Tailoring the texture and mechanical properties of 3%Y_(2)O_(3)p/ZGK200 composites fabricated by unidirectional and cross rolling followed by annealing

3%Y_(2)O_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 h.The microstructure,texture and mechanical properties of rolled and annealed composites were systematically studied.The rolled composites exhibited a heterogeneous microstructure,consisting of deformed grains elongated along rolling direction(RD)and Y_(2)O_(3)particles bands distributed along RD.After annealing,static recrystallization(SRX)occurred and most deformed grains transformed into equiaxed grains.A non-basal texture with two strong T-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR,indicating that rolling path had great influences on texture of the composites.After annealing process,R-texture component disappeared or weakened,as results,a non-basal texture with double peaks tilting from normal direction(ND)to transverse direction(TD)and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites,respectively.The yield strength of rolled composites after UR showed obvious anisotropy along RD and TD while a low anisotropic yield strength was obtained after CR.Some Y_(2)O_(3)particles broke during rolling.The fracture of the composites was attributed to the existence of Y_(2)O_(3)clusters and interfacial debonding between particles and matrix during tension,as a result,the ductility was not as superior as matrix alloy.

A Simplified Method for the Stress Analysis of Underground Transfer Structures Crossing Multiple Subway Tunnels

According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer structure spanning multiple subway tunnels was proposed.Deliberating on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam model.The resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer structure.The research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent tunnels.The established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate action.The pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.

Analysis on the crossing obstacle of wheel-track hybrid mobile robot

A novel wheel-track hybrid mobile robot with many movement patterns is designed.According to different environments,it can switch between the pure wheel pattern and the pure track one.According to a homogeneous coordinate transformation matrix,gravity stability and its obstacle performance are analyzed.Its gravity equation and climbing obstacle conditions are established.Experimental results show that this hybrid mobile robot could fully possess the advantages of both the wheel and the track mechanisms and achieve a good obstacle climbing capability.

The Obstacles,Paths and Mechanisms of the Sustainable Development of Farmers' Cooperatives in Hebei Province

Based on the description of the major role played by famers' cooperatives in developing rural economy and in increasing the income of farmers,the obstacles of the sustainable development of famers' cooperatives in Hebei Province are introduced.Firstly,the cooperative mechanism is imperfect;secondly,the development is substandard;thirdly,the coverage of preferential policy is limited;fourthly,the capitals and financing problem are difficult;fifthly,the operation is single;sixthly,the construction of marketing channels is the weak;seventhly,the professional talents are scarce.The sustainable development paths of famers' cooperatives in Heibei Province are analyzed.Firstly,conducting value-added processing and taking the way of materialized development,industrialized operation and enterprise-style management;secondly,implementing agricultural quality and brand strategy and moving into the high level market;thirdly,constructing modern agricultural marketing and taking the road of supermarket agriculture;fourthly,enforcing the management of information and getting efficiency from information;fifthly,developing recycling agriculture and taking the way of improving resource efficiency.There are five ways for establishing the operational mechanism of sustainable development of farmers' cooperatives in Heibei Province.The government should innovate the cooperation mechanism;innovating training and education mechanism;innovating production mechanism;innovating financial mechanism;innovating marketing mechanism.

The obstacle crossing ability analysis and improvement of the cable inspection robot

In this paper, the climbing obstacle capability of the previous special cable inspection robot （ Model Number： XS1T-1） is analyzed. Static equations are established to analyze the relationships between the external forces and the maximum height of an obstacle. Parameters affecting the obstacle crossing ability are obtained. According to the analysis results, an innovated small volume, simple structure and light weight climbing mechanism is proposed （Model Number： XS1T-2）. A simplified kinematics model of the mechanism is established. With two powered wheels, the obstacle crossing ability of the XSIT-2 is improved apparently. For the robot moving without deflection, the relationships of two powered input torques are deduced. The comparison of the simulation results clearly shows that the climbing ability of XS1T-2 is obviously improved, and it can meet the demands of inspection.

Research on Incentive Mechanism and Analysis of the Obstacles in the Application of Low-carbon Logistics Technology

Low-carbon logistics technology is a modem technology with green environmental protection concept as the core, which can effectively reduce the carbon emissions of all links in logistics activities, and thus achieve the goal of maximizing the use of resources and reducing environmental pollution. With the deepening of the concept of environmental protection, the application of low-carbon logistics technology is not only an inevitable choice for adapting to social development and responding to environmental protection slogans, but also an inevitable choice for the logistics industry to achieve sustainable development goals. Based on the brief introduction of low-carbon logistics technology, this paper analyzes the main obstacles of the application of the technology, and proposes corresponding incentive mechanism according to the obstacle factors, aiming at alleviating the resistance in the practical application of low-carbon logistics technology and promoting the realization of low-carbon logistics development.

The Obstacles in Cross-cultural Communication

In Cross-cultural communication,the ability of the languages and the ability of the cultures are the crucial factors in the communicating activities.People with the same cultural background communicate with each other easily and smoothly,and understand each other better,and there are fewer or no obstacles in their communication at all.The different cultural backgrounds and traditions,the different social customs and everyday living habits,and the different values all will affect the communication quality and will surely result in obstacles in cross-cultural communication. The obstacles which frequently occur in the cross-cultural communication are:ethnocentrism,stereotyping, prejudice,and the different cultural backgrounds.In order to do away with the obstacles and to make the communication smoothly and successfully,the communicating parties both should observe the cooperative principles and politeness principles.And what's more,they must discard their own prejudices,and respect others,together to fulfill the cross-cultural communicating activities.

Mechanism of necking defect of 6082 aluminium alloy rolled by cross-wedge rolling method based on material thermal properties

Necking defects have long troubled the application of cross-wedge rolling technology in aluminium alloy shaft parts.To accurately predict necking defects,new judgement conditions are established based on the thermal performance of 6082 aluminium alloy.The limit-sectional shrinkage without necking defects is achieved by combining theoretical calculation and finite-element model analysis,which couples heat transfer and deformation.In this paper,a 6082 aluminium alloy extruded rod with a 40 mm diameter rolled at a preheated temperature of 500℃and a rolling angular velocity of 1 rad/s is taken as an example.The simulation and experimental results show that necking defects do not occur on the rolled pieces if the sectional shrinkage is below the limit-sectional shrinkage but will occur when the sectional shrinkage is above it.The results prove that the prediction model of necking defects in cross-wedge rolling of 6082 aluminum alloy is feasible,and this research provides a theoretical basis for the qualified aluminum alloy shafts produced by the cross-wedge rolling.

Circular Obstacle Avoidance Control of the Compass-Type Biped Robot Based on a Blending Method of Discrete Mechanics and Nonlinear Optimization

This paper considers an obstacle avoidance control problem for the compass-type biped robot, especially circular obstacles are dealt with. First, a sufficient condition such that the swing leg does not collide the circular obstacle is derived. Next, an optimal control problem for the discrete compass-type robot is formulated and a solving method of the problem by the sequential quadratic programming is presented in order to calculate a discrete control input. Then, a transformation method that converts a discrete control input into a continuous zero-order hold input via discrete Lagrange-d’ Alembert principle is explained. From the results of numerical simulations, it turns out that obstacle avoidance control for the continuous compass-type robot can be achieved by the proposed method.

Dehydration Mechanism of Secondary Cross-linked Gels

In this paper, microscopic characteristics of preformed gels （PGs） and secondary cross-linked gels （SCG） with the same concentration were analyzed by atomic force microscopy （AFM）. Experimental results indicate that the microstructure of secondary cross-linked gels is a thick 3-D network, in which micro-holes and irregular macro-holes are embedded. The maximum width of the irregular macro-holes is 200 nm. In the SCG two different chemical bonds were formed, which leads to the structural inhomogeneity and the asymmetry of the crosslinking density. The structural inhomogeneity of SCG results in the formation of irregular macro-holes. The excessive cross-linking density is the primary reason for dehydration of SCG and the presence of irregular macro-holes in SCG can facilitate dehydration.

Energy evolution mechanism and failure criteria of jointed surrounding rock under uniaxial compression

The object of this article is to investigate the energy evolution mechanism and failure criteria of cross-jointed samples containing an opening during deformation and failure based on the uniaxial compression test and rock energy principle.The results show that the energy evolution characteristics of the samples correspond to a typical progressive damage mode.The peak total energy,peak elastic energy,and total input energy of the samples all first decrease and then increase with an increase of half of the included angle,reaching their minimum values when this angle is 45°,while the dissipated energy generally increases with this angle.The existence of the opening and cross joints can obviously weaken the energy storage capacity of the rock,and the change in the included angle of the cross joint has a great influence on the elastic energy ratio of the sample before the peak stress,which leads to some differences in the distribution laws of the input energy.The continuous change and the subsequent sharp change in the rate of change in the energy consumption ratio can be used as the criteria of the crack initiation and propagation and the unstable failure of the sample,respectively.

Method for Six-Legged Robot Stepping on Obstacles by Indirect Force Estimation

Adaptive gaits for legged robots often requires force sensors installed on foot-tips,however impact,temperature or humidity can affect or even damage those sensors.Efforts have been made to realize indirect force estimation on the legged robots using leg structures based on planar mechanisms.Robot Octopus III is a six-legged robot using spatial parallel mechanism（UP-2UPS） legs.This paper proposed a novel method to realize indirect force estimation on walking robot based on a spatial parallel mechanism.The direct kinematics model and the inverse kinematics model are established.The force Jacobian matrix is derived based on the kinematics model.Thus,the indirect force estimation model is established.Then,the relation between the output torques of the three motors installed on one leg to the external force exerted on the foot tip is described.Furthermore,an adaptive tripod static gait is designed.The robot alters its leg trajectory to step on obstacles by using the proposed adaptive gait.Both the indirect force estimation model and the adaptive gait are implemented and optimized in a real time control system.An experiment is carried out to validate the indirect force estimation model.The adaptive gait is tested in another experiment.Experiment results show that the robot can successfully step on a 0.2 m-high obstacle.This paper proposes a novel method to overcome obstacles for the six-legged robot using spatial parallel mechanism legs and to avoid installing the electric force sensors in harsh environment of the robot＇s foot tips.

Study on deuteron formation mechanism in nucleon-induced reactions

The mechanism of deuteron formation in neutron-induced reactions is studied within the framework of the isospin-dependent quantum molecular dynamics model,using the GEMINI code.The influence of the n+p→d reaction channel is investigated by analyzing the deuteron production cross sections in the neutron-induced reactions12C(n,d),16O(n,d),and 28Si(n,d),with incident energies of 20-100 MeV.By including the n+p→d reaction channel when modeling the collision,the deuteron production cross sections increase,optimizing the cross-section results and bringing them closer to the experimental data values.This indicates that the n+p→d reaction channel is an important mechanism for enhancing deuteron production.

Study on Filling Cross-Roadway in Fully-Mechanized Coal Faces with High Water-Content Material

A new method using high water content material to mechanically fill cross roadways to form artificial bottom for coal faces was introduced. The reasonable determination of filling range, the optimization of the compounding ratio of high water content material, and the filling technique were discussed in detail. This new method has been spread after industrial testing in Baodian Colliery. Compared with the traditional method, the manual wooden chock method, the new one decreases about 40% of the filling range and cost in dealing every one set of cross roadway in the testing condition.

A Facile Route for the Large Scale Fabrication of Graphene Oxide Papers and Their Mechanical Enhancement by Cross-linking with Glutaraldehyde

A facile route for the large scale production of graphene oxide(GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates.Significant enhancement in mechanical stiffness(341%) and fracture strength(234%) of GO paper have been achieved upon modification with a small amount(less than 10 wt%) of glutaraldehyde(GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.

Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

The preparing method,rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied.The results show that when the low chromium semi-steel bar is forged from55mm to50mm,cross-rolled into grinding ball at 1 000-1 050℃,air cooled and tempered at 550℃for 2h,the best mechanical properties,especially the abrasive resistance under the action of hard abrasive,can be obtained.

Microstructure and Mechanical Properties of Molybdenum Sheet after Cross Rolling Processing

A substantial body of work exists here that describe the relationship between the microstructure, ingot processing and fabrication and mechanical properties of molybdenum sheet after cross rolling process. The objective of this study is to clarify how much the crossing rolling process procedure affects the microstructure, texture and mechanical property of this type of materials. This experiment begins from the power metallurgy to the final molybdenum strip (0.15mmxlOOmmx2000mm) through the cross rolling processing procedure. As a result, good mechanical property, improved elongation, enhanced ductility for further process, such as deep drawing and punching, and the reduced difference of the strength and plasticity between the parallel to rolling direction and perpendicular to rolling direction are achieved by the cross rolling processing procedure. According to discussing all the details about this experiment, it is confirmed that cross rolling molybdenum sheet can provide a concise and comprehensive explanation of processes and can guarantee the optical mechanical property and suitable for large production.

RESISTANT MECHANISMS OF CISPLATIN IN HUMAN LUNG ADENOCARCINOMA CELL LINE A_(549)DDP

To study the resistant mechanisms of cisplatin in human lung adenocarcinoma cell line A 549 DDP. A 549 DDP cells was established by stepwise increasing concentration of cisplatin (CDDP) in medium. Interstrand cross linked DNA (ICL) was measured by ethidium bromide fluorescence assay. The intracellular and intranuclear accumulation of cisplatin was measured by atomic absorption spectrometry. The removal of GS X was determined by FCM and fluorescence microscopy. Results: The A 549 DDP cell line was 8.9 fold resistance relative to the parental A 549 cell line. The formation of ICL in A 549 was 6.28 times higher than that in A 549 DDP cells. The intracellular and intranuclear accumulation of cisplatin in A 549 cells was 5.9 times and 4.1 times higher than that in A 549 DDP cells, respectively. The ability of GS X pump pumped GS X complex (GS Pt) in A 549 DDP cells was higher than that in A 549 . The repair rate in A 549 DDP cells was 2 times higher than that in A 549 . Conclusions: Decreased accumulation and increased export of cisplatin might be the main mechanism of cisplatin resistant A 549 DDP cells while the enhanced repair capacity of DNA may play a role in CDDP resistance.

Theoretical Studies on the Mechanism of Photocycloaddition Reaction Between 6 Azauracil and Acetone

The mechanism of photocycloaddition reaction between 6-azauracll and acetone was studied by using semiemptrical SCFMO AMI method. It was found that this reaction is not a concerted one. The calculated results are as follows:(1) A T1 state exciplex is on the T1 state energy surface; (2) T exciplex as a reactant will proceed along the energy surface of T1 state to form a diradical intermediate. The energy barrier of this reaction step is 63. 6 kJ/mol; (3) The T1 state diradical intermediate happens to be close in energy to the ground state intermediate with a similar geometry. Such a situation turns out to be very favorable for an intersystem crossing (jump from the T, state to the ground state) ; (4) The final product will be formed from the ground S0 state intermediate via an energy barrier 88. 2 kJ/mol.

Theoretical Study of the Photochemical Reaction Mechanism of Bicyclo[4.1.0]heptane

The photochemical reaction of bicyclo[4.1.0]heptane was studied at the complete active space SCF（CASSCF） level with a 6-31G^＊ basis set. A muhireference MP2 algorithm that has been implemented in the Gaussian program was used to correct the energetics for the dynamic correlation. Starting from the Franck-Condon excitation of bicyclo [ 4.1.0 ] heptane, the reaction is via two bonds＇ breakage to give rise to 1,6-heptdiene. One internal conversion （IC） and two intersystem crossing points（ISC） were located and are discussed separately. The reaction proceeds to its own characteristic product on the ground state.