Ultra-shallow junction formation by spike annealing in a lamp-based or hot-walled rapid thermal annealing system: effect of ramp-up rate

Ultra-shallow p-type junction formation has been investigated using 1050°C spike anneals in lamp-based and hot-walled rapid thermal processing (RTP) systems. A spike anneal may be characterized by a fast ramp-up to temperature with only a fraction of a second soak-time at temperature. The effects of the ramp-up rate during a spike anneal on junction depth and sheet resistance were measured for rates of 40, 70 and 155°C/s in a lamp-based RTP, and for 50 and 85°C/s in a hot-walled RTP. B⁺ implants of 0.5, 2 and 5 keV at doses of 2×10¹⁴ and 2×10¹⁵ cm⁻² were annealed. A significant reduction in junction depth was observed at the highest ramp-up rate for the shallower 0.5-keV B implants, while only a marginal improvement was observed for 2- and 5-keV implants. It is concluded that high ramp-up rates can achieve the desired ultra-shallow junctions with low sheet resistance but only when used in combination with spike anneals and the lowest energy implants.     

Protein‐Based Hydrogels that Actuate Self‐Folding Systems

An approach to build a chemomechatronic system inspired by self‐folding robots is described. This system, which comprises a protein‐based hydrogel bound to a low‐profile laminate, responds to different aqueous environments by undergoing geometric transformations. This response is dependent on the thickness and stiffness of the templating hydrogel, which directly regulates the diffusion of water into and out of the platform to initiate its reversible shape changes. When modified to include more complex geometries, these controllable shape changes can also be used to selectively trigger multiple folding events, illustrating a new platform for chemically initiated mechatronic devices. Together, these data show how compositionally discrete components are physically, chemically, and mechanically coupled together to generate a new actuator for biohybrid self‐folding systems.     

Spatial heterogeneity enhances and modulates excitability in a mathematical model of the myometrium

The muscular layer of the uterus (myometrium) undergoes profound changes in global excitability prior to parturition. Here, a mathematical model of the myocyte network is developed to investigate the hypothesis that spatial heterogeneity is essential to the transition from local to global excitation which the myometrium undergoes just prior to birth. Each myometrial smooth muscle cell is represented by an element with FitzHugh–Nagumo dynamics. The cells are coupled through resistors that represent gap junctions. Spatial heterogeneity is introduced by means of stochastic variation in coupling strengths, with parameters derived from physiological data. Numerical simulations indicate that even modest increases in the heterogeneity of the system can amplify the ability of locally applied stimuli to elicit global excitation. Moreover, in networks driven by a pacemaker cell, global oscillations of excitation are impeded in fully connected and strongly coupled networks. The ability of a locally stimulated cell or pacemaker cell to excite the network is shown to be strongly dependent on the local spatial correlation structure of the couplings. In summary, spatial heterogeneity is a key factor in enhancing and modulating global excitability.     

Vulnerability Analysis of Future Public Water Supply Under Changing Climate Conditions: A Study of the Moy Catchment,Western Ireland

An application of the Water Evaluation and Planning tool Version 21 (WEAP21) is developed to analyse the vulnerability of the future public water supply in the River Moy catchment, western Ireland. The River Moy’s future hydrology is modelled using the WEAP21 integrated rainfall runoff module and an ensemble of statistically downscaled future climate series. This approach facilitates the identification of the most vulnerable future public water supplies without being constrained by the availability of historically observed streamflow records. The model is calibrated by linking the model-independent parameter estimation tool (PEST) with the hydrological model and verified by reproducing observed streamflow records. This research suggests an emerging vulnerability to water stress of the public water supply sector under the four modelled scenarios, for areas which currently have plenty of water available. These results present a basis for future planning and management of the Moy catchment and its water resources.     

Reconstruction of partially occluded objects encoded in three-dimensional scenes by using digital holograms

We propose a task-specific digital holographic capture system for three-dimensional scenes, which can reduce the amount of data sent from the camera system to the receiver and can effectively reconstruct partially occluded objects. The system requires knowledge of the object of interest, but it does not require a priori knowledge of either the occlusion or the distance the object is from the camera. Subwindows of the camera-plane Fresnel field are digitally propagated to reveal different perspectives of the scene, and these are combined to overcome the unknown foreground occlusions. The nature of the occlusions and the effect of subwindows are analyzed thoroughly by using the Wigner distribution function. We demonstrate that a careful combination of reconstructions from subwindows can reveal features that are not apparent in a reconstruction from the whole hologram. We provide results by using optically captured digital holograms of real-world objects and simulated occlusions.