Electrodeposition of CoCu Nanostructures

Electrodeposition is a key component in the microelectronic industry because it has the following advantages: low cost, easy operation and the capability to deposit into irregular geometries such as recessed and curved areas. In this dissertation, CoCu alloys were investigated to fabricate multilayers, microdevices and microposts. All of these multilayer structures were composed of nanometric copper and cobalt-rich layers in order to obtain magnetoresistance, a phenomenon where the resistance of multilayer structures decreases with increases of external magnetic field. An investigation was carried out in order to evaluate appropriate plating conditions during multilayered thin film deposition, with the aim to obtain higher magnetoresistance at lower magnetic field. The effects of layer size, pH, bilayer number, seed layer and nickel component on the magnetoresistance of multilayered thin films were experimentally explored. A magnetoresistance of 5 % was obtained with the saturation field of less than 3000 Oe on the multilayered thin films by a conventional pulse method. An alternative electrodeposition process, which is referred to as pulse train in this dissertation, was first applied to study its effect on magnetoresistance of multilayered thin films. A pulse train control deposition of the cobalt layer during the fabrication of CoCu/Cu multilayers can improve magnetoresistance over the conventional square-wave pulse. A maximum 7-8 % magnetoresistance was obtained. The conditions that resulted in the best GMR in thin films were employed to fabricate a multilayered microdevice by combining UV lithography and electrodeposition. The geometric effects of the microdevices on their magnetoresistance were investigated in detail. The pulse train control method was also employed to improve the magnetoresistance of the microdevices. High aspect ratio CoCu/Cu multilayered microstructures were also electrodeposited. A single sulfate electrolyte with sodium citrate was employed to successfully fabricate 500 ìm tall microposts prepared by x-ray lithography. A giant magnetoresistance of 4 % was demonstrated in a single 500 ìm tall micropost. It is the first demonstration of GMR in a micropost exceeding a 10 ìm. A detailed investigation of the effects of the layer thickness, plating potentials, nickel component and the pulse train method on the magnetoresistance of microposts was performed

On Forms of Infringement and Protection of Short Video Advertising

Short video advertising is a type of short video that can generate direct commercial benefits. Short video advertising wins out in terms of content, and its broadcast volume grows rapidly. Especially with the development of Internet economy, with well-known short video bloggers using platforms to sell products, advertisements are gradually the same as short videos and appear more and more on short video platforms. Short video advertising itself has the characteristics of marketing, coupled with the characteristics of its length, fast transmission, in the era of Internet fragmentation is widely used as a way of entertainment for the masses, a variety of resulting copyright issues will also trigger wider attention from all walks of life. This paper uses inductive analysis to analyze the marketing strategy and infringement risk of short video advertising, and makes clear the copyright protection system of short video advertising, and promote the healthy and orderly development of short video advertising industry

H.E.A.R.T.

Healthy parenting and family resilience in early childhood has been shown to be an important factor in building emotional resilience for the children: it illustrates that when parents have higher emotional resilience, their children tend to have higher emotional resilience as well. However, the tools that available in the market right now only teach people what emotional resilience rather than how to practice it in daily life. This report describes our project to create a virtual reality tool that can not only teach the importance of emotional resilience, but also help the parents develop personal resilience. The system is based on the VR Empathy Training Tool created by a former senior design project in which the user can interact with a crying child and learn how to handle stress under certain circumstances. The new system will add new features so that it can inform users about their stress level and allow the users to track their progress

Understanding the role of orthopaedic implant dissolution ions in bone remodelling

The ions released from materials used in orthopaedic repair can affect bone remodelling. These ions can be released as unintentional by-products of implant wear or can be intentionally released as part of implant design (e.g. bioactive glasses, cements and hydrogel). Furthering the understandings of how these ions (with a focus on Cobalt (Co) and Silicate (Si)) interact in vitro in this study, these ions affect bone remodelling and will allow the development of new materials with improved outcomes following implantation. The effects of these ions on bone remodelling cells, specifically on monocytes, osteoblasts and osteoclasts were performed and potential mechanistic cellular pathways (the hypoxia inducible factor (HIF) pathway and Fenton reaction) were investigated. This included the development of a new in vitro model of bone resorption using a sub-clone of mouse macrophage cell-line (RAW264.7), creating a novel non- primary cell line that demonstrates bone resorbing activity. Co ions, at concentration range below 200μM reported in the bone implant interface of failed implants (25-100μM), were found to increase the sub-unit of Tartrate resistant acid phosphatase 5b (TRAP-5b) expression, this enzyme is osteoclast specific in the osteoclast sub-clone cell lines, hence correlated to increased osteolysis (p<0.001). Co ions also increased osteoblast expression of the osteoclastic differentiation factor RANKL, reactive oxygen species (ROS) generation and macrophage phagocytic activity (p<0.001). These results suggest that Co ions may contribute inflammatory osteolysis and cause aseptic implant failure. Furthermore, inhibition of the HIF pathway using echinomycin (an inhibitor of HIF-1a transcriptional factor binding), reduced these Co ion dependent osteoclastogenic and inflammatory effects, supplying evidence of Co ion stabilization of the HIF-1a pathway. Bioactive glasses release Si which hypothesise to encourage bone formation. There is, however, little understanding of how Si interacts with osteoclasts. A possible cellular mechanism for this inhibition was investigated, whereby Si was found (concentration dependently) to inhibit ROS generation in osteoclasts via the Fenton reaction. The addition of iron (II) ions (10 μM FeCl2) restored osteoclastogenesis (p<0.001), suggesting, for the first time, that Si chelation of iron, may be responsible for enhanced bone formation. These results furthered our understanding on how Co and Si released from materials influence bone remodelling and may enable the development of materials that control bone resorption and bone formation depending on the disease and patient

Statistical analysis of variability properties of the Kepler blazar W2R 1926+42

We analyzed Kepler light curves of the blazar W2R 1926+42 that provided nearly continuous coverage from quarter 11 through quarter 17 (589 days between 2011 and 2013) and examined some of their flux variability properties. We investigate the possibility that the light curve is dominated by a large number of individual flares and adopt exponential rise and decay models to investigate the symmetry properties of flares. We found that those variations of W2R 1926+42 are predominantly asymmetric with weak tendencies toward positive asymmetry (rapid rise and slow decay). The durations (D) and the amplitudes (F0) of flares can be fit with log-normal distributions. The energy (E) of each flare is also estimated for the first time. There are positive correlations between logD and logE with a slope of 1.36, and between logF0 and logE with a slope of 1.12. Lomb-Scargle periodograms are used to estimate the power spectral density (PSD) shape. It is well described by a power law with an index ranging between -1.1 and -1.5. The sizes of the emission regions, R, are estimated to be in the range of 1.1*10^15 cm - 6.6*10^16 cm. The flare asymmetry is difficult to explain by a light travel time effect but may be caused by differences between the timescales for acceleration and dissipation of high-energy particles in the relativistic jet. A jet-in-jet model also could produce the observed log-normal distributions

Online Localization and Tracking of Multiple Moving Speakers in Reverberant Environments

We address the problem of online localization and tracking of multiple moving speakers in reverberant environments. The paper has the following contributions. We use the direct-path relative transfer function (DP-RTF), an inter-channel feature that encodes acoustic information robust against reverberation, and we propose an online algorithm well suited for estimating DP-RTFs associated with moving audio sources. Another crucial ingredient of the proposed method is its ability to properly assign DP-RTFs to audio-source directions. Towards this goal, we adopt a maximum-likelihood formulation and we propose to use an exponentiated gradient (EG) to efficiently update source-direction estimates starting from their currently available values. The problem of multiple speaker tracking is computationally intractable because the number of possible associations between observed source directions and physical speakers grows exponentially with time. We adopt a Bayesian framework and we propose a variational approximation of the posterior filtering distribution associated with multiple speaker tracking, as well as an efficient variational expectation-maximization (VEM) solver. The proposed online localization and tracking method is thoroughly evaluated using two datasets that contain recordings performed in real environments.Comment: IEEE Journal of Selected Topics in Signal Processing, 201