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High-precision standard enthalpy of formation for polycyclic aromatic hydrocarbons predicting from general

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1743-1750 doi: 10.1007/s11705-022-2184-9

摘要： The standard enthalpy of formation is an important predictor of the reaction heat of a chemical reaction. In this work, a high-precision method was developed to calculate accurate standard enthalpies of formation for polycyclic aromatic hydrocarbons based on the general connectivity based hierarchy (CBH) with the discrete correction of atomization energy. Through a comparison with available experimental findings and other high-precision computational results, it was found that the present method can give a good description of enthalpy of formation for polycyclic aromatic hydrocarbons. Since CBH schemes can broaden the scope of application, this method can be used to investigate the energetic properties of larger polycyclic aromatic hydrocarbons to achieve a high-precision calculation at the CCSD(T)/CBS level. In addition, the energetic properties of CBH fragments can be accurately calculated and integrated into a database for future use, which will increase computational efficiency. We hope this work can give new insights into the energetic properties of larger systems.

关键词： standard enthalpy of formation polycyclic aromatic hydrocarbons connectivity based hierarchy high-precision calculation

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Conceptual design of compliant translational joints for high-precision applications

Guangbo HAO,Haiyang LI,Xiuyun HE,Xianwen KONG

《机械工程前沿（英文）》 2014年第9卷第4期页码 331-343 doi: 10.1007/s11465-014-0321-y

摘要：

Compliant translational joints (CTJs) have been extensively used in precision engineering and microelectromechanical systems (MEMS). There is an increasing need for designing higher-performance CTJs. This paper deals with the conceptual design of CTJs via three approaches: parallelogram based method, straight-line motion mechanism based method and combination based method. Typical emerging CTJ designs are reviewed by explaining their design principles and qualitatively analyzing their characteristics. New CTJs are proposed using three approaches, including an asymmetric double parallelogram mechanism with slaving mechanism, several compact and symmetric double parallelogram mechanisms with slaving mechanisms and a general CTJ using the center drift compensation and a CTJ using Roberts linkage and several combination designs. This paper provides an overview of the current advances/progresses of CTJ designs and lays the foundation for further optimization, quantitative analysis and characteristic comparisons.

关键词： compliant mechanisms translational joints conceptual design parallelogram straight-line motion combination method

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Fast forward kinematics algorithm for real-time and high-precision control of the 3-RPS parallel mechanism

Yue WANG, Jingjun YU, Xu PEI

《机械工程前沿（英文）》 2018年第13卷第3期页码 368-375 doi: 10.1007/s11465-018-0519-5

摘要：

A new forward kinematics algorithm for the mechanism of 3-RPS (R: Revolute; P: Prismatic; S: Spherical) parallel manipulators is proposed in this study. This algorithm is primarily based on the special geometric conditions of the 3-RPS parallel mechanism, and it eliminates the errors produced by parasitic motions to improve and ensure accuracy. Specifically, the errors can be less than 10^-6 . In this method, only the group of solutions that is consistent with the actual situation of the platform is obtained rapidly. This algorithm substantially improves calculation efficiency because the selected initial values are reasonable, and all the formulas in the calculation are analytical. This novel forward kinematics algorithm is well suited for real-time and high-precision control of the 3-RPS parallel mechanism.

关键词： 3-RPS parallel mechanism forward kinematics numerical algorithm parasitic motion

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Processing of high-precision ceramic balls with a spiral V-groove plate

Ming FENG,Yongbo WU,Julong YUAN,Zhao PING

《机械工程前沿（英文）》 2017年第12卷第1期页码 132-142 doi: 10.1007/s11465-017-0436-z

摘要：

As the demand for high-performance bearings gradually increases, ceramic balls with excellent properties, such as high accuracy, high reliability, and high chemical durability used, are extensively used for high-performance bearings. In this study, a spiral V-groove plate method is employed in processing high-precision ceramic balls. After the kinematic analysis of the ball-spin angle and enveloped lapping trajectories, an experimental rig is constructed and experiments are conducted to confirm the feasibility of this method. Kinematic analysis results indicate that the method not only allows for the control of the ball-spin angle but also uniformly distributes the enveloped lapping trajectories over the entire ball surface. Experimental results demonstrate that the novel spiral V-groove plate method performs better than the conventional concentric V-groove plate method in terms of roundness, surface roughness, diameter difference, and diameter decrease rate. Ceramic balls with a G3-level accuracy are achieved, and their typical roundness, minimum surface roughness, and diameter difference are 0.05, 0.0045, and 0.105 mm, respectively. These findings confirm that the proposed method can be applied to high-accuracy and high-consistency ceramic ball processing.

关键词： bearing ceramic ball spiral V-groove kinematic analysis trajectory

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水工高精混凝土施工技术创新与实践

周厚贵

《中国工程科学》 2013年第15卷第9期页码 4-8

摘要：

本文以三峡工程升船机中的高精混凝土施工为背景，阐述了水工高精混凝土的涵义、施工技术要点以及施工实践。详细介绍了三峡升船机高精混凝土施工的主要精度控制标准、高精度测量技术、高精混凝土施工技术和混凝土形体检测结果。

关键词：高精混凝土施工技术三峡工程升船机

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High-precision gyro-stabilized control of a gear-driven platform with a floating gear tension device

《机械工程前沿（英文）》 2021年第16卷第3期页码 487-503 doi: 10.1007/s11465-021-0635-5

摘要： This study presents an improved compound control algorithm that substantially enhances the anti-disturbance performance of a gear-drive gyro-stabilized platform with a floating gear tension device. The tension device can provide a self-adjustable preload to eliminate the gap in the meshing process. However, the weaker gear support stiffness and more complex meshing friction are also induced by the tension device, which deteriorates the control accuracy and the ability to keep the aim point of the optical sensors isolated from the platform motion. The modeling and compensation of the induced complex nonlinearities are technically challenging, especially when base motion exists. The aim of this research is to cope with the unmeasured disturbances as well as the uncertainties caused by the base lateral motion. First, the structural properties of the gear transmission and the friction-generating mechanism are analyzed, which classify the disturbances into two categories: Time-invariant and time-varying parts. Then, a proportional-integral controller is designed to eliminate the steady-state error caused by the time-invariant disturbance. A proportional multiple-integral-based state augmented Kalman filter is proposed to estimate and compensate for the time-varying disturbance that can be approximated as a polynomial function. The effectiveness of the proposed compound algorithm is demonstrated by comparative experiments on a gear-drive pointing system with a floating gear tension device, which shows a maximum 76% improvement in stabilization precision.

关键词： inertially stabilized platform floating gear tension device nonlinear friction disturbance compensation proportional multiple-integral observer

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High-precision diffusion measurement of ethane and propane over SAPO-34 zeolites for methanol-to-olefin

Dali Cai, Yu Cui, Zhao Jia, Yao Wang, Fei Wei

《化学科学与工程前沿（英文）》 2018年第12卷第1期页码 77-82 doi: 10.1007/s11705-017-1684-5

摘要： The methanol-to-olefin (MTO) process has attracted much attention and many problems including lifetime and selectivity of light olefins have all been connected to the diffusion problems in zeolite crystals. However, a quantitative study of diffusion problems in SAPO-34 zeolites is lacking. In this paper, we performed a high-precision diffusion measurement of the diffusion behavior of ethane and propane, which represent ethylene and propylene respectively, over SAPO-34. The diffusions of ethane and propane over fresh and coked SAPO-34 zeolites with different crystal sizes were carefully studied. Ethane and propane show different diffusion behavior in SAPO-34. The diffusion of ethane is almost not influenced by the crystal size and coke percentage, whereas that of propane is strongly affected. A slower diffusion velocity was observed in bigger crystals, and the diffusion velocity decline significantly with the coke percentage increasing. The diffusion coefficient was calculated with both the internal and surface diffusion models, and the results show that the surface diffusion plays a key role in the diffusion process of both ethane and propane. We believe that this work would be helpful for understanding the diffusion of different molecules in SAPO-34 zeolites, and may lay the foundation of MTO research.

关键词： diffusion measurement methanol-to-olefin process

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Green Construction of National Speed Skating Oval

《工程管理前沿（英文）》 2022年第9卷第1期页码 170-176 doi: 10.1007/s42524-021-0177-x

关键词： super large-span cable net structure CO₂ Transcritical Direct-cooling Ice Making System dynamic high-precision construction measurement green construction National Speed Skating Oval

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高阶高斯积分节点的高精度数值计算

张庆礼,王晓梅,殷绍唐,江海河

《中国工程科学》 2008年第10卷第2期页码 35-40

摘要：

在工程数值计算、X射线衍射线形分析、光谱学等领域常使用高斯数值积分，高斯积分的节点及权重因子是数值积分的必须数据。研究了高次勒让德、拉盖尔和厄米多项式的零点，即高斯-勒让德、高斯-拉盖尔、高斯-厄米积分的节点的计算方法，给出了一种有效的高精度数值算法——搜索迭代方法（scan-iteration method，SIM）。根据勒让德、拉盖尔、厄米多项式的特点，对拉盖尔多项式、厄米多项式的定义稍做变化后，获得了计算多项式值的稳定递推关系。求它们的根时，先在一定范围内以一定的步长搜索根所在的

关键词：高斯积分勒让德多项式拉盖尔多项式厄米多项式求根

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High resolution satellite imaging sensors for precision agriculture

Chenghai YANG

《农业科学与工程前沿（英文）》 2018年第5卷第4期页码 393-405 doi: 10.15302/J-FASE-2018226

摘要：

The central concept of precision agriculture is to manage within-field soil and crop growth variability for more efficient use of farming inputs. Remote sensing has been an integral part of precision agriculture since the farming technology started developing in the mid to late 1980s. Various types of remote sensors carried on ground-based platforms, manned aircraft, satellites, and more recently, unmanned aircraft have been used for precision agriculture applications. Original satellite sensors, such as Landsat and SPOT, have commonly been used for agricultural applications over large geographic areas since the 1970s, but they have limited use for precision agriculture because of their relatively coarse spatial resolution and long revisit time. Recent developments in high resolution satellite sensors have significantly narrowed the gap in spatial resolution between satellite imagery and airborne imagery. Since the first high resolution satellite sensor IKONOS was launched in 1999, numerous commercial high resolution satellite sensors have become available. These imaging sensors not only provide images with high spatial resolution, but can also repeatedly view the same target area. The high revisit frequency and fast data turnaround time, combined with their relatively large aerial coverage, make high resolution satellite sensors attractive for many applications, including precision agriculture. This article will provide an overview of commercially available high resolution satellite sensors that have been used or have potential for precision agriculture. The applications of these sensors for precision agriculture are reviewed and application examples based on the studies conducted by the author and his collaborators are provided to illustrate how high resolution satellite imagery has been used for crop identification, crop yield variability mapping and pest management. Some challenges and future directions on the use of high resolution satellite sensors and other types of remote sensors for precision agriculture are discussed.

关键词： high resolution satellite sensor multispectral imagery precision agriculture spatial resolution temporal resolution

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基于超声引导的高精度机器人辅助HIFU 乳腺癌治疗系统 Article

Tianhan Tang,Takashi Azuma,Toshihide Iwahashi,Hideki Takeuchi,Etsuko Kobayashi,Ichiro Sakuma

《工程（英文）》 2018年第4卷第5期页码 702-713 doi: 10.1016/j.eng.2018.07.008

摘要：

乳腺癌是女性中最常见的癌症。高强度聚焦超声（波）（HIFU）是一种很有前景的非介入式治疗方法。为了提高HIFU 治疗的精确度和降低治疗成本，开发了一套基于超声引导（US）的五自由度辅助HIFU 系统。搭建了一套功能齐全的样机，它可以轻松地实现三维超声图像重建、目标分割、治疗路径生成和HIFU 自动照射等功能。利用线模型实现点定位，并且在异构组织模型上对凝固区域进行评估。在超声引导下，HIFU 治疗区域的中心偏离目标治疗区域中心不到2 mm。规划治疗区域周围出现的超调值远低于在临床使用的允许值。对于乳腺癌的治疗，本系统有足够的准确性。

关键词： HIFU 乳腺癌超声引导医疗机器人准确性评估

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高精度太赫兹异频回溯天线阵列 Correspondence

Zhong-bo ZHU, Wei-dong HU, Tao QIN, Sheng LI, Xiao-jun LI, Jiang-jie ZENG, Xian-qi LIN, Leo P. LIGTHART

《信息与电子工程前沿（英文）》 2020年第21卷第3期页码 377-383 doi: 10.1631/FITEE.1900581

摘要：未来通信系统将工作于更高频率，并提供更高传输速率。频率提升将导致难以提供区域宽波束覆盖，因此灵活捷变的波束跟踪将成为技术发展的必然趋势。本文报道的太赫兹波束回溯天线阵列可为灵活捷变的波束跟踪提供良好解决方案。该天线阵列接收40 GHz的导频信号，回溯波束传输的信号是120 GHz。仿真结果表明文中所述具有三明治堆叠结构的天线阵列可成功实现入射波的回溯功能。天线辐射方向图显示该天线阵列在20°入射波条件下，其回溯波束在19.9°位置处，增益为23.87 dB，回溯方向相对误差仅为0.5%。这意味着在5 km传输距离下，水平误差仅为8.7 m。

关键词：太赫兹；回溯天线阵列；太赫兹通信；共轭混频

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Coordinate system applied to magnetic suspension project between Shanghai and Hangzhou

SHI Yimin, WANG Lihua, LUO Yan

《结构与土木工程前沿（英文）》 2008年第2卷第3期页码 288-292 doi: 10.1007/s11709-008-0041-7

摘要： In order to satisfy the requirement for route location of a magnetic suspension project between Shanghai and Hangzhou, this paper proposes to adopt a new form of geodetic coordinate system, which is defined by meridians and parallel circles but with two coordinate parameters expressed by length. Not only the coordinate systems for route location along the whole line can be unified, but also the precision of lengths and angles obtained from simple formulas are very high and there are not any map projection distortions. This has been proven by calculation.

关键词： requirement projection calculation Shanghai precision

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量子地球物理深部探测技术及装备发展战略研究

林君 ,嵇艳鞠 ,赵静 ,佟训乾 ,易晓峰

《中国工程科学》 2022年第24卷第4期页码 156-166 doi: 10.15302/J-SSCAE-2022.04.017

摘要： The development of a High data rate atom interferometric gravimeterHIDRAG for gravity map matching navigationA high-sensitivity MEMS gravimeter with a large dynamic range [J].How grain boundaries limit supercurrents in high-temperature superconductors [J].

关键词：矿产资源深部探测量子高精度测量超导量子电磁探测超导重力探测冷原子绝对重力探测