检索结果-南通市图书馆

Gas film/regenerative composite cooling characteristics of the liquid oxygen/liquid methane (LOX/LCH4) rocket engine

引用

Journal of Zhejiang University-science A(Applied Physics & Engineering) 2024年第8期25卷 631-649页

作者： Xinlin LIU Jun SUN Zhuohang JIANG Qinglian LI Peng CHENG Jie SONG science and technology on Scramjet Laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

The thermal protection of rocket engines is a crucial aspect of rocket engine *** this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling *** accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust ***,key parameters related to heat transfer performance were *** results demonstrate that the model is sufficiently accurate to be used as a preliminary design *** temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer *** addition,the performance of composite cooling is observed to be superior to regenerative *** the gas film flow rate results in higher cooling efficiency and a lower gas-side wall ***,the position at which the gas film is introduced greatly impacts the cooling *** optimal introduction position for the gas film is determined when the film is introduced from a single row of *** optimal introduction position results in a more uniform wall temperature distribution and reduces the peak ***,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall *** results provide a basis for the design of gas film/regenerative composite cooling systems.

关键词： Liquid oxygen/liquid methane(LOX/LCH4)rocket engine Gas film cooling Regenerative cooling Heat transfer characteristics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

4D-MAP:Multipath Adaptive Packet Scheduling for Live Streaming over QUIC

引用

Journal of Computer science & technology 2024年第1期39卷 159-176页

作者：宋丛溪韩彪苏金树 college of Computer science and technology National University of Defense TechnologyChangsha 410073China

In recent years,live streaming has become a popular application,which uses TCP as its primary transport *** UDP Internet Connections(QUIC)protocol opens up new opportunities for live ***,how to leverage QUIC to transmit live videos has not been studied *** paper first investigates the achievable quality of experience(QoE)of streaming live videos over TCP,QUIC,and their multipath extensions Multipath TCP(MPTCP)and Multipath QUIC(MPQUIC).We observe that MPQUIC achieves the best performance with bandwidth aggregation and transmission ***,network fluctuations may cause heterogeneous paths,high path loss,and band-width degradation,resulting in significant QoE *** by the above observations,we investigate the multipath packet scheduling problem in live streaming and design 4D-MAP,a multipath adaptive packet scheduling scheme over ***,a linear upper confidence bound(LinUCB)-based online learning algorithm,along with four novel scheduling mechanisms,i.e.,Dispatch,Duplicate,Discard,and Decompensate,is proposed to conquer the above problems.4D-MAP has been evaluated in both controlled emulation and real-world networks to make comparison with the state-of-the-art multipath transmission *** results reveal that 4D-MAP outperforms others in terms of improving the QoE of live streaming.

关键词： multipath transmission live streaming Quick UDP Internet Connections(QUIC) quality of experience(QoE) packet scheduling

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Topological superconductors with spin-triplet pairings and Majorana Fermi arcs

引用

Chinese Physics B 2024年第8期33卷 453-458页

作者：黄石罗熙 college of science University of Shanghai for Science and TechnologyShanghai 200093China

We construct a three-dimensional topological superconductor Bogoliubov–de Gennes(BdG)Hamiltonian with the normal state being a three-dimensional topological *** introducing inter-orbital spin-triplet pairings term△3,there are topological Majorana nodes in the bulk and they are connected by Majorana Fermi arcs on the surface,similar to the case of Weyl ***,by adding an inversion-breaking term to the normal state,momentum-independent pairing terms with different parities can coexist in the Bd G Hamiltonian,which creates more Majorana modes similar to Andreev bound states and a richer phase diagram.

关键词： topological surface states topological superconductors topological nodes Weyl points Majorana Fermi arcs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Vector Dominance with Threshold Searchable Encryption (VDTSE) for the Internet of Things

引用

Computers, Materials & Continua 2024年第6期79卷 4763-4779页

作者： Jingjing Nie Zhenhua Chen college of Safety science and Engineering Xi’an University of Science and TechnologyXi’an710054China college of Computer science and technology Xi’an University of Science and TechnologyXi’an710054China

The Internet of Medical Things(IoMT)is an application of the Internet of Things(IoT)in the medical *** is a cutting-edge technique that connects medical sensors and their applications to healthcare systems,which is essential in smart ***,Personal Health Records(PHRs)are normally kept in public cloud servers controlled by IoMT service providers,so privacy and security incidents may be ***,Searchable Encryption(SE),which can be used to execute queries on encrypted data,can address the issue ***,most existing SE schemes cannot solve the vector dominance threshold *** response to this,we present a SE scheme called Vector Dominance with Threshold Searchable Encryption(VDTSE)in this *** use a Lagrangian polynomial technique and convert the vector dominance threshold problem into a constraint that the number of two equal-length vectors’corresponding bits excluding wildcards is not less than a threshold ***,we solve the problem using the proposed technique modified in Hidden Vector Encryption(HVE).This technique makes the trapdoor size linear to the number of attributes and thus much smaller than that of other similar SE schemes.A rigorous experimental analysis of a specific application for privacy-preserving diabetes demonstrates the feasibility of the proposed VDTSE scheme.

关键词： Internet of Things(IoT) Internet of Medical Things(IoMT) vector dominance with threshold searchable encryption(VDTSE) threshold comparison electronic healthcare

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bioinspired sensing-memory-computing integrated vision systems: biomimetic mechanisms, design principles, and applications

引用

science China(Information sciences) 2024年第5期67卷 5-27页

作者： Yujie HUANG Yinlong TAN Yan KANG Yabo CHEN Yuhua TANG Tian JIANG Institute for Quantum Information and State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology college of Advanced Interdisciplinary Studies National University of Defense Technology Institute for Quantum science and technology College of ScienceNational University of Defense Technology

With the explosion of sensory data in the Internet of Things(Io T) era, conventional machine vision systems are becoming increasingly difficult to meet the requirements of high efficiency, low energy consumption, and low latency due to their inherent shortcomings of separate sensing, memory, and computing units. Inspired by the retina and neuromorphic computing, the sensing-memory-computing integrated vision system(SMCVS) that features low power consumption, low latency, and high parallelism has been considered a promising technology to surpass the von Neumann architecture and realize strong artificial ***, novel materials like two-dimensional semiconductors and quantum dots with novel optoelectronic performance provide hardware carriers for implementing integrated sensing-memory-computing architectures,attracting considerable attention. This paper reviews the recent research progress in bioinspired vision systems in terms of biomimetic mechanisms, design principles, computational architectures, and ***, the biomimetic mechanisms are illustrated to guide the design of high-performance artificial visual perception systems. Then the research progress of optoelectronic-synapse-based bioinspired vision systems in the device principles and applications including image filtering, color recognition, visual adaptation, and motion detection are summarized. Finally, the challenges and future developing directions of the SMCVS are provided regarding bionic application, architecture design, and device fabrication.

关键词： sensing-memory-computing architecture neuromorphic computing retinomorphic device image recognition visual system

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

GS-orthogonalization OMP method for space target detection via bistatic space-based radar

引用

Chinese Journal of Aeronautics 2024年第7期37卷 333-351页

作者： Shuyu ZHENG Libing JIANG Qingwei YANG Yingjian ZHAO Zhuang WANG National Key Laboratory of science and technology on Automatic Target Recognition College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China

A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar ***,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space *** be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization *** solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this ***,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are ***,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space ***,the RCM and DFM are corrected by the compensation function correlated with the estimated motion ***,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo *** simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection.

关键词： Bistatic space-based radar High-speed maneuvering space targets detection Range Cell Migration(RCM) Doppler Frequency Migration(DFM) Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Single transition-metal atoms anchored on a novel Diracdispersiveπ-πconjugated holey graphitic carbon nitride substrate:computational screening toward efficient bifunctional OER/ORR electrocatalysts

引用

Rare Metals 2024年第8期43卷 3819-3832页

作者： Chun-Yao Fang Xi-Hang Zhang Qiang Zhang Di Liu Xiao-Meng Cui Jing-Cheng Xu Cheng-Long Shi Meng-Yu Yang college of science University of Shanghai for Science and TechnologyShanghai 200093China School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China

Nonprecious-metal-group single-metal-atom catalysts with bifunctional catalytic capabilities toward the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)are highly sought after in energy-conversion and storage ***,producing renewable and sustainable energy sources remains ***,single-transition metal atoms anchored onπ-πconjugated two-dimensional(2D)graphitic carbon nitride substrates formπ-d conjugated conductive channels that enhance the overall electrocatalytic ***,firstprinciples calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride(gC_(10)N_(3))as a promising 2D electrocatalyst substrate to support single-transition metal(TM,from Sc to Au).The"donation-acceptance"charge interaction in the TM-N_(2)moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g-C_(10)N_(3)and Rh@gC_(10)N_3,making them effective bifunctional OER/ORR electrocatalysts with IrO_(2)/Pt-beyond overpotentials being as low as 0.39/0.38 V and 0.54/0.44 V,***,they possess high stability and conductivity and are less susceptible to oxidation and corrosion under working *** guarantees high activity under ambient ***,the origin of the OER/ORR activity of TM@g-C_(10)N_(3) is explained using multilevel descriptors:intrinsic(p,Bader charge,integral crystal orbital Hamilton population(ICOHP),bond length,and d-band center(εd).In particular,for optimal Ni@g-C_(10)N_(3),the clear hybridization between the Ni-d orbital and surface O-p orbital causes the paired electrons to occupy the bonding *** enables OH~*to be adsorbed on the Ni@g-C_(10)N_(3),thereby achieving the highest catalytic performance.

关键词： First-principles calculation Oxygen evolution reaction Oxygen reduction reaction Bifunctional electrocatalysts Single-metal-atom electrocatalysts

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Density functional theory study of B- and Si-doped carbons and their adsorption interactions with sulfur compounds

引用

Carbon Energy 2024年第2期6卷 195-208页

作者： Peng Guo Hong Zhang Shuliang Dong Libao An college of Mechanical Engineering North China University of Science and TechnologyTangshanHebeiChina college of Life sciences North China University of Science and TechnologyTangshanHebeiChina

Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion *** this paper,properties of intrinsic B or Si single-atom doped,and B-Si codoped graphene(GR)and graphdiyne(GDY)were investigated by using density functional theory-based calculations,in which the optimal doping configurations were explored for potential applications in adsorbing sulfur *** showed that both B or Si single-atom doping and B-Si codoping could substantially enhance the electron transport properties of GR and GDY,improving their surface ***,B and Si atoms displayed synergistic effects for the codoped configurations,where B-Si codoped GR/GDY exhibited much better performance in the adsorption of sulfurcontaining chemicals than single-atom doped *** addition,results demonstrated that,after B-Si codoping,the adsorption energy and charge transfer amounts of GDY with sulfur compounds were much larger than those of GR,indicating that B-Si codoped GDY might be a favorable material for more effectively interacting with sulfur reagents.

关键词： adsorption density functional theory doping graphdiyne graphene sulfur compounds

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Deterioration Reason and Improvement Measure of the Retarding Effect of Protein Retarder on Phosphorus Building Gypsum

引用

Journal of Wuhan University of technology(Materials science) 2024年第4期39卷 962-967页

作者：刘志刚 TANG Zezheng 杨立荣 WANG Chunmei XIE Yuantao LIU Yisen college of Materials science and Engineering North China University of Science and TechnologyTangshan 063210China

The retarding effect of protein retarder on phosphorus building gypsum(PBG)and desulfurization building gypsum(DBG)was investigated,and the results show that protein retarder for DBG can effectively prolong the setting time and displays a better retarding effect,but for PBG shows a poor retarding ***,the deterioration reason of the retarding effect of protein retarder on PBG was investigated by measuring the pH value and the retarder concentration of the liquid phase from vacuum filtration of PBG slurry at different hydration time,and the measure to improve the retarding effect of protein retarding on PBG was *** pH value of PBG slurry(<5.0)is lower than that of DBG slurry(7.8-8.5).After hydration for 5 min,the concentration of retarder in liquid phase of DBG slurry gradually decreases,but in liquid phase of PBG slurry continually increases,which results in the worse retarding effect of protein retarder on *** liquid phase pH value of PBG slurry can be adjusted higher by sodium silicate,which is beneficial to improvement in the retarding effect of the *** adding 1.0%of sodium silicate,the initial setting time of PBG was efficiently prolonged from 17 to 210 min,but little effect on the absolute dry flexural strength was observed.

关键词： protein retarder phosphorus building gypsum deterioration reason improvement measure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dietary sodium acetate and sodium butyrate attenuate intestinal damage and improve lipid metabolism in juvenile largemouth bass(Micropterus salmoides) fed a high carbohydrate diet by reducing endoplasmic reticulum stress

引用

Animal Nutrition 2024年第1期16卷 443-456页

作者： Liulan Zhao Liangshun Cheng Yifang Hu Xiaohui Li Yihui Yang Jin Mu Lianfeng Shen Guojun Hu Kuo He Haoxiao Yan Qiao Liu Song Yang college of Animal science and technology Sichuan Agricultural University

High-carbohydrate(HC) diets decrease the intestinal levels of sodium acetate(SA) and sodium butyrate(SB) and impair the gut health of largemouth bass; however, SA and SB have been shown to enhance immunity and improve intestinal health in farmed animals. Thus, the present study was to investigate the effects of dietary SA and SB on HC diet-induced intestinal injury and the potential mechanisms in juvenile largemouth bass. The experiment set five isonitrogenous and isolipidic diets, including a lowcarbohydrate diet(9% starch)(LC), a high carbohydrate diet(18% starch)(HC), and the HC diet supplemented with 2 g/kg SA(HCSA), 2 g/kg SB(HCSB) or a combination of 1 g/kg SA and 1 g/kg SB(HCSASB).The feeding experiment was conducted for 8 weeks. A total of 525 juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were used. The results showed that dietary SA and SB improved the weight gain rate and specific growth rate (P<0.05) and ameliorated serum parameters(alkaline phosphatase, acid phosphatase, glutamate transaminase, and glutamic oxaloacetic transaminase)(P<0.05). And, importantly, dietary SA and SB repaired the intestinal barrier by increasing the expression levels of zonula occludens-1, occludin, and claudin-7(P<0.05), reduced HC-induced intestinal damage, and alleviated intestinal inflammation and cell apoptosis by attenuating HC-induced intestinal endoplasmic reticulum stress(P<0.05). Further results revealed that dietary SA and SB reduced HC-induced intestinal fat deposition by inhibiting adipogenesis and promoting lipolysis(P<0.05). In summary, this study demonstrated that dietary SA and SB attenuated HC-induced intestinal damage and reduced excessive intestinal fat deposition in largemouth bass.

关键词： Sodium acetate Sodium butyrate High carbohydrate diet Endoplasmic reticulum stress Intestine health Lipid metabolism

来源：评论

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：