Nitride-Based ultraviolet metal-semiconductor-metal photodetectors with a low-temperature GaN layer

The GaN metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors with a low-temperature (LT)-GaN layer have been demonstrated. It was found that we could achieve a two orders of magnitude smaller, photodetector-dark current by introducing a LT-GaN layer, which could be attributed to the larger Schottky-barrier height between the Ni/Au metal contact and the LT-GaN layer. It was also found that photodetectors with the LT-GaN layer could provide a larger photocurrent to dark-current contrast ratio and a larger UV-to-visible rejection ratio. The maximum responsivity was found to be 3.3 A/W and 0.13 A/W when the photodetector with a LT-GaN layer was biased at 5 V and 1 V, respectively.     

A Vlsi Neural Network Processor Based on Hippocampal Model

The hippocampal region of the brain system can be analyzed with the nonlinear system modeling approach. The input-output relationship of the neural units is best represented by the kernel functions of different complexities. The modeling expression of the first and second order kernels are computed in analog current-mode instead of digital data processing in order to fully explore massively parallel processing capability of the neural networks. Two distinct methods are utilized: the table-look-up approach and the model-based approach. The former can achieve high accuracy but consumes large silicon area while the latter saves silicon area and maintains moderately high accuracy. Circuit-level simulation results and experimental data from two test structures are presented.     

A general replacement of a system subject to shocks

A system is subject to shocks that arrive according to a nonhomogeneous Poisson process. The system is replaced at age T at a fixed cost c₀. If the k-th shock arrives at time S_k<T, it is either a fatal shock with probability p(S_k) or a nonfatal shock with probability 1−p(S_k). The fatal shock causes the system total breakdown, and the system is replacd at a cost c_∞. The nonfatal shock weakens the system and makes it more expensive to run. The aim of the paper is to find the optimal T which minimizes the long run expected cost per unit time of the policy. Various special cases are considered.     

An efficient VLSI design for a residue to binary converter for general balance moduli (2/sup n/-3,2/sup n/+1,2/sup n/-1,2/sup n/+3)

In this paper, we present a new four-moduli set (2/sup n/-3,2/sup n/+1,2/sup n/-1,2/sup n/+3) and an efficient residue to binary (R/B) converter design. The merits of the proposed four-moduli set include 1) larger dynamic range; 2) higher degree of parallelism for conversion; 3) balanced bit-width for internal RNS arithmetic operations; and 4) flexible moduli set selection. According to the relation between the proposed moduli, the divide-and-conquer technique is used to design a two-level converter architecture which has lower hardware cost and shorter critical delay. For the R/B converter designed with 12-b (n=3), our architecture has about 47% saving in hardware cost and 40% saving in critical delay compared to the last work.     

In-situ XRD investigations on structure changes of ZrO2-coated LiMn0.5Ni0.5O2 cathode materials during charge

The structural changes of pristine and ZrO₂-coated LiMn_0.5Ni_0.5O₂ cathode materials were investigated by using in situ X-ray diffraction (XRD) during charging process. An obviously solid solution phase transition from a hexagonal structure (H1) to another hexagonal structure (H2) was observed during the charging process at a constant current of 0.3 mA in the potential range of 2.5–5.7 V. The second hexagonal structure has a shorter a-axis and a longer c-axis before the crystal collapse. Before the structure collapses the c-axis length increases to maximum and then significantly decreases to 14.1 Å. The c-axis length of the pristine and ZrO₂-coated LiMn_0.5Ni_0.5O₂ increases to the maximum at the charge capacity of 119.2 and 180.9 mAh g⁻¹, respectively. It can be concluded that the ZrO₂ coating can strongly stabilize the crystal structure of the LiMn_0.5Ni_0.5O₂ compound from the comparison of the lattice parameter variations between the pristine and the ZrO₂-coated LiMn_0.5Ni_0.5O₂ compounds upon charge. The potential fluctuation resulting from the decomposition of electrolytes starts at the charge capacity of around 200 and 260 mAh g⁻¹ for the pristine and ZrO₂-coated LiMn_0.5Ni_0.5O₂, respectively. It suggests that the ZrO₂ coating layer can impede the reaction between the cathode material and electrolyte.     

Relationships among interpersonal conflict, requirements uncertainty, and software project performance

Interpersonal conflict and user requirements uncertainty are pervasive phenomena that plague information systems projects. Relevant literature indicates that interpersonal conflicts can negatively affect information system (IS) projects, even after controlling for the effects of conflict management and resolution. However, the negative emotional characteristics of conflict alone have limited explanatory power with regard to IS project success. The purpose of this study is to provide additional insights into this phenomenon by examining the impact on IS project performance made by the interaction between interpersonal conflict and requirement uncertainty (which comprises both diversity and instability). The authors surveyed the top 1600 companies in Taiwan and the results revealed that requirements instability would lead to potential interpersonal conflict and interpersonal conflict was directly associated with requirements diversity which, in turn, was negatively associated with final project performance.     

Anp32a Promotes Neuronal Regeneration after Spinal Cord Injury of Zebrafish Embryos

After spinal cord injury (SCI) in mammals, neuronal regeneration is limited; in contrast, such regeneration occurs quickly in zebrafish. Member A of the acidic nuclear phosphoprotein 32 (ANP32a) family is involved in neuronal development, but its function is controversial, and its involvement in zebrafish SCI remains unknown. To determine the role of zebrafish ANP32a in the neuronal regeneration of SCI embryos, we microinjected ANP32a mRNA into embryos from zebrafish transgenic line Tg(mnx1:GFP) prior to SCI. Compared to control SCI embryos, the results showed that the regeneration of spinal cord and resumption of swimming capability were promoted by the overexpression of ANP32a mRNA but reduced by its knockdown. We next combined fluorescence-activated cell sorting with immunochemical staining of anti-GFAP and immunofluorescence staining against anti-PH3 on Tg(gfap:GFP) SCI embryos. The results showed that ANP32a promoted the proliferation and cell number of radial glial cells at the injury epicenter at 24 h post-injury (hpi). Moreover, when we applied BrdU labeling to SCI embryos derived from crossing the Tg(gfap:GFP) and Tg(mnx1:TagRFP) lines, we found that both radial glial cells and motor neurons had proliferated, along with their increased cell numbers in Anp32a-overexpression SCI-embryos. On this basis, we conclude that ANP32a plays a positive role in the regeneration of zebrafish SCI embryos.     

Prostate cancer: local staging with endorectal magnetic resonance imaging

BACKGROUND: Prostate cancer has received increasing attention during the past decades. Staging of tumors before treatment is imperative for planning appropriate therapy. The purpose of this study is to assess the role of endorectal magnetic resonance imaging (MRI) in local staging of prostate cancer. METHODS: Endorectal MRI was performed in 31 patients with histologically-proven prostate cancer. MRI was done three to 100 days (mean, 32.1 days) after either transrectal ultrasonography (TRUS) with biopsy or transurethral resection of the prostate (TURP). Radical prostatectomies were performed within two weeks after MRI. The diagnostic accuracy of endorectal MRI for local tumor staging, specifically for extracapsular extension (ECE) and seminal vesicle invasion (SVI), was evaluated by correlating MRI results with histopathologic findings of whole-mount specimens. RESULTS: The accuracy of endorectal MRI for the detection of tumor presence and estimation of tumor volume was 48%. Sensitivity, specificity and positive predictive value for evaluation of ECE were 88%, 69% and 80%, respectively, and for SVI, were 66%, 84% and 50%, respectively. The overall accuracy of MRI in local tumor staging (using the TMN system) was 61%. Accuracy in differentiating localized from invasive cancer was 84%. CONCLUSION: Endorectal MRI is not accurate enough to detect tumor presence or estimate tumor volume. Diagnostic accuracy for local tumor staging is unsatisfactory. However, endorectal MRI is highly accurate in differentiating localized (stage B) from invasive (stage C) cancer.