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High-efficiency ultrasonic assisted drilling of CFRP/Ti stacks under non-separation type and dry conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 275-291页

作者： Enze YING Zehua ZHOU Daxi GENG Zhenyu SHAO Zhefei SUN Yihang LIU Lianxing LIU Xinggang JIANG Deyuan ZHANG School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China beijing Chenjing Electronics company Limited Beijing 100015China Aerospace Times Feihong Technology company Limited Beijing 100094China

In this study,to address the low efficiency for conventional ultrasonic-assisted drlling(UAD)of carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks,feasibility experiments of non-separation UAD,in which continuous cutting between the tool and the workpiece occurs at a high feed rate,are carried *** experimental results indicate that,compared to conventional separation UAD,the non-separation UAD effectively reduces the cutting forces by 24.2%and 1.9%for CFRP stage and 22.1%and 2.6%for the Ti stage at the feed rates of 50 and 70μm/r,***,the non-separation UAD significantly improves hole quality,including higher hole diameter accuracy,lower hole surface roughness,and less hole *** addition,the non-separation UAD can decrease adhesive tool *** study demonstrates that,compared to conventional drilling(CD),the non-separation UAD can effectively improve drilling quality and tool life while maintaining high efficiency.

关键词： Carbon fiber-reinforced plastic and titanium alloy(CFRP/Ti)stacks Ultrasonic-assisted drlling(UAD) Cutting force Surface integrity Tool wear

A sustainable process to 100%bio-based nylons integrated chemical and biological conversion of lignocellulose

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Green Energy & Environment 2024年第2期9卷 390-402页

作者： Ruijia Hu Ming Li Tao Shen Xin Wang Zhuohua Sun Xinning Bao Kequan Chen Kai Guo Lei Ji Hanjie Ying Pingkai Ouyang Chenjie Zhu College of biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjingChina National Engineering Research Center for biotechnology Nanjing Tech UniversityNanjingChina beijing Key Laboratory of Lignocellulosic Chemistry Beijing Forestry UniversityBeijingChina

Considerable progress has been made in recent years to the development of sustainable polymers from bio-based *** this study,100%bio-based nylons were prepared via an integrated chemical and biological process from *** novel nylons were obtained by the melt polymerization of 3.propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate *** to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3.propyladipic acid from lignin with high *** structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>3.,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.

关键词： Lignocellulose Lignin Reductive catalytic fractionation Bio-based nylon

Microscopic experiment on efficient construction of underground gas storages converted from water-invaded gas reservoirs

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Petroleum Exploration and Development 2024年第1期51卷 203-212页

作者： JIANG Tongwen QI Huan WANG Zhengmao LI Yiqiang WANG Jinfang LIU Zheyu CAO Jinxin PetroChina company Limited Beijing 100007China National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China College of Petroleum Engineering China University of Petroleum(Beijing)Beijing 102249China PetroChina Petroleum&New Energies company Beijing 100007China PetroChina Research Institute of Petroleum Exploration&Development Beijing 100083China

Based on the microfluidic technology,a microscopic visualization model was used to simulate the gas injection process in the initial construction stage and the bottom water invasion/gas injection process in the cyclical injection-production stage of the underground gas storage(UGS)rebuilt from water-invaded gas *** analysis of the gas-liquid contact stabilization mechanism,flow and occurrence,the optimal control method for lifecycle efficient operation of UGS was *** results show that in the initial construction stage of UGS,the action of gravity should be fully utilized by regulating the gas injection rate,so as to ensure the macroscopically stable migration of the gas-liquid contact,and greatly improve the gas sweeping capacity,providing a large pore space for gas storage in the subsequent cyclical injection-production *** the cyclical injection-production stage of UGS,a constant gas storage and production rate leads to a low pore space *** increasing the gas storage and production rate,that is,transitioning from small volume to large volume,can continuously break the hydraulic equilibrium of the remaining fluid in the porous media,which then expands the pore space and flow *** is conducive to the expansion of UGS capacity and efficiency for purpose of peak shaving and supply guarantee.

关键词： water-invaded gas-reservoir underground gas storage cyclical injection-production gas-water contact gas storage and production rate UGS capacity expansion control method

Molecular mechanisms underlying the negative effects of transient heatwaves on crop fertility

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Plant Communications 2024年第9期5卷 101-115页

作者： Qian Yao Ping Li Xin Wang Shuhua Liao Pu Wang Shoubing Huang College of Agronomy and biotechnology China Agricultural UniversityBeijing 100193China

Transient heatwaves occurring more frequently as the climate warms,yet their impacts on crop yield are severely underestimated and even *** lasting only a few days or even hours during sensitive stages,such as microgametogenesis and flowering,can significantly reduce crop yield by disrupting plant *** advances in multi-omics and GWAS analysis have shed light on the specific organs(e.g.,pollen,lodicule,style),key metabolic pathways(sugar and reactive oxygen species metabolism,Ca2+homeostasis),and essential genes that are involved in crop responses to transient heatwaves during sensitive *** review therefore places particular emphasis on heat-sensitive stages,with pollen development,floret opening,pollination,and fertilization as the central narrative *** multifaceted effects of transient heatwaves and their molecular basis are systematically reviewed,with a focus on key structures such as the lodicule and tapetum.A number of heat-tolerance genes associated with these processes have been identified in major crops like maize and *** mechanisms and key heat-tolerance genes shared among different stages may facilitate the more precise improvement of heat-tolerant crops.

关键词： heat stress floret fertility pollen pollen tube growth seed set molecular mechanism

Deep Learning-Based Secure Transmission Strategy with Sensor-Transmission-Computing Linkage for Power Internet of Things

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Computers, Materials & Continua 2024年第3期78卷 3267-3282页

作者： Bin Li Linghui Kong Xiangyi Zhang Bochuo Kou Hui Yu Bowen Liu State Grid beijing Urban District Power Supply company Beijing100034China

The automatic collection of power grid situation information, along with real-time multimedia interaction between the front and back ends during the accident handling process, has generated a massive amount of power grid data. While wireless communication offers a convenient channel for grid terminal access and data transmission, it is important to note that the bandwidth of wireless communication is limited. Additionally, the broadcast nature of wireless transmission raises concerns about the potential for unauthorized eavesdropping during data transmission. To address these challenges and achieve reliable, secure, and real-time transmission of power grid data, an intelligent security transmission strategy with sensor-transmission-computing linkage is proposed in this paper. The primary objective of this strategy is to maximize the confidentiality capacity of the system. To tackle this, an optimization problem is formulated, taking into consideration interruption probability and interception probability as constraints. To efficiently solve this optimization problem, a low-complexity algorithm rooted in deep reinforcement learning is designed, which aims to derive a suboptimal solution for the problem at hand. Ultimately, through simulation results, the validity of the proposed strategy in guaranteed communication security, stability, and timeliness is substantiated. The results confirm that the proposed intelligent security transmission strategy significantly contributes to the safeguarding of communication integrity, system stability, and timely data delivery.

关键词： Secure transmission deep learning power Internet of Things sensor-transmission-computing

New model of linkage evolution for the transtensional fault systems in the Nanpu Sag of Bohai Bay Basin: Insight from seismic interpretation and analogue modelling

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Petroleum Science 2024年第4期21卷 2287-2310页

作者： Yu-Heng Wang Fu-Sheng Yu Bao-Yin Zhao Ling-Jian Meng College of Geosciences China University of Petroleum (Beijing) State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum (Beijing) Jidong Oilfield company PetroChina Limited Company

The evolution of faults within the same stress field is frequently influenced by numerous factors,involving the reactivation of pre-existing structures, stress transmission through ductile detachment layers, and the growth, interaction, as well as linkage of new fault segments. This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag(NPS) of the Bohai Bay Basin(BBB),China. High-resolution three-dimensional(3.) seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock, and they dip synthetically to the reactivated fault at depth. During the NW-SE extension in the Eocene, the predominant movement of the pre-existing fault is strike-slip. Subsequently,during the N-S extension since the Oligocene, inclined at *** the pre-existing fault, forming splay fault segments and ultimately creating large en-echelon arcuate faults linked by relay ramps. Using fault throw-distance(T-D) and laser scanning, we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement. Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures, bending splay faults in the termination zone, and normal fault segments responding to the regional stress *** interaction between faults occurs among normal faults and strike-slip faults, and the kinematic unification of the two fault systems is accomplished in the intersection zone. As the faults continue to evolve, the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults. The ductile detachment layer significantly contributes to the uniform distribution of strain, resulting in narrow shear zones and discontinuous normal faults in its absence.

关键词： Analogue modelling Transtensional deformation Fault linkage Fault intersection zone Nanpu Sag of Bohai Bay basin

Univariate Time Series Anomaly Detection Based on Hierarchical Attention Network

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Tsinghua Science and Technology 2024年第4期29卷 1181-1193页

作者： Zexi Chen Dongqiang Jia Yushu Sun Lin Yang Wenjie Jin Ruoxi Liu State Grid beijing Electric Power company Beijing 100031China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China

In order to support the perception and defense of the operation risk of the medium and low voltage distribution system, it is crucial to conduct data mining on the time series generated by the system to learn anomalous patterns, and carry out accurate and timely anomaly detection for timely discovery of anomalous conditions and early alerting. And edge computing has been widely used in the processing of Internet of Things (IoT) data. The key challenge of univariate time series anomaly detection is how to model complex nonlinear time dependence. However, most of the previous works only model the short-term time dependence, without considering the periodic long-term time dependence. Therefore, we propose a new Hierarchical Attention Network (HAN), which introduces seven day-level attention networks to capture fine-grained short-term time dependence, and uses a week-level attention network to model the periodic long-term time dependence. Then we combine the day-level feature learned by day-level attention network and week-level feature learned by week-level attention network to obtain the high-level time feature, according to which we can calculate the anomaly probability and further detect the anomaly. Extensive experiments on a public anomaly detection dataset, and deployment in a real-world medium and low voltage distribution system show the superiority of our proposed framework over state-of-the-arts.

关键词： edge computing anomaly detection univariate time series self-attention

Enzymatic C1 reduction using hydrogen in cofactor regeneration

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Frontiers of Chemical Science and Engineering 2024年第7期18卷 33-40页

作者： Ruishuang Sun Chenqi Cao Qingyun Wang Hui Cao Ulrich Schwaneberg Yu Ji Luo Liu Haijun Xu beijing Bioprocess Key Laboratory Beijing University of Chemical TechnologyBeijing 100029China Institute of biotechnology Rheinisch-Westfälische Technische Hochschale(RWTH)AachenAachen 52074Germany

Carbon dioxide fixation presents a potential solution for mitigating the greenhouse gas *** carbon dioxide fixation,C1 compound reduction requires a high energy *** calculations suggest that the energy source for cofactor regeneration plays a vital role in the effective enzymatic C1 *** utilizes renewable hydrogen to achieve the regeneration and supply cofactor nicotinamide adenine dinucleotide(NADH),providing a driving force for the reduction reaction to reduce the thermodynamic barrier of the reaction cascade,and making the forward reduction pathway thermodynamically *** on the regeneration of cofactor NADH by hydrogenase,and coupled with formaldehyde dehydrogenase and formolase,a favorable thermodynamic mode of the C1 reduction pathway for reducing formate to dihydroxyacetone(DHA)was designed and *** resulted in accumulation of 3.3.19μmol·L^(-1) DHA after 2 h,and conversion reaching 7.47%.These results indicate that enzymatic utilization of hydrogen as the electron donor to regenerate NADH is of great significance to the sustainable and green development of bio-manufacturing because of its high economic efficiency,no by-products,and environment-friendly ***,formolase efficiently and selectively fixed the intermediate formaldehyde(FALD)to DHA,thermodynamically pulled formate to efficiently reduce to DHA,and finally stored the low-grade renewable energy into chemical energy with high energy density.

关键词： [NiFe]-hydrogenase SH formolase NADH regeneration C1 compound reduction thermodynamic calculation

A review of reservoir damage during hydraulic fracturing of deep and ultra-deep reservoirs

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Petroleum Science 2024年第1期21卷 384-409页

作者： Kun Zhang Xiong-Fei Liu Dao-Bing Wang Bo Zheng Tun-Hao Chen Qing Wang Hao Bai Er-Dong Yao Fu-Jian Zhou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing102617China Tuha Downhole Operation company CNPC Xibu Drilling Engineering Company LimitedShanshan838200XinjiangChina

Deep and ultra-deep reservoirs have gradually become the primary focus of hydrocarbon exploration as a result of a series of significant discoveries in deep hydrocarbon exploration *** reservoirs present unique challenges due to their deep burial depth(4500-8882 m),low matrix permeability,complex crustal stress conditions,high temperature and pressure(HTHP,150-200℃,105-155 MPa),coupled with high salinity of formation ***,the costs associated with their exploitation and development are exceptionally *** deep and ultra-deep reservoirs,hydraulic fracturing is commonly used to achieve high and stable *** hydraulic fracturing,a substantial volume of fluid is injected into the ***,statistical analysis reveals that the flowback rate is typically less than 3.%,leaving the majority of the fluid trapped within the ***,hydraulic fracturing in deep reservoirs not only enhances the reservoir permeability by creating artificial fractures but also damages reservoirs due to the fracturing fluids *** challenging“three-high”environment of a deep reservoir,characterized by high temperature,high pressure,and high salinity,exacerbates conventional forms of damage,including water sensitivity,retention of fracturing fluids,rock creep,and proppant *** addition,specific damage mechanisms come into play,such as fracturing fluid decomposition at elevated temperatures and proppant diagenetic reactions at HTHP ***,the foremost concern in deep oil and gas development lies in effectively assessing the damage inflicted on these reservoirs by hydraulic fracturing,comprehending the underlying mechanisms,and selecting appropriate ***'s noteworthy that the majority of existing studies on reservoir damage primarily focus on conventional reservoirs,with limited attention given to deep reservoirs and a lack of systematic *** light of this,our approach entails initially summarizin

关键词： Artificial fracture Deep and ultra-deep reservoir Fracture conductivity Fracturing fluid Hydraulic fracturing Reservoir damage