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弹簧式角度可调节机夹车刀研究与应用设计 认领
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作者 马廷辉 《山东化工》 CAS 2021年第1期150-151,共2页
涉及一种车床用切削大螺旋升角的弹簧机夹式螺纹刀具。此车刀通过旋转刀头的角度,可以车削不同螺距或旋向的螺纹,具有良好的技术经济效果,因此得到了方泛的应用。下面详细的介绍一下这把刀的结构及实施方法。
关键词 角度 机夹车刀 车削 可调
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小方还连铸机正角部纵裂漏钢的分析与改进 认领
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作者 郭达 《南方金属》 CAS 2021年第1期45-48,共4页
针对莱钢小方坯连铸机正角部纵裂漏钢的现状、成因进行分析,查找工艺、设备中存在的问题,通过优化结晶器及足辊段工艺、操作等措施,铸坯冷却均匀性、冷却效果得到大幅度提升,有效解决了小方坯正角部纵裂漏钢。
关键词 小方坯 角部纵裂 漏钢 原因 措施
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基于CAV444的无接触式电容角度传感器 认领
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作者 秦玉伟 胡涛成 《河南科学》 2021年第1期37-41,共5页
针对传统的差动式电容角度传感器的线性度不高和测量精度低的缺陷,设计了一种新型的无接触式电容角度传感器.通过CAV444芯片把该传感器的电容变换量转换成差分电压输出,经过放大电路处理后,经A/D转换,利用单片机读取与角度相对应的电压... 针对传统的差动式电容角度传感器的线性度不高和测量精度低的缺陷,设计了一种新型的无接触式电容角度传感器.通过CAV444芯片把该传感器的电容变换量转换成差分电压输出,经过放大电路处理后,经A/D转换,利用单片机读取与角度相对应的电压值.实验结果表明,该电容角度传感器实现了对角度的精确测量,能够得到线性输出的电压值. 展开更多
关键词 CAV444 电容传感器 角度 差分电压
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Accuracy of Transvaginal Ultrasound in Prediction of Latency Period in Women with Preterm Premature Rupture of Membranes 认领
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作者 Ahmed Shrief Abd Elhamid Ahmed Hamdi El-Sefi Tarek Aly Raafat 《妇产科期刊(英文)》 2020年第11期1616-1630,共15页
<strong>Background:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Preterm prelabor ruptur... <strong>Background:</strong><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> Preterm prelabor rupture of membranes (PPROM) is a major cause of Pretem Birth (PTB), Pretem Birth (PTB) is the most significant cause of perinatal morbidity and mortality worldwide. Cervical length (CL), posterior uterocervical angle (PUCA) and anterior uterocervical angle (AUCA) have been postulated in several studies to have an important role in prediction of PTB. Up to our knowledge, this is the first study that combines the three cervical parameters in prediction of latency period in women with PPROM. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Aim</span></b></span></span><span><span><span style="font-family:""> <b><span style="font-family:Verdana;">of</span></b> <b><span style="font-family:Verdana;">the</span></b> <b><span style="font-family:Verdana;">Work:</span></b> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">To assess the accuracy of cervical length, posterior uterocervical angle and anterior uterocervical angle in prediction of latency period in women with Preterm prelabor rupture of membranes. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;">Subjects</span></b></span></span><span><span><span style="font-family:""> <b><span style="font-family:Verdana;">and</span></b> <b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> A </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Prospective cohort study</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> on </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana; 展开更多
关键词 Preterm Prelabor Rupture of Membranes Latency Period Transvaginal Ultrasound Posterior Uterocervical Angle Anterior Uterocervical Angle Cervical Length
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A comprehensive survey on the methods of angle of attack measurement and estimation in UAVs 认领
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作者 L.SANKARALINGAM C.RAMPRASADH 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第3期749-770,共22页
Angle of Attack(AOA) is a crucial parameter which directly affects the aerodynamic forces of an aircraft.The measurement of AOA is required to ensure a safe flight within its designed flight envelop.This paper intends... Angle of Attack(AOA) is a crucial parameter which directly affects the aerodynamic forces of an aircraft.The measurement of AOA is required to ensure a safe flight within its designed flight envelop.This paper intends to summarise a comprehensive survey on the measurement techniques and estimation methods for AOA, specifically in Unmanned Aerial Vehicle(UAV) applications.In the case of UAVs, weight constraint plays a major role as far as sensor suites are concerned.This results in selecting a suitable estimation method to extract AOA using the available data from the autopilot.The most feasible and widely employed AOA measurement technique is by using the Multi-Hole Probes(MHPs).The MHP measures the AOA regarding the pressure variations between the ports.Due to the importance of MHP in AOA measurement, the calibration methods for the MHP are also included in this paper.This paper discusses the AOA measurement using virtual AOA sensors, their importance and the operation. 展开更多
关键词 Angle of attack estimation Angle of attack measurement Angle of attack vane Five-hole probe Multi-hole probe Multi-hole probe calibration Nine-hole probe Seven-hole probe Virtual angle of attack sensor
The Angles and Main Angles of Some Special Graphs 认领
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作者 Haicheng Ma Shang Gao 《应用数学(英文)》 2020年第6期480-490,共11页
The eigenvalues of the adjacency matrix of a graph are called the eigenvalues of the graph. Let the vector <em>e<sub>j</sub></em> =(0, <span style="font-size:12.8px;white-space:normal;&... The eigenvalues of the adjacency matrix of a graph are called the eigenvalues of the graph. Let the vector <em>e<sub>j</sub></em> =(0, <span style="font-size:12.8px;white-space:normal;">…</span> , 1, … , 0)<sup>T</sup> and the all -1 vector <em>j</em> =(1, 1, <span style="font-size:12.8px;white-space:normal;">…</span>,1)<sup>T</sup>, the cosine of the (acute) angle formed by the vector <em>e<sub>j</sub></em> and the eigensubspace is called an angle of the graph. The cosine of the (acute) angle formed by the vector <em>j</em> and the eigensubspace is called a main angle of the graph. The angles and main angles are all important parameters on the graph, and they can be combined with the eigenvalues of the graph to determine the degree sequence of the graph, the number of triangles, quadrilaterals and pentagons on the graph, and the characteristic polynomials of the complement graph, but there is little study on the angles and main angles of the graph. In this paper, we determine the angles and main angles of the complete graph, the cube graph, the Petersen graph, the cycle and the complete bipartite graph. 展开更多
关键词 Adjacency Matrix EIGENVALUE ANGLE Main Angle
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Physical simulation of mixing on a C-H2 smelting reduction reactor with different tracer feeding positions 认领
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作者 Jin-yin Xie Bo Wang Jie-yu Zhang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2020年第9期1018-1034,共17页
With the growing demand for energy saving,emission reduction,and green metallurgy,we had designed a new C-H2 smelting reduction reactor.In order to solve the key problem that the heat transfer efficiency from high tem... With the growing demand for energy saving,emission reduction,and green metallurgy,we had designed a new C-H2 smelting reduction reactor.In order to solve the key problem that the heat transfer efficiency from high temperature oxidation zone in upper region to low temperature reduction zone in lower region is low in traditional metallurgical reduction reactor,a water simulation was adopted to optimize the mean residence time and to improve the transmission efficiency within the reactor.According to the modified Froude similarity,a water model experimental reactor with a ratio of 1:1 to the prototype was constructed.In the prototype,the feed port was used to feed preheated ore and flux.In order to simulate the effect of different feeding positions of the tracer on the mixing behavior in the molten pool,four points of tracer feeding position were arranged for a systematic study.At the same time,based on double-row side nozzle with thick slag layer in a C-H2 smelting reduction reactor,nine influencing factors,including relative angle between upper and lower side nozzles,were studied.The experimental results showed that the tracer feeding position had a great influence on the mean residence time,and the relative angle also had a great influence on tracer feeding position.Finally,through comprehensive analysis,the optimal condition parameters were obtained under different tracer feeding positions.These results provide valuable help for the design and optimization of the C-H2 smelting reduction reactor. 展开更多
关键词 Smelting reduction reactor Tracer feeding position Double-row side blowing Mean residence time Relative angle Horizontal angle Vertical angle
Comparison of measurements of anterior chamber angle via anterior segment optical coherence tomography and ultrasound biomicroscopy 认领
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作者 Zi-Yan Yu Ting Huang +1 位作者 Lu Lu Bo Qu 《世界临床病例杂志》 SCIE 2020年第15期3249-3258,共10页
BACKGROUND Glaucoma is an irreversible optic neuropathy with the loss of visual field and decrease of vision.The variable clinical manifestations may result in differential diagnostic difficulties.The early screening ... BACKGROUND Glaucoma is an irreversible optic neuropathy with the loss of visual field and decrease of vision.The variable clinical manifestations may result in differential diagnostic difficulties.The early screening and diagnosis of glaucoma are currently experiencing a demand for anterior segment analysis tools that can gather more information with one short measurement.Therefore,we analyzed the agreement,difference,and correlation of chamber angle parameters such as angel opening distance at 500μm(AOD500)and trabeculo-iris space area at 500μm^2(TISA500)measured by anterior segment optical coherence tomography(ASOCT)and ultrasound biomicroscopy(UBM).AIM To compare the differences,correlation,and agreement in measuring AOD500 and TISA500 by AS-OCT and UBM.METHODS Both AS-OCT and UBM were performed to measure AOD500 and TISA500 in 45 subjects(72 eyes).All subjects without glaucoma were collected from October 2015 to August 2016 at the Ophthalmology Department of the Fourth Affiliated Hospital of China Medical University.Data of the two groups(AOD500 and TISA500)were compared by nonparametric tests.Pearson correlative analysis and Bland-Altman analysis were used to compare the correlation and agreement.RESULTS There were no significant differences between AS-OCT and UBM in measuring AOD500(P1=0.110,P2=0.633,P3=0.078,and P4=0.474)and TISA500(P1=0.584,P2=0.889,P3=0.297,and P4=0.550)of the four quadrants of the anterior chamber angle.There was a high correlation in measuring AOD500(r1=0.562,r2=0.671,r3=0.635,and r4=0.720;P<0.001)and TISA500(r1=0.584,r2=0.889,r3=0.297,and r4=0.550;P<0.001).There was a good agreement in measuring AOD500 and TISA500 by the two modalities.CONCLUSION There is a high correlation and agreement between AOD500 and TISA500 measurements by AS-OCT and UBM.They are interchangeable under some circumstances.AS-OCT proves to be a better early screening tool for glaucoma. 展开更多
关键词 Anterior segment-optical coherence tomography Primary angle closure glaucoma Anterior chamber angle Angel opening distance at 500 m Trabeculo-iris space area at 500 m^2
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Biocontamination Risk of <i>Staphylococcus aureus</i>in Dairy Manufacturing Presence of Two Types of UHT Milk 认领
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作者 Safae Tankiouine Hafida Zahir +5 位作者 Mourad El Goulli Kaoutar El Fazazi Abdelwahid Assaidi Taoufik Hakim Mostafa El Louali Hassan Latrache 《食品与营养科学(英文)》 2020年第8期824-835,共12页
The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamina... The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamination risk of materials commonly used in dairy manufacturing,</span><span style="font-family:""> </span><span style="font-family:Verdana;">adhesion of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> on glass coated by two kinds of UHT milk (whole milk and skimmed milk) was investigated. It is known that adhesion is mainly governed by surface physicochemical properties, for that,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the effect of milk components on physicochemical properties of glass and bacterial surfaces were exanimated through contact angle measurements. MATLAB software was used to evaluate the ability of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">S.</span></i><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:Verdana;">adhesion on glass.</span><span style="font-family:""> </span><span style="font-family:Verdana;">The hydrophobic quantitative and electron acceptor characteristics of the glass appear to increase with the presence of fat in milk, while its electron donor property</span><span style="font-family:""> </span><span style="font-family:Verdana;">decreases with this component. The percentage of occupied surface of untreated glass was more important than in treated surfaces for 50% of the strains studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">As well, the percentage of occupied surface by bacterial strains in untreated glass by skimmed milk is g 展开更多
关键词 Physicochemical Properties Skimmed UHT Milk Whole UHT Milk Contact Angle ADHESION Staphylococcus aureus
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An Analysis of the Characters of Chinese Calligraphy Art Based on Mathematical Elements 认领
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作者 Yuexi Wu 《应用科学(英文)》 2020年第2期25-40,共16页
Mathematics is an effective way to measure or describe things objectively and accurately. It is of great significance to accurately master stroke trend, font structure and component position to improve the level of ca... Mathematics is an effective way to measure or describe things objectively and accurately. It is of great significance to accurately master stroke trend, font structure and component position to improve the level of calligraphy art. This paper tries to use mathematical elements to analyze the art of calligraphy. It is concluded that through the knowledge of angle, golden section, structure and curve in mathematics, the rule of stroke trend, font structure, component position, and work shape as well as the overall layout of characters can be identified. 展开更多
关键词 CALLIGRAPHY MATHEMATICS ANGLE Structure CURVE
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Performances Analysis of a System of Localization by Angle of Arrival UWB Radio 认领
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作者 Salick Diagne Thierry Val +2 位作者 Abdou Karim Farota Bouya Diop Ognadon Assogba 《通讯、网络与系统学国际期刊(英文)》 2020年第2期15-27,共13页
The increasingly widespread use of sensor and actuator networks and in general of the Internet of Things (IoT) in several areas of precision, imposes upon localization systems that can often equip them with a robust a... The increasingly widespread use of sensor and actuator networks and in general of the Internet of Things (IoT) in several areas of precision, imposes upon localization systems that can often equip them with a robust and more precise localization. It is in this sense that UWB technology has proved to be one of the most powerful communication technologies for these localization systems;thanks, in particular to the bandwidth occupied instantaneously by the signal allowing a very fine temporal resolution. Constructors have set up localization kits based on various technologies. These kits facilitate in a way the work of localization of users. In this paper, we present results on the performance study of the Decawave PDoA Kit. This Kit uses the PDoA (Phase Difference of Arrival) to determine the Angle of Arrival (AoA) parameter with UWB technology. This study is in context of localization by AoA for an application to protect agricultural crops against grain-eating birds. The results of the study show overall AoA measurement errors around 10 degrees in an ideal environment. 展开更多
关键词 ANGLE of ARRIVAL (AoA) LOCALIZATION UWB PDoA
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Wettability, Thermal and Sliding Behavior of Thermally Sprayed Fly Ash Premixed Red Mud Coatings on Mild Steel 认领
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作者 Harekrushna Sutar Birupakshya Mishra +4 位作者 Rabiranjan Murmu Sangram Patra Sarat Chandra Patra Subash Chandra Mishra Debashis Roy 《材料科学与应用期刊(英文)》 2020年第1期12-26,共15页
The present experimental work reveals the surface characteristics like wettability, thermal and sliding wear behaviour of plasma-sprayed red mud (RM) coatings premixed with fly ash (FA). Varying weight % of FA (10, 20... The present experimental work reveals the surface characteristics like wettability, thermal and sliding wear behaviour of plasma-sprayed red mud (RM) coatings premixed with fly ash (FA). Varying weight % of FA (10, 20, 30 and 40)—RM composite powder is used as precursor for coating. Atmospheric plasma-sprayed coatings are developed at different operating power like 5 kW, 10 kW, 15 kW and 20 kW separately on mild steel substrate. Tribological behaviour viz. sliding wear properties are studied at distinct operating load (10N, 15N, 20N, 25N), speed (40 rpm, 50 rpm, 60 rpm, 70 rpm) and track diameter of 100 mm using a pin on disc tribometer for duration of 30 minutes with 3 minute gap period for each experiment. The DSC and TGA experiments of the coatings are performed to understand the high temperature application areas. The contact angle result signifies the wettability of the prepared coatings is principally a function of composition. The reaction of surface roughness and spraying power is in-significant on water contact angle (WCA). In conclusion, the sliding wear experiments are optimized by Taguchi method to ascertain the influencing parameter on wear. 展开更多
关键词 Red MUD FLY Ash Contact Angle DSC TGA Sliding Wear
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Simulation on Sequential Construction Process and Structure of the Pisa Tower 认领
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作者 Jun Geng Zuping Meng +1 位作者 Bangxun Yin Liufei Zhu 《房屋建造与规划研究(英文)》 2020年第1期30-41,共12页
The leaning of structures happens all around the world and generates impacts on different extents;thus, it is important to learn about the causes behind. In this report, the sequential construction of a typical leanin... The leaning of structures happens all around the world and generates impacts on different extents;thus, it is important to learn about the causes behind. In this report, the sequential construction of a typical leaning structure, the Tower of Pisa, is discussed and simulated by using a finite element code, PLAXIS. The simulation is performed on a two-dimensional plane with simplifications taken into consideration in making modeling feasible under limitations. Three distinct models are built with one as a control variable, while the other two models are set up with exact eccentricity. Data are obtained from the analysis and are plotted in a graph to clearly show the relationship between the tilting angle and construction phases. With reasonable and completed simulation, the study is able to show the significant role compressible subsoil plays in impacting the tilting performance of a tall building. 展开更多
关键词 The Leaning TOWER of PISA TILTING Angle SEQUENTIAL CONSTRUCTION SUBSOIL TILTING Performance PLAXIS
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Variable Selection via Biased Estimators in the Linear Regression Model 认领
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作者 Manickavasagar Kayanan Pushpakanthie Wijekoon 《统计学期刊(英文)》 2020年第1期113-126,共14页
Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable selection as well as for handling the multicollinearity problem simultaneously in the linear regression model. LASSO produces estimates havi... Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable selection as well as for handling the multicollinearity problem simultaneously in the linear regression model. LASSO produces estimates having high variance if the number of predictors is higher than the number of observations and if high multicollinearity exists among the predictor variables. To handle this problem, Elastic Net (ENet) estimator was introduced by combining LASSO and Ridge estimator (RE). The solutions of LASSO and ENet have been obtained using Least Angle Regression (LARS) and LARS-EN algorithms, respectively. In this article, we proposed an alternative algorithm to overcome the issues in LASSO that can be combined LASSO with other exiting biased estimators namely Almost Unbiased Ridge Estimator (AURE), Liu Estimator (LE), Almost Unbiased Liu Estimator (AULE), Principal Component Regression Estimator (PCRE), r-k class estimator and r-d class estimator. Further, we examine the performance of the proposed algorithm using a Monte-Carlo simulation study and real-world examples. The results showed that the LARS-rk and LARS-rd algorithms,?which are combined LASSO with r-k class estimator and r-d class estimator,?outperformed other algorithms under the moderated and severe multicollinearity. 展开更多
关键词 Variable SELECTION Least ABSOLUTE SHRINKAGE and SELECTION OPERATOR (LASSO) Least Angle Regression (LARS) Elastic Net (ENet) Biased ESTIMATORS
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Comparative New Insight into the Tectonic Origin of Folds and Thrust Faults of an Extensional Basin: Soke-Kusadasi Basin, Aegean, Western Turkey 认领
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作者 Bulent Dogan 《地球科学学刊:英文版》 SCIE CAS CSCD 2020年第3期582-595,共14页
The Aegean area of the western Anatolian region of Turkey,controlled by the low-angle detachment normal fault system,forms an extensional province,the West Anatolian Extensional Province(WAEP).The tectonic deformation... The Aegean area of the western Anatolian region of Turkey,controlled by the low-angle detachment normal fault system,forms an extensional province,the West Anatolian Extensional Province(WAEP).The tectonic deformation which occurred in the Miocene Period,including the Plio–Quaternary Period has created different structures in both the basement rocks and intra-basin deposits of the crust.One of these structures,high-angle normal faults,controls the supradetachment Soke-Kusadasi Basin(SKB).Within this basin,there are folds with different axes and thrust faults with a north-northwestnortheast(N,NW,NE)trend.These folds and thrust faults in the SKB deformed the sedimentary structures of intra-basin deposits.The folds and thrust faults,which caused the rotation of beddings and imbrications in the SKB,are mainly associated with the tectonic process of the low angle detachment normal fault,which affected the SKB and the Aegean part of western Anatolia.In the SKB,during the process of extensional deformation associated with primary low angle detachment normal faulting,the ramp-flat and inversion geometry observed in the basement rocks and basin deposits of the crust caused folds and thrust faults in only intra-basin deposits.In the WAEP,it is determined for the first time that the folds and thrust faults causing limited shortening deformed the Plio–Quaternary sediments. 展开更多
关键词 low angle detachment normal fault high angle normal fault fold thrust fault BEDDING extensional supradetachment basin
Remote Absolute Roll-Angle Measurement in Range of 180°Based on Polarization Modulation 认领
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作者 Xiuguo Chen Jinbao Liao +3 位作者 Honggang Gu Chuanwei Zhang Hao Jiang Shiyuan Liu 《纳米制造与计量(英文)》 2020年第3期228-235,共8页
Remote measurement of object orientation is often required in many applications.Out of the six degrees of freedom(DoF)that determine object orientation in space,the roll angle is the most difficult to measure using op... Remote measurement of object orientation is often required in many applications.Out of the six degrees of freedom(DoF)that determine object orientation in space,the roll angle is the most difficult to measure using optical methods.In this letter,we propose a remote Stokes roll-angle sensor that measures roll angles from the detected Stokes vectors of modulated polarized light retroreflected from a sensing unit comprised simply of a retarder and a planar reflection mirror.Experimental results have shown that the proposed sensor can realize absolute roll angle measurement in an unprecedented range of 180°with a maximum absolute error of less than 0.25°and a measurement resolution of better than 0.01°.The proposed sensor adopts a coaxial design and takes the advantages of compactness,simplicity and low cost,and moreover,can be further expanded to a three-DoF angle sensor due to the sensitivity of the sensing unit to other two kinds of angles(pitch and yaw). 展开更多
关键词 Roll angle Angle sensor Polarization modulation Stokes polarimeter
Synthesis and Characterization of Superhydrophobic-Superoleophobic and Anti-Corrosion Coatings via Sol-Gel Process 认领
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作者 Mohammad Reza Heshmati Sahar Amiri Maryam Hosseini-Zori 《有机高分子材料期刊(英文)》 2020年第1期1-15,共15页
Superoleophobic nanocomposite coatings with improved hydrophobic properties were obtained by incorporation of a perfluoroalkyl polymer in hybrid sol-gel matrix containing silica and titania nanoparticles. SiO2 and TiO... Superoleophobic nanocomposite coatings with improved hydrophobic properties were obtained by incorporation of a perfluoroalkyl polymer in hybrid sol-gel matrix containing silica and titania nanoparticles. SiO2 and TiO2 nanoparticles were synthesized based on sol-gel precursors utilizing tetraethyl orthosilicate, 3-glycidoxypropyl trimethoxysilane, and tetra (n-butyl orthotitanate). SEM and EDX images of the coating demonstrated that a Silica nanosphere had been aggregated in superporous structure. The analysis results show that nano-sized inorganic particles (10 - 20 nm) have a uniform distribution and dispersion. By increasing the PFOTES, the oleophobicity of coatings increased due to lowering of surface energy in the presence of fluoropolymer. Results of EIS measurement show that PFOTES and TiO2 nanoparticles increased anti-corrosion property of hybrid coatings. This method introduces a simple way to produce water- and oil-repellent self-cleaning coatings on large areas of different substrates like glass, ceramic, metal and composites. 展开更多
关键词 SUPER-HYDROPHOBIC Super-Oleophobic SOL-GEL PERFLUOROALKYL POLYMER (1H 1H 2H 2H)-Perfluorooctyltriethoxysilane Contact ANGLE
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Transient Stability Analysis of 33 KV Transmission Network of Egi Community, Nigeria 认领
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作者 Promise Elechi Christopher Okwuchukwu Ahiakwo Ugochukwu Nureedin Okwu 《电力能源(英文)》 2020年第3期18-35,共18页
Transient analysis of 33 KV power transmission line stability of Egi communi-ty is considered in this research work with the aim of reducing the frequency of fault occurrence and voltage collapse in the network. The s... Transient analysis of 33 KV power transmission line stability of Egi communi-ty is considered in this research work with the aim of reducing the frequency of fault occurrence and voltage collapse in the network. The supply is taken from Egi generating station located at Total Nigeria Limited Gas Plant Obite at voltage level of 33 KV to Egi communities. This work focuses on the transient nature of network stability since transient fault is the most dangerous in elec-trical systems. The swinging of the generator rotor in the event of transient three-phase short circuit fault can be monitored by the circuit breakers and the protective relays which causes mal-functioning of the circuit breakers and pro-tective relays leading to abnormal behavior of the network. Therefore, data obtained from the power station were used as a case study of Independent Power Producer (IPP) in Nigeria. For investigation of the power angle, angular velocity, rotor angle differential changes, and angular velocity differential changes, an electrical transient analyzer tool was employed (ETap version 16.00) for circuit breaker and protective relay time setting of (0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60). The work used the Trapezoidal numerical technique for data analysis. The graphs were plotted using Matlab R2015a and the results obtained showed that when a symmetrical three-phase short circuit fault occur at one or any of the feeders, the fault must be cleared as quick as possible through the coordination of the circuit breakers and protective relays. For this research work, 17 cycles corresponding to relay time setting of t = 0.34 s were recommended and at each cycle, changes in time with respect to changes in rotor angle, angular velocity, rotor differential and angular velocity differential were calculated on the power network simultaneously. The results demonstrated that the Trapezoidal method is numerically stable, accurate and has faster respond time when compared to Modified Euler and swing equat 展开更多
关键词 ROTOR Angle Transient Stability SWING Equation ANGULAR Speed Differential Changes Trapezoidal RULE Fault CLEARING TIME Critical CLEARING TIME
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A Novel Model of Charged Leptons 认领
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作者 Dianfu Wang Xiao Liang Yanqing Guo 《现代物理(英文)》 2020年第3期448-454,共7页
A novel model of charged leptons is presented, which contains two basics hypotheses. The first hypothesis is that the Yukawa coupling between Higgs field and charged leptons is the weak interaction, the Higgs field is... A novel model of charged leptons is presented, which contains two basics hypotheses. The first hypothesis is that the Yukawa coupling between Higgs field and charged leptons is the weak interaction, the Higgs field is a scalar intermediate boson which changes the chirality of charged leptons in the weak interaction. The other hypothesis is that the flavor eigenstates of charged leptons are the superposition states of left-handed and right-handed elementary Weyl spinors before the electroweak symmetry breaking. According to this model, the Yukawa coupling constants between Higgs field and three generations of charged leptons are considered to be a universal constant, and the difference of the masses of different charged leptons is due to the different left-right mixing angles of their flavor eigenstates. 展开更多
关键词 CHARGED LEPTONS WEAK EIGENSTATES Left-Right MIXING ANGLE
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Dynamics of Interaction of a Single Fiber with a Headset of a Sampling Drum 认领
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作者 Yuldashev Jamshid Umarov Akbarjon Sarimsakov Olimjon 《工程(英文)(1947-3931)》 2020年第6期347-355,共9页
The article presents an analysis of the dynamics of interaction of a single fiber with the sampling drum of a headset during pneumomechanical spinning. The regularity is investigated and the equation of the movement o... The article presents an analysis of the dynamics of interaction of a single fiber with the sampling drum of a headset during pneumomechanical spinning. The regularity is investigated and the equation of the movement of fibers on the surface of the tooth of the sampling drum headset is obtained. It was found that the dependences of the movement of fibers along the tooth at different angles of inclination, the distribution of fiber tension along the arc, and the distribution of fiber speeds in the region of the sampling arc have an increase property. As a result of the analysis of the tension and speed of the fibers, it was found that with the increase in the sampling zone, the tension force and speed of the fiber increase. 展开更多
关键词 Fibers Sampling ANGLE Friction Force FRICTION SPEED RADIUS Fiber Complex
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