检索结果-南通市图书馆

Modification of POSS and their tribological properties and resistant to space atomic oxygen irradiation as lubricant additive of multialkylated cyclopentanes

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第5期12卷 884-896页

作者： Xingwei WANG chaoyang zhang Chen ZHAO Yijing LIANG Ming zhang Wufang YANG Bo YU Qiangliang YU Meirong CAI Feng ZHOU Weimin LIU State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai264000China

Developing functional additive resistant to space atomic oxygen(AO)irradiation through simple molecular design and chemical synthesis to enhance the lubricating performance of multialkylated cyclopentanes(MACs)oil is a significant challenge.Herein,sulfur-containing polyhedral oligomere silsesquioxane(POSS)were synthesize via a click-chemistry reaction of octavinyl polyhedral oligomeric with alkyl sulfide.The reduce-friction(RF),anti-wear(AW)properties and anti-AO irradiation of POSS-S-R as MACs base oil additives in atmospheric and simulated space environments were systematically investigated for the first time.Results demonstrate that POSS-S-R not only possesses outstanding anti-AO irradiation capacity but also effectively improves the RF and AW of MACs in atmospheric or simulated space surroundings.This improvement is due to the excellent anti-AO irradiation properties of the POSS structure itself and the high load-carrying ability of silicon-containing and sulfur-containing compounds generated by tribo-chemical reactions,which effectively separates the direct contact of the friction interface.We believe that this synthesized POSS-S-R is a promising additive for space lubricants.

关键词： POSS additive reduce-friction anti-wear multialkylated cyclopentanes(MACs) resistant atomic irradiation

Analysis of oil shedding and ligaments formation on bearing rotary elements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第2期36卷 377-387页

作者： Donglei ZHU Guoding CHEN Yanjun LI chaoyang zhang Lin WANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China China Gas Turbine Establishment Chengdu 610500China

For designing efficient lubrication system of an aeroengine bearing chamber,sufficient knowledge on oil/air two-phase flow characteristics is required.When analyzing bearing chamber two-phase flow,the essential prerequisite is quantifying the oil ligaments,which are detached from bearing rotary elements and shed into the bearing chamber.Related investigations are mainly targeted at liquid shedding on the rotating disk as opposed to the bearing rotary elements.Moreover,the research based on bearing rotary elements is conducted by experiment.Due to the limited operating conditions,experimental studies cannot guide engineering applications.To overcome these limitations,a theoretical model is established in this paper,for revealing the mechanism of oil shedding from bearing rotary elements and quantifying the shedding ligaments.The theoretical model is validated against experimental results from classical studies.In addition,the correlation for shedding ligaments number based on aeroengine bearing structural and operational parameters is obtained via theoretical analysis.The analytical results demonstrate that oil shedding and ligaments formation appear at the edge of bearing inner race outer-periphery.The number of shedding ligaments increases with the rise of shaft rotational speed while decreases with the growth of oil viscosity.

关键词： Aeroengine bearing chamber Ligaments Lubrication Mechanical analysis Shedding Wave

Benchmark calculations and error cancelations for bond dissociation enthalpies of X-NO_(2)

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2023年第4期22卷 144-155页

作者： Jian Liu Xudong He Ying Xiong Fude Nie chaoyang zhang Institute of Chemical Materials China Academy of Engineering PhysicsP.O.Box 919-311China

Safety plays an important role in determining the applicability of energetic compounds,and the bond dissociation enthalpy(BDE)of the“trigger bond”X-NO_(2) provides useful information to evaluate various safety properties.Accurate and rapid calculation of the BDE of X-NO_(2) is of great significance to perform the high-throughput design of energetic compounds,which becomes an increasingly popular means of materials design.We conduct a benchmark BDE calculation for 44 X-NO_(2) samples extracted from the iBond database,with the accuracies of 55 quantum chemistry calculation levels evaluated by the experimentally measured values.Only four levels have the global mean-absolute deviation(MAD)less than 10 kJ/mol,but no calculation level can achieve that all the local MADs of each category less than 10 kJ/mol.We propose a simple correction strategy for the original calculation deviations,and apply it to 30 calculation levels screened out through a series of accuracy assessments and obtain the corrected MAD<6 kJ/mol in some cases.We define a normalized time-cost(NTC)to evaluate the time-cost of each calculation level,and confirm that PBE0-D3/6-31G^(**)(MAD=6.4 kJ/mol,NTC?0.8)works the best for most cases,followed by M062X/6-31g^(**),M062X/6-311g^(**)andɷB97XD/6-311g^(**),based on an insight into the accuracy-cost trade.The present work provides an accurate and fast solution for calculating XNO_(2) BDE via quantum chemical methods,and is expected to be beneficial to enhance the safety prediction efficiency of energetic compounds.

关键词： Complex waveform scaling Analytical blast modeling Hopkinson-Cranz Scaled distance

A 3D CFD simulation of oil spray-collection and delivery process in an aeroengine inter-shaft bearing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第9期35卷 366-378页

Under-race lubrication applied to the inter-shaft bearing of aeroengine is characterized by spray oil collection and oil delivery to the bearing via flow-path structure. Droplet splashing induced by the collision between spray oil and the scoop as well as oil flowing characteristics in the flow-path influence bearing lubrication efficiency. In previous investigations, the spray oil collection and oil delivery analysis were separated, and the effect of droplet splashing on bearing lubrication efficiency was not considered. Moreover, time-varying characteristics of oil delivered to the bearing were not accounted for. This is caused by time variations of the circumferential position of rollers and under-race feed holes. To overcome these limitations, a numerical model which integrates the spray oil collection and oil delivery analysis is proposed in this paper. The model is embedded with the function of calculating the flow rate of splashing droplets and analyzing time-varying characteristics of the oil fed to the bearing. Furthermore, the numerical model is validated by experimental investigation. The proposed numerical model facilitates the accurate calculation of bearing lubrication efficiency as well as the design of an efficient lubrication structure.

关键词： Integrated Inter-shaft bearing Splash-spray Time-varying Under-race lubrication

Screening and identification of candidate Fusarium wilt-resistance genes from pumpkin

在线全文

学校读者我要写书评

暂无评论

Horticultural Plant Journal 2022年第5期8卷 583-592页

作者： Jun Xu Qianqian Xian Ke Wang Jingping Dong chaoyang zhang Shengli Du Xuewen Xu Xuehao Chen School of Horticulture and Plant Protection Yangzhou UniversityYangzhouJiangsu 225009China Huai’an Key Laboratory for Agricultural Biotechnology Huaiyin Institute of Agricultural Sciences in Xuhuai Region of Jiangsu ProvinceHuai’anJiangsu 223001China State Key Laboratory of Vegetable Germplasm Innovation Tianjin 300192China

Pumpkin(Cucurbita moschata)has been widely used as cucumber(Cucumis sativus L.)rootstock to defend against Fusarium wilt(FW)and increase cucumber yields and profits.However,the resistance genes and mechanisms underlying the FW tolerance in pumpkin are poorly understood.Here we analyzed the transcriptome of pumpkin inoculated with the cucumber FW causal agent Fusarium oxysporum f.***.cucumerinum(Foc),and obtained 3152 and 4735 upregulated genes induced by Foc at 24h after Foc inoculation compared with at 0h and 24h non-inoculated control,respectively.Next,404 common differentially expressed genes(DEGs)were screened using the criterion log_(2) FPKM(fold change)≥2.In total,206 of 404 DEGs were predominantly expressed in roots,which is the first tissue that Foc contacts and invades.140 DEGs were selected and classified into four groups(pathogenesis resistance,secondary metabolism-related,transcription factor and signal binding)based on their functional descriptions.Then,29 genes having high expression levels were selected to investigate the expression patterns induced by a Foc inoculation.Among them,16 genes were significantly induced by Foc and showed high expression levels at various treatment time points.These candidate genes may act as positive regulators of FW resistance in pumpkin and provide effective resources for improving cucumber FW resistance through breeding programs.

关键词： Pumpkin Rootstock Transcriptome Fusarium wilt Resistance genes

Stable dispersibility of bentonite-type additive with gemini ionic liquid intercalation structure for oil-based drilling

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第2期11卷 201-215页

作者： chaoyang zhang Rui DONG Xingang WANG Yijing LIANG Ming zhang Qiangliang YU Zhongping TANG Huiying LV Liping WANG Meirong CAI Feng ZHOU Weimin LIU State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100039China PetroChina Lanzhou Lubricating Oil R&D Institute Lanzhou 730060China

In this study,the direct intercalation of gemini ionic liquids(ILs)with different alkyl chains into the bentonite(BT)interlayer as a high-performance lubricating additive for base oil 500SN was investigated.The purpose of modifying BT with an IL is to improve the dispersion stability and lubricity of BT in lubricating oil.The dispersibility and tribological properties of IL–BT as oil-based additives for 500SN depend on the increase in interlamellar space in BT and improve as the chain length is increased.More importantly,the IL–BT nanomaterial outperforms individual BT in improving wear resistance,owing to its sheet layers were deformed and sprawled in furrows along the metal surface,thereby resulting in low surface adhesion.Because of its excellent lubrication performance,IL-modified BT is a potential candidate for the main component of drilling fluid.It can be used as a lubricating additive in oil drilling and oil well construction to reduce equipment damage and ensure the normal operation of equipments.

关键词： ionic liquid modified bentonite nanomaterial oil-based additive

Characterization of a Novel Gene, srpA, Conferring Resistance to Streptogramin A, Pleuromutilins, and Lincosamides in Streptococcus suis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2022年第2期8卷 85-94页

作者： chaoyang zhang Lu Liu Peng zhang Jingpo Cui Xiaoxia Qin Lichao Ma Kun Han Zhanhui Wang Shaolin Wang Shuangyang Ding zhangqi Shen College of Veterinary Medicine China Agricultural UniversityBeijing 100193China Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety and Beijing Laboratory for Food Quality and Safety China Agricultural UniversityBeijing 100193China

Antimicrobial resistance is undoubtedly one of the greatest global health threats. The emergence of multidrug-resistant(MDR) Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus(MRSA), vancomycin-resistant Enterococcus faecium(VRE), and β-lactamase-resistant Streptococcus pneumonia, has severely limited our antibiotic arsenal. Numerous ribosome-targeting antibiotics, especially pleuromutilins, oxazolidinones, and streptogramins, are viewed as promising alternatives against aggressive MDR pathogens. In this study, we identified a new adenosine triphosphate(ATP)-binding cassete(ABC)-F family determinant, srp A, in Streptococcus suis(S. suis) by means of a comparative analysis of the whole-genome sequences of tiamulin(TIA)-resistant and TIA-sensitive bacteria. Functional cloning confirmed that the deduced gene can mediate cross-resistance to pleuromutilins, lincosamides, and streptogramin A in S. suis and S. aureus. A sequence alignment revealed that Srp A shares the highest amino acid identity with Vga(E)(36%) and shows canonical characteristics of ABC-F family members.In Srp A-ribosome docked compounds, the extended loop region of Srp A approaches the valnemulinbinding pocket in the ribosome peptidyl-transferase center and competes with bound valnemulin. A detailed mutational analysis of the loop residues confirmed that this domain is crucial for Srp A activity,as substitutions or truncations of this region affect the efficiency and specificity of antibiotic resistance.Intracellular antibiotics accumulation indicated that Srp A does not act as an efflux pump, while a ribosome binding assay supported the protective effects of Srp A on the ribosome by preventing antibiotic binding as well as displacing bound drugs. These findings clarify the mechanisms underlying resistance to ribosomal antibiotics.

关键词： SrpA Streptococcus suis Antibiotic resistance Ribosome ABC-F family proteins

Lignin composite ionic liquid lubricants with excellent anti-corrosion,anti-oxidation,and tribological properties

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第7期11卷 1239-1252页

作者： chaoyang zhang Zhiquan YANG Qing HUANG Xingwei WANG Wufang YANG Chunyu ZHOU Bo YU Qiangliang YU Meirong CAI Feng ZHOU State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China PetroChina Lanzhou Lubricating Oil R&D Institute Lanzhou 730060China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264006China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Yantai 264006China

A new type of lubricating material(BTA-P_(4444)-Lig)was synthesized by combining lignin with tetrabutylphosphorus and benzotriazole.The tribological properties,corrosion resistance,and anti-oxidation properties of BTA-P_(4444)-Lig as a lubricant were investigated.The lubricating material exhibits excellent friction reduction and wear resistance,as well as good thermal stability and excellent oxidation resistance.Mechanistic analysis reveals that the active elements N and P in the lubricating material react with the metal substrate,and the reaction film effectively blocks direct contact between the friction pairs,affording excellent friction reduction and wear resistance.At the same time,the phenolic hydroxyl group in lignin reacts with oxygen free radicals to form a resonance-stable semi-quinone free radical,which interrupts the chain reaction and affords good anti-oxidant activity.

关键词： lignin lubrication ionic liquid anti-oxidant

Network reconstructions with partially available data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2017年第3期12卷 117-123页

作者： chaoyang zhang Yang Chen Gang Hu Departraent of Physics Ningbo University Ningbo 315211 China School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China Department-of-Physics Beijing- Normal University Beijing 100875 China

Many practical systems in natural and social sciences can be described by dynamical networks. Day by day we have measured and accumulated huge amounts of data from these networks, which can be used by us to further our understanding of the world. The structures of the networks producing these data are often unknown. Consequently, understanding the structures of these networks from available data turns to be one of the central issues in interdisciplinary fields, which is called the network recon- struction problem. In this paper, we considered problems of network reconstructions using partially available data and some situations where data availabilities are not sufficient for conventional network reconstructions. Furthermore, we proposed to infer subnetwork with data of the subnetwork available only and other nodes of the entire network hidden; to depict group-group interactions in networks with averages of groups of node variables available; and to perform network reconstructions with known data of node variables only when networks are driven by both unknown internal fast-varying noises and unknown external slowly-varying signals. All these situations are expected to be common in practical systems and the methods and results may be useful for real world applications.

关键词： network reconstruction dynamics data analysis