＆T） resource allocation efficiency of different cities in different periods has been figured out, which, uncovers the distributional difference and change law of S＆T resource allocation efficiency from the time-space dimension. Based on that, this paper has analyzed and discussed the spatial distribution pattern and evolution trend of S＆T resource allocation efficiency in different cities by virtue of the Exploratory Spatial Data Analysis （ESDA）. It turned out that：（1） the average of S＆T resource allocation efficiency in cities at prefecture level and above has always stayed at low levels, moreover, with repeated fluctuations between high and low, which shows a decreasing trend year by year. Besides, the gap between the East and the West is widening. （2） The asymmetrical distribution of S＆T resource allocation effi- ciency presents a spatial pattern of successively decreasing from Eastern China, Central China to Western China. The cities whose S＆T resource allocation efficiency are at higher level and high level take on a cluster distribution, which fits well with the 23 forming urban agglomerations in China. （3） The coupling degree between S＆T resource allocation efficiency and economic environment assumes a certain positive correlation, but not completely the same. The differentiation of S＆T resource allocation efficiency is common in regional devel- opment, whose existence and evolution are directly or indirectly influenced by and regarded as the reflection of many elements, such as geographical location, the natural endowment and environment of S＆T resources and so on. （4） In the perspective of the evolution of spatial structure, S＆T resource allocation efficiency of the cities at prefecture level and above s

关键词： science and technology (S&T) resources cities at prefecture level and above modified Data Envelop-ment Analysis (DEA) Exploratory Spatial Data Analysis (ESDA) allocation efficiency

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Distribution patterns of clonal plants in the subnival belt of the Hengduan Mountains,SW China

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Plant Diversity 2020年第5期42卷 386-392页

作者： Yongqian Gao Jinxuan Zheng Xiangqun Lin fan du Faculty of Forestry Southwest Forestry University300 Bailong RoadKunming650224YunnanPR China Yunnan Forestry Technological College 1 JindianKunming650224YunnanPR China Forest Inventory and Planning Institute of Yunnan Province Kunming650051YunnanChina

Clonal reproduction(i.e.,production of potentially independent offspring by vegetative growth)is thought to provide plants with reproductive ***,studying the evolution of clonal reproduction in local floras is crucial for our understanding of the adaptive mechanisms plants deploy in stressful environments such as alpine *** this study,we characterized clonal plant species in the subnival belt of the Hengduan Mountains(a global biodiversity hotspot with extreme environmental conditions in southwest China),in order to determine the effects of sex system,growth form,and elevational distribution on *** compiled clonality data of angiosperm species belonging to 41 families in the subnival belt of the Hengduan Mountains using published *** the 793 species recorded in the region,47.92%(380 species)are clonal *** sex system and growth form had significant effects on the occurrence of clonal reproduction:unisexual species(79.79%)were more likely to be clonal than bisexual species(43.63%),and herbaceous species(51.04%)were more likely to be clonal than woody species(16.67%).Compared with non-alpine-endemic species(44.60%),alpine-endemic species(58.33%)showed a significantly higher proportion of clonal *** logistic regression analysis showed a positive association between incidence of clonality and elevational range,indicating that species distributed at high elevations are more likely to be ***,the elevational gradients in clonality were contingent on sex system or growth *** study reveals that plants in the subnival belt of the Hengduan Mountains might optimize their probability of reproduction through clonal reproduction,a finding that adds to our growing understanding of plant's adaptations to harsh alpine environments.

关键词： Alpine Clonal reproduction Hengduan mountains Sexual reproduction Subnival belt

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Low threshold anti-Stokes Raman laser on-chip

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Photonics Research 2019年第8期7卷 926-932页

作者： HYUNGWOO CHOI DONGYU CHEN fan du RENE ZETO ANDREA ARMANI Mork Family Department of Chemical Engineering and Materials Science University of Southern CaliforniaLos AngelesCalifornia90089USA Ming Hsieh Department of Electrical Engineering-Electrophysics University of Southern CaliforniaLos AngelesCalifornia90089USA

Raman lasers based on integrated silica whispering gallery mode resonant cavities have enabled numerous applications from telecommunications to biodetection. To overcome the intrinsically low Raman gain value of silica, these devices leverage their ultrahigh quality factors(Q), allowing submilliwatt stimulated Raman scattering(SRS) lasing thresholds to be achieved. A closely related nonlinear behavior to SRS is stimulated anti-Stokes Raman scattering(SARS). This nonlinear optical process combines the pump photon with the SRS photon to generate an upconverted photon. Therefore, in order to achieve SARS, the efficiency of the SRS process must be high. As a result, achieving SARS in on-chip resonant cavities has been challenging due to the low lasing efficiencies of these devices. In the present work, metal-doped ultrahigh Q(Q > 10~7) silica microcavity arrays are fabricated on-chip. The metal-dopant plays multiple roles in improving the device performance. It increases the Raman gain of the cavity material, and it decreases the optical mode area, thus increasing the circulating intensity. As a result, these devices have SRS lasing efficiencies that are over 10× larger than conventional silica microcavities while maintaining low lasing thresholds. This combination enables SARS to be generated with submilliwatt input powers and significantly improved anti-Stokes Raman lasing efficiency.

关键词： SRS Raman Low threshold anti-Stokes Raman laser on-chip Stokes

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A Hybrid Improved Genetic Algorithm and Its Application in Dynamic Optimization Problems of Chemical Processes

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Chinese Journal of Chemical Engineering 2013年第2期21卷 144-154页

作者： SUN fan du Wenli QI Rongbin QIAN Feng ZHONG Weimin Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of Education East China University of Science and Technology Shanghai 200237 China

The solutions of dynamic optimization problems are usually very difficult due to their highly nonlinear and multidimensional nature. 13enetic algorithm （GA） has been proved to be a teasibte method when the gradient is difficult to calculate. Its advantage is that the control profiles at all time stages are optimized simultaneously, but its convergence is very slow in the later period of evolution and it is easily trapped in the local optimum. In this study, a hybrid improved genetic algorithm （HIGA） for solving dynamic optimization problems is proposed to overcome these defects. Simplex method （SM） is used to perform the local search in the neighborhood of the optimal solution. By using SM, the ideal searching direction of global optimal solution could be found as soon as possible and the convergence speed of the algorithm is improved. The hybrid algorithm presents some improvements, such as protecting the best individual, accepting immigrations, as well as employing adaptive crossover and Ganssian mutation operators. The efficiency of the proposed algorithm is demonstrated by solving several dynamic optimization problems. At last, HIGA is applied to the optimal production of secreted protein in a fed batch reactor and the optimal feed-rate found by HIGA is effective and relatively stable.

关键词： genetic algorithm simplex method dynamic optimization chemical process

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