1,491 research outputs found
The Effect of Yttrium on Wear, Corrosion and Corrosive Wear of Mg-Al Alloys
No full textMagnesium remarkably deserves considerable interest from industry especially transportation sector because of its high strength to weight ratio. However, poor wear resistance and low corrosion resistance of magnesium are barriers to extend use of its alloys. Yttrium is one of rare-earth elements which has been demonstrated effectiveness in improving the corrosion resistance and tribological properties of some metallic alloys. In this work, the effects of yttrium on wear, corrosion and corrosive wear of as-cast Mg-3 wt% Al and AZ31 alloys were investigated. It was shown that the added yttrium increased the dry wear resistance of the alloys through the formation of a harder second phases. The corrosion resistance of the alloys was evaluated in tap water and salt solution. A small amount of added Y improved the corrosion resistance but such benefit decreased at higher yttrium contents. Corrosive wear tests were performed in the same environment for the alloys. The improvement in corrosive wear resistance mainly came from the reduction of corrosion-wear synergy caused by the added yttrium, which increased both hardness and corrosion resistance. Relevant mechanisms to express the observations and the correlation between the performance and microstructure were analyzed and discussed in details. In addition to modification of the corrosion potential of bulk magnesium through alloying elements, tailoring its surface oxide film is an alternative approach for enhanced resistance to corrosion. In this study, effects of small amounts of a yttrium on the strength of surface oxide film formed on Mg-3 wt% Al alloy and its adherence to the substrate were investigated. It is demonstrated that the yttrium addition decreased the component ratio of hydroxides to oxides, mainly Mg(OH)2 to MgO, in the surface oxide film, leading to markedly enhanced mechanical strength and resistance to scratch with stronger adherence to the substrate. However, as the nominal yttrium concentration exceeded a certain level, the beneficial effect of Y on the film was weakened. Efforts were made to clarify underlying mechanisms. Surface modification is an effective approach for increasing wear and corrosion resistance of materials without affecting their bulk properties. Among various surface modification techniques, aluminizing is an economical and effective one which has been applied to various alloys. The effectiveness of aluminizing might be further enhanced by alloying with rare earth elements such as yttrium. In this research, effects of yttrium-incorporated aluminizing on the resistance of AZ31 alloy to corrosion, wear, and corrosive wear were investigated. The study demonstrates that aluminizing can be beneficial to the resistance of the alloy to wear, corrosion and corrosive wear. The addition of yttrium increased the benefits, largely attributed to the associated passive film. Effectiveness of aluminizing can be further enhanced by surface nanocrystallization. In this study, effects of surface nanocrystallization on the effectiveness of aluminizing in enhancing the resistance of AZ31 alloy to corrosion, wear and corrosive wear were investigated. The results demonstrated that aluminizing was effective to increase the resistance of the Mg alloy to surface failures. Surface nanocrystallization expanded the improvement, largely attributed to increased surface hardness and enhanced passivation capability
Deep Geological Structure Analysis of the Dongyang Area, Fujian, China: Insights from Integrated Gravity and Magnetic Data
No full textTo explore the deep geological structure of the Dongyang area in Fujian, China, gravity data from the area and its surroundings were collected and processed. Additionally, a high-precision magnetic survey was conducted in the Zhongxian region of this area, with subsequent analysis of the magnetic anomalies. Through the integration of regional geological data, a comprehensive analysis was carried out on the characteristics of gravity–magnetic anomalies and deep geological structures in the Dongyang area. The study indicates that the primary portion of the Dongyang area lies southwest of the expansive circular volcanic structure spanning Dehua to Yongtai. Two significant residual gravity anomalies were identified within the region, interpreted as the Xiaoban-Shuangqishan and Dongyang-Lingtouping residual gravity-positive anomalies. In the Zhongxian region, the magnetic field exhibits complexity with notable amplitude variations. Positive anomalies predominate in the western and northern sectors, while localized positive anomalies are prominent in the eastern region. The central area portrays a circular and disordered mix of positive and negative anomalies. Particularly distinctive are the band-shaped and fan-shaped negative anomalies curving from northeast to southeast through the central region. Various positive and negative anomalies of varying strengths, gradients, and orientations overlay both positive and negative magnetic backgrounds in specific locales. Moreover, the Dongyang area showcases well-developed fault structures, primarily oriented in northeast and northwest directions. Leveraging the regional magnetic attributes in conjunction with regional geological data, 39 faults were deduced in the Zhongxian region of the Dongyang area, delineating three promising mineralization zones
Ni gu Yue fu: [er juan]. v.1
No full text[李東陽撰] ; 謝鐸, 潘辰評點 ; 陳建通考.綫裝, 1函.框19.5x13公分, 9行20字, 小字雙行同. 白口, 四周單邊, 對黑魚尾. 版心上鐫題名, 中鐫卷次, 下鐫葉次. 行間有圈點.分上, 下卷.前有弘治甲子[1504]李東陽書引 ; 卷末有[嘉靖]丙申[1536]白賁言及刻書事.見《香港中文大學圖書館古藉善本書錄》(2001, p. 239)Xian zhuang, 1 han.Kuang 19.5 x 13 gong fen, 9 hang 20 zi, xiao zi shuang hang tong. Bai kou, si zhou dan bian, dui hei yu wei. Ban xin shang juan ti ming, zhong juan juan ci, xia juan ye ci. Hang jian you quan dian.Fen shang, xia juan.Qian you Hongzhi jia zi [1504] Li Dongyang shu yin ; juan mo you [Jiajing] bing shen [1536] Bai Fen yan ji ke shu shi.Jian "Xianggang Zhongwen da xue tu shu guan gu ji shan ben shu lu" (2001, p. 239)[Li Dongyang zhuan] ; Xie Duo, Pan Chen ping dian ; Chen Jiantong kao
sj-docx-1-npx-10.1177_1934578X221103036 - Supplemental material for Synthesis and Antitumor Activity of Staurosporine Derivatives
No full textSupplemental material, sj-docx-1-npx-10.1177_1934578X221103036 for Synthesis and Antitumor Activity of Staurosporine Derivatives by Gang Li, Dan Wu, Yanchao Xu, Wenwen He, Dongyang Wang, Weiming Zhu and Liping Wang in Natural Product Communications</p
[[alternative]]Li Dongyang poetic theory of the “Book of Songs” interpretation
No full text[[abstract]]江確立「詩」的「義界」是論詩的先決條件，歷代的文人論詩時所下的定義，因時代、地域、個人而有所不同，無論是從言志、具音樂性的文字、重情采詞藻的作品、具教化功能等各種角度切入，都有許多的思考。但各家或偏執於某端，或僅重視詩的功能，多未能全面地對種種問題進行精確的討論。而古典詩發展至明代，對於詩歌創作的觀念，趨向了復古與開新兩端。而西涯在此復古思潮中扮演著承先啟後的地位，且西涯言詩亦較為全面討論有關「詩」的種種問題，其近承滄浪之言、遠祖彥和之語，並融儒家詩教之說以救滄浪之弊；又言及「格調說」成為明清「格調派」理論的基礎；其言「詩在六經別為一教」，則將魏晉以來發展的「文筆之辨」的觀念，以「詩文之辨」作為最後總結，並肯定「臺閣體」的地位；又以「識先而力後」的工夫論孟子的「知言養氣」說作為文學創作的基礎工夫。可見西涯對於《詩經》的詩學詮釋在明代有著承先啟後的地位，並且建構的詩學論述也幾乎圍繞著「詩三百」的詮解而發。本文鑒於歷來對於李東陽與茶陵派詩觀的文章雖亦不少，但除了連文萍《明代茶陵派詩論研究》（1989 年東吳大學中文系碩士論文），以及柯惠馨《李東陽詩學理論研究》（2012 新竹教育大學中文系碩士論文）有全面性論述外，尚未有系統性的討論，也未有針對李東陽詮釋《詩經》的理論論述。故筆者便承繼過往對於元末明初地域詩學、臺閣體對《詩經》的詩學詮釋，進一步對西涯的《詩經》詮釋加以分析闡述，希望能對此論題有補綴之功。[[abstract]]T Establishment of ”poetry” of ”community justice” Poetry is a prerequisite, the definition of scholar on ancient poem next time, because of the times, geographic, personal and different, whether from ambition, a musical text, Emotion adopt various angles rhetoric works, with features such as cut enlightenment, there are many thinking. But each or paranoid certain end, or only pay attention to the function of poetry, more comprehensively failed to accurately discuss the problems. The development of classical poetry to the Ming Dynasty, for the concept of poetry, the trend of retro and new open at both ends. The West career playing in this retro trend in the past with the future status and the West Ya Yan poetry has a more comprehensive discussion of the various issues related to ”poetry”, which is close to bearing Changlang words, our ancient ancestors yin and language, and melt say Confucianists Poetry to save Changlang disadvantages; Speaking again, ”says style” became the basis of Ming and Qing ”style faction” theory; his words, ”the poem in six by another as a religion,” the idea, since the Wei and Jin will be the development of ”writing Distinction”, and with ”Distinction poetry” as a final conclusion, and certainly ”Taiwan Pavilion body” status; Youyi 'knowledge before and after the force, ”the effort of Mencius” Shanghai Museum raise gas, ”said the foundation as a literary work. West visible career for the ”Book of Songs” has a poetic interpretation of the past with the future status of the Ming Dynasty, and the construction is almost poetic discourse around Explanation of ”Three Hundred Poems” of hair. This paper has always given the outlook for Li Dongyang Poetry and send articles chaling although also a lot, but even apart from Bing Wen, ”the Ming Dynasty Poetry School chaling research” (1989 Soochow University Department of Master's thesis), and Ke Huixin ”Li Dongyang poetic theory research ”(2012 Hsinchu University Department of Education Master's thesis) has a comprehensive discussion, but yet there is a systematic discussion also not against Li Dongyang interpretation of” the Book of Songs ”theory discussed. Therefore, I will inherit the past for Yuanmomingchu geographical poetics, Taiwan Pavilion body on the ”Book of Songs” poetic interpretation, further west career of ”The Book of Songs” interpretation to be analyzed and discussed, hoping to have a patch of the power of this topic
Retrospective Analysis of 2019-nCov-Infected Cases in Dongyang, Southeastern China
No full textThe 2019 novel coronavirus (2019-nCov) has caused increasing number of infected cases globally. This study was performed to analyze information regarding the transmission route and presence of viral nucleic acids on several clinical samples. Confirmed 2019-nCov-infected cases were identified in Dongyang and were treated according to guidelines for the diagnosis of 2019-nCov infection released by the National Health Commission. Information regarding the contacts that the infected people had was collected to determine whether it caused clustered cases. A series of successive nucleic acid examination of feces, oropharyngeal swabs, and sputum was also performed, and the results were analyzed. A total of 19 confirmed cases of 2019-nCov infection were identified in Dongyang, Zhejiang Province, China. Five cases showed severe symptoms, and the remaining ones showed mild manifestations. Ten cases infected from two asymptomatic individuals were clustered into two groups. Among 14 cases with consecutive nucleic acid test results, four patients showed positive results in feces after their negative conversion in oropharyngeal swabs. Asymptomatic individuals with the virus could cause 2019-nCov clustered cases, and the clustered cases may differ from sporadic cases on age and length of hospitalization. In addition, nucleic acids in feces last longer than those in oropharyngeal swabs
Migration and native place in and after the Ming : the ancestral hometown and domicile of Li Dongyang (1447–1516)
No full textThis dissertation examines the long-term effects of the great population movements of the early Ming period (1368–1424) in China by studying the geocultural identity of internal migrants and their descendants. Such people, were affiliated with multiple places, administratively and socioculturally. It focuses on the representation of migration and its legacies in literary writings by the migrants’ descendants in mid-Ming (1425–1521), in particular the case of Li Dongyang (1447–1517), through both his own writing and posthumous commemoration of him in late imperial China (1368–1911). During the early Ming, at least one-sixth of the population migrated within the empire. Migrants and their descendants were registered and required to remain in their new domiciles. They were separated from their ancestral hometowns, which were nonetheless administratively and culturally significant, for example being recorded in civil service examination records. As the descendant of family of military migrants, Li held two different geographical identities: a person from his ancestral hometown of Chaling in modern-day Hunan province and a registered resident of Beijing. Although modern scholarship has treated Li as the leader of a “Chaling Literary School,” focusing on his connection with Chaling, I argue that he was more closely tied to Beijing. This dissertation shows that he treated these two “homes” differently and did not fully belong to either. While defining himself as a person of Chaling to acknowledge his familial roots, he expressed a personal attachment to Beijing as his place of birth, residence, and afterlife. This dissertation argues that this reflection of past migration should also be considered a significant feature of his literary works. After Li’s lifetime, the complexity of his geographical identity is reflected in his portrayal by different groups: Hunan officials in the capital regarded him as a person from their native home, whereas local Beijing literati thought of him as a neighbor in the past. Migrants and their descendants like Li has multiple geocultural identities that could be invoked to different ends, in their lifetimes and afterward.Arts, Faculty ofAsian Studies, Department ofGraduat
Geochemistry and geochronology of the Dongyang gold deposit in southeast China: Constraints on ore genesis
No full textMesozoic magmatism and lithospheric destruction in East China exerted significant control on gold metallogeny. Here, we investigate the mineralogy, geochemistry, geochronology, and isotopic systematics of the Dongyang gold deposit in southeast China to constrain its origin and geodynamics. This is a newly discovered epithermal gold deposit along the Circum–Pacific metallogenic belt and is characterized by intense silicification and sericitization. The C–H–O isotope data suggest deep magmatic sources of the ores and indicate that the ore‐forming fluids comprised a mixture of magmatic water and meteoric water. The S–Pb values of the pyrite indicate magmatic origin for the sulfur, and deposit was derived mostly from crustal sources, mixed with mantle materials. The Rb–Sr dating of the pyrite from the ore deposit shows an age of 164.2 ± 9.9 Ma, whereas the zircon U–Pb SHRIMP ages of the rhyolite porphyry is 160.9 ± 0.5 Ma, suggesting that the timing of mineralization is close to that of the crystallization of the dykes. In conjunction with previous studies on similar deposits, we suggest that the gold mineralization was the response of continental lithospheric thinning in southeast China triggered by the subduction of the Palaeo‐Pacific Ocean Plate.Nan Xu, Sheng‐Rong Li, Cai‐lai Wu, M. Santos
Geochronology, geochemistry, and Pb–Hf isotopes of mineralization-related magmatism in the Dongyang gold deposit, Fujian Province, southeastern China
No full textThe recently discovered Dongyang low-sulphidation epithermal Au deposit is located in Fujian Province. The Au mineralization hosted in rhyolite porphyry and the Lower Jurassic Nayuan Formation continental volcanic rocks is considered to be related to intermediate–acidic intrusions (rhyolite porphyry, quartz diorite porphyry, and dacite porphyry). The zircon U–Pb ages of these samples are 160.3 ± 0.8, 156.6 ± 0.8, and 154.1 ± 0.6 Ma, respectively, and the sulphide Rb–Sr isotope isochron age is 152.4 ± 1.7 Ma, indicating a temporal link between porphyry emplacement and Au mineralization. Porphyries are enriched in large-ion lithophile elements and light rare earth elements and slightly depleted in heavy rare earth elements and high field strength elements, belong to the high-potassium calc-alkaline or shoshonitic series, and show characteristics of volcanic arcs or active continental margins. Moreover, the εHf(t) values of the porphyries range from −11.6 to −7.6, −11.2 to −5.4, and −9.8 to −4.6, respectively. The 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb values of the ore minerals are from 38.417 to 38.406, 15.603, and from 18.179 to 18.175, respectively. Pb and Hf isotopes indicate that the intermediate–acidic magma related to mineralization originated from Mesoproterozoic lower crust. Consequently, these data favour an intermediate–acidic magma origin for Au mineralization in the Dongyang deposit. Integrating new and published data on the tectonic evolution, we suggest that the rhyolite porphyry, quartz diorite porphyry, dacite porphyry, and associated Au mineralization in the Dongyang deposit formed at 160–152 Ma in an extensional environment related to subduction of the Palaeo-Pacific Plate beneath the South China block.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Molecular simulation for physicochemical properties of liquid mixtures with industrial applications
No full textLiquid mixture is everywhere in the chemical industry and widely studied by researchers.
An accurate prediction of its physicochemical property is of vital importance in developing efficient process optimization. However, measurements from experiment are usually time consuming and inefficient. Furthermore, clear understanding of many of fundamental physicochemical phenomena hasn't been obtained, which restricts the development of novel products. Molecular simulation techniques have become an impressive tool to deal with these challenges during past decades. This thesis mainly applied molecular simulation to predict the physicochemical properties of industrially relevant mixtures and investigate the molecular mechanism behind observed phenomena. Among various properties, cohesive energy is the central focus, which reveals intermolecular interactions between molecules of different types. Mixture systems of two different areas of application were studied.
The first is amorphous polymer-plasticizer mixtures, which, with varying composition, correspond to plastic products of different grades for application in different areas. The most important class of plasticizers are phthalate diesters, in which di (2-ethylhexyl) phthalate (DEHP) is the most frequently used compound. However, phthalates are prone to migration loss from the host poly(vinyl chloride) (PVC), which results in the contamination of surrounding environment, gradual deterioration of plastics performance, and potential harm to human health. It has thus prompted tightening governmental regulation on their usage. With this background, we aim to address three challenges: (I) model plasticized PVC to predict its physicochemical property, (II) obtain molecular insight into plasticization and plasticizer diffusion pattern inside PVC, (III) correlate plasticizer performance -- compatibility, efficacy, and mobility -- with its molecular structure. Cohesive energy plays a central role especially in understanding plasiticzer compatibility and migration tendency.
Our modeling and simulation protocol is firstly tested on phthalates, where the simulated plasticization efficacy and thermodynamic compatibility with the host polymer agree well with all known experimental observations. Furthermore, through simulation of plasticizer diffusion pattern, we found relaxation of the alkyl side chains is a key factor in plasticizer migration. Next, we expand our simulation to a wider group of plasticizers including adipates, trimellitates, and citrates. The computed mixing enthalpy and Young's modulus again show an excellent agreement with available experimental data. Dependance of plasticizer performance on seven molecular design parameters are evaluated. The obtained relationship clearly tells us decreasing leg length or increasing branching on the leg will raise plasticizer compatibility with PVC, changing the torso group from benzene ring to alkane chain will highly improve plasticizer efficacy, and attaching three legs on the torso will decrease plasticizer mobility. As a side outcome, we also report a nontrivial chain-length dependence of the cohesive energy and solubility parameter of long-chain polymers, which is an important consideration in the calculation of these quantities using molecular simulation.
The second area is azeotropes, the separation of which in chemical processes is usually very difficult due to the same composition in vapor and liquid phases at the azeotropic point. So far, a fundamental understanding of azeotrope formation is still missing. In this thesis, we aim to address two fundamental questions: (I) the mechanism for ethanol/benzene azeotrope formation, (II) classification of different polar-polar positive azeotropes.
First, Gibbs ensemble Monte Carlo (GEMC) simulation is performed to predict the vapor-liquid equilibrium (VLE) phase diagram of ethanol/benzene, including an azeotrope point. The results match well with experiments. Free energy and cohesive energy profiles analyses are then performed. From a thorough liquid structure analysis, we conclude a three-stage mechanism for azeotrope formation: 1) formation of small ethanol clusters at low composition, 2) microscopic phase separation between ethanol and benzene, 3) isolation of benzene. This approach is then extended to four additional polar-polar mixtures (ethyl acetate/methanol, ethyl acetate/ethanol, ethanol/water, and 1-propanol/water) to obtain their VLE diagrams, which again match well with experiments. Free energy and cohesive energy analyses indicate that there are two types of mechanisms, a three-stage mechanism with weak cross-interactions (for the first two mixtures) and a three-stage mechanism with strong cross-interactions (for the last two mixtures). So far, our analyses on mixture liquid micro-structure can partially prove the existence and classification of those mechanisms.
Overall, the successful prediction in physicochemical properties of two liquid mixtures with very different molecular scales proves the robustness of our study strategy, which could be used to study any liquid mixtures and understand their related physicochemical phenomena.ThesisDoctor of Philosophy (PhD
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