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Effects of Pilot Fuel Ratio on Combustion Process:Flow Field Structure and Pollutant Emissions

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Journal of Thermal Science 2023年第6期32卷 2321-2335页

作者： ZONG Chao JI Chenzhen cheng jiaying ZHU Tong Postdoctoral Station of Mechanical Engineering Tongji UniversityShanghai201804China School of Mechanical Engineering Tongji UniversityShanghai201804China

As the only controllable means of a micro gas turbine(MGT)combustor during unit operation,pilot fuel ratio(PFR)is the key to achieving stable combustion and low pollutant emission.This paper discusses the influence of PFR on the inner flow field structure and pollutant emissions.The steady-state three-dimensional RANS method with a 40-step reduced methane-air kinetics mechanism is used to study the reaction flow field and species field with PFR of 9.0%,12.7%,15.2%and 17.6%.Results show that,with the decrease in PFR,the axial velocity and temperature near the central axis of the combustion chamber show a tendency to decrease.A similar separation phenomenon occurred in the core pyrolysis reaction zone(measured by HCO)and oxidation zone(measured by OH),which is more conducive to promoting the oxidation of CO.The quantitative effect of the pilot flame on nitrogen oxides(NO_(x))was separated by using inert gas instead of nitrogen in combustion air.It was found that the NOx produced by the pilot flame under the operation condition with a PFR of 9.0%was 3.2×10^(−6),accounting for 17.4%of the total NOx emission,which was twice that of PFR.

关键词： micro gas turbine pilot fuel ratio flow field structure carbon monoxide nitrogen oxide

一种应用于大尺寸测量系统的坐标系自动标定方法

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光子学报 2024年第3期53卷 167-179页

作者：张晓晖张嘉颖刘青李金童杨启航吕佳铭尚婷成鹏飞西安理工大学自动化与信息工程学院西安710048

针对现有方法在标定过程中过于繁琐的问题,提出了一种应用于大尺寸测量系统的坐标系全自动标定方法。该方法通过固定两个在测量单元局部坐标系已知坐标的测量节点作为标记靶,测量单元之间相互测量彼此的标记靶获得标记靶上的测量点在不... 详细信息

针对现有方法在标定过程中过于繁琐的问题,提出了一种应用于大尺寸测量系统的坐标系全自动标定方法。该方法通过固定两个在测量单元局部坐标系已知坐标的测量节点作为标记靶,测量单元之间相互测量彼此的标记靶获得标记靶上的测量点在不同坐标系下的坐标值,利用这些坐标值建立三维几何约束,从而自动标定不同坐标系之间的坐标转换关系。借助于精密激光定位系统平台进行实验验证,结果表明,所提方法可以实现测量单元局部坐标系之间的自动标定,降低了坐标系标定过程中的人工成本。在距离测量单元布站区域约2 m,大小为5 000 mm×5 000 mm×500 mm的测量空间中长度测量的精度在0.46 mm/m以内,测试点三维坐标测量的标准偏差在0.026 mm以内,可以满足绝大部分工业测量的需求。该方法极大的提高了系统的标定效率,有望为具有自动标定功能的大尺寸测量设备的产品化提供新的理论基础。

关键词：大尺寸测量系统自动标定标记靶几何约束工业测量

浅析个性化基台及基台冠桥产品临床评价关注点

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中国医疗器械杂志 2024年第2期48卷 217-220页

作者：程玮璐张译丹吉丽郭佳莹张庆刘英慧国家药品监督管理局医疗器械技术审评中心北京市100081 国家药品监督管理局医疗器械技术审评检查大湾区分中心深圳市518045 四川省食品药品审查评价及安全监测中心成都市610017 国家药品监督管理局医疗器械技术审评检查长三角分中心上海市201210

目的个性化基台及基台冠桥产品申报量逐年增加,但目前对于该类产品的同品种临床评价没有明确要求,该研究主要介绍了个性化基台及基台冠桥产品的临床评价关注点,以期对该类产品的申报注册提供参考。方法通过总结个性化基台及冠桥产品的... 详细信息

目的个性化基台及基台冠桥产品申报量逐年增加,但目前对于该类产品的同品种临床评价没有明确要求,该研究主要介绍了个性化基台及基台冠桥产品的临床评价关注点,以期对该类产品的申报注册提供参考。方法通过总结个性化基台及冠桥产品的临床评价审评情况,明确其临床评价时的研究内容。结果该研究中介绍了注册申请人需要考虑的性能要求及同品种产品临床数据的具体要求。结论个性化基台及基台冠桥产品在中国境内上市时可参考本研究相关内容,主要通过体外测试研究论证等同性。

关键词：个性化基台基台冠桥临床评价

Polarization engineering in porous organic polymers for charge separation efficiency and its applications in photocatalytic aerobic oxidations

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Science China Chemistry 2024年第3期67卷 1000-1007页

作者： Kun Wu Pei-Wen cheng Xin-Yi Liu Ji Zheng Xiao-Wei Zhu Mo Xie Puxin Weng Weigang Lu Dan Li College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and ApplicationsJinan UniversityGuangzhou 510632China Guangdong Rare Earth Photofunctional Materials Engineering Technology Research Center School of Chemistry and EnvironmentJiaying UniversityMeizhou 514015China

Photocatalytic aerobic oxidation reactions are largely governed by the efficiency of charge separation and subsequent reactive oxygen species(ROS) generation. Herein, we report a polarization engineering strategy to promote the charge separation and ROS generation efficiency by substituting the benzene unit with furan/thiophene in porous organic polymers(POPs). Benefiting from the extent of local polarization, the thiophene-containing POP(JNU-218) exhibits the best photocatalytic performance in aerobic oxidation reactions, with a yield much higher than those for the furan-containing POP(JNU-217) and the benzenecontaining POP(JNU-216). Experimental studies and theoretical calculations reveal that the increase of local polarization can indeed reduce the exciton binding energy, and therefore facilitate the separation of electron-hole pairs. This work demonstrates a viable strategy to tune charge separation and ROS generation efficiency by modulating the dipole moments of the building blocks in porous polymeric organic semiconductors.

关键词： porous organic polymer local polarization photocatalytic aerobic oxidation charge separation reactive oxygen species exciton binding energy

基于红外热成像的古建筑墙内暗柱材料缺失检测

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北京林业大学学报 2024年第3期46卷 132-144页

作者：王皓宇彭林张厚江雷智勋王辉张典唐家英管成北京林业大学工学院北京100083 北京林业大学木材无损检测国际联合研究所北京100083 故宫博物院北京100001

【目的】墙内暗柱是木结构古建筑的重要承重构件之一,因其处于潮湿和缺乏通风的环境,故多存在腐朽及由严重腐朽导致的材料缺失等缺陷,容易失去原有的承载能力和稳定性。墙内暗柱自身构造导致现有的检测手段受限,易造成不可逆的损坏。故... 详细信息

【目的】墙内暗柱是木结构古建筑的重要承重构件之一,因其处于潮湿和缺乏通风的环境,故多存在腐朽及由严重腐朽导致的材料缺失等缺陷,容易失去原有的承载能力和稳定性。墙内暗柱自身构造导致现有的检测手段受限,易造成不可逆的损坏。故本研究基于红外热成像原理开展墙内暗柱材料缺失缺陷检测理论与试验研究,以期为基于红外热成像的墙内暗柱缺陷状况无损检查方法的建立奠定部分前期基础。【方法】首先,从理论角度探讨古建筑墙内暗柱传热过程,推导稳态下木柱区域与纯墙体区域的温度公式,分析影响木柱材料缺失缺陷区域温度变化的因素;然后,建立试验模型,进行墙内暗柱缺陷红外检查试验,采集红外图像;最后,通过分析所获得的红外热图,探讨墙内暗柱材料缺失缺陷大小与墙体表面温度分布之间的关系。【结果】(1)理论研究表明:由于木材的横向导热系数远小于墙体导热系数,加热面加热温度相同的情况下,木柱墙体外表面所对应的温度偏低;墙内暗柱的检测效果主要受到缺陷尺寸,即缺陷高度、缺陷深度的影响。(2)试验结果表明:在稳态热传导下,木柱处的墙体外表面温度要低于纯墙体,即木柱处红外图像的颜色更浅;木柱缺陷的存在会使缺陷处墙体表面温度变高,红外图像颜色变深;木柱缺陷高度越大,缺陷导致的高温范围越大;木柱缺陷深度越大,缺陷区域温度值越高。(3)在非稳态热传导下,木柱中线温差分别与木柱缺陷高度(R^(2)≥0.964)、深度(R^(2)≥0.951)呈极强的正相关。(4)在木柱缺陷较小的情况下,墙体表面温度不因缺陷的存在而发生明显改变。【结论】木柱的缺陷高度与深度是影响缺陷红外热成像检测效果的主要因素,红外热成像法应用于古建筑墙内暗柱材料缺失缺陷的筛查与评估是可行的。

关键词：古建筑墙内暗柱缺陷红外热成像无损检测

Cecal microbiota transplantation:unique influence of cecal microbiota from divergently selected inbred donor lines on cecal microbial profile,serotonergic activity,and aggressive behavior of recipient chickens

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畜牧与生物技术杂志:英文版 2023年第5期14卷 1986-2001页

作者： Yuechi Fu jiaying Hu Marisa A.Erasmus Huanmin Zhang Timothy A.Johnson Hengwei cheng Department of Animal Sciences Purdue UniversityWest LafayetteIN 47907USA Avian Disease and Oncology Laboratory USDA-ARSEast LansingMI 48823USA Livestock Behavior Research Unit USDA-ARSWest LafayetteIN 47907USA

Background Accumulating evidence from human trials and rodent studies has indicated that modulation of gut microbiota affects host physiological homeostasis and behavioral characteristics.Similarly,alterations in gut micro-biota could be a feasible strategy for reducing aggressive behavior and improving health in chickens.The study was conducted to determine the effects of early-life cecal microbiota transplantation(CMT)on cecal microbial composi-tion,brain serotonergic activity,and aggressive behavior of recipient chickens.Methods Chicken lines 63 and 72 with nonaggressive and aggressive behavior,respectively,were used as donors and a commercial strain Dekalb XL was used as recipients for CMT.Eighty-four 1-d-old male chicks were randomly assigned to 1 of 3 treatments with 7 cages per treatment and 4 chickens per cage(n=7):saline(control,CTRL),cecal solution of line 6_(3)(6_(3)-CMT),and cecal solution of line 7_(2)(7_(2)-CMT).Transplantation was conducted via oral gavage once daily from d 1 to 10,and then boosted once weekly from week 3 to 5.At weeks 5 and 16,home-cage behavior was recorded,and chickens with similar body weights were assigned to paired aggression tests between the treat-ments.Samples of blood,brain,and cecal content were collected from the post-tested chickens to detect CMT-induced biological and microbiota changes.Results 63-CMT chickens displayed less aggressive behavior with a higher hypothalamic serotonergic activity at week 5.Correspondingly,two amplicon sequence variants(ASVs)belonging to Lachnospiraceae and one Ruminococ-caceae UCG-005 ASV were positively correlated with the levels of brain tryptophan and serotonin,respectively.7_(2)-CMT chickens had lower levels of brain norepinephrine and dopamine at week 5 with higher levels of plasma serotonin and tryptophan at week 16.ASVs belonging to Mollicutes RF39 and GCA-900066225 in 7_(2)-CMT chickens were nega-tively correlated with the brain 5-hydroxyindoleacetic acid(5-HIAA)at week 5,and one Bacteroides ASV was negatively correlated with plas

关键词： Aggressive behavior Cecal microbiota transplantation Chicken Microbiota-gut-brain axis Serotonergic activity

汽车车身板用高强Al-Mg-Si-(Ag/Cu)合金的时效工艺

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金属热处理 2024年第5期49卷 179-185页

作者：吴蔚陈嘉颖郭锐王茹袁悠悠邱铨强程翔翔巨佳南京工程学院材料科学与工程学院、江苏省先进结构材料与应用重点实验室江苏南京211167

采用硬度测试、拉伸试验、显微观察仪器等研究不同时效处理工艺下Al-Mg-Si、Al-Mg-Si-Ag、Al-Mg-Si-Cu合金的时效强化特性及微观结构。结果表明,Ag的加入使得铝合金峰值时效的硬度值有所改进,其峰值硬度为141.01 HV0.5,较Al-Mg-Si和Al-M... 详细信息

采用硬度测试、拉伸试验、显微观察仪器等研究不同时效处理工艺下Al-Mg-Si、Al-Mg-Si-Ag、Al-Mg-Si-Cu合金的时效强化特性及微观结构。结果表明,Ag的加入使得铝合金峰值时效的硬度值有所改进,其峰值硬度为141.01 HV0.5,较Al-Mg-Si和Al-Mg-Si-Cu合金的峰值硬度值增加9.35%和1.53%。这是由于Al-Mg-Si-Ag合金在峰值时效阶段形成的析出强化相β″粒径更加微小,其平均长度较Al-Mg-Si和Al-Mg-Si-Cu合金减少40.05%和23.09%,位置分散更加广。根据对比试验可得,Ag微合金化使Al-Mg-Si合金具有更加明显的沉淀强化效果。因此,Al-Mg-Si-Ag合金具有更优良的综合性能,该研究将为设计新型汽车车身板材的热处理工艺制定提供了一定的理论支持。

关键词： Al-Mg-Si 热处理工艺显微组织性能微合金化

Compact yellow-orange Nd:YVO_(4)/PPMgLN laser at 589 nm

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Optoelectronics Letters 2023年第11期19卷 641-645页

作者： MA Lei FENG Xinkai CHEN Huaixi cheng Xing CHEN jiaying LIANG Wanguo College of Chemistry and Material Fujian Normal UniversityFuzhou 350008China Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China

We propose and make a compact yellow-orange laser of the Nd-doped yttrium vanadate(Nd:YVO_(4))/periodically poled Mg-doped lithium niobate(PPMgLN)module by Raman frequency-doubling at 589 nm.By reasonably designing the size of the Nd:YVO_(4)and 5 mol%PPMgLN crystals,cavity length and coating parameter,a compact 589 nm laser module with a total size of 3 mm×10 mm×1.5 mm is fabricated.In the laser module,the input surface of Nd:YVO_(4)crystal is end-pumped by an 808 nm laser diode(LD).Under the effect of linear resonant cavity structure,the output surface of PPMgLN crystal with a period of 9.48μm generates 589 nm yellow-orange light.The experimental results show that the maximum output power at 589 nm is 390 mW at the pump power of 3 W with the optical-optical conversion efficiency of 13%and the stability of the output power is less than 2%within 3 h.

关键词： Nd: PPMgLN laser

人工智能辅助压缩感知3D重建用于5.0T MR加速全脑超高分辨血管壁成像

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中国医学影像技术 2024年第5期40卷 699-702页

作者：贾森冯飞戚玉龙张辉赵佳盈程静张磊张娜刘新郑海荣梁栋中国科学院深圳先进技术研究院劳特伯生物医学成像研究中心广东深圳518055 北京大学深圳医院医学影像科广东深圳518036 中国科学院深圳先进技术研究院医学人工智能研究中心广东深圳518055

缺血性脑卒中是我国发病率和死亡率最高的疾病,动脉粥样硬化斑块破裂堵塞血管形成血栓系主要病因[1-2]。相比血管造影,MR血管壁成像(vessel wall imaging,VWI)检测颅内斑块、区分管壁病变等的敏感度和特异度均更高;但颅内血管走行纡曲。

关键词：血管壁磁共振成像深度学习压缩感知前瞻性研究

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