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Optoelectronics Letters 2024年第5期20卷 265-271页

作者： QI Hexin ZHOU Xuefang ZHANG Yinghui YANG Guowei BI Meihua hu miao School of Communication Engineering Hangzhou Dianzi UniversityHangzhou 310018China

A switchable and tunable multi-wavelength Brillouin erbium-doped fiber laser(MWBEFL) is designed and experimentally demonstrated. A Sagnac loop filter is employed as the switcher to obtain the double Brillouin frequency shift(BFS) of 0.172 nm(~20 GHz) and the quadruple BFS of 0.35 nm(~40 GHz). The working principles of the proposed laser are theoretically analyzed. The experimental results show that up to 8 Stokes lines with a wavelength interval of 0.172 nm can be obtained. When the Sagnac loop filter is used, two different output spectra with wavelength interval of 0.35 nm are obtained by adjusting the polarization controller(PC) and the optical signal-to-noise ratio(OSNR) is greater than 33 dB. By adjusting the Brillouin pump(BP) wavelength to investigate the tunability of the fiber laser, the output of 2—5 laser channels can be realized corresponding to 20 nm wavelength range. This approach is simple and can be employed for the microwave generation of other frequency ranges subject to the filtering shift of the Sagnac loop.

关键词： fiber laser filter

Thickening progression mechanism of silica fume-oil well cement composite system at high temperatures

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Petroleum Science 2024年第4期21卷 2793-2805页

作者： Hang Zhang miao-miao hu Peng-Peng Li Guo-Qing Liu Qing-Lu Chang Jie Cao Ming Liu Wen-hua Xu Xiu-Jian Xia Jin-Tang Guo School of Chemical Engineering and Technology Tianjin University Zhejiang Institute of Tianjin University Haihe Laboratory of Sustainable Chemical Transformations CNPC Engineering Technology R&D Company Limited

This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C) in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering. Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C, but when temperature reached above130.C, it would aggravate the bulging degree of thickening curves and significantly extend the thickening time, meanwhile causing the abnormal “temperature-based thickening time reversal” and“dosage-based thickening time reversal” phenomena in the range of 130-160.C and 170-180.C respectively. At 130-160.C, the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH) crystal. The introduced silica fume would be attracted to the cement minerals' surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier” to hinder further hydration of the inner cement minerals. This “adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the “temperature-based thickening time reversal” phenomenon. At 170-180.C, the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated, thus the “temperature-based thickening time reversal” vanished and the “dosage-based thickening time reversal” was presented.

关键词： Silica fume Oil well cement Thickening time reversal Pozzolanic reaction Adsorptive barrier CH and C−S−H

Scheduling Model and Algorithm of Construction Equipment under Milestone Constraint

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Meteorological and Environmental Research 2024年第3期15卷 32-35,41页

作者： miao hu College of Science and Technology of China Three Gorges University Yichang 443002China

The scheduling of construction equipment is a means to realize network *** the large-scale and low-cost requirements of engineering construction,the cooperation among members of the engineering supply chain has become very important,and effective coordination of project plans at all levels to optimize the resource management and scheduling of a project is helpful to reduce project duration and *** this paper,under the milestone constraint conditions,the scheduling problems of multiple construction devices in the same sequence of operation were described and hypothesized mathematically,and the scheduling models of multiple equipment were *** Palmer algorithm,CDS algorithm and Gupta algorithm were respectively used to solve the optimal scheduling of construction equipment to achieve the optimization of the construction *** optimization scheduling of a single construction device and multiple construction devices was solved by using sequencing theory under milestone constraint,and these methods can obtain reasonable results,which has important guiding significance for the scheduling of construction equipment.

关键词： Milestone Equipment scheduling Resource constraint Algorithm analysis

Chiral Pair Density Waves with Residual Fermi Arcs in RbV3Sb5

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Chinese Physics Letters 2024年第9期41卷 88-92页

作者： Xiao-Yu Yan Hanbin Deng Tianyu Yang Guowei Liu Wei Song hu miao Zhijun Tu Hechang Lei Shuo Wang Ben-Chuan Lin Hailang Qin Jia-Xin Yin Department of Physics Southern University of Science and TechnologyShenzhen 518055China Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTennessee 37831USA Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices Department of PhysicsRenmin University of ChinaBeijing 100872China Key Laboratory of Quantum State Construction and Manipulation(Ministry of Education) Renmin University of ChinaBeijing 100872China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area Shenzhen 518055China

The chiral 2×2 charge order has been reported and confirmed in the kagome superconductor RbV3Sb5,while its interplay with superconductivity remains elusive owing to its lowest superconducting transition temperature Tc of about 0.85K in the AV3Sb5 family(A=K,Rb,Cs)that severely challenges electronic spectroscopic ***,utilizing dilution-refrigerator-based scanning tunneling microscopy down to 30 mK,we observe chiral 2×2 pair density waves with residual Fermi arcs in *** find a superconducting gap of 150eV with substantial residual in-gap *** spatial distribution of this gap exhibits chiral 2×2 modulations,signaling a chiral pair density wave(PDW).Our quasi-particle interference imaging of the zero-energy residual states further reveals arc-like *** discuss the relation of the gap modulations with the residual Fermi arcs under the space-momentum correspondence between PDW and Bogoliubov Fermi states.

关键词： Fermi chiral utilizing

Nonreciprocal single-photon scattering mediated by a driven Λ-type three-level giant atom

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Communications in Theoretical Physics 2024年第11期 115-124页

作者： Xiaopei Zhang Haozhen Li Ran Zeng miao hu Mengmeng Xu Xuefang Zhou Yang Lan Xiuwen Xia Jingping Xu Yaping Yang School of Communication Engineering Hangzhou Dianzi University Zhejiang Province Key Laboratory of Quantum Technology and Device Zhejiang University Institute of Atomic and Molecular Physics and Functional Materials School of Mathematics and Physics Key Laboratory of Advanced Micro-Structured Materials of Ministry of Education School of Physics Science and Engineering Tongji University

A waveguide-QED with giant atoms, which is capable of accessing various limits of a small one,provides a new paradigm to study photon scatterings. Thus, how to achieve nonreciprocal photon transmissions via such a giant atom setup is highly desirable. In this study, the nonreciprocal single-photon scattering characteristics of a double-driven Λ-type three-level giant atom, where one of the transition couples to a 1D waveguide at two separate points, and the other is driven by two coherent driving fields, are investigated. It is found that a frequency-tunable single-photon diode with an ideal contrast ratio can be achieved by properly manipulating the local coupling phases between the giant atom and the waveguide, the accumulation phase between the two waveguide coupling points, the Rabi frequencies and phase difference of the two driven fields. Compared to the previous single driving schemes, on the one hand, the presence of the second driving field can provide more tunable parameters to manipulate the nonreciprocal single-photon scattering behavior. On the other hand, here perfect nonreciprocal transmission for photons with arbitrary frequencies is achievable by tuning the driving phases while the two driving fields keep on turning, which provides an alternative way to control the nonreciprocal single-photon scattering. Furthermore, the results reveal that both the location and width of each optimal nonreciprocal transmission window is also sensitive to the driving detuning, and a single-photon diode with wide or narrow bandwidth can be realized based on demand. These results may be beneficial for designing nonreciprocal single-photon devices based on a double-driven giant atom setup.

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基于多波长分组的无源光网络故障监测系统设计及系统抗干扰性能分析

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光学学报 2024年第1期44卷 420-429页

作者：金哲怡毕美华滕旭阳胡淼杭州电子科技大学通信工程学院浙江杭州310018 上海交通大学区域光纤通信网与新型光通信系统国家重点实验室上海200240

提出了一种基于多波长分组的无源光网络系统监测方案,用于解决基于反射型的故障监测方案中用户之间易发生因干扰导致的链路状态误判的问题。该方案将不同波长分配到不同组,实现不同光网络单元(ONU)组之间的识别,从而避免不同组成员之间... 详细信息

提出了一种基于多波长分组的无源光网络系统监测方案,用于解决基于反射型的故障监测方案中用户之间易发生因干扰导致的链路状态误判的问题。该方案将不同波长分配到不同组,实现不同光网络单元(ONU)组之间的识别,从而避免不同组成员之间的干扰。在此基础上,将与光路终端距离相近的ONU分配到不同组内,以此降低组内ONU发生相互干扰的概率。此外,还研究了用户数量、传输脉冲功率和脉冲宽度对该系统性能的影响。通过理论推导与仿真可知,在检测波长通道数为4、检测光脉宽为10-8s、用户数量为16、最大距离差为2 km的无源光网络系统用户中,检测信号的信噪比为9.06 dB,识别精度为2 m。这些结果表明,基于多波长分组的无源光网络监测系统方案能够支持对大容量无源光网络系统的监控,并且在易发生干扰的用户数量较多的情况下具有较好的性能。

关键词：光通信光编码故障监测用户分布信噪比信号干扰比

基于维纳过程的低温环境下齿轮泵性能退化研究

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中国铁道科学 2024年第2期45卷 155-163页

作者：邱战国胡淼邢群雁宋宏智中国铁道科学研究院集团有限公司通信信号研究所北京100081 中国铁路电务技术中心北京100081

针对低温环境下(5℃以下)温度对齿轮泵性能退化的影响,以驼峰车辆减速器齿轮泵为研究对象,以流量为性能退化分析指标,建立齿轮泵流量计算模型;采用带有线性函数或指数函数漂移项的维纳过程模型,建立包含工作压力、温度和等效磨损间隙的... 详细信息

针对低温环境下(5℃以下)温度对齿轮泵性能退化的影响,以驼峰车辆减速器齿轮泵为研究对象,以流量为性能退化分析指标,建立齿轮泵流量计算模型;采用带有线性函数或指数函数漂移项的维纳过程模型,建立包含工作压力、温度和等效磨损间隙的多参数齿轮泵性能退化过程模型;通过齿轮泵流量计算模型的分析结果与现场试验数据对比,建模分析低温环境下齿轮泵性能退化过程中环境温度、工作压力对齿轮泵性能退化的影响。结果表明:低温环境下齿轮泵的性能退化与环境温度存在强相关性;线性漂移模型较指数漂移模型有更优的统计拟合效果;包含多参数带漂移的维纳过程模型能有效表征齿轮泵的性能退化过程。

关键词：齿轮泵驼峰车辆减速器维纳过程模型性能退化模型环境温度

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改进YOLOv7的自动驾驶目标检测算法

计算机工程与应用 2024年第11期60卷 165-172页

作者：胡淼姜麟陶友凤张志坚昆明理工大学理学院昆明650500

能否准确实时检测出道路上的车辆、行人等物体对自动驾驶车辆十分重要。针对自动驾驶场景下,车辆在行驶中存在的漏检,小目标检测效果差的问题,提出一种改进YOLOv7算法的自动驾驶目标检测算法。修改网络中扩充感受野的模块,减少感受野模... 详细信息

能否准确实时检测出道路上的车辆、行人等物体对自动驾驶车辆十分重要。针对自动驾驶场景下,车辆在行驶中存在的漏检,小目标检测效果差的问题,提出一种改进YOLOv7算法的自动驾驶目标检测算法。修改网络中扩充感受野的模块,减少感受野模块的大小,提高模型速度的同时增强对图片特征信息的提取能力。在主干网络输出端引入双层路由注意力机制,提高模型对小目标物体的检测性能。用EIOU损失函数替换算法原本的CIOU损失函数,将预测框与真实框的高度与宽度的差异最小化,加快模型收敛速度的同时达到更好的定位效果。实验结果表明:在KITTI数据集上,改进后的YOLOv7算法进行目标检测时,其mAP达到94.7%,在原YOLOv7算法上提升了3.1个百分点,并且在小目标物体检测上获得了更高的检测精度,有效提升了模型对小目标检测效果。

关键词：自动驾驶小目标检测 YOLOv7 注意力机制损失函数

呼吸道假丝酵母定植与细菌性呼吸机相关性肺炎的关系

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中华医院感染学杂志 2024年第13期34卷 1949-1953页

作者：孙伟戴诚胡苗苗李亮孙浩阜阳市第二人民医院呼吸与危重症医学科安徽阜阳236015 浙江省医疗诊断数字技术重点实验室迪安诊断技术集团股份有限公司浙江杭州310030

目的探究呼吸道假丝酵母定植与细菌性呼吸机相关性肺炎(VAP)的关系。方法法选取阜阳市第二人民医院150例细菌性VAP患者为研究对象,根据是否发生呼吸道假丝酵母定植分为定植组67例和非定植组83例,比较两组呼吸道分泌物中细菌菌株分布情... 详细信息

目的探究呼吸道假丝酵母定植与细菌性呼吸机相关性肺炎(VAP)的关系。方法法选取阜阳市第二人民医院150例细菌性VAP患者为研究对象,根据是否发生呼吸道假丝酵母定植分为定植组67例和非定植组83例,比较两组呼吸道分泌物中细菌菌株分布情况、呼吸道分泌物中淀粉样蛋白(SAA)、C-反应蛋白(CRP)、白细胞介素-6(IL-6)水平,分析SAA、CRP和IL-6水平与定植组临床指标的相关性及其对呼吸道假丝酵母定植的诊断价值。结果定植组革兰阳性菌检出率高于非定值组(P<0.05);定植组VAP确诊时机械通气天数低于非定植组(P<0.05),发热、痰量增多、痰液性状改变占比、呼吸道分泌物中β-葡聚糖水平、SAA、CRP及IL-6水平、临床肺部感染评分(CPIS)高于非定植组(P<0.05);Pearson相关系数分析显示,SAA、CRP及IL-6水平与定植组VAP确诊时机械通气天数、CPIS评分、β-葡聚糖均呈正相关(P<0.05);受试者工作特征(ROC)曲线显示,SAA、CRP及IL-6水平单独及联合预测细菌性VAP患者呼吸道假丝酵母定植的曲线下面积(AUC)为0.720、0.7230.750和0.883,联合诊断价值更高(P<.0.05)。结论呼吸道假丝酵母定植可加快细菌性VAP患者病情进展,其通过影响SAA、CRP和IL-6表达调控机体免疫失衡,可作为细菌性VAP重点监测内容。

关键词：假丝酵母定植呼吸机相关性肺炎淀粉样蛋白 C-反应蛋白白细胞介素-6

遗传算法优化变分模态分解在轴承故障特征提取中的应用

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噪声与振动控制 2024年第1期44卷 148-153,204页

作者：单玉庭刘韬褚惟缪护昆明理工大学机电工程学院昆明650500 云南省科技厅云南省先进装备智能制造技术重点实验室昆明650500 昆明云内动力股份有限公司昆明650500

针对变分模态分解(Variational Mode Decomposition,VMD)过程中模态分量个数和惩罚参数大小依赖先验知识,单一或顺序优化单一参数可能导致局部最优的问题,提出以包络熵和包络峭度因子作为适应度函数,利用遗传算法全局寻优的特点,对VMD... 详细信息

针对变分模态分解(Variational Mode Decomposition,VMD)过程中模态分量个数和惩罚参数大小依赖先验知识,单一或顺序优化单一参数可能导致局部最优的问题,提出以包络熵和包络峭度因子作为适应度函数,利用遗传算法全局寻优的特点,对VMD的模态分量个数和惩罚参数组合进行优化。通过最优参数组合下的VMD对信号进行分解,可以获得多个本征模态分量(Intrinsic Mode Function,IMF),选择适应度函数最小IMF分量作为有效IMF分量进行包络解调,从中提取轴承信号的故障特征频率。对多种轴承故障类型信号进行分析并与其他方法对比,结果表明所提方法能有效提取轴承故障特征,有助于实现微弱故障条件下轴承故障特征频率的准确提取。

关键词：故障诊断变分模态分解包络熵包络峭度因子遗传算法包络解调