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Parasitic rotation evaluation and avoidance of 3-UPU parallel mechanism

Haibo QU, Yuefa FANG, Sheng GUO

《机械工程前沿（英文）》 2012年第7卷第2期页码 210-218 doi: 10.1007/s11465-012-0317-4

摘要：

Based on the prototype of 3-UPU (universal-prismatic-universal joint) parallel mechanism proposed by Tsai [ ], the parasitic rotation evaluation is performed and calculated the bound of instability of SNU Seoul National University 3-UPU parallel mechanism. Through analysis of the terminal constraint system of the 3-UPU parallel mechanism, the equation about the parasitic rotation and limited clearance is presented. Then the norm of possible parasitic rotation is employed to evaluate the mechanism stability with limited clearance. The higher this number the worst is the pose, the lower it is the best it is. And the contour atlas of parasitic rotation is obtained, which can be used for further analysis and design. With the practice experiment result of SUN 3-UPU parallel mechanism, we find it’s bound of instability, which indicates there will appear the parasitic rotation when the number exceeds the bound. Finally, the method for avoidance of possible parasitic motions is presented by adding redundantly actuated limbs.

关键词： parallel mechanism 3-UPU (universal-prismatic-universal joint) parasitic motions limited clearance redundantly actuated limbs

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A rolling 3-UPU parallel mechanism

Zhihuai MIAO, Yan’an YAO, Xianwen KONG

《机械工程前沿（英文）》 2013年第8卷第4期页码 340-349 doi: 10.1007/s11465-013-0282-6

摘要：

A novel rolling mechanism is proposed based on a 3-UPU parallel mechanism in this paper. The rolling mechanism is composed of two platforms connected by three UPU (universal-prismatic-universal) serial-chain type limbs. The degree-of-freedom of the mechanism is analyzed using screw theory. Gait analysis and stability analysis are presented in detail. Four rolling modes of the mechanism are discussed and simulated. The feasibility of the rolling mechanism is verified by means of a physical prototype. Finally, its terrain adaptability is enhanced through planning the rolling gaits.

关键词： parallel mechanism rolling mechanism screw theory

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Universal influenza virus vaccines: what can we learn from the human immune response following exposure

null

《医学前沿（英文）》 2017年第11卷第4期页码 471-479 doi: 10.1007/s11684-017-0602-z

摘要：

Several universal influenza virus vaccine candidates based on eliciting antibodies against the hemagglutinin stalk domain are in development. Typically, these vaccines induce responses that target group 1 or group 2 hemagglutinins with little to no cross-group reactivity and protection. Similarly, the majority of human anti-stalk monoclonal antibodies that have been isolated are directed against group 1 or group 2 hemagglutinins with very few that bind to hemagglutinins of both groups. Here we review what is known about the human humoral immune response to vaccination and infection with H7 subtype influenza viruses on a polyclonal and monoclonal level. It seems that unlike vaccination with H5 hemagglutinin, which induces antibody responses mostly restricted to the group 1 stalk domain, H7 exposure induces both group 2 and cross-group antibody responses. A better understanding of this phenomenon and the underlying mechanisms might help to develop future universal influenza virus vaccine candidates.

关键词： universal influenza virus vaccine hemagglutinin stalk H7N9

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A feasibility study on the design and walking operation of a biped locomotor via dynamic simulation

null

《机械工程前沿（英文）》 2016年第11卷第2期页码 144-158 doi: 10.1007/s11465-016-0391-0

摘要：

A feasibility study on the mechanical design and walking operation of a Cassino biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degrees-of-freedom tripod leg mechanisms with a parallel manipulator architecture. Planning of the biped walking gait is performed by coordinating the motions of the two leg mechanisms and waist. A three-dimensional model is elaborated in SolidWorks^® environment in order to characterize a feasible mechanical design. Dynamic simulation is carried out in MSC.ADAMS^® environment with the aims of characterizing and evaluating the dynamic walking performance of the proposed design. Simulation results show that the proposed biped locomotor with proper input motions of linear actuators performs practical and feasible walking on flat surfaces with limited actuation and reaction forces between its feet and the ground. A preliminary prototype of the biped locomotor is built for the purpose of evaluating the operation performance of the biped walking gait of the proposed locomotor.

关键词： feasibility study biped locomotor biped walking mechanical design dynamic simulation tripod leg mechanism 3-UPU parallel manipulator

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Design of a novel RTD-based three-variable universal logic gate

Mao-qun YAO,Kai YANG,Cong-yuan XU,Ji-zhong SHEN

《信息与电子工程前沿（英文）》 2015年第16卷第8期页码 694-699 doi: 10.1631/FITEE.1500102

摘要： Traditional CMOS technology faces some fundamental physical limitations. Therefore, it has become very important for the integrated circuit industry to continue to develop modern devices and new design methods. The threshold logic gate has attracted much attention because of its powerful logic function. The resonant tunneling diode (RTD) is well suited for implementing the threshold logic gate because of its high-speed switching capability, negative differential resistance (NDR) characteristic, and functional versatility. In this paper, based on the Reed-Muller (RM) algebraic system, a novel method is proposed to convert three-variable non-threshold functions to the XOR of multiple threshold functions, which is simple and has a programmable implementation. With this approach, all three-variable non-threshold functions can be presented by the XOR of two threshold functions, except for two special functions. On this basis, a novel three-variable universal logic gate (ULG3) is proposed, composed of two RTD-based universal threshold logic gates (UTLG) and an RTD-based three-variable XOR gate (XOR3). The ULG3 has a simple structure, and a simple method is presented to implement all three-variable functions using one ULG3. Thus, the proposed ULG3 provides a new efficient universal logic gate to implement RTD-based arbitrary -variable functions.

关键词： Resonant tunneling diode (RTD) Threshold logic gate Reed-Muller expansion Universal logic gate

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Tuning the electronic structure of NiCoP arrays through V doping for pH-universal hydrogen evolution

Yu Lin, Jinlei Wang, Duanlin Cao, Yaqiong Gong

《化学科学与工程前沿（英文）》 2021年第15卷第5期页码 1134-1146 doi: 10.1007/s11705-020-2014-x

摘要： The exploration of cost-effective, high-performance, and stable electrocatalysts for the hydrogen evolution reaction (HER) over wide pH range (0–14) is of paramount importance for future renewable energy conversion technologies. Regulation of electronic structure through doping vanadium atoms is a feasible construction strategy to enhance catalytic activities, electron transfer capability, and stability of the HER electrode. Herein, V-doped NiCoP nanosheets on carbon fiber paper (CFP) (denoted as V -NiCoP/CFP) were constructed by doping V modulation on NiCoP nanosheets on CFP and used for pH-universal HER. Benefiting from the abundant catalytic sites and optimized hydrogen binding thermodynamics, the resultant V -NiCoP/CFP demonstrates a significantly improved HER catalytic activity, requiring overpotentials of 46.5, 52.4, and 85.3 mV to reach a current density of 10 mA·cm in 1 mol·L KOH, 0.5 mol·L H SO , and 1 mol·L phosphate buffer solution (PBS) electrolytes, respectively. This proposed cation-doping strategy provides a new inspiration to rationally enhance or design new-type nonprecious metal-based, highly efficient, and pH-universal electrocatalysts for various energy conversion systems.

关键词： hydrogen evolution reaction transition metal phosphides pH-universal vanadium doping carbon fiber paper

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Recent advances in “universal” influenza virus antibodies: the rise of a hidden trimeric interface in

Yulu Wang, Dan Hu, Yanling Wu, Tianlei Ying

《医学前沿（英文）》 2020年第14卷第2期页码 149-159 doi: 10.1007/s11684-020-0764-y

摘要： Influenza causes seasonal outbreaks yearly and unpredictable pandemics with high morbidity and mortality rates. Despite significant efforts to address influenza, it remains a major threat to human public health. This issue is partially due to the lack of antiviral drugs with potent antiviral activity and broad reactivity against all influenza virus strains and the rapid emergence of drug-resistant variants. Moreover, designing a universal influenza vaccine that is sufficiently immunogenic to induce universal antibodies is difficult. Some novel epitopes hidden in the hemagglutinin (HA) trimeric interface have been discovered recently, and a number of antibodies targeting these epitopes have been found to be capable of neutralizing a broad range of influenza isolates. These findings may have important implications for the development of universal influenza vaccines and antiviral drugs. In this review, we focused on the antibodies targeting these newly discovered epitopes in the HA domain of the influenza virus to promote the development of universal anti-influenza antibodies or vaccines and extend the discovery to other viruses with similar conformational changes in envelope proteins.

关键词： influenza virus neutralizing antibody hemagglutinin globular head region trimeric interface

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Construction of a universal recombinant expression vector that regulates the expression of human lysozyme

Shen LIU, Shengzhe SHANG, Xuezhen YANG, Huihua ZHANG, Dan LU, Ning LI

《农业科学与工程前沿（英文）》 2018年第5卷第3期页码 382-389 doi: 10.15302/J-FASE-2018211

摘要：

The mammary gland provides a novel method for producing recombinant proteins in milk of transgenic animals. A key component in the technology is the construction of an efficient milk expression vector. Here, we established a simple method to construct a milk expression vector, by a combination of homologous recombination and digestion-ligation. Our methodology is expected to have the advantages of both plasmid and bacterial artificial chromosome (BAC) vectors. The BAC of mouse whey acidic protein gene (mWAP) was modified twice by homologous recombination to produce a universal expression vector, and the human lysozyme gene (hLZ) was then inserted into the vector by a digestion-ligation method. The final vector containing the 8.5 kb mWAP 5′ promoter, 4.8 kb hLZ genomic DNA, and 8.0 kb mWAP 3′ genomic DNA was microinjected into pronuclei of fertilized mouse embryos, to successfully generate two transgenic mouse lines that expressed recombinant human lysozyme (rhLZ) in milk. The highest expression level of rhLZ was 0.45 g·L⁻¹, and rhLZ exhibited the same antibacterial activity as native hLZ. Our results have provided a simple approach to construct a universal milk expression vector, and demonstrated that the resulting vector regulates the expression of hLZ in milk.

关键词： BAC recombinant methods gene expression human lysozyme transgenic mice milk expression vector

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基于RTD三变量通用逻辑门的函数综合算法 Article

Mao-qun YAO, Kai YANG, Ji-zhong SHEN, Cong-yuan XU

《信息与电子工程前沿（英文）》 2017年第18卷第10期页码 1654-1664 doi: 10.1631/FITEE.1601730

摘要：首先，提出真值矩阵的概念，并提出一种运用真值矩阵将任意n变量逻辑函数分解成3变量子集函数的非相交分解算法；在上述工作基础上，提出用基于RTD通用阈值逻辑门（universal threshold logicgates, UTLG）、基于RTD三变量异或门XOR3和基于RTD三变量通用逻辑门ULG3实现n变量逻辑函数的综合算法。当n变量逻辑函数为可直接非相交分解函数时，用所提出算法实现的电路十分简单；当n变量逻辑函数为不可直接非相交分解函数时，用所提算法实现的电路比用单一UTLG门或ULG3门实现n变量逻辑函数的电路简单。

关键词：共振隧穿器件（RTD）；非相交分解算法；通用逻辑门；真值矩阵；函数综合算法

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Calculating frictional force with considering material microstructure and potential on contact surfaces

XU Zhongming, HUANG Ping

《机械工程前沿（英文）》 2007年第2卷第4期页码 474-477 doi: 10.1007/s11465-007-0082-y

摘要： A method based on the energy dissipation mechanism of an Independent Oscillator model is used to calculate the frictional force and the friction coefficient of interfacial friction. The friction work is calculated with considering the potential change of contact surfaces during sliding. The potential change can be gained by a universal adhesive energy function. The relationships between frictional force and parameters of a tribo-system, such as surface energy and microstructure of interfacial material, are set up. The calculation results of the known experimental data denote that the frictional force is nearly proportional to the surface energy of the material, nearly inversely proportional to the scaling length, and independent of the lattice constant. The results agree with that of adhesion friction equations. They also agree with the experimental results performed with an atomic-force microscope under the ultra high vacuum condition.

关键词： coefficient dissipation mechanism universal adhesive interfacial Independent Oscillator

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采矿过程中磨料水射流性能通用预测方法

Eugene Averin

《工程（英文）》 2017年第3卷第6期页码 888-891 doi: 10.1016/j.eng.2017.12.004

摘要：

极端采矿条件下的硬岩破碎可采用磨料水射流（AWJ）技术，这种技术能够在不产生粉尘的条件下有效切割难以机械加工的材料。这种技术还可用于爆破、本安和消防安全。就断裂力学而言，每一种可被破坏的材料均可被视为韧性或脆性材料。因此，需要找到一种无论使用AWJ 对何种材料进行切割都能精确预测其效率的方法。该问题可通过能量守恒法加以解决，它显示了材料去除量与AWJ 动能之间的比例。本文介绍了基于能量守恒法的预测方法，并提出如何达到最有效破坏水平的建议，以及关于涉及磨料流量与水流量、靶距和磨料颗粒粒径关系值的合理范围的建议。本文还提供了基于断裂力学的临时结构法确定材料破坏起始阈值条件的参数。

关键词：磨料水射流能量守恒法切割深度断裂力学阈值速度采矿

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Monte Carlo simulation of the diffusion-limited aggregating process of particle suspension systems

Jiajing XU, Lin ZHANG, Yongjian TANG, Wei DAI, Wenwen SHAN,

《化学科学与工程前沿（英文）》 2010年第4卷第3期页码 270-274 doi: 10.1007/s11705-009-0273-7

摘要： The aggregating process of particle suspension systems is a very universal phenomena and crucial for various processes both in nature and in industry. In this paper, the aggregating process was simulated with off-lattice diffusion-limited cluster-cluster aggregation (DLCA) Monte Carlo programs. The self-similar fractal structures of aggregates have been clearly demonstrated by the statistical analysis of gyration radius distribution and the existence of a scaling distribution of the reduced cluster size. The fractal dimension determined from the relationship between mass and gyration radius of aggregates was 1.80 or so. The fractal dimension of the aggregates drawn from the radial distribution function and structure factor of a single aggregate is about 1.90–2.10. It was also showed that, along with the increasing of particle volume fraction, the fractal dimension will increase in a nearly square root manner, and the spatial range of the fractal structure appearing becomes narrower. Also, the gelation transition can only occur in a particle suspension system where the particle volume fraction is greater than a critical value.

关键词： cluster-cluster aggregation distribution function relationship process universal

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临床诊断标准实施和全城症状排查对武汉新冠病毒肺炎疫情防控的效果评价 Article

魏永越, 魏良敏, 姜玥, 沈思鹏, 赵杨, 郝元涛, 杜志成, 唐金陵, 张志杰, 姜庆五, 李立明, 陈峰, 沈洪兵

《工程（英文）》 2020年第6卷第10期页码 1141-1146 doi: 10.1016/j.eng.2020.04.008

摘要：结果显示，若维持2月14日以前防控措施不变，那么预测将于3月25日和4月29日，每日新增病例数分别降至100例和10例以下，将于5月31日首次现零。而事实上，截至3月6日，武汉市每日新增病例数降至100例以下，截至3月11日降至10例以下，3月18日首次实现零增长，较之模型预测结果分别提前了19 d、49 d和74 d。截至3月30日，实际累计病例数为50 006例，比模型预测值减少19 951例。

关键词： COVID-19 SEIR+Q传染病动力学模型临床诊断标准全城症状排查干预效果评价

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通过一个等价雷诺数揭示层流到湍流的转捩区域 Article

陈晓东

《工程（英文）》 2019年第5卷第3期页码 576-579 doi: 10.1016/j.eng.2018.09.013

摘要：

Flow transition from laminar to turbulent mode (and vice versa)—that is, the initiation of turbulence—is one of the most important research subjects in the history of engineering. Even for pipe flow, predicting the onset of turbulence requires sophisticated instrumentation and/or direct numerical simulation, based on observing the instantaneous flow structure formation and evolution. In this work, a local Reynolds number equivalence γ (ratio of local inertia effect to viscous effect) is seen to conform to the Universal Law of the Wall, where γ = 1 represents a quantitative balance between the abovementioned two effects. This coincides with the wall layer thickness (y⁺ = 1, where y⁺ is the dimensionless distance from the wall surface defined in the Universal Law of the Wall). It is found that the characteristic of how the local derivative of γ against the local velocity changes with increasing velocity determines the onset of turbulence. For pipe flow, γ ≈ 25, and for plate flow, γ ≈ 151.5. These findings suggest that a certain combination of γ and velocity (nonlinearity) can qualify the source of turbulence (i.e., generate turbulent energy). Similarly, a re-evaluation of the previous findings reveals that only the geometrically narrow domain can act locally as the source of turbulence, with the rest of the flow field largely being left for transporting and dissipating. This understanding will have an impact on the future large-scale modeling of turbulence.

关键词：局部等价雷诺数转捩壁面律管流平板流动建模

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Single and joint effects of HHCB and cadmium on zebrafish (

Lei ZHANG, Jing AN, Qixing ZHOU

《环境科学与工程前沿（英文）》 2012年第6卷第3期页码 360-372 doi: 10.1007/s11783-011-0353-z

摘要： As an important type of emerging pollutants, ecological toxicity and risk of artificial musks are increasingly concerned. Thus, single and joint toxic effects of 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8- hexamethylcyclopenta-gamma-2-benzopyran (HHCB) as one of the most widely applied artificial musks and cadmium (Cd) as an toxic metal on zebrafish ( ) were investigated by the exposure of zebrafish to various concentrations of HHCB or/and Cd in feculent water containing bedloads. The results indicated that the joint effect of HHCB and Cd changed during different exposure times within 120 h. The index of the antioxidant enzyme system including superoxide dismutase (SOD) and peroxidase (POD), and malondialdehyde (MDA) were sensitive and induced in the zebrafish stressed by Cd, and content of soluble protein (SP) was sensitive to HHCB and could be used as a biomarker for HHCB. Joint effects on antioxidant enzymes depended more on the effect of single Cd in the first one or two days. However, in the rest exposure days, the effect of HHCB began to dominate in the joint effect during the exposure process.

关键词： 1 3 4 6 7 8-hexahydro-4 6 6 7 8 8-hexamethylcyclopenta-gamma-2-benzopyran (HHCB) cadmium (Cd) antioxidant biomarker feculent water containing bedloads