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Numerical study on the effective thermal conductivity and thermal tortuosity of porous media with different morphologies

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Science China Technological Sciences 2024年第6期67卷 1685-1694页

作者： DU Shen LI dong LI meng-Jie HE Ya-ling Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power Engineering Xi’an Jiaotong University

Effective thermal conductivity and thermal tortuosity are crucial parameters for evaluating the effectiveness of heat conduction within porous media. The direct pore-scale numerical simulation method is applied to investigate the heat conduction processes inside porous structures with different morphologies. The thermal conduction performances of idealized porous structures are directly compared with real foams across a wide range of porosity. Real foam structures are reconstructed using X-ray computed tomography and image processing techniques, while Kelvin and Weaire-Phelan structures are generated through periodic unit cell reconstruction. The detailed temperature fields inside the porous structures are determined by solving the heat conduction equation at the pore scale. The results present that the equivalent thermal conductivity of Kelvin and Weaire-Phelan structures is similar to and greater than that of the real foam structure with the same strut porosity. The thermal tortuosity of real foam structure is relatively larger and the heat conduction path becomes straighter by adopting the anisotropic design. The thermal tortuosity of the fluid channels for Kelvin, Weaire-Phelan, and real foam structures is close to one. The thermal conductivity of porous structures with heat transfer fluid increases as the thermal conductivity ratio of fluid to solid becomes larger. A small porosity of porous media leads to a larger equivalent thermal conductivity due to the dominant contribution of porous skeleton in the heat conduction process. Correlations derived from parallel and series models, as well as the Maxwell-Eucken models,provide decent predictions of effective thermal conductivity, with an average error of less than 8% in the entire range of thermal conductivity ratio.

关键词： volumetric solar receiver porous morphology direct pore-scale simulation equivalent thermal conductivity thermal tortuosity empirical correlation

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Recovery and in-situ reduction of precious metals by graphdiyne and graphdiyne oxide for antibacterial use

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Rare Metals 2024年第4期43卷 1747-1757页

作者： Ming-Ji Jiang Ya-Na Zhang ling-Shen meng Jing Kang Yong-Jun Li Alideertu dong College of Chemistry and Chemical Engineering Inner Mongolia University Engineering Research Center of Dairy Quality and Safety Control Technology Ministry of EducationInner Mongolia University Department of Chemistry University of Zurich Laboratory of Organic Solids and Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of Sciences

Based on the in-situ self-reduction and chemical stability,graphdiyne（GDY） and graphdiyne oxide（GDYO） are used as trapping agents to investigate the ability for recovering Au3+,Ag+,and Pd2+under different pH values and interfering ions.Under strong acidity at pH=1,these two agents demonstrate high select recovery towards the three precious metal ions,which could be insitu reduced to nanoparticles（NPs）.In addition,superparamagnetic Fe3O4NPs are deposited on the surfaces of GDY and GDYO.The magnetic responses enable GDYFe3O4to recover precious metals conveniently and efficiently by the aid of an external magnetic field.This study also confirms the antibacterial activity of the as-recovered NPs deposited on GDY and GDYO against Escherichia coli and Staphylococcus aureus(1 × 10～5 colony-forming unit（CFU）·ml-1),and the antibacterial rates are 100%.This strategy of recovering precious metals and subsequently reusing to combat pathogens will be of great significance for environmental remediation and biomedical applications.

关键词： Graphdiyne In-situ reduction Recovery Precious metals Antibacterial

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Enhanced cyclic stability of partially disordered spinel cathodes through direct fluorination with gaseous fluorine

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Rare Metals 2024年第4期43卷 1635-1646页

作者： Yong-Nian Ma ling-Chen Kong Shao-Shan Chen Yong Wang Li-dong Sun Cong Peng meng-meng Qin Yu Li Wei Feng Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin University Institute of Advanced Technology and Equipment Beijing University of Chemical Technology

Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of cation disorder can effectively suppress the detrimental two-phase reaction to realize high capacities in a wide voltage range.However,the continuous capacity decay during cycles has hindered the widespread application of these cathode materials.Inorganic fluorides exhibit excellent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially disordered spinel cathode(Li1.6Mn1.6O3.7F0.3,LMOF1.6) was initially applied to investigate the impacts of fluorination on the surface structure and electrochemical performances.The inorganic fluorinated layer,mainly containing LiF,was distributed uniformly on the surface of LMOF1.6nanoparticles after fluorination for an appropriate time without the turbulence caused by the valency of manganese cation,which improved the capacity retention and rate capability by the suppression of structural damage,parasitic reaction,and cation dissolution.The LMOF1.6cathode fluorinated for 0.5 h exhibited a capacity of283.6 mAh·g-1at 50 mA·g-1and an enhanced capacity retention of 29.6% after 50 cycles in the voltage range of1.5-4.8 V,as compared to the pristine LMOF1.6 with only27.9% capacity retention.

关键词： Spinel-type cathodes Direct fluorination Capacity retention ability High rate capability

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Fully fluorinated hybrid zeolite imidazole/Prussian blue analogs with combined advantages for efficient oxygen evolution reaction

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Chinese Chemical Letters 2024年第6期35卷 222-228页

作者： Jiayu Xu meng Li Baoxia dong Ligang Feng School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

Hybrid metal-organic framework(MOF)derivatives play a significant role in the novel catalyst development in energy conversion reactions.Here,we demonstrated the low-temperature fully fluorinated zeolitic imidazole framework(ZIF)coupled with a three-dimensional open framework Prussian blue analog(PBA)with combined advantages for electrocatalytic oxygen evolution reaction(OER)in water splitting reaction.The spectroscopic analysis and the electrochemical studies revealed the combined advantages of efficient electronic effect and active site synergism.Because of good conductivity improvement by Ndoped carbon derived from ZIF and the high electrochemical surface area and active site exposure from PBA derivatives,good catalytic performance was obtained on the optimal catalyst of Co Ni ZIF/Co Fe-PBAF-300,which required a low overpotential of 250 m V to reach 10 m A/cm^(2)loaded on the glassy carbon electrode,with Tafel slope of 47.4 m V/dec,and very high dynamic and steady stability.In addition,the multi-component with the mixed structure from highly polar metal fluorides promoted the easy formation of the active phase as revealed by the post-sample analysis.The current results showed a novel composite catalyst materials development from the hybrid MOF derivatives,which would be promising in the electrolysis of water oxidation reactions and energy-relevant catalysis reactions.

关键词： Metal-organic framework Zeolitic imidazole framework Prussian blue analog Fluoridation Multi-component Oxygen evolution reaction

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Improving photochemical indicators for attributing ozone sensitivities in source apportionment analysis

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Journal of Environmental Sciences 2024年第9期143卷 235-246页

作者： Xiaohui Du Wei Tang Zhongzhi Zhang Yang Yu Yang Li ling Huang Greg Yarwood Fan meng Atmospheric Environment Institute Chinese Research Academy of Environmental SciencesBeijing 100012China College of Water Sciences Beijing Normal UniversityBeijing 100857China Asia Center for Air Pollution Research United Nations Environment Programme Asia and the Pacific OfficeNishi-kuNiigata-shi 9502144Japan School of Environmental and Chemical Engineering Shanghai UniversityShanghai 200444China Ramboll NovatoCalifornia 94945USA

Comprehensive Air Quality Model with extensions(CAMx)-Decoupled Direct Method(DDM)simulations of first-order ozone(O_(3))sensitivity to nitrogen oxides(NO_(x))and volatile organic compounds(VOCs)emissions were performed and combined with modelled P_(H_(2)O_(2))/P_(HNO_(3))ratios to obtain a range of thresholds for determining O_(3)-sensitivity regimes for different areas of China.Utilising the new threshold ranges for photochemical indicators,the method for determining O_(3)formation in the Ozone Source Apportionment Technology(OSAT)module within CAMx was improved by a dynamically varied threshold of P_(H_(2)O_(2))/P_(HNO_(3))ratio.The O_(3)concentration contributions in the newly added transition regime were apportioned to NO_(x)and VOCs emissions in proportion to the relationship between the P_(H_(2)O_(2))/P_(HNO_(3))ratio and first-order O_(3)sensitivity.The source contributions of O_(3)concentrations from different emission sectors from June to September 2019 were compared using the original and improved CAMx-OSAT.The results showed that the O_(3)concentration contributions changed significantly in the NO_(x)-limited regime,with a maximum decrease of 21.89%,while the contributions increased by up to 7.57%in the VOC-limited regime,and were within 15μg/m^(3)in the transition regime.The modified OSAT module enabled a more sophisticated attribution of O_(3)to precursor emissions and may have far-reaching implications for informing O_(3)pollution control policy.

关键词： O_(3) modeling O_(3)-sensitivity regimes Ozone source apportionment technology Photochemical indicators

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Physiotherapy for patients with depression:Recent research progress

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World Journal of Psychiatry 2024年第5期14卷 635-643页

作者： Hui-ling Liu Jing Sun Shi-Feng meng Ning Sun Department of Mental Health First Clinical Medical College of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina Department of Rehabilitation First Hospital of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina Department of Mental Health First Hospital of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina

Depression,a common mental illness,seriously affects the health of individuals and has deleterious effects on society.The prevention and treatment of depression has drawn the attention of many researchers and has become an important social issue.The treatment strategies for depression include drugs,psychotherapy,and physiotherapy.Drug therapy is ineffective in some patients and psychotherapy has treatment limitations.As a reliable adjuvant therapy,physiotherapy compensates for the shortcomings of drug and psychotherapy and effectively reduces the disease recurrence rate.Physiotherapy is more scientific and rigorous,its methods are diverse,and to a certain extent,provides more choices for the treatment of depression.Physiotherapy can relieve symptoms in many ways,such as by improving the levels of neurobiochemical molecules,inhibiting the inflammatory response,regulating the neuroendocrine system,and increasing neuroplasticity.Physiotherapy has biological effects similar to those of antidepressants and may produce a superimposed impact when combined with other treatments.This article summarizes the findings on the use of physiotherapy to treat patients with depression over the past five years.It also discusses several methods of physiotherapy for treating depression from the aspects of clinical effect,mechanism of action,and disadvantages,thereby serving as a reference for the in-depth development of physiotherapy research.

关键词： Depression Physiotherapy Non-pharmacological Rehabilitation therapy Recent advances

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ResNeSt-biGRU: An Intrusion Detection Model Based on Internet of Things

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Computers, Materials & Continua 2024年第4期79卷 1005-1023页

作者： Yan Xiang Daofeng Li Xinyi meng Chengfeng dong Guanglin Qin School of Computer and Electronics Information Guangxi UniversityNanning530004China Guangxi Colleges and Universities Key Laboratory of Multimedia Communications and Information Processing Guangxi UniversityNanning530004China

The rapid expansion of Internet of Things (IoT) devices across various sectors is driven by steadily increasingdemands for interconnected and smart technologies. Nevertheless, the surge in the number of IoT device hascaught the attention of cyber hackers, as it provides them with expanded avenues to access valuable data. Thishas resulted in a myriad of security challenges, including information leakage, malware propagation, and financialloss, among others. Consequently, developing an intrusion detection system to identify both active and potentialintrusion traffic in IoT networks is of paramount importance. In this paper, we propose ResNeSt-biGRU, a practicalintrusion detection model that combines the strengths of ResNeSt, a variant of Residual Neural Network, andbidirectionalGated RecurrentUnitNetwork (biGRU).Our ResNeSt-biGRUframework diverges fromconventionalintrusion detection systems (IDS) by employing this dual-layeredmechanism that exploits the temporal continuityand spatial feature within network data streams, a methodological innovation that enhances detection accuracy.In conjunction with this, we introduce the PreIoT dataset, a compilation of prevalent IoT network behaviors, totrain and evaluate IDSmodels with a focus on identifying potential intrusion traffics. The effectiveness of proposedscheme is demonstrated through testing, wherein it achieved an average accuracy of 99.90% on theN-BaIoT datasetas well as on the PreIoT dataset and 94.45% on UNSW-NB15 dataset. The outcomes of this research reveal thepotential of ResNeSt-biGRU to bolster security measures, diminish intrusion-related vulnerabilities, and preservethe overall security of IoT ecosystems.

关键词： Internet of Things cyberattack intrusion detection internet security

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(Lu_(1/7)Yb_(1/7)Sc_(1/7)Er_(1/7)Y_(1/7)Ho_(1/7)Dy_(1/7))_(2)Si_(2)O_(7)high entropy rare-earth disilicate with low thermal conductivity and excellent resistance to CMAS corrosion

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Journal of Advanced Ceramics 2024年第5期13卷 549-560页

作者： Xu Wang Mingyu meng Feihan Xu ling Liu Lihong Gao Shizhen Zhu Zhuang Ma School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing 100081China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063000China

Low thermal conductivity,compatible thermal expansion coefficient,and good calcium–magnesium–aluminosilicate(CMAS)corrosion resistance are critical requirements for environmental barrier coatings used on silicon-based ceramics.RE2Si2O7(RE=rare earth)has been widely recognized as one of the most promising candidates for environmental barrier coatings due to its good water vapor corrosion resistance.However,the relatively high thermal conductivity and poor resistance to CMAS corrosion have limited its practical application.Inspired by the high entropy effect,in this work,a novel rare earth disilicate(Lu_(_(1/7))Yb_(_(1/7))Sc_(_(1/7))Er_(_(1/7))Y_(_(1/7))Ho_(_(1/7))Dy_(_(1/7)))2Si2O7((7RE_(_(1/7)))2Si2O7)has been designed and synthesized by a solid reaction process.(7RE_(_(1/7)))2Si2O7 showed a low thermal conductivity of 1.81 W·m^(−1)·K^(−1)at 1273 K.Furthermore,the thermal expansion coefficient of(7RE_(_(1/7)))_(2)Si_(2)O_(7)(4.07×10^(−6)℃^(−1)from room temperature(RT)to 1400℃)is close to that of the SiC-based ceramic matrix composites(SiC-CMCs)((4.5–5.5)×10^(−6)℃^(−1)).Additionally,(7RE_(_(1/7)))2Si2O7 exhibited excellent resistance to CMAS corrosion.When exposed to CMAS at 1300℃for 48 h,the reaction layer thickness was 22μm.The improved performance of(7RE_(_(1/7)))2Si2O7 highlights its potential as a promising candidate for thermal/environmental barrier coatings.

关键词： high entropy disilicate (Lu_(1/7)Yb_(1/7)Sc_(1/7)Er_(1/7)Y_(1/7)Ho_(1/7)Dy_(1/7))_(2)Si_(2)O_(7)((7RE_(1/7))_(2)Si_(2)O_(7)) high-temperature thermal properties calcium-magnesium-aluminosilicate(CMAS)corrosion

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Heavy-atom engineered hypoxia-responsive probes for precisive photoacoustic imaging and cancer therapy

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Chinese Chemical Letters 2024年第4期35卷 316-320页

作者： ling-ling Wu Xiangchuan meng Qingyang Zhang Xiaowan Han Feiya Yang Qinghua Wang Hai-Yu Hu Nianzeng Xing Department of Urology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China State Key Laboratory of Bioactive Substances and Function of Natural Medicine Institute of Materia MedicaPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100050China

Photoacoustic agents combining photodynamic therapy(PDT) and photothermal therapy(PTT) functions have emerged as potent theranostic agents for combating cancer. The molecular approaches for enhancing the near-infrared(NIR)-absorption and maximizing non-radiative energy transfer are essential for effective photoacoustic imaging(PAI) and therapy applications. In addition, such molecules with high specificity and affinity to cancer cells are urgently needed, which would further decrease the side effect during treatments. In this study, we applied a heavy-atom engineering strategy and introduced p-aminophenol,-thio, and-seleno moieties into NIR heptamethine cyanine(Cy7) skeleton(Cy7-X-NH_(2), X = O, S, Se) to significantly increase photothermal conversion efficiency for PTT and promote intersystem crossing for PDT.Additionally, we designed a series of nitroreductase(NTR)-activated photoacoustic probes(Cy7-X-NO_(2),X = O, S, Se), and target hypoxic tumors with NTR overexpression. Our prostate cancer targeting probe,Cy7-Se-NO_(2)-KUE, exhibited specific tumor photoacoustic signals and effective tumor killing through outstanding synergistic PTT/PDT in vivo. These findings highlighted a versatile strategy for cancer photoacoustic diagnosis and enhanced phototherapy.

关键词： Heavy-atom effect Phototherapy Photoacoustic imaging Hypoxia-responsive Prostate cancer

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Association of DNA methylation/demethylation with the functional outcome of stroke in a hyperinflammatory state

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Neural Regeneration Research 2024年第10期19卷 2229-2239页

作者： Yubo Wang ling Zhang Tianjie Lyu Lu Cui Shunying Zhao Xuechun Wang meng Wang Yongjun Wang Zixiao Li Vascular Neurology Department of NeurologyBeijing Tiantan HospitalCapital Medical UniversityBeijingChina China National Clinical Research Center for Neurological Diseases Beijing Tiantan HospitalCapital Medical UniversityBeijingChina National Center for Healthcare Quality Management in Neurological Diseases Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Chinese Institute for Brain Research BeijingChina Research Unit of Artificial Intelligence in Cerebrovascular Disease Chinese Academy of Medical SciencesBeijingChina Beijing Engineering Research Center of Digital Healthcare for Neurological Diseases BeijingChina

Inflammation is closely related to stroke prognosis, and high inflammation status leads to poor functional outcome in stroke. DNA methylation is involved in the pathogenesis and prognosis of stroke. However, the effect of DNA methylation on stroke at high levels of inflammation is unclear. In this study, we constructed a hyperinflammatory cerebral ischemia mouse model and investigated the effect of hypomethylation and hypermethylation on the functional outcome. We constructed a mouse model of transient middle cerebral artery occlusion and treated the mice with lipopolysaccharide to induce a hyperinflammatory state. To investigate the effect of DNA methylation on stroke, we used small molecule inhibitors to restrain the function of key DNA methylation and demethylation enzymes. 2,3,5-Triphenyltetrazolium chloride staining, neurological function scores, neurobehavioral tests, enzyme-linked immunosorbent assay, quantitative reverse transcription PCR and western blot assay were used to evaluate the effects after stroke in mice. We assessed changes in the global methylation status by measuring DNA 5-mc and DNA 5-hmc levels in peripheral blood after the use of the inhibitor. In the group treated with the DNA methylation inhibitor, brain tissue 2,3,5-triphenyltetrazolium chloride staining showed an increase in infarct volume, which was accompanied by a decrease in neurological scores and worsening of neurobehavioral performance. The levels of inflammatory factors interleukin 6 and interleukin-1 beta in ischemic brain tissue and plasma were elevated, indicating increased inflammation. Related inflammatory pathway exploration showed significant overactivation of nuclear factor kappa B. These results suggested that inhibiting DNA methylation led to poor functional outcome in mice with high inflammation following stroke. Further, the effects were reversed by inhibition of DNA demethylation. Our findings suggest that DNA methylation regulates the inflammatory response in stroke and has an important role in the functional out

关键词： DNA demethylation DNA methylation DNMT3A functional outcome hyperinflammatory state interleukin neuroinflammation stroke TET2

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