M-type channels selectively control bursting in rat dopaminergic neurons

Midbrain dopaminergic neurons in the substantia nigra, pars compacta and ventral tegmental area are critically important in many physiological functions. These neurons exhibit firing patterns that include tonic slow pacemaking, irregular firing and bursting, and the amount of dopamine that is present in the synaptic cleft is much increased during bursting. The mechanisms responsible for the switch between these spiking patterns remain unclear. Using both in-vivo recordings combined with microiontophoretic or intraperitoneal drug applications and in-vitro experiments, we have found that M-type channels, which are present in midbrain dopaminergic cells, modulate the firing during bursting without affecting the background low-frequency pacemaker firing. Thus, a selective blocker of these channels, 10,10-bis(4-pyridinylmethyl)-9(10H)- anthracenone dihydrochloride, specifically potentiated burst firing. Computer modeling of the dopamine neuron confirmed the possibility of a differential influence of M-type channels on excitability during various firing patterns. Therefore, these channels may provide a novel target for the treatment of dopamine-related diseases, including Parkinson's disease and drug addiction. Moreover, our results demonstrate that the influence of M-type channels on the excitability of these slow pacemaker neurons is conditional upon their firing pattern. © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Centrifuge testing of monopiles subject to cyclic lateral loading

Monopiles supporting offshore wind turbines are subjected to cyclic lateral loading. The properties of the applied cyclic lateral load are known to have an effect on the accumulation of permanent displacement and rotation at the pile head. The results of centrifuge testing on model piles show that certain loading regimes lead to the development of locked in soil stresses around the pile. These locked in soil stresses change the stiffness of the monopile response to cyclic lateral loading and the natural frequency of the pile-soil system. © 2014 Taylor & Francis Group.

On the application of LES to seal geometries

Five Large Eddy Simulation (LES) and hybrid RANS-NLES (Reynolds-Averaged Navier-Stokes-Numerical-LES) methods are used to simulate flow through a labyrinth seal geometry and are contrasted with RANS solutions. Results show that LES and RANS-NLES is capable of accurately predicting flow behaviour of two seal flows with a scatter of less than 5 %. RANS solutions show the potential to perform poorly for the turbulence models tested. LES and hybrid RANS-NLES are found to be consistent and in agreement with measurements, providing a flexible numerical platform for design investigations. It also allows greater flow physics insights. © Springer Science+Business Media Dordrecht 2013.

Linear multimodal actuation through discrete coupling

Due to technological limitations, robot actuators are often designed for specific tasks with narrow performance goals, whereas a wide range of behaviors is necessary for autonomous robots in uncertain complex environments. In an effort to increase the versatility of actuators, we introduce a new concept of multimodal actuation (MMA) that employs dynamic coupling in the form of clutches and brakes to change its mode of operation. The dynamic coupling allows motors and passive elements such as springs to be engaged and disengaged within a single actuator. We apply the concept to a linear series elastic actuator which uses friction brakes controlled online for the dynamic coupling. With this prototype, we are able to demonstrate several modes of operation including stiff position control, series elastic actuation as well as the possibility to store and release energy in a controlled manner for explosive tasks such as jumping. In this paper, we model the proposed concept of actuation and show a systematic performance analysis of the physical prototype that we developed in our laboratory. © 1996-2012 IEEE.

Toward a human-like biped robot with compliant legs

Conventional models of bipedal walking generally assume rigid body structures, while elastic material properties seem to play an essential role in nature. On the basis of a novel theoretical model of bipedal walking, this paper investigates a model of biped robot which makes use of minimum control and elastic passive joints inspired from the structures of biological systems. The model is evaluated in simulation and a physical robotic platform with respect to the kinematics and the ground reaction force. The experimental results show that the behavior of this simple locomotion model shows a considerable similarity to that of human walking. © 2006 The authors.

近空间升华沉积CdTe薄膜的微结构和PL谱

用近空间华法在CdS薄膜上沉积了CdTe薄膜。研究了在两种保护气氛下所沉积的多晶CdTe薄膜在后处理后的微结构、表面形貌及光致发光(PL)谱，并研究了CdTe表面的CdS/CdTe界面的P谱的区别，根据薄膜的微结构对碲化镉在太阳电池中的应用进行了讨论。

大功率In(Ga)As/GaAs量子点激光器

利用分子束外延技术和S-K生长模式，系统研究了InAs/GaAs材料体系应变自组装量子点的形成和演化。研制出激射波长λ≈960nm,条宽100μnm,腔长800μm的In(Ga)As/GaAs量子点激光器

基于CPLD多路QAC的逻辑电路设计

主要介绍了多道电荷幅度转换器(QAC)的逻辑电路部分。包括积分控制电路和仲裁电路。用可程逻辑器件CPLD来构建这部分电路,和常规的逻辑器件相比其突出特点是:元件少、成本低、功耗低。并且在速度上完全可以替代ECL器件,适合于构建大型的逻辑电路。

HIRFL-CSR主环电子冷却模拟计算

以16O8 + 为例 ,用电子冷却模拟程序计算了冷却时间随离子能量、初始发射度、初始动量分散、离子流强以及离子电荷态的变化规律 ,研究了储存环在冷却段的 β函数和色散函数对冷却时间的影响