A theory of （4＋1）-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields （pe...A theory of （4＋1）-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields （pentad）, defined globally on a manifold M, and gravity is attributed to the torsion. The Lagrangian density is quadratic in the torsion tensor. We then give the exact five-dimensional solution. The solution is a generalization of the familiar Schwarzschild and Kerr solutions of the four-dimensional teleparallel equivalent of general relativity. We also use the definition of the gravitational energy to calculate the energy and the spatial momentum.展开更多
Junior English for China’ is based on the ’Five-Step’ teachingmethod: Revision, Presentation, Drilling, Practice, Consolidation. Each step has itsown particular methodology and requires the teacher to adopt a certa...Junior English for China’ is based on the ’Five-Step’ teachingmethod: Revision, Presentation, Drilling, Practice, Consolidation. Each step has itsown particular methodology and requires the teacher to adopt a certain role. Thispaper is a discussion of the "Five-Step Method".展开更多
In order to ensure machining stability,curvature continuity and smooth cutting force are very important so as to meet the constraints of both cutting force and kinematics of machine tools.For five-axis flank milling,i...In order to ensure machining stability,curvature continuity and smooth cutting force are very important so as to meet the constraints of both cutting force and kinematics of machine tools.For five-axis flank milling,it is difficult to meet both of the constraints because tool path points and tool axis vectors interact with each other.In this paper,multiple relationships between tool path points and tool axis vectors with cutting force and kinematics of machine tools are established,and the strategies of corner-looping milling and clothoidal spirals are combined so as to find feasible solutions under both of the constraints.Tool path parameters are iterated by considering the maximum cutting force and the feasible range of the tool axis vector,and eventually a curvature continuity five-axis flank milling tool path with smooth cutting force is generated.Machining experimental results show that the conditions of cutting force are satisfied,vibration during the process of machining is reduced,and the machining quality of the surface is improved.展开更多
AIM: To determine changes in the antibiotic resistance of Helicobacter pylori(H. pylori) in southern Taiwan after failure of first-line standard triple therapy.METHODS: We analyzed 137 H. pylori-infected isolates from...AIM: To determine changes in the antibiotic resistance of Helicobacter pylori(H. pylori) in southern Taiwan after failure of first-line standard triple therapy.METHODS: We analyzed 137 H. pylori-infected isolates from patients who experienced eradication failure after standard first-line triple therapy from January2010 to December 2014. The H. pylori strains were tested for susceptibility to amoxicillin, clarithromycin,levofloxacin, metronidazole and tetracycline using the E-test method. The minimal inhibitory concentration(MIC) was determined by the agar dilution test.MIC values of ≥ 0.5, ≥ 1, ≥ 1, ≥ 4 and ≥ 8 mg/L were considered to be the resistance breakpoints for amoxicillin, clarithromycin, levofloxacin, tetracycline and metronidazole, respectively.RESULTS: A high resistance rate was found for clarithromycin(65%-75%) and metronidazole(30%-40%)among patients who failed first-line standard therapy.The resistance levels to amoxicillin and tetracycline remained very low; however, levofloxacin resistance was as high as 37.5% in 2010 but did not increase any further during the past 5 years. The rates of resistance to these antibiotics did not show a statistically significant upward or downward trend.CONCLUSION: Antibiotic resistance of H. pylori remains a problem for the effective eradication of this pathogen and its associated diseases in Taiwan. High clarithromycin resistance indicated that this antibiotic should not be prescribed as a second-line H. pylori eradication therapy. Moreover, levofloxacin-based second-line therapy should be used cautiously, and the local resistance rates should be carefully monitored.展开更多
Aiming at the problem of low machining accu- racy and uncontrollable thermal errors of NC machine tools, spindle thermal error measurement, modeling and compensation of a two turntable five-axis machine tool are resea...Aiming at the problem of low machining accu- racy and uncontrollable thermal errors of NC machine tools, spindle thermal error measurement, modeling and compensation of a two turntable five-axis machine tool are researched. Measurement experiment of heat sources and thermal errors are carried out, and GRA（grey relational analysis） method is introduced into the selection of tem- perature variables used for thermal error modeling. In order to analyze the influence of different heat sources on spindle thermal errors, an ANN （artificial neural network） model is presented, and ABC（artificial bee colony） algorithm is introduced to train the link weights of ANN, a new ABC- NN（Artificial bee colony-based neural network） modeling method is proposed and used in the prediction of spindle thermal errors. In order to test the prediction performance of ABC-NN model, an experiment system is developed, the prediction results of LSR （least squares regression）, ANN and ABC-NN are compared with the measurement results of spindle thermal errors. Experiment results show that the prediction accuracy of ABC-NN model is higher than LSR and ANN, and the residual error is smaller than 3 pm, the new modeling method is feasible. The proposed research provides instruction to compensate thermal errors and improve machining accuracy of NC machine tools.展开更多
The flow field in a cold model of 2500 t/d five-stage cyclone preheater and precalciner system was numerically simulated. Renault stress model (RSM) turbulent model was adopted to simulate the flow field, and a hybrid...The flow field in a cold model of 2500 t/d five-stage cyclone preheater and precalciner system was numerically simulated. Renault stress model (RSM) turbulent model was adopted to simulate the flow field, and a hybrid mesh scheme was selected to generate calculation mesh. With the first order upwind difference, finite-volume method was used to convert turbulent equations into difference equations pressure-velocity coupling which were solved by the classic simple algorithm, and during the course of numerical solution, mesh self-adapting technology was applied. The main flow field structures of the whole system and each part of the cold model were studied by analyzing the simulation results.展开更多
The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation...The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation in June 2003. The side slopes of the ship lock are characterized by great height（170 m）, steepness （70 m in height of upright slope）, and great length （over 7000 m in total length）. Inassociation with the ship lock, the surrounding rocks in slope have a high potential to deform, withwhich the magnitude of deformation is restricted. Monitoring results show that the deformation of thefive-step ship lock high slopes of the TGP primarily occurred in excavation period, and deformationtended to be stable and convergent during operation period, suggesting the allowable ranges of deformation.At present, the slopes and lock chambers are stable, and the ship lock works well under normaloperation condition, enabling the social and economic benefits of the TGP. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC syst...To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP （rotation tool center point control） and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter＇s position and orientation can be directly carried out in the CNC system.展开更多
Compared with the traditional non-cutting measurement,machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the users.However,measurement and c...Compared with the traditional non-cutting measurement,machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the users.However,measurement and calculation of the machining tests in the literature are quite difficult and time-consuming.A new method of the machining tests for the trunnion axis of five-axis machine tool is proposed.Firstly,a simple mathematical model of the cradle-type five-axis machine tool was established by optimizing the coordinate system settings based on robot kinematics.Then,the machining tests based on error-sensitive directions were proposed to identify the kinematic errors of the trunnion axis of cradle-type five-axis machine tool.By adopting the error-sensitive vectors in the matrix calculation,the functional relationship equations between the machining errors of the test piece in the error-sensitive directions and the kinematic errors of C-axis and A-axis of five-axis machine tool rotary table was established based on the model of the kinematic errors.According to our previous work,the kinematic errors of C-axis can be treated as the known quantities,and the kinematic errors of A-axis can be obtained from the equations.This method was tested in Mikron UCP600 vertical machining center.The machining errors in the error-sensitive directions can be obtained by CMM inspection from the finished test piece to identify the kinematic errors of five-axis machine tool trunnion axis.Experimental results demonstrated that the proposed method can reduce the complexity,cost,and the time consumed substantially,and has a wider applicability.This paper proposes a new method of the machining tests for the trunnion axis of five-axis machine tool.展开更多
This paper presents the modeling of electrical I-V verification of photovoltaic modules using five-parameter models based on the minimum usage of input data, which are usually provided by manufacturer’s datasheet. Ho...This paper presents the modeling of electrical I-V verification of photovoltaic modules using five-parameter models based on the minimum usage of input data, which are usually provided by manufacturer’s datasheet. However, we vary them with a step of 10-4, the ideality factor between 0.0 and 4 for each iteration in order to choose the value, which gives a minimal relative error of the maximum power point. Moreover, when is known, the other four parameters (i.e., Rs, I0, Iph and Rsh) are known. Finally, the effectiveness of this approach is then validated through comparison of the experimental results data under outdoor weather conditions.展开更多
In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no ...In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.展开更多
In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inv...In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inversion is carried out based on the array resistivity log. The mud invasion process is numerically simulated based on the oil-water flow equation and water convection diffusion equation. The results show that the radial resistivity of a fresh mud-invaded oil-bearing layer presents complex distribution characteristics, such as nonlinear increase, increasing to decreasing and low resistivity annulus, and the resistive invasion profile of a water layer is monotonic. Under specific conditions, array resistivity log can reflect these changes and the array induction log is more sensitive. Nevertheless, due to the effect of factors like large invasion depth, reservoir physical and oil-bearing properties, the measured apparent resistivity may differ greatly from the actual mud filtrate invasion profile in an oil-bearing layer. We proposed a five-parameter formation model to simulate the complex resistivity distribution of fresh mud-invaded formation. Then, based on the principle of non-linear least squares, the measured array resistivity log is used for inversion with the Marquardt method. It is demonstrated that the inverted resistivity is typically non-monotonic in oil-bearing layers and is monotonic in water layers. Processing of some field data shows that this is helpful in achieving efficient reservoir fluid recognition.展开更多
Four new five-coordinated anionic tin(Ⅳ) complexes with a form of [R_ n NH_ 4- n ][PhSn( μ 2-SCH_2COO)_2] were synthesized via the reaction of mercaptoacetic acid with phenyltin trichloride in the presence of dif...Four new five-coordinated anionic tin(Ⅳ) complexes with a form of [R_ n NH_ 4- n ][PhSn( μ 2-SCH_2COO)_2] were synthesized via the reaction of mercaptoacetic acid with phenyltin trichloride in the presence of different organic bases and characterized by means of IR, 1H NMR and MS spectroscopies. The crystal structure of [( i -Pr)_2NH_2] [PhSn( μ 2-SCH_2COO)_2] was determined by X-ray diffraction. In the crystal structure,the tin atom is five-coordinated and exists in trigonal bipyramid geometry with cell parameters a =1.1766(11) nm, b =1.3144(14) nm, c =1.3336(15) nm,β =90° and Z =4.展开更多
Objective:To observe the therapeutic effect differences among five-knee-point acupuncture combined with Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction(身痛逐瘀汤 generalized p...Objective:To observe the therapeutic effect differences among five-knee-point acupuncture combined with Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction(身痛逐瘀汤 generalized pain stasis-expelling decoction),simple five-knee-point acupuncture and simple Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction in treating knee osteoarthritis(KOA).Methods:A total of 126 KOA patients were randomized into a five-knee-point acupuncture combined with Chinese medication package warm compress therapy group(combined treatment group),where there were 42 cases,including 28 cases of unilateral KOA and 14 cases of bilateral KOA,totally 56 affected knees involved,a Chinese medication package warm compress therapy group(medication package group,42 cases,including 22 cases of unilateral KOA,20 cases of bilateral KOA,totally 62 affected knees involved)and a five-knee-point acupuncture group(five-knee-point group,42 cases,including 27 cases of unilateral KOA,15 cases of bilateral KOA,totally 57 affected knees involved).The basic health education was provided in all of the groups.Additionally,in the combined treatment group,acupuncture was applied to the five knee points on the affected side for 30 min.The warm compress with herbal package of Shēntòng Zhúyū Decoction was given for 10 to 15 min.In the medication package group,the warm compress with Shēntòng Zhúyū Decoction was exerted on the affected area for 10 to 15 min.In the fiveknee-point group,acupuncture was applied to SP 10,ST 34,EX-LE 2,EX-LE 4 and ST 35 and the needles were retained for 30 min.The treatment in each group was given once a day,consecutively for 2 weeks.Before and after treatment,the visual analogue scale(VAS)and Lysholm knee scale were adopted to evaluate the pain degree and knee joint motor function in KOA patients.The clinical therapeutic effects were evaluated too.Results:A total of 121 cases accomplished the final observation and 5 cases were dropped out in the three groups,in which,2 cases(2 affected knees)were dropped out in the combined treatment group,1 case(2 affected knees)in the medication package group and 2 cases(3 affected knees)in the fiveknee-point group.VAS scores after treatment were all lower than those before treatment in the three groups and the scores of Lysholm knee scale were all higher than those before treatment,indicating the significant differences(all P<0.05).The total effective rate was 98.1%(53/54)in the combined treatment group,which was higher than 86.7%(52/60)in the medication package group and 92.6%(50/54)in the five-knee-point group,indicating the significant differences(all P<0.05).After treatment,VAS score(2.24±1.24)in the combined medication group was lower than(2.48±1.08)in the medication package group and(2.63 ± 1.44)in the five-knee-point group,presenting the significant difference(all P<0.05).The score of Lysholm knee scale was(60.50±13.76)in the combined medication group,higher than(52.23±11.65)in the medication package group and(52.14±11.77)in the five-knee-point group,indicting the significant differences(all P<0.05).Conclusion:Compared with the simple application of Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction or the five-knee-point acupuncture therapy,five-knee-point acupuncture combined with Shēntòng Zhúyū Decoction relieves the clinical symptoms of KOA patients more effectively and achieves a better clinical therapeutic effect.展开更多
Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while litt...Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while little mechanism is designed to implement the function. A symmetrical five-bar linkage consisting of two revolute joints and three prismatic joints is presented. Inverse kinematics and forward kinematics are obtained first. Then inverse singularities and direct singularities of the mechanism are gained. The global stiffness index is defined based on the results of kinematics analysis. Finally, optimal dimensional synthesis of the mechanism in terms of maximum stiffness is conducted by genetic algorithms. The calculation results show that with the length of both the two linkage a=830 mm, the interacting angle of the two guides 2δ=4.48 radian, and the maximum range of displacement of the two carriers dmax=940 mm, the mechanism achieves highest rigidity and its workspace is singularity-free, which covers the human left and right arm range of motion. The proposed novel mechanism featuring high rigidity and a singularity-free workspace can provide rehabilitation training, also solve the problem of quantitative measure of arm stiffness.展开更多
In this paper, the executive of the 10th Five- Year Plan in the field of environmental protection and ecological constrution is reviewed, and the charactristics of economic growth and its environmental impact on the 1...In this paper, the executive of the 10th Five- Year Plan in the field of environmental protection and ecological constrution is reviewed, and the charactristics of economic growth and its environmental impact on the 11^th Five-Year Plan is forecasted and analyzed. A principal idea of eavironmental protection and ecological construction is put forward for the 11^th Five-Year Plan pertod： strensgthen the point treatment in key areas and set the main targets based on the idea. The relating countermeasures in national level are proposed as follows： set up appropriate ideas for official achievements by launching resources and environmental cost acconting; adjust the industrial struacture actively by industrial policies and strenuous work; develop circular economy, change the mode of environmental protecgon from end treatment to headstream and proeess control： strengthen the market mechanism in the process of pollution treatment, set up the system of ＂who treats who benefits＂ ; perfect interrelated laws and standards, strengthen the ability of environmental munagement; lay extra emphasis on two key targets： water pollution tretment in key river basins and management of the reserves; and combine the ecological consnuction and poverty alleviation in higher level.展开更多
The dissociation energy and equilibrium bond length as explicit parameters are used to establish an improved five-parameter exponential-type potential energy model for diatomic molecules. We demonstrate that the five-...The dissociation energy and equilibrium bond length as explicit parameters are used to establish an improved five-parameter exponential-type potential energy model for diatomic molecules. We demonstrate that the five-parameter exponential-type potential is identical to the Tietz potential for diatomic molecules. It is observed that the improved five-parameter exponential-type potential can well model the internuclear interaction potential energy curve for the ground electronic state of the carbon monoxide molecule by the utilization of the experimental values of three molecular constants.展开更多
Based on the monitoring data of water quality of more than 40 centralized drinking water sources in 40 towns （townships or streets） of Kaixian County in the first and second half of each year during the ＂Twelfth Fi...Based on the monitoring data of water quality of more than 40 centralized drinking water sources in 40 towns （townships or streets） of Kaixian County in the first and second half of each year during the ＂Twelfth Five-year Plan＂ period, the changing rules of the water quality were studied to provide scientific references for the improvement of drinking water safety of urban and rural residents and drinking water quality. The re- sults show that the water quality of centralized drinking water sources in Kaixian County improved year by year during the ＂Twelfth Five-year Plan＂ period, and most monitoring sites with water quality exceeding the standard are distributed in reservoirs. Total phosphorus, total nitrogen, chemical oxygen demand, and permanganate index exceeded the standard obviously. Main pollution sources are domestic pollution and non-point source pol- lution caused by excessive discharge of nitrogen, phosphorus and organic pollutants. To improve drinking water quality, it is suggested that some towns can get drinking water from other reservoirs, surface water or underground water with better quality instead of previous reservoirs with water quality exceeding the standard, and the control of non-point source pollution should be enhanced.展开更多
Both the seat and cab system of truck play a vital role in ride comfort.The damping matching methods of the two systems are studied separately at present.However,the driver,seat,and cab system are one inseparable whol...Both the seat and cab system of truck play a vital role in ride comfort.The damping matching methods of the two systems are studied separately at present.However,the driver,seat,and cab system are one inseparable whole.In order to further improve ride comfort,the seat suspension is regarded as the fifth suspension of the cab,a new idea of ＂Five-suspensions＂ is proposed.Based on this idea,a 4 degree-of-freedom driver-seat-cab coupled system model is presented.Using the tested cab suspensions excitations as inputs and seat acceleration response as compared output,the simulation model is built.Taking optimal ride comfort as target,a new method of damping collaborative optimization for Five-suspensions is proposed.With a practical example of seat and cab system,the damping parameters are optimized and validated by simulation and bench test.The results show the seat vertical frequency-weighted RMS acceleration values tested for the un-optimized and optimized Five-suspensions are 0.50 m/s～2 and 0.39 m/s～2,respectively,with a decrease by 22.0%,which proves the model and method proposed are correct and reliable.The idea of ＂Five-suspensions＂ and the method proposed provide a reference for achieving global optimal damping matching of seat suspension and cab suspensions.展开更多
文摘A theory of （4＋1）-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields （pentad）, defined globally on a manifold M, and gravity is attributed to the torsion. The Lagrangian density is quadratic in the torsion tensor. We then give the exact five-dimensional solution. The solution is a generalization of the familiar Schwarzschild and Kerr solutions of the four-dimensional teleparallel equivalent of general relativity. We also use the definition of the gravitational energy to calculate the energy and the spatial momentum.
文摘Junior English for China’ is based on the ’Five-Step’ teachingmethod: Revision, Presentation, Drilling, Practice, Consolidation. Each step has itsown particular methodology and requires the teacher to adopt a certain role. Thispaper is a discussion of the "Five-Step Method".
基金supported by the National Natural Science Foundation of Chin-China Aerospace Science and Technology Corporation on Advance Manufacturing(No.U1537209)National Natural Science Foundation of China(No.51775278)Jiangsu Province Outstanding Youth Fund of China(No.BK20140036).
文摘In order to ensure machining stability,curvature continuity and smooth cutting force are very important so as to meet the constraints of both cutting force and kinematics of machine tools.For five-axis flank milling,it is difficult to meet both of the constraints because tool path points and tool axis vectors interact with each other.In this paper,multiple relationships between tool path points and tool axis vectors with cutting force and kinematics of machine tools are established,and the strategies of corner-looping milling and clothoidal spirals are combined so as to find feasible solutions under both of the constraints.Tool path parameters are iterated by considering the maximum cutting force and the feasible range of the tool axis vector,and eventually a curvature continuity five-axis flank milling tool path with smooth cutting force is generated.Machining experimental results show that the conditions of cutting force are satisfied,vibration during the process of machining is reduced,and the machining quality of the surface is improved.
文摘AIM: To determine changes in the antibiotic resistance of Helicobacter pylori(H. pylori) in southern Taiwan after failure of first-line standard triple therapy.METHODS: We analyzed 137 H. pylori-infected isolates from patients who experienced eradication failure after standard first-line triple therapy from January2010 to December 2014. The H. pylori strains were tested for susceptibility to amoxicillin, clarithromycin,levofloxacin, metronidazole and tetracycline using the E-test method. The minimal inhibitory concentration(MIC) was determined by the agar dilution test.MIC values of ≥ 0.5, ≥ 1, ≥ 1, ≥ 4 and ≥ 8 mg/L were considered to be the resistance breakpoints for amoxicillin, clarithromycin, levofloxacin, tetracycline and metronidazole, respectively.RESULTS: A high resistance rate was found for clarithromycin(65%-75%) and metronidazole(30%-40%)among patients who failed first-line standard therapy.The resistance levels to amoxicillin and tetracycline remained very low; however, levofloxacin resistance was as high as 37.5% in 2010 but did not increase any further during the past 5 years. The rates of resistance to these antibiotics did not show a statistically significant upward or downward trend.CONCLUSION: Antibiotic resistance of H. pylori remains a problem for the effective eradication of this pathogen and its associated diseases in Taiwan. High clarithromycin resistance indicated that this antibiotic should not be prescribed as a second-line H. pylori eradication therapy. Moreover, levofloxacin-based second-line therapy should be used cautiously, and the local resistance rates should be carefully monitored.
基金Supported by National Natural Science Foundation of China(Grant No.51305244)Shandong Provincal Natural Science Foundation of China(Grant No.ZR2013EEL015)
文摘Aiming at the problem of low machining accu- racy and uncontrollable thermal errors of NC machine tools, spindle thermal error measurement, modeling and compensation of a two turntable five-axis machine tool are researched. Measurement experiment of heat sources and thermal errors are carried out, and GRA（grey relational analysis） method is introduced into the selection of tem- perature variables used for thermal error modeling. In order to analyze the influence of different heat sources on spindle thermal errors, an ANN （artificial neural network） model is presented, and ABC（artificial bee colony） algorithm is introduced to train the link weights of ANN, a new ABC- NN（Artificial bee colony-based neural network） modeling method is proposed and used in the prediction of spindle thermal errors. In order to test the prediction performance of ABC-NN model, an experiment system is developed, the prediction results of LSR （least squares regression）, ANN and ABC-NN are compared with the measurement results of spindle thermal errors. Experiment results show that the prediction accuracy of ABC-NN model is higher than LSR and ANN, and the residual error is smaller than 3 pm, the new modeling method is feasible. The proposed research provides instruction to compensate thermal errors and improve machining accuracy of NC machine tools.
文摘The flow field in a cold model of 2500 t/d five-stage cyclone preheater and precalciner system was numerically simulated. Renault stress model (RSM) turbulent model was adopted to simulate the flow field, and a hybrid mesh scheme was selected to generate calculation mesh. With the first order upwind difference, finite-volume method was used to convert turbulent equations into difference equations pressure-velocity coupling which were solved by the classic simple algorithm, and during the course of numerical solution, mesh self-adapting technology was applied. The main flow field structures of the whole system and each part of the cold model were studied by analyzing the simulation results.
文摘The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation in June 2003. The side slopes of the ship lock are characterized by great height（170 m）, steepness （70 m in height of upright slope）, and great length （over 7000 m in total length）. Inassociation with the ship lock, the surrounding rocks in slope have a high potential to deform, withwhich the magnitude of deformation is restricted. Monitoring results show that the deformation of thefive-step ship lock high slopes of the TGP primarily occurred in excavation period, and deformationtended to be stable and convergent during operation period, suggesting the allowable ranges of deformation.At present, the slopes and lock chambers are stable, and the ship lock works well under normaloperation condition, enabling the social and economic benefits of the TGP. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
基金supported by the National Basic Research Program of China (No. 2011CB302400)the Important National Science & Technology Specific Projects (No. 2013ZX04007031).
文摘To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP （rotation tool center point control） and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter＇s position and orientation can be directly carried out in the CNC system.
基金Supported by National Nature Science Foundation of China(Grant No.51175461)Science Fund for Creative Research Groups of National Natural Science Foundation of China(Grant No.51221004)Program for Zhejiang Leading Team of S&T Innovation of China(Grant No.2009R50008)
文摘Compared with the traditional non-cutting measurement,machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the users.However,measurement and calculation of the machining tests in the literature are quite difficult and time-consuming.A new method of the machining tests for the trunnion axis of five-axis machine tool is proposed.Firstly,a simple mathematical model of the cradle-type five-axis machine tool was established by optimizing the coordinate system settings based on robot kinematics.Then,the machining tests based on error-sensitive directions were proposed to identify the kinematic errors of the trunnion axis of cradle-type five-axis machine tool.By adopting the error-sensitive vectors in the matrix calculation,the functional relationship equations between the machining errors of the test piece in the error-sensitive directions and the kinematic errors of C-axis and A-axis of five-axis machine tool rotary table was established based on the model of the kinematic errors.According to our previous work,the kinematic errors of C-axis can be treated as the known quantities,and the kinematic errors of A-axis can be obtained from the equations.This method was tested in Mikron UCP600 vertical machining center.The machining errors in the error-sensitive directions can be obtained by CMM inspection from the finished test piece to identify the kinematic errors of five-axis machine tool trunnion axis.Experimental results demonstrated that the proposed method can reduce the complexity,cost,and the time consumed substantially,and has a wider applicability.This paper proposes a new method of the machining tests for the trunnion axis of five-axis machine tool.
文摘This paper presents the modeling of electrical I-V verification of photovoltaic modules using five-parameter models based on the minimum usage of input data, which are usually provided by manufacturer’s datasheet. However, we vary them with a step of 10-4, the ideality factor between 0.0 and 4 for each iteration in order to choose the value, which gives a minimal relative error of the maximum power point. Moreover, when is known, the other four parameters (i.e., Rs, I0, Iph and Rsh) are known. Finally, the effectiveness of this approach is then validated through comparison of the experimental results data under outdoor weather conditions.
文摘In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.
基金funded by the National Natural Science Foundation (41174009)National Major Science &Technology Projects (2011ZX05020, 2011ZX05035,2011ZX05003, 2011ZX05007)
文摘In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inversion is carried out based on the array resistivity log. The mud invasion process is numerically simulated based on the oil-water flow equation and water convection diffusion equation. The results show that the radial resistivity of a fresh mud-invaded oil-bearing layer presents complex distribution characteristics, such as nonlinear increase, increasing to decreasing and low resistivity annulus, and the resistive invasion profile of a water layer is monotonic. Under specific conditions, array resistivity log can reflect these changes and the array induction log is more sensitive. Nevertheless, due to the effect of factors like large invasion depth, reservoir physical and oil-bearing properties, the measured apparent resistivity may differ greatly from the actual mud filtrate invasion profile in an oil-bearing layer. We proposed a five-parameter formation model to simulate the complex resistivity distribution of fresh mud-invaded formation. Then, based on the principle of non-linear least squares, the measured array resistivity log is used for inversion with the Marquardt method. It is demonstrated that the inverted resistivity is typically non-monotonic in oil-bearing layers and is monotonic in water layers. Processing of some field data shows that this is helpful in achieving efficient reservoir fluid recognition.
文摘Four new five-coordinated anionic tin(Ⅳ) complexes with a form of [R_ n NH_ 4- n ][PhSn( μ 2-SCH_2COO)_2] were synthesized via the reaction of mercaptoacetic acid with phenyltin trichloride in the presence of different organic bases and characterized by means of IR, 1H NMR and MS spectroscopies. The crystal structure of [( i -Pr)_2NH_2] [PhSn( μ 2-SCH_2COO)_2] was determined by X-ray diffraction. In the crystal structure,the tin atom is five-coordinated and exists in trigonal bipyramid geometry with cell parameters a =1.1766(11) nm, b =1.3144(14) nm, c =1.3336(15) nm,β =90° and Z =4.
文摘Objective:To observe the therapeutic effect differences among five-knee-point acupuncture combined with Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction(身痛逐瘀汤 generalized pain stasis-expelling decoction),simple five-knee-point acupuncture and simple Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction in treating knee osteoarthritis(KOA).Methods:A total of 126 KOA patients were randomized into a five-knee-point acupuncture combined with Chinese medication package warm compress therapy group(combined treatment group),where there were 42 cases,including 28 cases of unilateral KOA and 14 cases of bilateral KOA,totally 56 affected knees involved,a Chinese medication package warm compress therapy group(medication package group,42 cases,including 22 cases of unilateral KOA,20 cases of bilateral KOA,totally 62 affected knees involved)and a five-knee-point acupuncture group(five-knee-point group,42 cases,including 27 cases of unilateral KOA,15 cases of bilateral KOA,totally 57 affected knees involved).The basic health education was provided in all of the groups.Additionally,in the combined treatment group,acupuncture was applied to the five knee points on the affected side for 30 min.The warm compress with herbal package of Shēntòng Zhúyū Decoction was given for 10 to 15 min.In the medication package group,the warm compress with Shēntòng Zhúyū Decoction was exerted on the affected area for 10 to 15 min.In the fiveknee-point group,acupuncture was applied to SP 10,ST 34,EX-LE 2,EX-LE 4 and ST 35 and the needles were retained for 30 min.The treatment in each group was given once a day,consecutively for 2 weeks.Before and after treatment,the visual analogue scale(VAS)and Lysholm knee scale were adopted to evaluate the pain degree and knee joint motor function in KOA patients.The clinical therapeutic effects were evaluated too.Results:A total of 121 cases accomplished the final observation and 5 cases were dropped out in the three groups,in which,2 cases(2 affected knees)were dropped out in the combined treatment group,1 case(2 affected knees)in the medication package group and 2 cases(3 affected knees)in the fiveknee-point group.VAS scores after treatment were all lower than those before treatment in the three groups and the scores of Lysholm knee scale were all higher than those before treatment,indicating the significant differences(all P<0.05).The total effective rate was 98.1%(53/54)in the combined treatment group,which was higher than 86.7%(52/60)in the medication package group and 92.6%(50/54)in the five-knee-point group,indicating the significant differences(all P<0.05).After treatment,VAS score(2.24±1.24)in the combined medication group was lower than(2.48±1.08)in the medication package group and(2.63 ± 1.44)in the five-knee-point group,presenting the significant difference(all P<0.05).The score of Lysholm knee scale was(60.50±13.76)in the combined medication group,higher than(52.23±11.65)in the medication package group and(52.14±11.77)in the five-knee-point group,indicting the significant differences(all P<0.05).Conclusion:Compared with the simple application of Chinese medication package warm compress therapy of Shēntòng Zhúyū Decoction or the five-knee-point acupuncture therapy,five-knee-point acupuncture combined with Shēntòng Zhúyū Decoction relieves the clinical symptoms of KOA patients more effectively and achieves a better clinical therapeutic effect.
基金Supported by National Natural Science Foundation of China(Grant No U1304510)Development Foundation for Outstanding Young Teachers of Zhengzhou University,China(Grant No.1421321076)
文摘Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while little mechanism is designed to implement the function. A symmetrical five-bar linkage consisting of two revolute joints and three prismatic joints is presented. Inverse kinematics and forward kinematics are obtained first. Then inverse singularities and direct singularities of the mechanism are gained. The global stiffness index is defined based on the results of kinematics analysis. Finally, optimal dimensional synthesis of the mechanism in terms of maximum stiffness is conducted by genetic algorithms. The calculation results show that with the length of both the two linkage a=830 mm, the interacting angle of the two guides 2δ=4.48 radian, and the maximum range of displacement of the two carriers dmax=940 mm, the mechanism achieves highest rigidity and its workspace is singularity-free, which covers the human left and right arm range of motion. The proposed novel mechanism featuring high rigidity and a singularity-free workspace can provide rehabilitation training, also solve the problem of quantitative measure of arm stiffness.
文摘In this paper, the executive of the 10th Five- Year Plan in the field of environmental protection and ecological constrution is reviewed, and the charactristics of economic growth and its environmental impact on the 11^th Five-Year Plan is forecasted and analyzed. A principal idea of eavironmental protection and ecological construction is put forward for the 11^th Five-Year Plan pertod： strensgthen the point treatment in key areas and set the main targets based on the idea. The relating countermeasures in national level are proposed as follows： set up appropriate ideas for official achievements by launching resources and environmental cost acconting; adjust the industrial struacture actively by industrial policies and strenuous work; develop circular economy, change the mode of environmental protecgon from end treatment to headstream and proeess control： strengthen the market mechanism in the process of pollution treatment, set up the system of ＂who treats who benefits＂ ; perfect interrelated laws and standards, strengthen the ability of environmental munagement; lay extra emphasis on two key targets： water pollution tretment in key river basins and management of the reserves; and combine the ecological consnuction and poverty alleviation in higher level.
基金Supported by the National Natural Science Foundation of China under Grant No.10675097the Sichuan Province Foundation of China for Fundamental Research Projects under Grant No.2018JY0468
文摘The dissociation energy and equilibrium bond length as explicit parameters are used to establish an improved five-parameter exponential-type potential energy model for diatomic molecules. We demonstrate that the five-parameter exponential-type potential is identical to the Tietz potential for diatomic molecules. It is observed that the improved five-parameter exponential-type potential can well model the internuclear interaction potential energy curve for the ground electronic state of the carbon monoxide molecule by the utilization of the experimental values of three molecular constants.
文摘Based on the monitoring data of water quality of more than 40 centralized drinking water sources in 40 towns （townships or streets） of Kaixian County in the first and second half of each year during the ＂Twelfth Five-year Plan＂ period, the changing rules of the water quality were studied to provide scientific references for the improvement of drinking water safety of urban and rural residents and drinking water quality. The re- sults show that the water quality of centralized drinking water sources in Kaixian County improved year by year during the ＂Twelfth Five-year Plan＂ period, and most monitoring sites with water quality exceeding the standard are distributed in reservoirs. Total phosphorus, total nitrogen, chemical oxygen demand, and permanganate index exceeded the standard obviously. Main pollution sources are domestic pollution and non-point source pol- lution caused by excessive discharge of nitrogen, phosphorus and organic pollutants. To improve drinking water quality, it is suggested that some towns can get drinking water from other reservoirs, surface water or underground water with better quality instead of previous reservoirs with water quality exceeding the standard, and the control of non-point source pollution should be enhanced.
基金Supported by National Natural Science Foundation of China(Grant No.51575325)Shandong Provincial Natural Science Foundation of China(Grant No.ZR2013EEM007)
文摘Both the seat and cab system of truck play a vital role in ride comfort.The damping matching methods of the two systems are studied separately at present.However,the driver,seat,and cab system are one inseparable whole.In order to further improve ride comfort,the seat suspension is regarded as the fifth suspension of the cab,a new idea of ＂Five-suspensions＂ is proposed.Based on this idea,a 4 degree-of-freedom driver-seat-cab coupled system model is presented.Using the tested cab suspensions excitations as inputs and seat acceleration response as compared output,the simulation model is built.Taking optimal ride comfort as target,a new method of damping collaborative optimization for Five-suspensions is proposed.With a practical example of seat and cab system,the damping parameters are optimized and validated by simulation and bench test.The results show the seat vertical frequency-weighted RMS acceleration values tested for the un-optimized and optimized Five-suspensions are 0.50 m/s～2 and 0.39 m/s～2,respectively,with a decrease by 22.0%,which proves the model and method proposed are correct and reliable.The idea of ＂Five-suspensions＂ and the method proposed provide a reference for achieving global optimal damping matching of seat suspension and cab suspensions.
