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电化学促进2,2,6,6-四甲基哌啶氧化物(TEMPO)介导的甘氨酸衍生物氧化脱氢Povarov/串联反应

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有机化学 2024年第3期44卷 940-950页

作者：李章健王振华郭剑峰方萍马聪刘润华梅天胜四川师范大学化学与材料科学学院成都610068 中国科学院上海有机化学研究所、金属有机化学国家重点实验室、中国科学院大学上海200032 中国科学院上海有机化学研究所、宁波中科新材料创制中心浙江宁波315800

研究了电化学氧化甘氨酸衍生物与烯烃之间的氧化脱氢Povarov/串联反应,其中氮氧自由基2,2,6,6-四甲基哌啶氧化物(TEMPO)作为媒介降低了电化学反应的电位,避免了某些富电子的芳胺在较高电位下的过氧化.它为甘氨酸衍生物的氮-α位官能团... 详细信息

研究了电化学氧化甘氨酸衍生物与烯烃之间的氧化脱氢Povarov/串联反应,其中氮氧自由基2,2,6,6-四甲基哌啶氧化物(TEMPO)作为媒介降低了电化学反应的电位,避免了某些富电子的芳胺在较高电位下的过氧化.它为甘氨酸衍生物的氮-α位官能团化提供了潜在的途径,并通过Shono氧化与Povarov反应的结合,开发了一种在温和条件下高产率合成喹啉衍生物的有效方法.

关键词：电化学 2,2,6,6-四甲基哌啶氧化物(TEMPO) Povarov反应 Shono氧化

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MRI诊断脊髓圆锥节细胞胶质瘤1例

中国临床医学影像杂志 2024年第7期35卷 530-531页

作者：沈天赐宋鑫洋郭建峰杨峰湖北医药学院附属襄阳市第一人民医院放射科湖北襄阳441000

病例女,53岁,因双侧腰部疼痛伴双下肢放射痛2周来我院骨科就诊。双侧腰部压痛,疼痛向双下肢放射,余未见明显异常。腰椎MRI平扫+增强:L1水平段脊髓内见等T1稍长T2类圆形异常信号影,边界较清,信号较均匀,大小14 mm×17 mm×24 mm。增强扫... 详细信息

病例女,53岁,因双侧腰部疼痛伴双下肢放射痛2周来我院骨科就诊。双侧腰部压痛,疼痛向双下肢放射,余未见明显异常。腰椎MRI平扫+增强:L1水平段脊髓内见等T1稍长T2类圆形异常信号影,边界较清,信号较均匀,大小14 mm×17 mm×24 mm。增强扫描病灶不均匀轻度强化,其内可见点条状强化灶,邻近脊膜见线状强化,考虑室管瘤膜可能性大。

关键词：神经节神经胶质瘤磁共振成像

基于多模态影像组学联合机器学习模型预测甲状腺乳头状癌颈部淋巴结转移的价值

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放射学实践 2024年第9期39卷 1152-1157页

作者：郭建峰宋鑫洋沈天赐杜梦颖纪旭东杨峰湖北医药学院附属襄阳市第一人民医院放射科湖北441000 湖北医药学院附属襄阳市第一人民医院超声科湖北441000

目的:构建基于超声、CT影像组学联合机器学习模型,探讨其预测甲状腺乳头状癌(PTC)颈部淋巴结转移(CLNM)的价值。方法:回顾性搜集198例经手术病理证实的PTC患者,其中CLNM组97例,无CLNM组101例,所有患者术前均接受甲状腺超声和增强CT扫描... 详细信息

目的:构建基于超声、CT影像组学联合机器学习模型,探讨其预测甲状腺乳头状癌(PTC)颈部淋巴结转移(CLNM)的价值。方法:回顾性搜集198例经手术病理证实的PTC患者,其中CLNM组97例,无CLNM组101例,所有患者术前均接受甲状腺超声和增强CT扫描,按照7:3的比例随机分为训练集和测试集。采用单因素和多因素回归分析PTC患者发生CLNM的临床独立风险因素,构建临床风险模型。基于超声和CT图像提取并筛选最优影像组学特征,分别使用逻辑回归(LR)、支持向量机(SVM)、随机森林(RF)、极度随机树(ET)、K邻近算法(KNN)、XGBoost、监督学习集成模型(Light GBM)、前馈神经网络多层感知器(MLP)等8个机器学习模型构建PTC患者CLNM影像组学预测模型。绘制受试者工作特征(ROC)曲线评估模型效能,筛选出最优影像组学模型联合临床风险模型构建诺模图,应用决策曲线分析(DCA)对比不同模型的临床获益。结果:临床影像特征中年龄、肿瘤最大直径、超声报告淋巴结状态和CT报告淋巴结状态被筛选出来作为临床独立风险因素(P<0.05)。从超声和CT图像中分别筛选出14个和12个影像组学特征。8个机器学习模型中SVM模型表现最优,其预测CLNM状态的AUC在训练集为0.951(95%CI:0.920~0.982),测试集为0.857(95%CI:0.764~0.950)。由临床模型和多模态影像组学模型构建的诺模图具有更好的预测效能,其预测CLNM状态的AUC在训练集为0.960(95%CI:0.933~0.987),测试集为0.890(95%CI:0.812~0.968)。DCA显示诺模图具有较高的临床净收益。结论:基于多模态影像组学联合机器学习模型可以更准确地预测PTC患者是否发生CLNM,具有一定的临床应用价值。

关键词：甲状腺乳头状癌淋巴结转移影像组学机器学习体层摄影术,X线计算机超声检查

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螺旋叶片对装运性能的影响与结构优化

科学技术与工程 2024年第27期24卷 11631-11637页

作者：落峻铭陈峙梁万吉张梦奇郭建锋太原科技大学机械工程学院太原030024 煤矿采掘装备国家工程实验室太原030032 山西能源学院机电工程系晋中030604

为了解决传统薄煤层采煤机装运效率低和载荷波动大的问题,以滚筒的螺旋叶片为研究对象,通过离散元仿真试验,研究不同螺旋升角下滚筒装运性能的变化规律。结果表明:直径为1200 mm的滚筒在螺旋升角逐渐增加的情况下,滚筒的装运效率从73.31... 详细信息

为了解决传统薄煤层采煤机装运效率低和载荷波动大的问题,以滚筒的螺旋叶片为研究对象,通过离散元仿真试验,研究不同螺旋升角下滚筒装运性能的变化规律。结果表明:直径为1200 mm的滚筒在螺旋升角逐渐增加的情况下,滚筒的装运效率从73.31%逐步提高至76.56%,当螺旋升角达到18°时获得最佳装运效率,螺旋升角由18°继续增长至30°时,滚筒的装运效率与螺旋升角呈负相关趋势。以最佳螺旋升角为基础,对螺旋叶片进行结构优化,仿真试验表明:优化后滚筒的装运效率提高了9.94%,载荷波动降低了22.59%。

关键词：薄煤层采煤机螺旋叶片最佳螺旋升角离散元分析结构优化

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基于表面肌电信号的操作员疲劳性研究

电光系统 2024年第2期 46-48,60页

作者：吕春彦魏玉凡郭建峰中国电子科技集团公司第二十七研究所郑州450047

文章通过采集操作人员表面肌电信号的方式,对操作员在操作过程中的疲劳状态进行了研究。利用软件绘制积分肌电和平均功率频率变化曲线图,客观评估操作人员的肌肉疲劳情况。

关键词：表面肌电疲劳积分肌电平均功率频率

Multi-objective optimization and evaluation of supercritical CO_(2) Brayton cycle for nuclear power generation

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Nuclear Science and Techniques 2024年第2期35卷 183-209页

作者： guo-Peng Yu Yong-feng Cheng Na Zhang Ping-jian Ming Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang 330013China

The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle *** models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear *** analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic *** show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic *** the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to *** performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,*** performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited *** the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.

关键词： Supercritical CO_(2)Brayton cycle Nuclear power generation Thermo-economic analysis Multi-objective optimization Decision-making methods

A BRIEF INTRODUCTION TO MERIDIAN PROJECT

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空间科学学报 2002年第Z1期22卷 35-38页

作者： WEI fengsi XIAO Zuo WU jian guo jianshan feng Xueshang Center for Space Science and Applied Research The Chinese Academy of Sciences Beijing 100080 P.R. China Department of Geophysics Peking University P.R. China Institute of Radio Propagation Ministry of Information Industry P.R.China Center for Space Science and Applied Research The Chinese Academy of Sciences Beijing 100080 P.R. China Center for Space Science and Applied Research The Chinese Academy of Sciences Beijing 100080 P.R. China

　　Early in 1994, sponsored by Chinese Academy of Sciences (CAS) and then the State Science and Technology Commission of China (SSTC, now Ministry of Sci ence and Technology), Chinese space scientists (including scientists from Taiwan) gathered together to discuss issues on the development of space physics researches in China. Following it, several special seminars were held to continue the discus sion which finally led to a proposal to CAS and SSTC for establishing a station chain along the 120°E to monitor the space environment. This proposal was care fully reviewed and thoroughly evaluated by many leading scientists in the com munity and then listed in the State Plan of Chinese Central Government in June 1997. The project then has been formally called as "Meridian Chain of Compre hensive Ground-Based Space Environment Monitors in the Eastern Hemisphere" "Meridian Project". After several years of preparations the project has been par tially initiated with the efforts devoted by institutes and universities involved.……

关键词： space environment Science and Technology

Exact Box-Constrained Economic Operating Region for Power Grids Considering Renewable Energy Sources

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 514-523页

作者： Huating Xu Bin feng Chutong Wang Chuangxin guo jian Qiu Mingyang Sun College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

The growing integration of renewable energy sources manifests as an effective strategy for reducing carbon emissions. This paper strives to efficiently approximate the set of optimal scheduling plans(OSPs) to enhance the performance of the steady-state adaptive cruise method(SACM) of power grid, improving the ability of dealing with operational uncertainties. Initially, we provide a mathematical definition of the exact boxconstrained economic operating region(EBC-EOR) for the power grid and its dispatchable components. Following this, we introduce an EBC-EOR formulation algorithm and the corresponding bi-level optimization models designed to explore the economic operating boundaries. In addition, we propose an enhanced big-M method to expedite the computation of the EBCEOR. Finally, the effectiveness of the EBC-EOR formulation, its economic attributes, correlation with the scheduling plan underpinned by model predictive control, and the significant improvement in computational efficiency(over twelvefold) are verified through case studies conducted on two test systems..

关键词： Exact box-constrained economic operating region(EBC-EOR) big-M method intelligent scheduling steady-state adaptive cruise uncertainty renewable energy source

Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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Defence Technology（防务技术） 2024年第4期34卷 217-224页

作者： Rui Zhao jian Zheng Jin guo Yunbo Shi Hengzhen feng Jun Tang Jun Liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss