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| 1 | Type synthesis of the rotational decoupled parallel mechanism based on screw theory显示文摘With the gradual deepening of study on the parallel mechanism,the difficulty brought by the existence of coupling to the theoretical analysis and practical application of parallel mechanisms is becoming increasingly apparent.The research on the decoupled parallel mechanism is currently one of the hot fields.Though most of the rotational parallel mechanisms,which has been widely used in spatial orientation fields,are not decoupled.It is comparative difficult for the synthesis of fully decoupled rotational parallel mechanisms,and the number of the existing parallel mechanisms which can realize rotational decoupling is limited.In addition,most of the existing rotational decoupled parallel mechanism are obtained depending on the experience of the researcher,and don't possess the general theoretical significance.Based on the screw theory,this paper presents the rotational conditions of the parallel mechanism through the analysis of the relationship between the degree of freedom of the parallel mechanism and its limbs.The synthesis rule of the limbs for decoupled rotational parallel mechanism is established according to the twist screw system of the limbs,which assures the decoupling of the rotations in each limb.The selection principle of the input pairs for the rotation driven limbs is proposed,then the type synthesis method for rotational decoupled parallel mechanisms is formed.With this type synthesis method,synthesis of the rotational decoupled parallel mechanisms is performed,which can provide a reference for the development of the novel type parallel mechanisms with independent intellectual property rights. | ZENG DaXing HUANG Zhen | 2011 | Science China(Technological Sciences)2011，54，4： | 49 |
| 2 | A general methodology for mobility analysis of mechanisms based on constraint screw theory显示文摘It is well known that the traditional Grübler-Kutzbach formula fails to calculate the mobility of some classical mechanisms or many modern parallel robots,and this situation seriously hampers mechani-cal innovation.To seek an efficient and universal method for mobility calculation has been a heated topic in the sphere of mechanism.The modified Grübler-Kutzbach criterion proposed by us achieved success in calculating the mobility of a lot of highly complicated mechanisms,especially the mobility of all recent parallel mechanisms listed by Gogu,and the Bennett mechanism known for its particular difficulty.With wide applications of the criterion,a systematic methodology has recently formed.This paper systematically presents the methodology based on the screw theory for the first time and ana-lyzes six representative puzzling mechanisms.In addition,the methodology is convenient for judgment of the instantaneous or full-cycle mobility,and has become an effective and general method of great scientific value and practical significance.In the first half,this paper introduces the basic screw theory,then it presents the effective methodology formed within this decade.The second half of this paper presents how to apply the methodology by analyzing the mobility of several puzzling mechanisms.Finally,this paper contrasts and analyzes some different methods and interprets the essential reason for validity of our methodology. | Zhen Huang JingFang Liu DaXing Zeng | 2009 | Science China(Technological Sciences)2009，52，5： | 30 |
| 3 | Biomimetic Shoulder Complex Based on 3-PSS/S Spherical Parallel Mechanism显示文摘The application of the parallel mechanism is still limited in the humanoid robot fields, and the existing parallel humanoid robot joint has not yet been reflected the characteristics of the parallel mechanism completely, also failed to solve the problem, such as small workspace, effectively. From the structural and functional bionic point of view, a three degrees of freedom(DOFs) spherical parallel mechanism for the shoulder complex of the humanoid robot is presented. According to the structure and kinetic characteristics analysis of the human shoulder complex, 3-PSS/S(P for prismatic pair, S for spherical pair) is chosen as the original configuration for the shouder complex. Using genetic algorithm, the optimization of the 3-PSS/S spherical parallel mechanism is performed, and the orientation workspace of the prototype mechanism is enlarged obviously. Combining the practical structure characteristics of the human shouder complex, an offset output mode, which means the output rod of the mechanism turn to any direction at the point a certain distance from the rotation center of the mechanism, is put forward, which provide possibility for the consistent of the workspace of the mechanism and the actual motion space of the human body shoulder joint. The relationship of the attitude angles between different coordinate system is derived, which establishs the foundation for the motion descriptions under different conditions and control development. The 3-PSS/S spherical parallel mechanism is proposed for the shoulder complex, and the consistence of the workspace of the mechanism and the human shoulder complex is realized by the stuctural parameter optimization and the offset output design. | HOU Yulei HU Xinzhe ZENG Daxing ZHOU Yulin | 2015 | Chinese Journal of Mechanical Engineering2015，28，1： | 22 |
| 4 | Comparative Analysis of Characteristics of the Coupled and Decoupled Parallel Mechanisms显示文摘The existence of coupling makes the parallel mechanism possess some special advantages over the serial mechanism, while it is just the coupling that brings about the parallel mechanism some limitations, such as complex workspace, high nonlinear relationship between input and output, difficulties in static and dynamic analysis, and the development of control system, which restricts its application fields. The decoupled parallel mechanism is currently one of the research focuses of the mechanism fields, while the study on the different characteristics between the decoupled and coupled parallel mechanisms has not been reported. Therefore, this paper performs the systematic comparative analysis of the 3-RPUR and the 3-CPR parallel mechanisms. The features of the two mechanisms are described and their movement forms are analyzed with screw theory. The inverse and forward displacement solutions are solved and the Jacobian matrices are obtained. According to the Jacobian matrices and by using the theory of physical model of the solution space, the workspace, dexterity, velocity, payload capability, and stiffness of the mechanisms are analyzed with plotting the indices atlases. The research results prove that the effects of the coupling on the parallel mechanism are double-side, and then the adoption of the decoupled parallel mechanism should be determined by the requirements of the concrete application situation. The contents of this paper should be useful for the type synthesis and practical application of the parallel mechanism. | ZENG Daxing HOU Yulei LU Wenjuan HUANG Zhen | 2010 | Chinese Journal of Mechanical Engineering2010，23，4： | 17 |
| 5 | Novel Mobility Formula for Parallel Mechanisms Expressed with Mobility of General Link Group显示文摘The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation.To make mobility calculation simple,considering avoiding virtual constraints,some new formulae have been presented,however these formulae can hardly intuitively reflect general link group’s restrictions on output member and its influences on independence of output parameters,which is premise to the judgment of the properties of mobility.Towards the problem to reveal the intrinsic relationship between the degree of freedom(DOF)of a mechanism,the link group,and the dimension of output parameters,also to avoid determination of virtual constraint,based on the new concepts of the'DOF of general link group'and'node parameters',a new formula in the calculation of the mobility of mechanisms is presented that is expressed with DOFs of the general link groups and rank of motion parameters of base point of the output link.It is named GOM(mobility of groups and output parameter)formula.On the basis of new concepts of'effective parameters'and'invalid parameters',a rule is put forward for solving the DOF of mechanisms with invalid parameters by GOM formula,that is,the base point parameters are the subset of effective parameters of link group.Thereafter,several examples are enumerated and the results coincide with the prototype data,which proves the validity of the proposed formula.Meanwhile,it is obtained that the necessary and sufficient condition for the judgment of output parameters independence is that each of the DOF of the link group is not less than zero.The proposed formula which is simple in calculation provides theoretical basis for the judgment of independence of output parameters and provides references for type synthesis of novel parallel mechanisms with independence requirements of their output parameters. | ZHANG Yitong LU Wenjuan MU Dejun YANG Yandong ZHANG Lijie ZENG Daxing | 2013 | Chinese Journal of Mechanical Engineering2013，26，6： | 14 |
| 6 | Type Synthesis and Characteristic Analysis of a Family of 2-DOF Rotational Decoupled Parallel Mechanisms显示文摘It is widely used for the rotational parallel mechanism in the field of spatial orientation. While owing to the existence of coupling, the forward kinematic solution and the control of the general rotational parallel mechanism are especially difficult. If decoupling can be realized, the kinematic analysis of the mechanism will be very simple. Presently, the research of the parallel mechanism is focused on the inverse solution and structure optimization, and there is a lack of rotation decoupled parallel mechanisms (DPMs). So this paper proposes a family of 2 degree of freedom (DOF) rotational DPMs based on the four-bar linkage mechanism, and performs a characteristic analysis. This family of DPMs is composed of a moving platform, a fixed base and three limbs. Taking U__RRU__SPU DPM as an example, the motion feature of this DPM is analyzed with the constraint screw method, and its mobility is calculated by using the Modified Kutzbach-Grübler criterion. The inverse and forward displacement problems of the proposed parallel mechanism are solved. The decoupled feature of the proposed parallel mechanism is validated by the deduction of the expression of the Jacobian matrix. Three kinds of singularity conditions of this DPM are discussed, and the atlases of the output parameter concerning different geometric parameters are plotted with the theory of the physical model of the solution space. The proposition and characteristic analysis of the novel rotational DPMs in this paper should be useful for further research and application of the parallel mechanisms. | ZENG Daxing Hou Yulei HUANG Zhen LU Wenjuan | 2009 | Chinese Journal of Mechanical Engineering2009，22，6： | 14 |
| 7 | RhMYB108,an R2R3-MYB transcription factor,is involved in ethylene-and JA-induced petal senescence in rose plants显示文摘Rose(Rosa hybrida)plants are major ornamental species worldwide,and their commercial value greatly depends on their open flowers,as both the quality of fully open petals and long vase life are important.Petal senescence can be started and accelerated by various hormone signals,and ethylene is considered an accelerator of petal senescence in rose.To date,however,the underlying mechanism of signaling crosstalk between ethylene and other hormones such as JA in petal senescence remains largely unknown.Here,we isolated RhMYB108,an R2R3-MYB transcription factor,which is highly expressed in senescing petals as well as in petals treated with exogenous ethylene and JA.Applications of exogenous ethylene and JA markedly accelerated petal senescence,while the process was delayed in response to applications of 1-MCP,an ethylene action inhibitor.In addition,silencing of RhMYB108 alter the expression of SAGs such as RhNAC029,RhNAC053,RhNAC092,RhSAG12,and RhSAG113,and finally block ethylene-and JA-induced petal senescence.Furthermore,RhMYB108 was identified to target the promoters of RhNAC053,RhNAC092,and RhSAG113.Our results reveal a model in which RhMYB108 functions as a receptor of ethylene and JA signals to modulate the onset of petal senescence by targeting and enhancing senescence-associated gene expression. | Shuai Zhang Qingcui Zhao Daxing Zeng Jiehua Xu Hougao Zhou Fenglan Wang Nan Ma Yonghong Li | 2019 | Horticulture Research2019，6，1： | 10 |
| 8 | Development and Calibration of a Hyperstatic Six-component Force/Torque Sensor显示文摘The six-component force/torque sensor has become one kind of the most important sensors with the ability of measuring all the external forces and torques. A novel hyperstatic six-component force/torque sensor based on the Stewart platform structure,which can be used for the force measurement of the robot wrist,is proposed,and its structural optimal design,finite element analysis and calibration experimentation is presented. The characteristic of the sensor structure is analyzed in comparison with the traditional Stewart platform-based sensor. The mathematical expression of the sensor's force mapping matrix is introduced. The condition number and generalized amplifying coefficient defined by singular values of force Jacobian matrix are used to evaluate the performances of isotropy and sensitivity of the sensor respectively. The optimal design of the sensor structure is performed with the objective of achieving high measurement sensitivity and good isotropy. The sensor prototype is fabricated,and the static and dynamic characteristics of the sensor are analyzed with finite element analysis software package ANSYS. The calibration device is manufactured,and the data acquisition and processing system is developed. The theoretical and experimental study of the static calibration of the sensor prototype is carried out. The results of simulation analysis and calibration experimentation prove the feasibility of the hyperstatic sensor structure,and the contents of this paper possess theoretical significance and engineering value for the further research and practical application of the six-component force sensor. | HOU Yulei YAO Jiantao ZENG Daxing CHEN Jie ZHAO Yongsheng | 2009 | Chinese Journal of Mechanical Engineering2009，22，4： | 9 |
| 9 | A late Mesozoic high plateau in eastern China:Evidence from basalt vesicular paleoaltimetry显示文摘Eastern China is made of a number of large and small continental fragments throughout late Paleozoic and Mesozoic time,and is still the best natural laboratory for examining kinematic models of continent tectonics.The paleoelevation history of eastern China provides direct insight into the tectonic processes in China.Here we present basalt-vesicularity based estimates of the paleoaltimetry of the early Cretaceous basalts in northern East China,which indicate that the studied basalt units were at an elevation of more than 4 kilometers in late Mesozoic.Two vesicular basaltic rocks have been collected form bottom to top along the lava flow outcrop in eastern Inner Mongolia.After the digital precessing to the sample cross-sections,and taking advantage of the stereological conversion method to acquire the bubble size distributions,paleoelevation estimate was calculated for East China in the early Cretaceous.The results show that the elevation has been near 4700±750 m when the lava flows was cooling,implying that there were highland regions in the northern part of the East China Plateau during the early Cretaceous.Combined with other geological evidence,we conclude that there was a high plateau with elevation near 5000 m above sea level in Eastern China during the late Mesozoic.This ancient high plateau in eastern China was most likely formed by the collision of the north and south China blocks. | XIA GuoQing YI HaiSheng ZHAO XiXi GONG DaXing JI ChangJun | 2012 | Chinese Science Bulletin2012，57，21： | 9 |
| 10 | Discovery of marine fossils in the upper part of the Permian Linxi Formation in Lopingian, Xingmeng area, China显示文摘Two important geological issues have a long history of debate in the Xingmeng area.The first concerns the final closure of the North China plate,Siberia plate and several intermediate massifs in the area,and the other concerns the folding and lifting of the Xingmeng Trough.Disagreements arise because of issues involving the tectonicpalaeogeographical environment of the Upper Permian deposits of the Linxi Formation.The Linxi Formation(Upper Permian)is generally considered to be either an exclusively continental deposit or separated into marineterrigenous facies deposited during the Lower to Middle Linxi Period and continental deposits in the Upper Linxi Period.However,in this study,large numbers of bryozoan and sponge spicule fossils were discovered for this first time in the thick limestone layers and lenses of the upper part of the Linxi Formation found in the Guandi section of Linxi county in eastern Inner Mongolia.At the same time,abundant bryozoan fossils were also found in sedimentary tuff slices that were collected from the upper part of the Taohuayingzi Formation from the Taohuayingzi section in Ar Horqin Banner,and abundant small connecting body crinoid stem fossils were found in the dark shale of the Yangjiagou Formation from the Yangjiagou section of Jiutai county,Jilin Province.These marine fossils provide the first evidence that the Xingmeng area was still a marine or mainly marine environment at the end of the late Permian.This not only provides conclusive evidence for the recognition of the above two major geological issues but also promotes changes in the approach towards research,exploration and development of oil and gas,shale gas(oil),and other mineral resources that are preserved in the late Permian layers of the Northeast-Xingmeng area. | Yongsheng Zhang Shugang Tian Zishun Li Yuexuan Gong Enyuan Xing Zhuozhuo Wang Daxing Zhai Cao Jie Su Kui Wang Meng | 2014 | Chinese Science Bulletin2014，59，1： | 6 |
| 11 | Y_(4)GeO_(8):Er^(3+),Yb^(3+) up-conversion phosphors for optical temperature sensor based on FIR technique显示文摘Herein,we reported novel Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors elaborated via conventional solid-state reaction.and we further explored their properties as optical thermometer by using fluorescence intensity ratio(FIR)method complemented by detailed analysis on crystal structure,up-conversion luminescence and energy transfer from Yb^(3+)to Er^(3+).Upon 980 nm laser excitation,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors present525,547 and 659 nm emission bands assigned to the characteristic transitions of Er^(3+).Furthermore,Y_(4)GeO_(8):Er^(3+),Yb^(3+)samples show outstanding temperature sensing performances.To be specific,the minimal temperature resolution is 0.03 K(303 K),and the relative sensitivity of FIR can be up to 1.152%/K(303 K).Hence,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors can be possible candidates for thermometry devices. | Yihang Chen Jing Chen Ye Tong Wenna Zhang Xiusha Peng Hai Guo Daxing Huang | 2021 | Journal of Rare Earths2021，39，12： | 5 |
| 12 | Optical properties of human normal small intestine tissue determined by Kubelka-Munk method in vitro显示文摘AIM: To study the optical properties of human normal small intestine tissue at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm,532 nm, 808 nm wavelengths of laser irradiation.METHODS: A double-integrating-sphere system, the basic principle of measuring technology of light radiation, and an optical model of biological tissues were used in the study.RESULTS: The results of measurement showed that there were no significant differences in the absorption coefficients of human normal small intestine tissue at 476.5 nm, 488 nm,496.5 nm laser in the Kubelka-Munk two-flux model (P>0.05).The absorption coefficients of the tissue at 514.5 nm, 532 nm,808 nm laser irradiation were obviously increased with the decrease of these wavelengths. The scattering coefficients of the tissue at 476.5 nm, 488 nm, 496.5 nm laser irradiation were increased with the decrease of these wavelengths.The scattering coefficients at 496.5 nm, 514.5 nm, 532 nm laser irradiation were obviously increased with the increase of these wavelengths. The scattering coefficient of the tissue at 532 nm laser irradiation was bigger than that at 808 nm.There were no significant differences in the total attenuation coefficient of the tissue at 476.5 nm and 488 nm laser irradiation (P>0.05). The total attenuation coefficient of the tissue at 488 nm, 496.5 nm, 514.5 nm, 532 nm, 808 nm laser irradiation was obviously increased with the decrease of these wavelengths, and their effective attenuation coefficient revealed the same trend. There were no significant differences among the forward scattered photon fluxe,backward scattered photon fiuxe, and total scattered photon fiuxe of the tissue at 476.5 nm, 488 nm, 496.5 nm laser irradiation. They were all obviously increased with attenuation of tissue thickness. The attenuations of forward and backward scattered photon fluxes, and the total scattered photon fiuxe of the tissue at 514.5 nm laser irradiation were slower than those at 476.5 nm, 488 nm, 496.5 nm laser irradiation respectively. The attenuations of forward and backward scattered photon fluxes, and total scattered photon fluxes at 532 nm laser irradiation were obviously slower than those at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm laser irradiation. The attenuations of forward and backward scattered photon fluxes, and total scattered photon fiuxe at 808 nm laser irradiation were all obviously slower than those at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm, 532 nm laser irradiation respectively.CONCLUSION: There are significant differences in optical parameters of human normal small intestine tissue in the Kubelka-Munk two-flux model at six different wavelengths of laser radiation. The results would provide a new method of information analysis for clinical diagnosis. | Hua-JiangWei DaXing Guo-YongWu YingJin Huai-MinGu | 2003 | World Journal of Gastroenterology2003，9，9： | 4 |
| 13 | State and Potential of Forest Carbon Market in China显示文摘China has been making efforts to improve climate changes which have drawn international attentions since China formally signed UN Climate Change Framework in 1992 and ratified Kyoto Protocol in August 2002. The area of China’s forest plantation ranks the first at present so global close attention is paid to forest carbon market in China. This article introduces that 5 110 million t of carbon dioxide equivalent have been sequestrated by China’s forest during 1980 to 2005, China will have 4.2 billion t of carbon dioxide emission reduction market potential and contribute more forest carbon credits to the international community. | TAN Xiufeng1 ZHOU Fengzhi2 1. Research Institute of Forestry Policy and Information, Chinese Academy of Forestry, Beijing100091, P. R. China 2. Huyuan Forest Farm, Daxing’anling, Huyuan 165033, P. R. China | 2010 | Chinese Forestry Science and Technology2010，9，1： | 4 |
| 14 | Over-Constraints and a Unified Mobility Method for General Spatial Mechanisms Part 2:Application of the Principle显示文摘The pre-research on mobility analysis presented a unified-mobility formula and a methodology based on reciprocal screw theory by HUANG, which focused on classical and modern parallel mechanisms. However its range of application needs to further extend to general multi-loop spatial mechanism. This kind of mechanism is not only more complex in structure but also with strong motion coupling among loops, making the mobility analysis even more complicated, and the relevant research has long been ignored. It is focused on how to apply the new principle for general spatial mechanism to those various multi-loop spatial mechanisms, and some new meaningful knowledge is further found. Several typical examples of the general multi-loop spatial mechanisms with motion couple even strong motion couple are considered. These spatial mechanisms include different closing way: over-constraint appearing in rigid closure, in movable closure, and in dynamic closure as well; these examples also include two different new methods to solve this kind of issue: the way to recognize over-constraints by analyzing relative movement between two connected links and by constructing a virtual loop to recognize over-constraints. In addition, over-constraint determination tabulation is brought to analyze the motion couple. The researches above are all based upon the screw theory. All these multi-loop spatial mechanisms with different kinds of structures can completely be solved by following the directions and examples, and the new mobility theory based on the screw theory is also proved to be valid. This study not only enriches and develops the theory and makes the theory more universal, but also has a special meaning for innovation in mechanical engineering. | LU Wenjuan ZENG Daxing HUANG Zhen | 2016 | Chinese Journal of Mechanical Engineering2016，29，1： | 4 |
| 15 | Mechanics Unloading Analysis and Experimentation of a New Type of Parallel Biomimetic Shoulder Complex显示文摘The structure design for high ratio of carrying capacity to deadweight is one of the challenges for the bionic mechanism,while the problem concerning high carrying capacity has not yet be solved for the existing shoulder complex.A new type biomimetic shoulder complex,which adopts 3-PSS/S(P for prismatic pair,S for spherical pair) spherical parallel mechanism(SPM),is proposed.The static equilibrium equations of each component are established by using the vector method and the equations for constrain forces with certain load are solved.Then the constrain force on the middle limb and that on the side limbs are compared in order to verify the unloading performance of the mechanism.In addition,the prototype mechanism of the shoulder complex is developed,and the force feedback experiment is conducted to verify the static analysis,which indicates that the middle limb suffers most of the external force and the effect of mechanics unloading is achieved.The 3-PSS/S spherical parallel mechanism is presented for the shoulder complex,and the realization of mechanics unloading is benefit for the improvement of the carrying capacity of the shoulder complex. | HOU Yulei LI Zhisen WANG Yi ZHANG Wenwen ZENG Daxing ZHOU Yulin | 2016 | Chinese Journal of Mechanical Engineering2016，29，4： | 4 |
| 16 | The maize late embryogenesis abundant protein Zm DHN13 positively regulates copper tolerance in transgenic yeast and tobacco显示文摘Late embryogenesis abundant (LEA) proteins accumulate in the late stage of plant seed development, and are upregulated in most plants during drought, cold, heat, or salinity stress. LEA proteins can be classified by amino-acid sequence into seven groups. Dehydrins belong to LEA protein group Ⅱ. In previous studies, the maize KS type dehydrin ZmDHN13 increased the tolerance of transgenic tobacco to oxidative stress. In the present study, ZmDHN13 was identified under copper stress conditions, and the protein was then characterized using transgenic yeast and tobacco plants to investigate its functions. ZmDHN13 bound Cu2+. Its overexpression in transgenic tobacco conferred tolerance to copper stress by binding metals and reducing the accumulation of reactive oxygen species (ROS). Three conserved domains displayed a cooperative effect under copper stress conditions. | Yang Liu Daxing Li Qiping Song Tianpeng Zhang Dequan Li Xinghong Yang | 2019 | The Crop Journal2019，7，3： | 3 |
| 17 | Characteristics and Implications Significance for Carbon and Oxygen Isotope Continuous Change of Zhenjia1 Well in The Northern Shaanxi Salt Basin显示文摘Zhenjia1 well located in the 2nd salt depression of the Northern Shaanxi Salt Basin(Zhang et al,2013),is the basis potash exploration wells,and its main purpose is marine potash prospection,combining with gas exploration.Drilling completion depth is 3443.6m, | XING Enyuan ZHANG Yongsheng ZHENG Mianping WANG Zhuozhuo PAN Wei ZHAI Daxing WU Feimeng | 2014 | Acta Geologica Sinica(English Edition)2014，88，S1： | 3 |
| 18 | Over-constraint and a Unified Mobility Method for General Spatial Mechanisms Part 1: Essential Principle显示文摘Compared with the parallel mechanisms, the mobility analysis of the general multi-loop spatial mechanisms(GMSMs) is more difficult to obtain correct results. The reason is that its multi-loop is formed through several times of closings and there also exists motion coupling even strong coupling, where the over-constraints are concealed. However, the mobility analysis for this kind of mechanisms has been paid few attentions. A new systemic methodology for analyzing mobility is proposed for GMSMs also based on the screw theory. The key issue for mobility analysis is to recognize the over-constraint. Firstly, three theorems are given and point out: the reason and site of over-constraint occurrence, calculating the number of over-constraints by the screw theory, and how to analyze the over-constraints for a single-loop mechanism as well. Then, three closing forms for GMSMs are proposed including rigid closure, movable closure and dynamic closure, and for the three different forms the different analysis methods are also given. Especially, for the most difficult issue of GMSMs with the multi-loop closure in many times and the inevitable motion coupling, two important methods are proposed: 'recognizing over-constraints by analyzing relative movement' and 'recognizing over-constraints by virtual loop'. The two methods are well used to solve the issue. Above-mentioned principles are not only systematic and effective but also unified. They provide a theoretical basis for the general multi-loop spatial mechanisms. | ZENG Daxing LU Wenjuan HUANG Zhen | 2015 | Chinese Journal of Mechanical Engineering2015，28，5： | 3 |
| 19 | Improving Stock Price Forecasting Using a Large Volume of News Headline Text显示文摘Previous research in the area of using deep learning algorithms to forecast stock prices was focused on news headlines,company reports,and a mix of daily stock fundamentals,but few studies achieved excellent results.This study uses a convolutional neural network(CNN)to predict stock prices by considering a great amount of data,consisting of financial news headlines.We call our model N-CNN to distinguish it from a CNN.The main concept is to narrow the diversity of specific stock prices as they are impacted by news headlines,then horizontally expand the news headline data to a higher level for increased reliability.This model solves the problem that the number of news stories produced by a single stock does not meet the standard of previous research.In addition,we then use the number of news headlines for every stock on the China stock exchange as input to predict the probability of the highest next day stock price fluctuations.In the second half of this paper,we compare a traditional Long Short-Term Memory(LSTM)model for daily technical indicators with an LSTM model compensated by the N-CNN model.Experiments show that the final result obtained by the compensation formula can further reduce the root-mean-square error of LSTM. | Daxing Zhang Erguan Cai | 2021 | Computers, Materials & Continua2021，，12： | 3 |
| 20 | Determination of optical properties of normal and adenomatous human colon tissues in vitro using integrating sphere techniques显示文摘AIM: The purpose of the present study is to compare the optical properties of normal human colon mucosa/submucosa and muscle layer/chorion, and adenomatous human colon mucosa/submucosa and muscle layer/chorion in vitro at 476.5, 488, 496.5, 514.5 and 532 nm. We believe these differences in optical properties should help differential diagnosis of human colon tissues by using optical methods.METHODS: In vitro optical properties were investigated for four kinds of tissues: normal human colon mucosa/submucosa and muscle layer/chorion, and adenomatous human colon mucosa/submucosa and muscle layer/chorion. Tissue samples were taken from 13 human colons (13 adenomatous, 13 normal). From the normal human colons a total of 26 tissue samples, with a mean thickness of 0.40 mm, were used (13 from mucosa/submucosa and 13 from muscle layer/chorion), and from the adenomatous human bladders a total of 26 tissue samples, with a mean thickness of 0.40 mm, were used (13 from mucosa/submucosa and 13 from muscle layer/chorion). The measurements were performed using a double-integratingsphere setup and the optical properties were assessed from these measurements using the adding-doubling method that was considered reliable.RESULTS: The results of measurement showed that there were significant differences in the absorption coefficients and scattering coefficients between normal and adenomatous human colon mucosa/submucosa at the same wavelength,and there were also significant differences in the two optical parameters between both colon muscle layer/chorion at the same wavelength. And there were large differences in the anisotropy factors between both colon mucosa/submucosa at the same wavelength, there were also large differences in the anisotropy factors between both colon muscle layer/chorion at the same wavelength.There were large differences in the value ranges of the absorption coefficients, scattering coefficients and anisotropy factors between both colon mucosa/submucosa,and there were also large differences in these value ranges between both colon muscle layer/chorion. There are the same orders of magnitude in the absorption coefficients for four kinds of colon tissues. The scattering coefficients of these tissues exceed the absorption coefficients by at least two orders of magnitude.CONCLUSION: There were large differences in the three optical parameters between normal and adenomatous human colon mucosa/submucosa at the same laser wavelength, and there were also large differences in these parameters between both colon muscle layer/chorion at the same laser wavelength. Large differences in optical parameters indicate that there were large differences in compositions and structures between both colon mucosa/submucosa, and between both colon muscle layer/chorion.Optical parameters for four kinds of colon tissues are wavelength dependent, and these differences would be useful and helpful in clinical applications of laser and tumors photodynamic therapy (PDT). | Hua-JiangWei DaXing Jian-JunLu Huai-MinGu Guo-YongWu YingJin | 2005 | World Journal of Gastroenterology2005，11，16： | 2 |
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