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Green and Sustainable Chemistry 2024年第2期14卷 17-28页

作者： Adel B. Shehata Abdulrahman R. Al Askar Mohammed A. Al Rasheed Abdulrahman M. Al Zahrany Fahd A. Al Kharraa Sowailem A. Al Sowailem Chemistry Department/National measurement and Calibration center (NMCC) Saudi Standards Metrology and Quality Organization (SASO) Riyadh Kingdom of Saudi Arabia

The determination of the ethanol content in food products is of fundamental importance for HALAL certification. In this work, an analytical method for the determination of ethanol in water by headspace gas chromatography with flame ionization detector (HS-GC-FID) has been developed and validated for the use in characterization of ethanol reference materials. The validation study was carried out in the linear calibration range 100 - 1500 mg/kg using the NIST SRM 2900, nominal 95.6%. The studied performance characteristics of the method were the limit of detection, LOD, the limit of quantification LOQ, selectivity, linearity, precision, recovery and bias. The validation results showed that the method is selective, precise, accurate and free from any significant bias. The LOD and LOQ were 1.27 and 3.86 mg/kg respectively and the estimated expanded uncertainty was 2% indicating that the method is fit for the purpose of certification of ethanol in water reference materials.

关键词： Ethanol HS-GC-FID Validation Linearity Precision Bias

Calibration of CO and CO₂ Monitors Used in Periodic Inspection of Vehicles at Fixed Stations for Environmental Control

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Green and Sustainable Chemistry 2024年第2期14卷 29-41页

作者： Adel Bassuoni Shehata Abdulrahman Rashed Al Askar Najjy Hamad Al Yami Abdullah Suleiman Al Owaysi Sultan K. Alharbi Chemistry Department National Measurement and Calibration Center (NMCC) Saudi Standards Metrology and Quality Organization (SASO) Riyadh Kingdom of Saudi Arabia

Global efforts for environmental cleanliness through the control of gaseous emissions from vehicles are gaining momentum and attracting increasing attention. Calibration plays a crucial role in these efforts by ensuring the quantitative assessment of emissions for informed decisions on environmental treatments. This paper describes a method for the calibration of CO/CO2 monitors used for periodic inspections of vehicles in cites. The calibration was performed in the selected ranges: 900 - 12,000 µmol/mol for CO and 2000 - 20,000 µmol/mol for CO2. The traceability of the measurement results to the SI units was ensured by using certified reference materials from CO/N2 and CO2/N2 primary gas mixtures. The method performance was evaluated by assessing its linearity, accuracy, precision, bias, and uncertainty of the calibration results. The calibration data exhibited a strong linear trend with R² values close to 1, indicating an excellent fit between the measured values and the calibration lines. Precision, expressed as relative standard deviation (%RSD), ranged from 0.48 to 4.56% for CO and from 0.97 to 3.53% for CO2, staying well below the 5% threshold for reporting results at a 95% confidence level. Accuracy measured as percent recovery, was consistently high (≥ 99.1%) for CO and ranged from 84.90% to 101.54% across the calibration range for CO2. In addition, the method exhibited minimal bias for both CO and CO2 calibrations and thus provided a reliable and accurate approach for calibrating CO/CO2 monitors used in vehicle inspections. Thus, it ensures the effectiveness of exhaust emission control for better environment.

关键词： Monitors Periodic Inspection CO/CO2 Calibration Linearity Precision Accuracy

Dual-comb soliton rains based on polarization multiplexing in a single-walled carbon nanotube mode-locked Er-doped fiber laser

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Chinese Optics Letters 2024年第5期22卷 62-67页

作者：赵悦秦莹贾凯琳陈丽陈广伟胡国庆武腾飞李慧宇贺敬文周哲海 Key Laboratory of Modern Optoelectronic measurement Technology in Mechanical Industry Beijing Information Science and Technology UniversityBeijing 100192China Key Laboratory of the Ministry of Education for Optoelectronic measurement Technology and Instruments Beijing Information Science and Technology UniversityBeijing 100192China Changcheng Institute of Metrology&measurement Beijing 100095China National Physical Experiment Teaching Demonstration center Beijing Jiaotong UniversityBeijing 100044China

We experimentally demonstrate tunable dual-comb soliton rains in a polarization multiplexing fiber laser based on a singlewalled carbon *** repetition frequency difference of dual-comb pulses is about 39 Hz,with a maximum extinction ratio of 29 *** suitable polarization states,one of the dual-comb pulses switches into soliton rain sequence with chirped isolating soliton *** signal-to-noise ratio reaches 61 dB,which is 11 dB higher than that of the normal dual-comb *** intervals between chirped isolating solitons are distributed progressively,and the number of isolating solitons can be flexibly tuned from 2 to 11 by adjusting polarization state or pump *** work will provide support for further understanding of interaction dynamics of solitons and give a new route to the application of precision measurement.

关键词： mode-locked fiber laser soliton rains dual-comb pulses gain relaxation dynamics single-walled carbon nanotube

Melittin enhanced intracellular trehalose with synergistic membrane stabilization of macromolecular protectants for cell cryopreservation

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Science China(Technological Sciences) 2024年第4期67卷 1160-1169页

作者： NIU QingJing GAO ShuHui ZHU KongYing REN LiXia YUAN XiaoYan School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin 300350China Analysis and measurement center Tianjin UniversityTianjin 300072China

Cryopreservation plays an essential role in biobanking and cell therapy,but the physiological toxicity of traditional cryoprotectants such as glycerol and dimethyl sulfoxide(DMSO)has raised safety issues for biomedical ***,a nonreducing disaccharide that accumulates in desiccation-or cold-tolerant organisms,has been considered as a biocompatible ***,a naturally occurring membrane-active cationic peptide,melittin,was utilized to facilitate membraneimpermeable trehalose entry into cells for effective cell ***(ethylene glycol)and poly(vinyl pyrrolidone)were applied as macromolecular protectants to improve the stabilization of cell *** the optimal protocol,the postthaw recovery of human red blood cells in freezing bags at a hematocrit of~50%could achieve 82.9%with favorable cell morphologies and physiological ***,the cryosurvival of L929 fibroblasts reached 84.3%compared to the conventional method using 10%(v/v)*** short,this work by using trehalose and melittin provides a biocompatible solvent-free approach for long-term cryostorage of cells.

关键词： melittin intracellular trehalose membrane stabilization macromolecular protectants cell cryopreservation

Characterization of the current crowding effect on chip surface using a quantum wide-field microscope

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Chinese Optics Letters 2024年第6期22卷 123-128页

作者： Rui Zhao Ding Wang Huan Fei Wen Yunbo Shi Jun Tang Jun Liu Science and Technology on Electronic Test&measurement Laboratory North University of ChinaTaiyuan 030051China

We characterize the current crowding effect for microwave radiation on a chip surface based on a quantum wide-field microscope combining a wide-field reconstruction technique. A swept microwave signal with the power of 0–30 d Bm is supplied to a dumbbell-shaped microstrip antenna, and the significant differences in microwave magnetic-field amplitudes attributed to the current crowding effect are experimentally observed in a 2.20 mm ×1.22 mm imaging area. The normalized microwave magnetic-field amplitude along the horizontal geometrical center of the image area further demonstrates the feasibility of the characterization of the current crowding effect. The experiments indicate the proposal can be qualified for the characterization of the anomalous area of the radio-frequency chip surface.

关键词： current crowding effect microwave field on chip surface quantum wide-field microscope nitrogen-vacancy center

Extending microwave-frequency electric-field detection through single transmission peak method

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Chinese Physics B 2024年第5期33卷 417-423页

作者：刘青陈进湛王赫张杰阮伟民伍国柱郑顺元罗景庭宋振飞 College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Institute for Technology Innovation National Institute of MetrologyShenzhen 518107China center for Advanced measurement Science National Institute of MetrologyBeijing 100029China

The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearly-resonant with the Rydberg transition *** the detuning of MW field increases,one of the transmission peaks(single peak)is easier to measure due to its increased *** can be found that the central symmetry point of the two transmission peaks f_(1/2)is only related to the detuning of MW field△_(MW)and central symmetry point f_(0)of resonant MW field,satisfying the relation f_(1/2)=△_(MW)/2+f_(0).Thus,we demonstrate a single transmission peak method that the MW E-field can be determined by interval between the position of single peak and f_(1/2).We use this method to measure continuous frequencies in a band from-200 MHz to 200 MHz of the MW *** experimental results and theoretical analysis are presented to describe the effectiveness of this *** 50 MHz<△_(MW)<200 MHz,this method solves the problem that the AT splitting cannot be measured by using the standard EIT-AT techniques or multiple atomic-level Rydberg atom schemes.

关键词： microwave electric field Rydberg atom electromagnetically induced transparency(EIT) Aulter-Towns splitting

Carbon Emission Factors Prediction of Power Grid by Using Graph Attention Network

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Energy Engineering 2024年第7期121卷 1945-1961页

作者： Xin Shen Jiahao Li YujunYin Jianlin Tang Weibin Lin Mi Zhou measurement center Yunnan Power Grid Co.Ltd.Kunming650000China Electric Power Research Institute China Southern Power Grid Co.Ltd.Guangzhou510530China Guangdong Provincial Key Laboratory of Intelligent measurement and Advanced Metering of Power Grid Guangzhou510530China

Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon *** method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power ***,it cannot provide carbon factor information *** address this issue,a prediction model based on the graph attention network is *** model uses a graph structure that is suitable for the topology of the power grid and designs a supervised network using the loads of the grid nodes and the corresponding carbon factor *** network extracts features and transmits information more suitable for the power system and can flexibly adjust the equivalent topology,thereby increasing the diversity of the *** input and output data are simple,without the power grid *** demonstrated its effect by testing IEEE-39 bus and IEEE-118 bus systems with average error rates of 2.46%and 2.51%.

关键词： Predict carbon factors graph attention network prediction algorithm power grid operating parameters

Enhanced photocatalytic ammonia oxidation activity and nitrogen selectivity over Ag/AgCl/N-TiO_(2) photocatalyst

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Journal of Environmental Sciences 2024年第4期138卷 395-405页

作者： Jiaojiao Guan Daorong Li Jiahui Feng Peng Xu Zhaonian Li Siqi Ge Hongxia Chen Kunfeng Zhang College of Environmental Engineering Henan University of TechnologyZhengzhou 450001China CAS Key Laboratory of Standardization and measurement for Nanotechnology National Center for Nanoscience and TechnologyBeijing 100190China Department of Chemistry Tsinghua UniversityBeijing 100084China

The removal of ammonia(NH_(3))emitted from agricultural and industrial activities is of great significance to protect human health and ecological *** NH_(3)oxidation to N2under mild conditions is a promising ***,developing visible light photocatalysts for NH_(3)oxidation is still in its ***,we fabricate N-TiO_(2)and Ag/AgCl/N-TiO_(2)photocatalysts by sol-gel and photodeposition methods,*** introduction of N not only endows TiO_(2)with visible light response(absorption edge at460 nm)but also results in the formation of heterophase junction(anatase and rutile).Thus,N-TiO_(2)shows 2.0 and 1.8 times higher than those over anatase TiO_(2)and commercial TiO_(2)for NH_(3)oxidation under full spectrum ***,surface modification of Ag can simultaneously enhance visible light absorption(generating localized surface plasmon resonance effect)and charge separation ***,the photocatalytic activity of Ag/AgCl/N-TiO_(2)is further ***,the presence of N and Ag also enhances the selectivity of N2product owing to the change of reaction *** work simultaneously regulates photocatalytic conversion efficiency and product selectivity,providing some guidance for developing highly efficient photocatalysts for NH_(3)elimination.

关键词： TiO_(2) Doping Surface modification Photocatalysis NH_(3)elimination

Dynamically enhanced Autler–Townes splitting by orthogonal XUV fields

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Chinese Physics B 2024年第7期33卷 344-350页

作者：吴立龙姜维超彭良友 Institute of Quantum Precision measurement College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China State Key Laboratory for Mesoscopic Physics and Frontiers Science center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China

Based on numerical solutions of the time-dependent Schr ¨odinger equation, we theoretically investigate the photoelectron spectrum of hydrogen atoms ionized by a pair of ultrashort, intense, and orthogonally polarized laser pulses with a relative time delay in a pump–probe configuration. The pump pulse resonantly excites electrons from the 1s and 2p levels,inducing Rabi oscillations. The resulting dynamically enhanced Autler–Townes(AT) splitting is observed in the photoelectron energy spectrum upon interaction with the second probe pulse. In contrast to the previous parallel-polarization scheme, the proposed orthogonal-polarization configuration enables the resolution of dynamically enhanced AT splitting over a considerably wider range of probe photon energies.

关键词： Autler–Townes splitting orthogonal XUV fields photoelectron spectra Rabi frequency

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Influence of cerium and yttrium addition on strength and electrical conductivity of pure aluminum alloys

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Journal of Rare Earths 2024年第3期42卷 600-611,I0006页

作者： Guojian Lin Lu Li Zhengwei Guo Xianjun Jia Xiao Wang Zhentao Yuan Guoxing Zhang Yun Zhan Quan Shan Zulai Li Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China Research center for Analysis and measurement Kunming University of Science and TechnologyKunming650093China City College Kunming University of Science and TechnologyKunming650051China

To develop pure aluminum alloys with high conductivity and strength, Al-0.2Ce and Al-0.2Ce-0.1Y alloys were prepared by rolling and annealing processes in this study. The effects of trace rare earth elements on the strength and electrical conductivity of the pure aluminum alloys were investigated. It is revealed that the addition of Ce and Y to pure aluminum can effectively enhance the strength and electrical conductivity of the alloys. In Al-0.2Ce, the addition of Ce can effectively refine the grain size of a-Al, with an average grain size of 90.68 μm in the as-cast state. The grain size of the alloy is further reduced to 87.55 μm by the simultaneous addition of Y. The synergistic addition of Ce and Y changes the properties of the alloy. The addition of Ce and Y also produces the Al_(11)Ce_(3) and Al_(3)Y second phases, which have coherent relationship with a-Al. The two-dimensional mismatch degree was calculated to be only 4.43%and 0.85%, respectively, which can provide a certain amount of nucleation substrate for a-Al in the incubation stage. The interfacial match between the L1_(2)structure of Al_(3)Y and a-Al was calculated using first-principles simulations. The results indicate that Al_(3)Y has a strong bonding effect with a-Al. Nanoscale second phases at grain boundaries can be effective in reducing resistivity due to dislocation *** second phases with better matching interfaces to the substrate have no positive effect on the scattering motion of electrons.

关键词： Pure aluminum Rare earths Impurity purification First-principles calculations Strength-conductivity contradiction