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Investigation of strata fractures during longwall mining:Original introscopic probe and image analysis methods
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作者 Mateusz Kudasik Marta Skiba +3 位作者 Jerzy Krawczyk Janusz Kruczkowski Mariusz Młynarczuk Norbert Skoczylas 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1049-1059,共11页
The research presented in this paper aimed to analyze the evolution of fractures in strata in relation to the progress of longwall mining.To achieve this objective,an introscopic probe equipped with a highresolution c... The research presented in this paper aimed to analyze the evolution of fractures in strata in relation to the progress of longwall mining.To achieve this objective,an introscopic probe equipped with a highresolution camera was developed,along with additional equipment that enables continuous recording of the internal surfaces of drainage boreholes exceeding 100 m in depth.The probe was utilized to test two methane drainage boreholes in the Z-3b longwall,which operates within the 501/3 coal seam of the Jankowice mine in Poland.Automatic image analysis methods were applied to evaluate the recorded images,based on a newly developed classificationsystem for fractures categorized by size and number.The results were compared with an analysis of changes in the methane capture rate from the drainage boreholes,which correlated with longwall mining progress.A strong correlation was observed between the number of fractures and the lithology of the strata layers.The largest number of fractures and their evolution were recorded in the coal layers,followed by the shale layers,while the sandstone layers exhibited the least number of fractures.Based on parallel measurements of the methane capture rate from the drainage boreholes during the progress of longwall mining,the extent of the strata's fracture zone was determined to range from 6 m to 36 m.Within the fracture zone,the strata are highly fractured,which leads to an increase in methane emissions through seepage and diffusion processes. 展开更多
关键词 COAL METHANE Coal fracture Introscopic probe Fracture zone
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A fluorescent probe regulated by trifluoromethyl and nitrogen-containing heterocycles for monitoring biothiol fluctuations in the brains of mice with schizophrenia
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作者 Chengcheng Zhang Zhe Wu +7 位作者 Ningning Jiang Yi Song Weina Geng Hongmei Liu Ming Jin Shuxiang Wang Jinchao Zhang Yutao Yang 《Chinese Chemical Letters》 2026年第1期440-443,共4页
Schizophrenia(SCZ) is a severe mental disorder with an unclear pathogenesis.Increasing evidence suggests that oxidative stress(OS) may contribute to the neuropathological processes underlying SCZ.Biothiols,key endogen... Schizophrenia(SCZ) is a severe mental disorder with an unclear pathogenesis.Increasing evidence suggests that oxidative stress(OS) may contribute to the neuropathological processes underlying SCZ.Biothiols,key endogenous antioxidants,have been proposed as potential biomarkers for the disease.However,due to the presence of the blood-brain barrier(BBB),fluorescent probes are rarely used to image biothiols in the brain of SCZ models.In this study,a series of fluorescent probes for biothiols were developed using dicyanoisophorone derivatives as fluorophores known for their excellent optical properties,and carboxylic esters as recognition units.A parallel synthesis and rapid screening strategy was employed to construct and optimize these probes.By introducing trifluoromethyl and benzothiazole groups into the fluorophore,the emission wavelength was successfully shifted into the near-infrared region.Additionally,various trifluoromethyl-substituted aromatic and nitrogen heterocyclic compounds were incorporated to optimize the carboxylic esters,thereby improving the probes' reactivity and lipophilicity.Systematic evaluation of the physicochemical characteristics,and optical performance led to the identification of DCIBT-11 as the most promising candidate.DCI-BT-11 demonstrated excellent BBB permeability and a good response to biothiols both in vitro and in vivo.Notably,DCI-BT-11 was used for the first time to visualize biothiol flux and assess the therapeutic effects of the antioxidant N-acetylcysteine(NAC) in the brains of SCZ mouse models,offering new insights into the role of OS in the pathogenesis and treatment of SCZ. 展开更多
关键词 Fluorescent probe Biothiol Blood-brain barrier SCHIZOPHRENIA Oxidative stress
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Unconventional application of a fluorescent probe for MS-based detection of multiple sulfur species in ferroptosis
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作者 Mengyu Cao Yiyan Yin +2 位作者 Jingyi Qin Jin Ouyang Na Na 《Chinese Chemical Letters》 2026年第1期552-556,共5页
Ferroptosis has exhibited great potential in therapies and intracellular reducing agents of sulfur species(RSSs) in the thiol-dependent redox systems are crucial in ferroptosis.This makes the simultaneous detection of... Ferroptosis has exhibited great potential in therapies and intracellular reducing agents of sulfur species(RSSs) in the thiol-dependent redox systems are crucial in ferroptosis.This makes the simultaneous detection of multiple RSSs significant for evaluating ferroptosis therapy.However,the traditional techniques,including fluorescent(FL) imaging and electrospray ionization-based mass spectrometry(MS) detection,cannot achieve the discrimination of different RSSs.Herein,simultaneous MS detection of multiple RSSs,including cysteine(Cys),homocysteine(Hcy),glutathione(GSH) and hydrogen sulfide(H_(2)S),was obtained upon enhancing ionization efficiency by a fluorescent probe(NBD-O-1).Based on the interaction between NBD-O-1 and RSSs,the complex of RSSs with a fragment of NBD-O-1 can be generated,which can be easily ionized for MS detection in the negative mode.Therefore,the intracellular RSSs can be well detected upon the incubation of He La cells with the probe of NBD-O-1,exhibiting the total RSS levels by the FL imaging and further providing expression of each RSS by enhanced MS detection.Furthermore,the RSSs during ferroptosis in He La cells have been evaluated using the present strategy,demonstrating the potential for ferroptosis examinations.This work has made an unconventional application of a fluorescent probe to enhance the detection of multiple RSSs by MS,providing significant molecular information for addressing the ferroptosis mechanism. 展开更多
关键词 Reducing sulfur species Ferroptosis Fluorescent probe Enhanced-ESI MS Intracellular detections
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Advances in cell-penetrating peptides for cytoplasmic delivery of fluorescent probes
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作者 Simei Zhong Peng Xu +3 位作者 Yunfei Wei Xinxin Duan Shanshan Zhao Yu-Hui Zhang 《Journal of Innovative Optical Health Sciences》 2026年第1期1-29,共29页
Fluorescent probes,with their superior optical properties and labeling versatility,have greatly advanced the visualization of intracellular molecules and subcellular structures.However,poor cytoplasmic delivery,caused... Fluorescent probes,with their superior optical properties and labeling versatility,have greatly advanced the visualization of intracellular molecules and subcellular structures.However,poor cytoplasmic delivery,caused by charge,size,or targeting groups,limits the effective use of many fluorescent probes in live cells.Recently,cell-penetrating peptides(CPPs)have emerged as efficient carriers,offering great potential for the cytoplasmic delivery of fluorescent probes in live cells.This review provides a comprehensive overview of CPPs as vehicles for probe delivery,outlining advances in their development,conjugation chemistries,and intracellular delivery mechanisms.Recent applications in live-cell imaging are highlighted and organized according to major CPP modification strategies,including sequence engineering,cyclization,hybrid design and enhancement by chemical reagents.Finally,the challenges that remain and the future outlook of this rapidly evolvingfield are discussed. 展开更多
关键词 Fluorescent probes cell-penetrating peptides live-cell cytoplasmic delivery
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Cavitation Control in Mixed-Flow Pumps through Blade Perforation
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作者 Chaoyu Wei Haipeng Zhang +4 位作者 Weidong Shi Yongfei Yang Linwei Tan Xianglong Wu Yurui Dai 《Fluid Dynamics & Materials Processing》 2026年第2期205-224,共20页
During high-speed operation,mixed-flow pumps are susceptible to cavitation,which destabilizes the internal flow,increases energy losses,and degrades hydraulic efficiency.To assess the effectiveness of blade perforatio... During high-speed operation,mixed-flow pumps are susceptible to cavitation,which destabilizes the internal flow,increases energy losses,and degrades hydraulic efficiency.To assess the effectiveness of blade perforation as a cavitation-mitigation strategy,in this study several mixed-flow pump models incorporating perforations were developed.Numerical simulations were performed for configurations with circular holes positioned at different locations along the blade leading edge,and the computational results were validated against experimental measurements.The findings indicate that the location of the perforations plays a decisive role in cavitation suppression.Moving from the blade rim toward the hub along the leading edge,the critical net positive suction head,NPSH_(cr),initially decreases and subsequently increases,while remaining consistently lower than that of the reference non-perforated configuration.The perforations promote the transfer of high-pressure fluid from the pressure side to the suction side of the blade,thereby alleviating local low-pressure regions.This pressure compensation significantly reduces the extent of low-pressure zones in the vicinity of the perforations,leading to a marked suppression of cavitation both locally and downstream of the perforated regions. 展开更多
关键词 Cavitation suppression numerical simulation mixed-flow pump blade perforation
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Oral ER-targeting near-infrared nanoprobes enable real-time intraoperative thoracic duct mapping in swine
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作者 Yutao Zhang Wennan Li +5 位作者 Qi Yu Maimaiti Subinuer Yaxing Shen Mingxiang Feng Zhiqian Guo Wei-Hong Zhu 《Science China Chemistry》 2026年第2期1008-1015,共8页
The thoracic duct(TD),the largest lymphatic vessel in the human body,plays a critical role in returning lymph to the circulatory system.However,its dynamic,distensible nature and concealed anatomical location make int... The thoracic duct(TD),the largest lymphatic vessel in the human body,plays a critical role in returning lymph to the circulatory system.However,its dynamic,distensible nature and concealed anatomical location make intraoperative visualization critically challenging and increase the risk of injury.Real-time,high-resolution assessment of TD leaks remains an urgent clinical need.Here,we present a breakthrough molecular engineering strategy that leverages an intestinally lipophilic fluorescent formulation for dynamic in vivo TD imaging.Our rationally designed cyanine derivative IR790+,known for its rapid membrane permeability and endoplasmic reticulum(ER)targeting localization,demonstrates unprecedented chylomicron affinity,which subsequently transports the dye through the lymphatic system to the TD.Notably,dynamic,high-contrast intraoperative TD imaging is achieved from rat models to swine models.Administered orally as near-infrared(NIR)fluorescent contrast agent,this ultra-stable IR790+@oil formulation,engineered via flash nanoprecipitation,surpasses conventional counterparts by enabling non-invasive,real-time identification of TD.Intriguingly,this first-reported ER-targeting NIR formulation,delivered orally,represents a paradigm shift in fluorescence-guided surgery,significantly improving intraoperative accuracy. 展开更多
关键词 near-infrared dye fluorescent probe oral administration cyanine surgical navigation thoracic duct formulation
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Enantioselective recognition of amino acids in water using emission-tunable chiral fluorescent probes
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作者 Yi-Xin Zhang Fang-Qi Zhang +5 位作者 Ao-Pei Peng Tao Jiang Ya-Xi Meng Yang Li Shuang-Xi Gu Yuan-Yuan Zhu 《Chinese Chemical Letters》 2026年第1期338-343,共6页
The detection of amino acid enantiomers holds significant importance in biomedical,chemical,food,and other fields.Traditional chiral recognition methods using fluorescent probes primarily rely on fluorescence intensit... The detection of amino acid enantiomers holds significant importance in biomedical,chemical,food,and other fields.Traditional chiral recognition methods using fluorescent probes primarily rely on fluorescence intensity changes,which can compromise accuracy and repeatability.In this study,we report a novel fluorescent probe(R)-Z1 that achieves effective enantioselective recognition of chiral amino acids in water by altering emission wavelengths(>60 nm).This water-soluble probe(R)-Z1 exhibits cyan or yellow-green luminescence upon interaction with amino acid enantiomers,enabling reliable chiral detection of 14 natural amino acids.It also allows for the determination of enantiomeric excess through monitoring changes in luminescent color.Additionally,a logic operation with two inputs and three outputs was constructed based on these optical properties.Notably,amino acid enantiomers were successfully detected via dual-channel analysis at both the food and cellular levels.This study provides a new dynamic luminescence-based tool for the accurate sensing and detection of amino acid enantiomers. 展开更多
关键词 Fluorescent probe Amino acid enantiomers Chiral recognition Aqueous solution Dynamic multicolor emissions
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Performance Evaluation of the Hybrid Heat Pump to Decarbonize the Buildings Sector:Energetic,Environmental and Economic Characterization
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作者 Miriam DiMatteo Domiziana Vespasiano +2 位作者 Gianluigi Lo Basso Costanza Vittoria Fiorini Andrea Vallati 《Energy Engineering》 2026年第2期1-37,共37页
Decarbonising the building sector,particularly residential heating,represents a critical challenge for achieving carbon-neutral energy systems.Efficient solutions must integrate both technological performance and rene... Decarbonising the building sector,particularly residential heating,represents a critical challenge for achieving carbon-neutral energy systems.Efficient solutions must integrate both technological performance and renewable energy sources while considering operational constraints of existing systems.This study investigates a hybrid heating system combining a natural gas boiler(NGB)with an air-to-water heat pump(AWHP),evaluated through a combination of laboratory experiments and dynamic modelling.A prototype developed in the Electrical and Energy Engineering Laboratory enabled the characterization of both heat generators,the collection of experimental data,and the calibration of a MATLAB/Simulink model,including emissions and exhaust analyses.Sensitivity analyses were performed to identify optimal configurations for energy efficiency and system control,accounting for interactions between subsystems.Results highlight that hybridisation significantly improves primary energy efficiency and reduces fuel consumption compared to conventional NGB-only systems.Environmental performance,assessed through CO_(2) and NOx emissions and renewable energy integration,demonstrates the benefits of partial electrification in the residential sector.Economic assessment further quantifies decarbonization costs and fuel savings,illustrating tradeoffs between low-capital,moderate-performance systems and high-efficiency,high-renewable solutions requiring larger investments.The analysis shows that strategic decisions for residential decarbonisation cannot be separated from system-wide considerations,including control strategies,component integration,and economic feasibility.The study underlines the importance of hybrid and renewable-based solutions as pivotal pathways for energy transition in the residential building sector. 展开更多
关键词 Hybrid heat pump laboratory measurements decarbonization environmental analysis energy analysis economic analysis
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Study on Temperature Field Distribution of Hydraulic Motor Pump and Heat Dissipation Simulation of Flow-Solid-Heat Coupled with Spoiler Cooling Device
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作者 Geqiang Li Kai Wang +3 位作者 Juntao Liu Zhengyang Han Shuai Wang Donglin Li 《Frontiers in Heat and Mass Transfer》 2026年第1期120-139,共20页
To explore the distribution law of the temperature field in the motor pump and the influence of the fanshaped DC channel with spoiler in the pump housing on its heat dissipation performance.This study takes the arc-ge... To explore the distribution law of the temperature field in the motor pump and the influence of the fanshaped DC channel with spoiler in the pump housing on its heat dissipation performance.This study takes the arc-gear type hydraulicmotor pump as the research object.In COMSOL,a coupled heat transfer simulationmodel of themotor pump’s fluid-solid coupling is established,and the internal temperature field characteristics are analyzed.To improve the heat dissipation effect of the motor pump,it is proposed to arrange spoiler in the fan-shaped DC channel of the pump housing to enhance heat dissipation.Three types of spoilers,namely,wing-shaped,inclined rectangle-shaped,and wave-shaped,are designed.The simulation results show that when the motor pump operates under rated conditions,due to the poor heat dissipation environment inside the motor pump,the high-temperature areas of the motor pump are concentrated in the rotor and permanent magnet parts.After arranging the spoiler,the turbulent kinetic energy and vorticity in the fan-shaped DC channel of the pump housing are significantly enhanced.All three spoiler structures can reduce the maximum temperature of each component of the motor.According to the comprehensive performance evaluation criterion(PEC),the inclined rectangle-shaped structure has the best comprehensive heat transfer performance(PEC=1.114),while the wave-shaped structure has higher heat transfer efficiency but greater pressure loss.The wing-shaped structure has relatively limited enhancement effect on heat dissipation.This study systematically quantifies the influence of different spoiler structures on heat dissipation performance and flowresistance characteristics,providing a solution for enhancing the heat dissipation of the motor pump. 展开更多
关键词 Motor pump fluid-solid coupling heat dissipation performance SPOILER enhancing the heat dissipation
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A NIR and ratiometric fluorescent probe for quantitative detection of SO_(2) derivatives in Chinese medicinal materials and bioimaging in vivo
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作者 Meitong Wu Ke Wu +7 位作者 Shumin Feng Li Xu Mi Lei Jianmei Chen Shuang Li Mian Qin Dahui Liu Guoqiang Feng 《Chinese Chemical Letters》 2026年第1期434-439,共6页
Sulfur dioxide(SO_(2)) and its derivatives have been recognized as harmful environmental pollutants.However,they are often produced during the processing of traditional Chinese medicines,potentially compromising the q... Sulfur dioxide(SO_(2)) and its derivatives have been recognized as harmful environmental pollutants.However,they are often produced during the processing of traditional Chinese medicines,potentially compromising the quality of these medicinal materials and contributing to various health issues.Due to a lack of effective monitoring and imaging tools,the physiological effects of excessive SO_(2) residues in traditional Chinese medicine remain unclear.Therefore,developing a rapid and effective tool for detecting SO_(2) is crucial for understanding its metabolic pathways and effects in vivo.In this study,we developed a near infrared(NIR) and ratiometric fluorescent probe,NIR-RS,which exhibits high sensitivity,selectivity,and rapid response for SO_(2) detection.Notably,NIR-RS accurately quantifies SO_(2) contents in Pinelliae rhizoma(P.rhizoma) samples,with recovery rates from 98.46 % to 102.40 %,and relative standard deviations(RSDs)< 5.0 %.For bioimaging applications,NIR-RS has low cytotoxicity and good mitochondrial-targeting ability,making it suitable for imaging exogenous and endogenous SO_(2) in mitochondria.Additionally,NIR-RS was successfully applied to image SO_(2) content of P.rhizoma samples within cells,revealing that high SO_(2) residue elevated mitochondria adenosine triphosphate(ATP) content,these findings reveal that P.rhizoma with excessive SO_(2) can affect the organism's growth mechanisms through alterations in ATP pathways.In vivo,SO_(2) was found to predominantly accumulate in the liver following gavage with P.rhizoma solution,with accumulation levels increasing in proportion to SO_(2) residue concentration.High SO_(2) concentrations in P.rhizoma can cause pulmonary fibrosis and gastric mucosal damage.This work provides a valuable tool for regulating SO_(2) content in P.rhizoma and may help researcher better understand the metabolism of SO_(2) derivatives and explore their physiological roles in biological systems. 展开更多
关键词 Fluorescent probe SO_(2)derivatives metabolism Quantitative analysis Pinelliae rhizoma Fluorescent imaging
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基于Pumplinx的核电站给水泵三维流场仿真
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作者 段程豫 《价值工程》 2026年第2期106-108,共3页
本文基于PumpLinx平台构建核电站给水泵全三维瞬态流场模型,采用分层网格与SST k-ω湍流模型耦合求解,揭示设计工况及事故序列下多物理场耦合机制。研究表明:外特性曲线在特定流量比时效率达极值,超流量工况扬程断裂源于叶轮前缘空化阻... 本文基于PumpLinx平台构建核电站给水泵全三维瞬态流场模型,采用分层网格与SST k-ω湍流模型耦合求解,揭示设计工况及事故序列下多物理场耦合机制。研究表明:外特性曲线在特定流量比时效率达极值,超流量工况扬程断裂源于叶轮前缘空化阻塞;子午面分析显示空化核心区集中于诱导轮吸力面及轮缘间隙,与低压区显著重合;高湍流动能分布于级间过渡段,主因几何失配诱发流动分离。研究成果为核电站多级给水泵的空化抑制与结构优化提供了高置信度仿真设计依据。 展开更多
关键词 给水泵 pumplinx 空化阻塞 子午面流场 气相分布 湍流模型
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用Pump-dump-probe瞬态吸收光谱监测分子高振动激发态动力学(英)
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作者 程继新 何国钟 +3 位作者 沈振文 双丰 赵仪 严以京 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 1998年第6期519-524,共6页
给出了监测外场激发下分子动力学过程的瞬态吸收信号的确切理论表述。在数值计算中,采用I2的一个二势能面系统,得到了监测基电子态高振动激发波包的吸收光谱。I2的B电子激发态被用作双光子pump-dump过程的中间态。提出了一个二阶差... 给出了监测外场激发下分子动力学过程的瞬态吸收信号的确切理论表述。在数值计算中,采用I2的一个二势能面系统,得到了监测基电子态高振动激发波包的吸收光谱。I2的B电子激发态被用作双光子pump-dump过程的中间态。提出了一个二阶差谱探测方案,即从弱响应区域的第5阶(pump-dump-probe)非线性光谱中提取分子动力学信息。 展开更多
关键词 pump-dump 瞬态吸收光谱 分子动力学 激发态
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基于量子级联激光器的Pump-Probe光路球晶雕刻实验
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作者 吕艳坤 卢杰 +2 位作者 苏凤梅 纪又新 李良彬 《高分子学报》 SCIE CAS CSCD 北大核心 2018年第3期374-379,共6页
利用2台中红外量子级联激光器(QCL)组成的泵浦探测(pump-probe)光路通过红外共振吸收对高分子球晶进行选择性熔融进而实现球晶雕刻.当QCL激光频率和分子基团振动频率相同时,会发生共振吸收,产生强烈的热效应,诱导样品快速熔融;QCL激光... 利用2台中红外量子级联激光器(QCL)组成的泵浦探测(pump-probe)光路通过红外共振吸收对高分子球晶进行选择性熔融进而实现球晶雕刻.当QCL激光频率和分子基团振动频率相同时,会发生共振吸收,产生强烈的热效应,诱导样品快速熔融;QCL激光具有高偏振性,优先诱导振动方向和红外激光偏振方向一致的基团发生共振吸收,因此可以实现选择性熔融;高分子球晶中有沿着各个方向的分子链并且取向方向确定,可以通过pump球晶不同部位来验证球晶雕刻的可行性.一台激光器(pump)对应分子链中基团的强吸收峰,共振加热诱导晶体熔融;另一台激光器(probe)对应分子特征基团(构象)的吸收峰,追踪结构变化;pump光可以选择性定点熔融,pump和probe 2束光均能在线追踪样品熔融程度,是该检测方法的突出优点.选用聚丁烯-1(iPB-1)为研究对象,实验结果显示,球晶熔融程度随基团振动方向与pump光偏振方向夹角的增大而减弱,证明了利用QCL在球晶尺度上进行雕刻是可行的,为原位在线研究快速熔融过程提供了新的研究途径,为定点调控晶型转变及晶体聚集态结构形态提供了思路. 展开更多
关键词 中红外量子级联激光器 pump-probe光路 偏振红外 红外共振吸收 球晶雕刻
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Analysis of femtosecond laser ionization/dissociation of polyatomic molecule C_6H_(10)O from one-colour pump-probe measurement 被引量:1
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作者 胡飞飞 周胜鹏 +6 位作者 胡湛 金明星 张栋栋 吴迪 成西会 姜殿武 丁大军 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1498-1502,共5页
This paper reports that a one-colour fs pump probe measurement has been carried out for studying photoionization/photodissociation of cyclohexanone (C6H10O) in intense laser field. Two of the fragments from eyclohex... This paper reports that a one-colour fs pump probe measurement has been carried out for studying photoionization/photodissociation of cyclohexanone (C6H10O) in intense laser field. Two of the fragments from eyclohexanone, C2H+ and C3H3+, are studied under 800 nm laser pump-probe and the results obtained show similar time evolutions. It proposes a feasible model for analysing the experimental observations of the one-colour fs pump-probe measurement. The results demonstrate that as an intermediate product, the excited molecular parent ions play a very important role in photionization/photodissociation processes in intense laser field. 展开更多
关键词 CYCLOHEXANONE fs pump-probe ionization/dissociation
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Nano-Metal Film Thermal Conductivity Measurement by using the Femtosecond Laser Pump and Probe Method 被引量:3
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作者 ZHU Li-Dan SUN Fang-Yuan +3 位作者 ZHU Jie TANG Da-Wei LI Yu-Hua GUO Chao-Hong 《Chinese Physics Letters》 SCIE CAS CSCD 2012年第6期231-234,共4页
Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thi... Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thin metal films with thicknesses from 50 to 200nm by using the femtosecond laser pump and probe method,and the experimental data are combined with the parabolic two-step model to enable us to measure thermal conductivity of the thin metal films.The measurement results of Ni and Al films show that,in the thickness range from tens to hundreds of nanometer,the thermal conductivity increases with the increasing thicknesses of the films,which agrees well with the previous conclusions. 展开更多
关键词 pump FEMTO CONDUCTIVITY
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Observation of a highly conductive warm dense state of water with ultrafast pump–probe freeelectron-laser measurements 被引量:1
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作者 Z.Chen X.Na +17 位作者 C.B.Curry S.Liang M.French A.Descamps D.P.DePonte J.D.Koralek J.B.Kim S.Lebovitz M.Nakatsutsumi B.K.Ofori-Okai R.Redmer C.Roedel M.Schörner S.Skruszewicz P.Sperling S.Toleikis M.Z.Mo S.H.Glenzer 《Matter and Radiation at Extremes》 SCIE CAS CSCD 2021年第5期1-12,共12页
The electrical conductivity of water under extreme temperatures and densities plays a central role in modeling planetary magnetic fields.Experimental data are vital to test theories of high-energy-densitywater and ass... The electrical conductivity of water under extreme temperatures and densities plays a central role in modeling planetary magnetic fields.Experimental data are vital to test theories of high-energy-densitywater and assess the possible development and presence of extraterrestrial life.These states are also important in biology and chemistry studies when specimens in water are confined and excited using ultrafast optical or free-electron lasers(FELs).Here we utilize femtosecond optical lasers to measure the transient reflection and transmission of ultrathin water sheet samples uniformly heated by a 13.6 nm FEL approaching a highly conducting state at electron temperatures exceeding 20000 K.The experiment probes the trajectory ofwater through the high-energy-density phase space and provides insights into changes in the index of refraction,charge carrier densities,andACelectrical conductivity at optical frequencies.At excitation energy densities exceeding 10MJ/kg,the index of refraction falls to n0.7,and the thermally excited free-carrier density reaches ne531027 m−3,which is over an order of magnitude higher than that of the electron carriers produced by direct photoionization.Significant specular reflection is observed owing to critical electron density shielding of electromagnetic waves.Themeasured optical conductivity reaches 23104 S/m,a value that is one to two orders of magnitude lower than those of simplemetals in a liquid state.At electron temperatures below 15000 K,the experimental results agreewell with the theoretical calculations using density-functional theory/molecular-dynamics simulations.With increasing temperature,the electron density increases and the system approaches a Fermi distribution.In this regime,the conductivities agree better with predictions from the Ziman theory of liquid metals. 展开更多
关键词 pump EXCEEDING state
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Ultrafast optical beam deflection in a pump probe configuration
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作者 梁玲亮 田进寿 +4 位作者 汪韬 吴胜利 李福利 王俊锋 高贵龙 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第9期268-275,共8页
Propagation of a signal beam in an Al Ga As/Ga As waveguide multiple-prism light deflector is theoretically investigated by solving the scalar Helmholtz equation to obtain the dependences of the temporal and spatial r... Propagation of a signal beam in an Al Ga As/Ga As waveguide multiple-prism light deflector is theoretically investigated by solving the scalar Helmholtz equation to obtain the dependences of the temporal and spatial resolvable characteristics of the ultrafast deflector on the material dispersion of Ga As including group velocity dispersion and angular dispersion,interface reflection,and interface scattering of multiple-prism deflector.Furthermore,we experimentally confirm that,in this ultrafast beam deflection device,the deflecting angle of the signal light beam is linear with the pump fluence and the temporal resolution of the ultrafast deflection is 10 ps.Our results show that the improvement of the temporal and spatial resolvable performances is possible by properly choosing the structural parameters and enhancing the quality of the device. 展开更多
关键词 pump probe ultrafast deflection multiple-prism light deflector temporal resolution
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煤矿排水工具“pump”(泵)在近代中国的译入与传播
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作者 周宁 徐礼静 《安徽理工大学学报(社会科学版)》 2025年第6期87-93,共7页
煤矿排水是煤矿开采过程中的关键环节。自晚清洋务运动时期起,近代中国煤炭开采开始引入机器,其中西方制造的“蒸汽泵”成为当时煤矿排水采用的主要设备之一。文章在追溯我国矿山排水工具发展史的基础上,分析英语词汇“pump”在近代中... 煤矿排水是煤矿开采过程中的关键环节。自晚清洋务运动时期起,近代中国煤炭开采开始引入机器,其中西方制造的“蒸汽泵”成为当时煤矿排水采用的主要设备之一。文章在追溯我国矿山排水工具发展史的基础上,分析英语词汇“pump”在近代中国的译入与传播过程,发现通过语义符码的跨文化重构,“pump”在汉语语境中完成了由“恒升车”“抽水筒”“唧筒”“帮浦”到“泵”的符号嬗变。这种基于汉语能指系统的概念整合,构建起技术知识本土化的知识再生产机制,使西方机械的技术原理得以准确转译,从语言层面消弭了技术传播的认知鸿沟。探究“pump”一词的汉译演变,既构筑起中西技术对话的知识桥梁,又揭示出晚清至民国时期知识精英在吸纳西方工业文明过程中,为打破语言障碍所采用的创造性策略。 展开更多
关键词 煤矿排水 技术概念 译入 传播
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Femtosecond Stimulated Raman Line Shapes:Dependence on Resonance Conditions of Pump and Probe Pulses
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作者 ChengChen Liang-dongZhu ChongFang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第4期492-502,614,615,共13页
Resonance enhancement has been increasingly employed in the emergent felntosecond stimu- lated Raman spectroscopy (FSRS) to selectively monitor molecular structure and dynamics with improved spectral and temporal re... Resonance enhancement has been increasingly employed in the emergent felntosecond stimu- lated Raman spectroscopy (FSRS) to selectively monitor molecular structure and dynamics with improved spectral and temporal resolutions and signal-to-noise ratios. Such joint eflforts by the technique- and application-oriented scientists and engineers have laid the foundation for exploiting the tunable FSRS methodology to investigate a great variety of photosensitive systems and elucidate the underlying functional mechanisms on molecular time scales. Dur- ing spectral analysis, peak line shapes remain a major concern with an intricate dependence on resonance conditions. Here, we present a comprehensive study of line shapes by tuning the Rarnan pump wavelength from red to blue side of the ground-state absorption band of the fluorescent dye rhodarnine 6G in solution. Distinct line shape patterns in Stokes and anti-Stokes FSRS as well as from the low to high-frequency modes highlight the competition between multiple third-order and higher-order nonlinear pathways, governed by difl^rent res- onance conditions achieved by Raman pump and probe pulses. In particular, the resonance condition of probe wavelength is revealed to play an important role in generating circular line shape changes through oppositely phased dispersion via hot luminescence (HL) pathways. Meanwhile, on-resonance conditions of the Rarnan pump could promote excited-state vibrational modes which are broadened and red-shifted from the coincident ground-state vibrational modes, posing challenges for spectral analysis. Certain strategies in tuning the Raman pump and probe to characteristic regions across an electronic transition band are discussed to improve the FSRS usability and versatility as a powerful structural dynamics toolset to advance chemical, physical, materials, and biological sciences. 展开更多
关键词 Ferntosecond stimulated Rarnan spectroscopy Resonance enhancement Ra- man pump and probe pulses Wavelength tunability Dispersive line shapes Stokes and anti-Stokes FSRS
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Elimination of the Coherent Artifact in a Pump-Probe Experiment by Directly Detecting the Background-Free Diffraction Signal
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作者 LIU Hui ZHANG Hang +3 位作者 SI Jin-Hai YAN Li-He CHEN Feng HOU Xun 《Chinese Physics Letters》 SCIE CAS CSCD 2011年第8期229-232,共4页
The influence of the coherent artifact in a semiconductor Ga-doped ZnO film on femtosecond pump-probe measurement is studied.The coherent artifact mixed into the pump-probe signal can be directly inspected by detectin... The influence of the coherent artifact in a semiconductor Ga-doped ZnO film on femtosecond pump-probe measurement is studied.The coherent artifact mixed into the pump-probe signal can be directly inspected by detecting the background-free first-order diffraction signal induced by the interference between the pump and probe pulses.Experimental results show that by varying the polarization angle or adjusting the relative intensity between the pump and probe pulses,the coherent artifact can be eliminated from the pump-probe measurement. 展开更多
关键词 measurement COHERENT probe
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