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Evaluation on Configuration Stiffness of Overconstrained 2R1T Parallel Mechanisms

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 62-82页

作者： xuejian Ma Zhenghe xu Yundou xu Yu Wang Jiantao Yao Yongsheng Zhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China

Currently,two rotations and one translation(2R1T)three-degree-of-freedom(DOF)parallel mechanisms(PMs)are widely applied in five-DOF hybrid machining ***,there is a lack of an effective method to evaluate the configuration stiffness of mechanisms during the mechanism design *** is a challenge to select appropriate 2R1T PMs with excellent stiffness performance during the design *** the operational status of 2R1T PMs,the bending and torsional stiffness are considered as indices to evaluate PMs'configuration ***,a specific method is proposed to calculate these stiffness ***,the various types of structural and driving stiffness for each branch are assessed and their specific values ***,a rigid-flexible coupled force model for the over-constrained 2R1T PM is established,and the proposed evaluation method is used to analyze the configuration stiffness of the five 2R1T PMs in the entire ***,the driving force and constraint force of each branch in the whole working space are calculated to further elucidate the stiffness evaluating results by using the proposed method *** obtained results demonstrate that the bending and torsional stiffness of the 2RPU/UPR/RPR mechanism along the x and y-directions are larger than the other four mechanisms.

关键词： Parallel mechanism Stiffness Over-constrained Three degrees of freedom

张力效果下的人性悖论——爱伦·坡《乌鸦》细读

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西藏民族学院学报（哲学社会科学版） 2009年第2期30卷 94-97页

作者：徐晓霞西藏民族学院人文学院陕西咸阳712082

《乌鸦》是世界经典名诗之一。魅力主要源自爱伦·坡主张的效果说,文本以修辞上的张力矛盾,力图达到悲伤、恐惧、绝望等美学效果,而艺术手法上的张力和效果之下,则折射的是理性与非理性、生与死等人性中的悖论。

关键词：乌鸦张力效果理性非理性

Loading capacity and emulsification phenomena of HREE extraction by dialkylphosphinic acids with different β,γ,δ-substituents

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Journal of Rare Earths 2024年第1期42卷 191-199,I0007页

作者： Junlian Wang Guodong xu Wen xu Jianguo Cui Yufu Chen Ziyong Chang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines Beijing100083China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou014030China

The relationship between dialkylphosphinic acid structure and their loading capacity for HREEs and emulsification phenomena has rarely been *** this paper,we took Lu extraction as an example to study the effect of β,γ,δ-substituents of dialkylphosphinic acids on their loading capacity and anti-emulsification performance for *** discuss conveniently,the dialkylphosphinic acids were classified into two groups:β-substituent group(P208,INET-1,P218,USTB-1 and P227)and γ,δ-substituent group(P218,P2132 and Cyanex 272).For β-substituent group extractants,their loading capacities are in the order P208(299.7 mg/L)≈INET-1(299.5 mg/L)>P218(270.8 mg/L)>>USTB-1(163.1 mg/L)>P227(151.4 mg/L),while their anti-emulsification/gelation performances are just in the opposite order P227>USTB-1>P218>P208≈INET-1 under the studied *** γ,δ-substituent group extractants,their loading capacities are in the order P218(270.8 mg/L)>P2132(192.3 mg/L)>Cyanex272(131.7 mg/L),while the anti-emulsification performance of P218 is better than those of P2132 and Cyanex *** loading capacity data given in the parentheses are obtained through repeatedly extracting Lu from ~4×10^(-4)mol/L of Lu aqueous feed solution with initial pH of 2.40 by 0.01 mol/L extractant at phase ratio A/O of 1:1.

关键词： Heavy rare earth element Dialkylphosphinic acid Extraction Loading capacity Emulsification

CO2-Induced Modulation of Si-O Bonds for Low Temperature Plastic Deformation of Amorphous Silica Nanoparticles with Enhanced Photoluminescence

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Energy & Environmental Materials 2024年第4期7卷 404-412页

作者： Kang Huang Wenzhuo Wu Song xu Pengfei Yan Zhongming Wei Qun xu Henan Institute of Advanced Technology Zhengzhou University College of Materials Science and Engineering Zhengzhou University State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences

Modulation of Si-O bonds under mild conditions has been a challenging issue in the field of material science,which is critical to manufacture highperformance silica-based optical and photonic ***,we introduce a nondestructive technique to achieve Si-O bond rearrangement,leading to plastic deformation and photoluminescence enhancement of amorphous silica nanoparticles using supercritical carbon dioxides in EtOH/H2O solution under mild temperature.

关键词： amorphous silica anisotropic stress photoluminescence plastic deformation supercritical CO2

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特发性肥厚性硬脑膜炎患儿的护理

护理学杂志 2021年第17期36卷 40-41页

作者：冷富华徐晓霞孔燕青岛市妇女儿童医院神经内科山东青岛266011 青岛市妇女儿童医院护理部山东青岛266011

对1例特发性肥厚性硬脑膜炎患儿给予甲泼尼龙静脉输注、口服醋酸泼尼松片抑制免疫反应,甘露醇静脉滴注脱水降压,以及营养神经等治疗,3周后患儿病情好转出院,随访2个月患儿病情稳定。住院期间密切观察患儿病情变化,加强用药护理、眼部护... 详细信息

对1例特发性肥厚性硬脑膜炎患儿给予甲泼尼龙静脉输注、口服醋酸泼尼松片抑制免疫反应,甘露醇静脉滴注脱水降压,以及营养神经等治疗,3周后患儿病情好转出院,随访2个月患儿病情稳定。住院期间密切观察患儿病情变化,加强用药护理、眼部护理、心理护理、安全护理、疼痛护理等,可促进患儿病情康复。

关键词：肥厚性硬脑膜炎中枢神经系统疾病用药护理眼部护理安全护理心理护理

Enhanced photocatalytic hydrogen production from Co-MOF/CN by nitrogen and sulfur co-doped coal-based carbon quantum dots

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Journal of Rare Earths 2024年第5期42卷 838-850,I0002页

作者： Shiyong xu Mei Li Yijun Wang Caiyun Gao Rongsheng xu Zhiliang jin School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan750021China Ningxia Key Laboratory of Solar Chemical Conversion Technology.North Minzu University.Yinchuan 750021China State Key Laboratory of National Ethnic Affairs Commission Chemical Technology.North Minzu University Yinchuan750021China

A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically *** effectively broaden the absorption of Co-MOF and CN in the visible *** new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=*** the same time,NSCQDs synergy Co-MOF/CN composites have good *** four cycles of hydrogen production,the performance remains relatively *** tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite *** semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was *** conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,*** e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.

关键词： Nitrogen and sulfur co-doped Coal-based carbon quantum dots Co-MOF CN Photocatalytic hydrogen evolution Rare earths

Quantitative Analysis of Frosting Characteristics on the Drip Tray of A Cryogenic Valve for LNG Ships

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China Ocean Engineering 2024年第4期38卷 572-585页

作者： BAI xu CHEN Guan-yu DU Yue xu Cao CHEN Jia-jing School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

Cryogenic valves play a crucial role in the production and transportation of liquefied natural gas(LNG),and are primarily responsible for efficiently controlling the inflow and outflow of LNG and regulating ***,due to their operation in low-temperature and high-humidity environments,crucial components such as drip trays are susceptible to frosting,which may lead to LNG leakage,thereby causing severe safety *** this study,the user-defined function(UDF)is employed to redevelop Fluent,which integrates the frost growth model with the Eulerian multiphase flow model,to conduct a quantitative analysis of frosting on drip trays of cryogenic *** effects of environmental parameters,such as wind speed,ambient temperature,air humidity,and cold surface temperature on the growth of the frost layer were *** study reveals a limiting wind speed between 1 m/s and 2 m/*** reaching this limit speed,the growth of the frost layer reaches its maximum,and further increases in the wind speed have no significant effect on the growth of the frost ***,the influence of the change in the flow field on droplet impingement and freezing during the growth of the frost layer is considered through the coupling method of the kinematic characteristics of water droplets and the collection coefficient of water *** study identifies the influence of different parameters on the droplet impact efficiency,leading to the modification of the frost layer on the drip tray.

关键词： LNG carrier drip tray frost effective impact coefficient

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自然拼读法在小学英语词汇教学中的应用探究

英语教师 2023年第3期23卷 185-187,191页

作者：徐晓霞甘肃省庆阳市华池县南梁希望小学甘肃庆阳745600

阐述自然拼读法的内涵。分析自然拼读法对小学英语词汇教学的作用,即提升词汇教学的方法性、体验性、探究性、实效性。结合教学实例,探究自然拼读法在小学英语词汇教学中的应用。指出自然拼读法能切实帮助学生解决英语词汇学习枯燥的问... 详细信息

阐述自然拼读法的内涵。分析自然拼读法对小学英语词汇教学的作用,即提升词汇教学的方法性、体验性、探究性、实效性。结合教学实例,探究自然拼读法在小学英语词汇教学中的应用。指出自然拼读法能切实帮助学生解决英语词汇学习枯燥的问题,提高词汇学习效率。

关键词：自然拼读法词汇教学小学英语

Expression Pattern of the Foreign Gene Regulated by the Tomato rbcS3A Promoter in Transgenic Tomato

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Agricultural Science & Technology 2013年第4期14卷 559-563页

作者：徐晓霞金烨杨万年华中师范大学生命科学学院湖北武汉430079

[Objective] This study aimed to reveal the expression pattern of foreign genes regulated by tomato rbcS3A promoter in transgenic tomato. [Method] Rubisco small subunit promoter rbcS3A was cloned by PCR, fused to the upstream of Gus coding region in a binary vector, and transformed into tomato plants mediated by Agrobacterium. Histochemical staining on PCR positive plants was performed to ana- lyze the expression pattern of the foreign gene regulated by the tomato rbcS3A pro- moter in transgenic tomato. [Result] A total of 15 positive plants were obtained, ac- counting for 33.3%. Histochemical staining showed that the expression level of Gus fusion gene was highest in mature leaf, lower in reproductive organs such as fruit, and not detected in seed. [Conclusion] More positive seedlings were obtained using the modified tissue culture method. Under the control of tomato rbcS3A promoter, exogenous gene highly expressed in transgenic plant leaves, but did not express in seeds and tomato pulp.

关键词： Tomato rbcS3A promoter Tomato Genetic transformation Gus staining