三吊臂分吊合放式起重装置设计

针对吊装过程中,有时需要有选择性地将集装箱有序放置这一问题,提出了三吊臂分吊合放式起重装置的整体设计方案。在机械部分方案设计中,应用TRIZ创新理论,化解了方案设计阶段的矛盾冲突,提出了将电机做配重的方案,实现了机械结构方案的优化设计。依据设计方案,应用轻型铝合金材料完成了整体框架的机械结构设计与制作,其中部分零部件采用Solidworks建模,3D打印。控制部分采用凌阳SPCE061A控制板作为起重装置的主控板,L298N模块作为起重装置的驱动模块,通过改变控制电压,实现自锁电机的正反转,完成重物的起吊;运动部分采用迈特纳姆轮,可实现全向移动;三个吊臂高度按叠放三箱牛奶的高度设计,节约材料,方便控制。利用G+unSPIDE软件完成程序编写,实现了对三吊臂单独起升,同时起升,自动复位,全向移动等动作的控制。为应对起吊突发情况,制定了处置预案,优化了行进路径。实践证明,本设计实用性强、稳定性好、完成速度快,并且拥有较好的应用前景。

浅谈图像、伴音合放式UHF 1KW电视载频精密偏置发射机的原理及维护

党的十七届六中全会强调，要大力发展公益性文化事业，完善覆盖城乡，结构合理，功能健全，实用高效的公共文化服务体系。电视作为重要的宣传思想文化阵地，在公共文化服务体系建设中，担负着重要责任。要以丰富多彩的文化艺术形式，充分发挥好引领风尚，教育人民，服务社会，推动发展的作用。而广播电视的无线覆盖正好弥补了在原有有线电视及无线电视加密的基础之上，部分边远地区及贫困人群收听收看广播电视信号难的问题。本文着重介绍了UHF 1KW图像图像、伴音合放式电视载频精密偏置发射机的原理及维护，并以我站设备为例，加以说明。

Change of Arctic sea-ice volume and its relationship with sea-ice extent in CMIP5 simulations

The future change of September Arctic sea-ice volume,simulated by 30 state-of-the-art climate models from the Coupled Model Intercomparison Project Phase 5（CMIP5）,is examined,which depends on both ice extent and ice thickness.In comparison with the September sea-ice extent,the September sea-ice volume has larger spread in the historical simulation but faster convergence in the projection simulation,especially in the context of increasing greenhouse gas emissions.This indicates that the ice volume might be more sensitive to external forcings than the ice extent.Using the averaged projection of those climate models from the 30 CMIP5 models that can better reflect the ‘observed＇ sea-ice volume climatology and variability,it is shown that the September sea ice volume will decrease to ~3000 km3 in the early 2060 s,and then level off under a medium-mitigation scenario.However,it will drop to ~3000 km3 in the early 2040 s and reach a near-zero ice volume in the mid-2070 s under a high-emission scenario.With respect to the historical condition,the reduction of the ice volume,associated with increasing greenhouse gas emissions,is more rapid than that of the ice extent during the twenty-first century.

Function Projective Synchronization of Fractional-Order Hyperchaotic System Based on Open-Plus-Closed-Looping

The purpose of this paper is to analyze the dynamic behavior of fractional-order four-order hyperchaotic Lii system, and use the Open-Plus-Closed-Looping （OPCL） coupling method to construct the system＇s corresponding response system, and then implement function projective synchronization （FPS） of fractional-order drive-response system with system parameters perturbation or not. Finally, the numerical simulations verify the effectiveness and robustness of this scheme.

Low Noise Distributed Amplifiers Using a Novel Composite-Channel GaN HEMTs

Low noise distributed amplifiers （DAs） using the novel low noise composite-channel Al0.3 Ga0.7N/ml0.05 Ga0.95 N/ GaN HEMTs （CC-HEMTs） with 1μm-gate-length are designed and fabricated. Simulated and measured results of the DAs are characterized. The measured results show that the low noise DAs have input and output VSWR （voltage standing wave ratio） of less than 2.0,associated gain of more than 7.0dB and gain ripple of less than ldB in the frequency range from 2 to 10GHz. Noise figure of the DAs is less than 5dB in the frequency range from 2 to 6GHz,and less than 6.5dB in the frequency range from 2 to 10GHz. The measured results agree well with the simulated ones.

Particle inertia effect on sediment dispersion in turbulent open-channel flows

Particle inertia effect plays a significant role in sediment dispersion which has not been fully elucidated.In this paper,the profound effect of particle inertia on the sediment dispersion was analyzed.The theoretical expression for the drift velocity based on the two-phase mixture theory in turbulent open channels is firstly introduced.The influence of particle inertia on sediment dispersion was investigated through three different aspects including vertical dispersion,motion,and flux properties based on the drift velocity.Results show that the dispersion of suspended sediment in turbulent open-channel flows is affected by three major processes including turbulence of water sediment mixtures,particle random motion,and collisions among particles,of which the contributions of particle turbulence and collisions to the sediment dispersion are remarkable for particles of high inertia.With respect to the vertical mean velocity and sediment flux,it shows that the predictive results agree well with the measurements when the term of particle inertia is considered.As a result,particle inertia considerably affects the behavior of suspended sediment.In particular,the influence of inertia must be accounted for in circumstances of flows laden with high-inertia particles.

Biologically inspired model of path integration based on head direction cells and grid cells

Some neurons in the brain of freely moving rodents show special firing pattern. The firing of head direction cells(HDCs) and grid cells(GCs) is related to the moving direction and distance, respectively. Thus, it is considered that these cells play an important role in the rodents' path integration. To provide a bionic approach for the vehicle to achieve path integration, we present a biologically inspired model of path integration based on the firing characteristics of HDCs and GCs. The detailed implementation process of this model is discussed. Besides, the proposed model is realized by simulation, and the path integration performance is analyzed under different conditions. Simulations validate that the proposed model is effective and stable.

Synchronization of two electrically coupled inspiratory pacemaker neurons

Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two inspiratory pacemaker neurons together,and studied various synchronous behaviors between them.We firstly compared the bifurcation diagrams between the coupled neurons and single neuron,and found that the coupled neurons had a more complicated bifurcation mode.By increasing the coupling strength,the regular variation of phase differences was illustrated so that asynchronous and some synchronous states could be observed.These synchronous states were also shown in detail by phase portraits and firing series.In addition,we explored the ranges of different synchronous states,which attributed to different ranges of membrane capacitance and coupling strength.

Synthesis and characterization of a new open-framework zinc phosphite (4,4-(C_5H_4N)_2(CH_2)_3)·[Zn_3(HPO_3)_4]

Employing 4,4＇-trimethylenedipyridine as a template, a new two-dimensional zinc phosphite （4,4＇-（CsH4N）2（CH2）3）＂ [Zna（HPO3）4] has been prepared at room temperature and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, powder X-ray diffraction, and thermogravimetric analysis. The compound crystallizes in the monoclinic space group P21/c, with cell parameters, a = 9.3309（19）/k, b = 14.798（3）A, c = 33.637（7）/k, β= 91.11（3）°, V = 4643.8（16） nm3 and Z = 4. The connectivity of the ZnO4 tetrahedra and HPO3 pseudo pyramids results in infinite corner-sharing 4-membered ring chains as second building units which are further linked by Zn-O-P bonds to form a 2-D layer that with interesting 8-membered ring channels along the [100] direction. The diprotonated 4,4＇-trimethylenedipyridine molecules sit in the middle of the layers along the [100] direction and interact with the framework via hydrogen bonds.

Decay Process of Quantum Open System at Finite Temperatures

Starting from the formal solution to the Heisenberg equation, we revisit an universal model for a quantum open system with a harmonic oscillator linearly coupled to a boson bath. The analysis of the decay process for a Fock state and a coherent state demonstrate that this method is very useful in dealing with the problems in decay process of the open system. For finite temperatures, the calculations of the reduced density matrix and the mean excitation number for the open system show that an initiaJ coherent state will evolve into a temperature-dependant coherent state after tracing over the bath variables. Also in short-time limit, a temperature-dependant effective Hamiltonian for the open system characterizes the decay process of the open system.