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A novel method for simultaneous measurement of^(222)Rn and^(220)Rn progeny concentrations measured by an alpha spectrometer

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Nucle.r Science and Techniques 2025年第1期36卷 127-139页

作者： Zhong-Kai Fan Jia-le.Sun Hao-Xuan Li Xiang-Ming Cai Hui Yang Shou-kang Qiu Yan-Liang Tan Jian Shan School of Nucle.r Science and Technology University of South ChinaHengyang 421001China Colle.e of Physics and Ele.tronic Engineering Hengyang Normal UniversityHengyang 421008China

The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in *** comple.e the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay *** model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle.counts of non-overlapping spectra within consecutive measurement cycle. to obtain the concentrations of^(222)Rn and^(220)Rn progeny in *** verification experiments were conducted using an alpha *** experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an accele.ation of 84%.The improved capability of the new method in distinguishing alpha particle. with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate *** proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.

关键词： ^(222)Rn ^(220)Rn Progeny concentration Nonlinear fitting method Alpha spectrometer

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Integrating well logs, 3D seismic, and earthquake data for comprehensive prediction of 3D in-situ stress orientations: A case study from the Weiyuan area in the Sichuan Basin, China

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Petrole.m Science 2025年第1期22卷 210-221页

作者： Huan Cao Yang Zhao Hai-Chao Chen le.le.Zhang Cheng-Gang Xian Ji-Dong Yang Lu Liu State Key Laboratory of Petrole.m Resources and Engineering and Unconventional Petroleum Research Institute China University of Petroleum (Beijing) Department of Geophysics China University of Petroleum (East China) Aramco Beijing Research Center Aramco Asia

Determining the orientation of in-situ stresses is crucial for various geoscience and engineering applications. Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(FMSs) derived from earthquake data and formation micro-imager(FMI) data from well ***, these techniques can be costly, depth-inaccurate, and may lack spatial coverage. To address this issue, we introduce the use of three-dimensional(3D) seismic data(active sources) as a lateral constraint to approximate the 3D stress orientation field. Recognizing that both stress and fracture patterns are closely related to seismic velocity anisotropy, we derive the orientation of azimuthal anisotropy from multi-azimuth 3D seismic data to compensate for the lack of spatial stress orientation information. We apply our proposed workflow to a case study in the Weiyuan area of the Sichuan Basin, China, a region targeted for shale.gas production. By integrating diverse datasets, including 3D seismic, earthquakes, and well logs, we develop a comprehensive 3D model of in-situ stress(orientations and magnitudes). Our results demonstrate that the estimated anisotropy orientations from 3D seismic data are consistent with the direction of maximum horizontal principal stress(SHmax) obtained from FMIs. We analyzed 12earthquakes(magnitude > 3) recorded between 2016 and 2020 for their FMSs and compressional axis(Paxis) orientations. The derived SHmax direction from our 3D stress model is 110°ES(East-South), which shows excelle.t agreement with the FMSs(within 3.96°). This close alignment validates the reliability and precision of our integrated method for predicting 3D SHmax orientations.

关键词： In-situ stress orientation SHmax Azimuthal velocity anisotropy Focal source mechanism Formation micro-imager

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Engineering strategies of biomaterial-assisted exosomes for skin wound repair:Latest advances and challe.ges

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Chinese Chemical le.ters 2025年第1期36卷 99-109页

作者： Yang Xu le.Ma Yang Wang Chunmeng Shi Institute of Rocket Force Medicine State Key Laboratory of Trauma and Chemical PoisoningThird Military Medical University(Army Medical University)Chongqing 400038China

The treatment of skin wounds,especially chronic wounds,remains a critical clinical challe.ge and places a heavy burden on patients and healthcare *** recent years,the engineering strategy of using biomaterial-assisted exosomes has emerged as a powerful tool for skin *** to treatments such as debridement and regular dressing changes,the design of biomaterial-assisted exosomes not only maintains the bioactivity of exosomes at the wound site but also provides an appropriate microenvironment for the repair of comple. tissues,thereby accele.ating wound *** review systematically introduces the general characteristics of exosomes and their functions in skin wound healing,highlights recent advances in classification of natural exosomes and engineering methods which enriching their functions in intercellular ***,various emerging and innovative approaches based on biomaterials delivery of exosomes are comprehensively *** review seeks to bring an in-depth understanding of bioactive dressings based on exosomes therapeutic strategies,aiming to facilitate new clinical application value.

关键词： Exosomes Biomaterials Hydrogel Delivery system Wound healing

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Emerging progress:photochemical transformation of nitroso compounds

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Science China Chemistry 2025年第1期68卷 118-133页

作者： Ze-le.Chen Qiang-Qiang Li Armido Studer Jun Xuan Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials School of Chemistry&Chemical EngineeringAnhui UniversityHefei 230601China Organisch-Chemisches Institut Universitat MünsterMunster 48149Germany

Nitroso compounds have emerged as highly valuable.reaction partners or reagents in organic synthesis due to their rich *** versatile.profile.of these compounds allows them to function as ele.trophile.,nucle.phile.,diradicals,and radical acceptors in diverse *** recent years,notable.progress has been made in harnessing photochemical reactions with nitroso compounds to prepare N,O-containing structures using mild and eco-friendly *** nitroso compounds like nitrosoarenes,acyloxy nitroso compounds,N-nitrosoamines and nitrites have received significant attention for their ability to introduce NO moieties into comple. mole.ule. that are otherwise difficult to *** this review,we provide an overview of the recent advancements in the visible.light-induced conversion of nitroso compounds,with particular emphasis on their role.as bifunctional reagents and acceptors of radicals,carbenes and nitrenes.

关键词： nitroso compounds photochemistry radical reaction carbene transformation nitrosoarenes

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Exotic hybrid pseudopotentials at finite temperature and chemical potential

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Chinese Physics C 2025年第1期49卷 186-194页

作者： le.Zhang Fei-Yang Cai Xun Chen Colle.e of Physics and Ele.tronic Science Hubei Normal UniversityHuangshi 435002China

Using gauge/gravity duality,we studied the exotic hybrid pseudopotentials at finite temperature and chemical *** Σ hybrid meson can be described by a model including an object calle."defect"on a string linking the quark and *** Σ_(u)^(-) hybrid potential at zero temperature and chemical potential was first proposed by Andreev and is perfectly *** this study,we extended the aforementioned model to finite chemical potential and compared the separate distance and pseudopotentials of Σ_(g)^(+) and Σ_(u)^(-).Unlike the Σ_(g)^(+) ground state,the Σ_(u)^(-),hybrid pseudopotentials no longer exhibit Coulomb-like behavior at short *** addition,temperature and chemical potential have a significant impact on the Σ_(u)^(-) hybrid *** screen distances and hybrid pseudopotentials of Σ_(u)^(-) significantly decrease when increasing temperature and chemical *** represented the melting diagram of Σ_(g)^(+) and Σ_(u)^(-) in the T-μ plane and confirmed that the quark-antiquark pair in Σ_(u)^(-) excited state is easier to melt than that in Σ_(g)^(+) ground state.

关键词： holographic QCD hybrid potential heavy quark

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Development of ESIPT-based specific fluorescent probes for bioactive species based on the protection-deprotection of the hydroxyl

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Chinese Chemical le.ters 2025年第2期36卷 49-56页

作者： Haixian Ren Yuting Du Xiaojing Yang Fangjun Huo le.Zhang Caixia Yin Department of Chemistry Xinzhou Normal University Research Institute of Applied Chemistry Shanxi University Department of Chemistry The University of Texas at Austin Key Laboratory of Chemical Biology and Mole.ular Engineering of Ministry of Education Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province Institute of Molecular ScienceShanxi University

Excited-state intramole.ular proton-transfer (ESIPT) based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity, a large Stokes shift, and potential for ratiometric sensing. In general, ESIPT-based fluorophore incorporates an intramole.ular hydrogen bonding interaction between a hydrogen bond donor (–OH and NH2are common) and a hydrogen bond acceptor(C=N and C=O). More, protection–deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission. Therefore, protection–deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes, where the potential key issue is sele.ting a protective group that can specifically le.ve in the presence of the target analyte. In this review, we mainly summarize the specific protecting groups (sites) and deprotection mechanisms for biologically important species (including reactive sulfur species (RSS), reactive oxygen species (ROS), enzymes, etc.), and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability, sele.tivity, response rate and assay system, etc. Based on the aforementioned, we further point out the current challe.ges and the potential future direction for developing ESIPT-based probes.

关键词： Bioimaging ESIPT Fluorescence probe Protection-deprotection Specificity

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Synthesis of intermetallic PtCo fuel cell catalysts from bimetallic core@shell structured nanoparticle.

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Journal of Energy Chemistry 2025年第2期101卷 1-6页

作者： le.Zhang le. Tong Shuai Li Chang-Song Ma Kun-Ze Xue Hai-Wei Liang Hefei National Research Center for Physical Sciences at the Microscale Department of Chemistry University of Science and Technology of China

The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells（PEMFCs）.However,forming intermetallic structures typically requires high-temperature annealing,posing a challe.ge for achieving well-size control and highly ordered *** we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo *** fabrication of the core@shell precursor involves using a mole.ular ligand containing both sulfur and oxygen donors to sele.tively bind with Pt colloidal nanoparticle. as the core and chelate Co ions as the *** high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticle.,preventing particle.sintering;meanwhile.Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic *** benefits enable.us to obtain the catalyst with finely dispersed nanoparticle.（～3.5 nm）and a high ordering degree of 72%.With 0.1 mgPt/cm2cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm2at 0.67 V（H2-air）,and a voltage loss of 26 mV at 0.8 A/cm2after the accele.ated durability test.

关键词： Bimetallic structure Fuel cells Intermetallic PtCo Oxygen reduction reaction

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Synthesis ofδ-MnO_(2)via ozonation routine for low temperature formaldehyde removal

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Journal of Environmental Sciences 2025年第1期147卷 642-651页

作者： Guijun Fan Yacong Guo Shaohua Chai le.Zhang Jian Guan Guojun Ma Ning Han Yunfa Chen State Key Laboratory of Multiphase Comple. Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Colle.e of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science and Technology on Particle.Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 361021China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Petrochemical Engineering&Environment Zhejiang Ocean UniversityZhoushan 316022China

Nowadays,it is still a challe.ge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle.the long-living indoor air ***,δ-MnO_(2)is successfully synthesized by a facile.ozonation strategy,where Mn^(2+)is oxidized by ozone(O_(3))bubble.in an alkaline *** presents one of the best catalytic properties with a low 100%conversion temperature of 85℃for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr).As a comparison,more than 6 times far longer oxidation time is needed if O3 is replaced by O_(2).Characterizations show that ozonation process generates a different intermediate of tetragonalβ-HMnO_(2),which would favor the quick transformation into the final productδ-MnO_(2),as compared with the relatively more thermodynamically stable.monoclinicγ-HMnO_(2)in the O_(2)***,HCHO is found to be decomposed into CO_(2)via formate,dioxymethyle.e and carbonate species as identified by room temperature insitu diffuse refle.tance infrared fourier transform *** these results show great potency of this facile.ozonation routine for the highly activeδ-MnO_(2)synthesis in order to remove the HCHO contamination.

关键词： δ-MnO_(2) Ozone oxidation HCHO oxidation In-situ DRIFTS

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Free vibration and transient response of double.curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-le School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double.curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam ele.ent is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assemble. stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excelle.t ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： double.curved beam finite ele.ent method functionally graded porous (FGP) material intermediate straight beam O313 vibration analysis

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Experimental verification of a PIV-based pressure field reconstruction technology in supersonic flows

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Science China Technological Sciences 2025年第3期68卷 243-261页

作者： Jie TIAN Jingle. XU Shun LIU le.CAI Colle.e of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics State Key Laboratory of Mechanics and Control of Aeronautics and Astronautics Structures Nanjing University of Aeronautics and Astronautics School of Energy and Power Engineering Jiangsu University

This study proposes a novel approach that involves applying the flux vector splitting(FVS) technique to discretize and approximate conservative Navier-Stokes equations and thus reconstruct pressure fields from planar velocimetry data in compressible.flows, especially for supersonic flows with strong shocks. Data are typically resolved by using the particle.image velocimetry(PIV) technique. Two supersonic experiments under Mach 2.9–3.0 conditions were conducted to generate strong shocks and investigate the performance of the FVS method, including oblique shock flow and shock wave/boundary layer interaction(SWBLI) couple. with flow separation. Reconstructed pressure fields were comprehensively evaluated. The shock polar results indicated that FVS method possessed higher accuracy in post-shock regions with a pressure ratio error of le.s than2%, especially for the areas downstream of the shock-shock intersection point and the shock-boundary intersection point, where the conventional Poisson method was ineffective and larger errors accumulated. Wall pressure in SWBLI flow also had better agreement. Furthermore, the performances of different methods were discussed from the perspective of the physical characteristics in supersonic flows, which explained the superiority of the FVS method because the pressure information was delivered along the characteristic direction of physical waves.

关键词： particle.image velocimetry supersonic flow pressure reconstruction flux vector splitting technique

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