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long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

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Journal of forestry Research 2024年第3期35卷 189-204页

作者： longfei Chen Zhibin he Wenzhi Zhao Xi Zhu Qin Shen Mingdan Song Zhengpeng li Junqia kong Shuping Yang Yuan Gao Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China State forestry Administration key laboratory of forest Resources and Environmental Management Beijing Forestry UniversityBeijing 100083People's Republic of China Academy of Agriculture and forestry Sciences Qinghai UniversityXining 810000People's Republic of China College of landscape Architecture Zhejiang A&F UniversityHangzhou 310000People's Republic of China

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental ***,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning *** significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on *** temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) *** increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial *** results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term ***,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) *** increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

关键词： heterotrophic respiration Autotrophic respiration long-term thinning impacts Cold seasons Subalpine plantations Temperature sensitivity

Tuning the optoelectronic properties for small organic compounds as organic solar cell applications

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Optoelectronics letters 2024年第7期20卷 412-417页

作者： hussein k.Mejbel lafy f.Al-Badry Department of Physics College of Education for Pure ScienceUniversity of Thi-QarNassiriya 64001Iraq Department of Physics College of ScienceUniversity of Thi-QarNassiriya 64001Iraq1

Recently,organic solar cells have attracted the attention of many researchers owing to flexibility,low cost,light weight and large-area applications,and significant improvement in the power conversion efficiency(PCE).In this work,we designed chains from organic compounds as donors and replaced the core unit in each series with a variety of acceptors in order to enhance their optical and electronic characterization and performance for power conversion efficiencies in organic solar *** utilized density functional theory(DfT)and time-dependent density functional theory(TD-DfT)to investigate the geometry optimization by using the Gaussian 09 *** electronic and optical properties were determined,which involve the lowest unoccupied molecular orbital(lUMO)and the highest occupied molecular orbital(hOMO)levels,the band gap energy,maximum absorption wavelength(λ_(max)),open circuit voltage(V_(oc)),and light harvesting efficiency(lhe).Our evaluation denotes that the small compounds suggested are predicted to exhibit the best performance compared to the first series(SC1),like a lower band gap energy,a lower hOMO energy level,a greater absorption range,and a larger PCE.

关键词： orbital occupied compounds

Dynamic tunable lWIR achromatic metalens comprising all-As_(2)Se_(3) microstructures

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Chinese Optics letters 2024年第6期22卷 191-195页

作者： Zhihao he Bingxia Wang Zhiang Qian kongsi Zhou Xiang Shen Yungui Ma laboratory of Infrared Materials and Devices The Research Institute of Advanced TechnologiesKey Laboratory of Photoelectric Detection Materials and Devices of Zhejiang ProvinceNingbo UniversityNingbo 315211China State key laboratory of Modern Optical Instrumentation Centre for Optical and Electromagnetic ResearchCollege of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZhejiang UniversityHangzhou 310058China

In the field of long-wave infrared(lWIR) thermal imaging, vital for applications such as military surveillance and medical diagnostics, metalenses show immense potential for compact, lightweight, and low-power optical systems. however, to date, the development of lWIR broadband achromatic metalenses with dynamic tunable focus, which are suitable for both coaxial and off-axis applications, remains a large unexplored area. herein, we have developed an extensive database of broadband achromatic all-As2Se3microstructure units for the lWIR range. Utilizing this database with the particle swarm optimization (PSO) algorithm, we have designed and demonstrated lWIR broadband achromatic metalenses capable of coaxial and off-axis focusing with three dynamic tunable states. This research may have potential applications for the design of compact, high-performance optical devices, including those with extreme depth-of-field and wide-angle imaging capabilities.

关键词： achromatic metalens long-wave infrared dynamic tunable focus

Stabilizing high-Nickel Cathodes via Interfacial hydrogen Bonding Effects Using a hydrofluoric Acid-Scavenging Separator

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Engineering 2024年第8期39卷 117-126页

作者： Shijie Zhong liwei Dong Botao Yuan Yueyao Dong Qun li Yuanpeng Ji Yuanpeng liu Jiecai han Weidong he National key laboratory of Science and Technology on Advanced Composites in Special Environments &Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080China MIIT key laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China Chongqing Research Institute Harbin Institute of TechnologyChongqing 401151China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Nickel-rich layered li transition metal oxides are the most promising cathode materials for high-energydensity li-ion ***,they exhibit rapid capacity degradation induced by transition metal dissolution and structural reconstruction,which are associated with hydrofluoric acid(hf)generation from lithium hexafluorophosphate *** potential for thermal runaway during the working process poses another *** are promising components to alleviate the aforementioned ***,an ultrathin double-layered separator with a 10 lm polyimide(PI)basement and a 2 lm polyvinylidene difluoride(PVDf)coating layer is designed and fabricated by combining a nonsolvent induced phase inversion process and coating *** PI skeleton provides good stability against potential thermal shrinkage,and the strong PI-PVDf bonding endows the composite separator with robust structural integrity;these characteristics jointly contribute to the extraordinary mechanical tolerance of the separator at elevated ***,unique hf-scavenging effects are achieved with the formation of-CO…h-f hydrogen bonds for the abundant hf coordination sites provided by the imide ring;hence,the layered Ni-rich cathodes are protected from hf attack,which ultimately reduces transition metal dissolution and facilitates long-term cyclability of the Ni-rich ***||NCM811 batteries(where“NCM”indicates liNi_(x)Co_(y)Mn_(1-x-y)O_(2))with the proposed composite separator exhibit a 90.6%capacity retention after 400 cycles at room temperature and remain sustainable at 60℃with a 91.4%capacity retention after 200 *** adopting a new perspective on separators,this study presents a feasible and promising strategy for suppressing capacity degradation and enabling the safe operation of Ni-rich cathode materials.

关键词： Nickel-rich cathodes Composite separator hf scavenging Transition metal dissolution long-term cyclability

flexible multilayer MEMS coils and their application in energy harvesters

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Science China(Technological Sciences) 2024年第4期67卷 1282-1293页

作者： ZhANG Jie hOU XiaoJuan QIAN Shuo BI XiaoXue hU DongXu lIU JianJun GENG WenPing MU Jiliang he Jian ChOU XiuJian Science and Technology on Electronic Test and Measurement laboratory North University of ChinaTaiyuan 030051China School of Software North University of ChinaTaiyuan 030051China

Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable *** electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power *** this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic *** core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring *** wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the *** output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural *** results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex *** the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 hz with a resistor of 3.5 kΩinternal ***,a 470μf capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb *** strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.

关键词： electromagnetic harvester mechanical energy harvesting multilayer MEMS coils magnetic levitation overall space magnetic field flexible planar coils

Analysis of the Oscillatory flows of Multiple Shock Waves in a Constant Area Duct

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Journal of Thermal Science 2024年第3期33卷 794-806页

作者： k JAMES Jintu kIM heuy Dong Department of Mechanical Engineering Andong National UniversityAndong36729Republic of Korea CAD-IT korea Co. Ltd.Seoul08591Republic of Korea

The oscillatory response of multiple shock waves to downstream perturbations in a supersonic flow is studied numerically in a rectangular *** shock waves are formed inside the duct at a shock Mach number of *** duct has an exit height of h,and the effect of duct resonance on multiple shock oscillations is investigated by attaching exit ducts of lengths 0h,50h,and *** downstream disturbance frequency varied from 10 hz to 200 hz to explore the oscillation characteristics of the multiple shock *** oscillatory response of shock waves under self-excited and forced oscillation conditions are analyzed in terms of wall static pressure,shock train leading-edge location,shock train length,and the size of the separation *** extent of the initial shock location increases with an increase in exit duct length for the self-excited oscillation *** analysis of the shock train leading edge and the spectral analysis of wall static pressure variations are *** variation in the shock train length is analyzed using the pressure ratio method for self-excited as well as forced *** RMS amplitude of the normalized shock train length(ζ_(ST))increases with an increase in the exit duct length for the self-excited oscillation *** the downstream perturbation frequency is increased,ζ_(ST)is decreased for exit duct *** all exit duct designs and downstream forcing frequencies,the size of the separation bubble grows and shrinks during the shock oscillations,demonstrating the dependence on duct resonance and forced oscillations.

关键词： shock train downstream disturbance supersonic flow shock wave boundary layer interaction duct resonance flow separation

A new technique for fault diagnosis in transformer insulating oil based on infrared spectroscopy measurements

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high Voltage 2024年第2期9卷 319-335页

作者： Mohamed M.f.Darwish Mohamed h.A.hassan Nagat M.k.Abdel-Gawad Matti lehtonen Diaa-Eldin A.Mansour Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland Department of Electrical Power Engineering Egypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityEgypt Department of Electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical *** gas analysis(DGA)is frequently used for this ***,DGA lacks the necessary level of accuracy to identify all equipment faults,particularly in their initial stages of ***,it does not have the capability for real-time monitoring and relies on manual sampling and laboratory testing,causing potential delays in fault ***,the interpretation of DGA data necessitates specialised expertise,which may pose difficulties for smaller entities that have limited access to ***,the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating *** inception faults that were considered in this study were the electrical fault(discharges of high energy)and the thermal fault(300°Chat,two test cells were crafted especially for serving the simulation processes inside the laboratory for both types of inception ***,six samples of pure paraffinic mineral oil were taken to be degraded in the *** that,all of them besides another sample that were not subjected to any kind of faults were taken to be examined by fourier transform infrared(fTIR)spectroscopy to obtain an overview of the oil's behaviour in each fault *** that,the fTIR analysis was initially verified utilising the DGA ***,for further affirmation,the dielectric dissipation factor(DDf)for all samples was *** the final analysis,the verification tests provide experimental evidence about the outperformance of this new optical technique in detecting the transformer's inception faults in addition to proving its potential for being a superior alternative to the well-known traditional diagnostic techniques.

关键词： fault diagnosis spectroscopy

Exploring noncoding variants in genetic diseases:from detection to functional insights

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Journal of Genetics and Genomics 2024年第2期51卷 111-132页

作者： ke Wu fengxiao Bu Yang Wu Gen Zhang Xin Wang Shunmin he Mo-fang liu Runsheng Chen huijun Yuan Institute of Rare Diseases West China Hospital of Sichuan UniversityChengduSichuan 610041China key laboratory of Systems health Science of Zhejiang Province School of Life ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhouZhejiang 310024China key laboratory of RNA Biology Center for Big Data Research in HealthInstitute of BiophysicsChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China State key laboratory of Molecular Biology State Key Laboratory of Cell BiologyShanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesShanghai 200031China

Previous studies on genetic diseases predominantly focused on protein-coding variations, overlooking the vast noncoding regions in the human genome. The development of high-throughput sequencing technologies and functional genomics tools has enabled the systematic identification of functional noncoding variants. These variants can impact gene expression, regulation, and chromatin conformation, thereby contributing to disease pathogenesis. Understanding the mechanisms that underlie the impact of noncoding variants on genetic diseases is indispensable for the development of precisely targeted therapies and the implementation of personalized medicine strategies. The intricacies of noncoding regions introduce a multitude of challenges and research opportunities. In this review, we introduce a spectrum of noncoding variants involved in genetic diseases, along with research strategies and advanced technologies for their precise identification and in-depth understanding of the complexity of the noncoding genome. We will delve into the research challenges and propose potential solutions for unraveling the genetic basis of rare and complex diseases.

关键词： Noncoding variation Genetic disease Research approach Challenge

Single-pilot operations in commercial flight:Effects on neural activity and visual behaviour under abnormalities and emergencies

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Chinese Journal of Aeronautics 2024年第8期37卷 277-292页

作者： Qinbiao lI Chun-hsien CheN kam k.h.NG Xin YUAN Cho Yin YIU human factors and Ergonomics laboratory Department of Aeronautical and Aviation EngineeringThe Hong Kong Polytechnic UniversityHong Kong Special Administrative Region 100872China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

With cutting-edge technologies and considering airline human-resource-saving,a single pilot in commercial jets could be technically *** changes in captains’natural behaviours are initially required to comprehend the specific safe human performance envelope for safeguarding single-pilot flight,particularly in high-risk *** paper investigates how captains’performance transforms for fixing emergencies when operating from Dual-Pilot Operations(DPO)to Single-Pilot Operations(SPO)through a physiological-based *** pilots flew an emergency-included flight with/without first officers’*** neural activities and scanning behaviours were recorded using a 32-channel Electroencephalogram(EEG)and glasses-based eye tracker,with the observation and post-experiment questionnaires to evaluate the flight operations and pilots’*** alone,there was a significantly increased cortical activity in h and b waves over the frontal,parietal,and temporal lobes during the more complicated emergencies,and pilots focused less on the primary flight display while spending significantly more time scanning the other *** physiological fluctuating patterns associated with risky operations in SPO were highlighted by cross-correlating multimodal *** experimental-based noteworthy insights may wish to inform commercial SPO measures to lessen the persistent physiological fluctuation,assisting airlines in creating SPO-oriented intelligent flight systems to give captains adequate support for assuring safer air transportation.

关键词： Aviation engineering Single pilot operations Behaviour changes Eye tracker Electroencephalogram