Analysis of the dielectric characteristics for polycrystalline Ba0.65Sr0.35TiO3 (II) – d.c. field dependence with a modified bias equation

The effect of direct-current (d.c.) biasing on the dielectric properties of Ba_0.65Sr_0.35TiO₃ (BST) with various grain sizes (0.87 μm to 5.43 μm) have been studied in the paraelectric state. The leakage current of BST samples is proportional to the biasing field. Specimens with larger grains exhibit higher leakage current under biasing. The bias equation used in the literature to predict the d.c. field dependence of permittivity is modified by introducing a bias exponent parameter β. This modified bias equation gives a better fit to the experimental results both in this study and in the literature. Similar trends of α (representing the distribution of relaxation times), β, and the variance of lattice distortion with grain sizes suggests that β is a material parameter. It is concluded that the temperature dependence, the frequency response and d.c. field effect for the dielectric characteristics of Ba_0.65Sr_0.35TiO₃ are all suppressed by the transition broadening.     

Scrapping small lots in a low-yield and high-price scenario

Some wafers in a lot may become spoiled after they are processed at a workstation; such a lot is called a small lot. In a low yield and high price scenario, scrapping small lots may increase revenue and profit; yet, this notion has seldom been examined. This study presents a model for formulating the decision-making problem of scrapping small lots. A genetic algorithm is used to solve the problem when the solution space is large. An exhaustive search method is used when the solution space is small. Some numerical examples are used to evaluate the outcome of scrapping small lots. The profit obtained by the proposed scrapping method may be up to 23% higher than that obtained without scrapping.     

Crosstalk-insensitive via-programming ROMs using content-aware design framework

Various code patterns of a via-programming read only memory (ROM) cause significant fluctuations in coupling noise between bitlines (BLs). This crosstalk between BLs leads to read failure in high-speed via-programmable ROMs and limits the coverage of applicable code patterns. This work presents a content-aware design framework (CADF) for via-programming ROMs to overcome the crosstalk induced read failure. The CADF ROMs employ a content-aware structure and correspondent code-structure programming algorithm to reduce the amount of coupling noise source while maintaining nonminimal BL load for crosstalk reduction. A 256-Kb conventional ROM and a 256-Kb CADF ROM were fabricated using a 0.25-/spl mu/m logic CMOS process. The measured results ascertain that the read induced read failure is suppressed significantly by CADF. The CADF ROM also reduced 86.2% and 94.5% in power consumption and standby current compared to the conventional ROM, respectively.     

Complementary operators method as the absorbing boundary conditionfor the beam propagation method

The recently proposed complementary operators method (COM) is applied to the beam propagation method (BPM). The spurious reflection using the COM can be several orders lower than that using other boundary conditions     

K-band monolithic InGaP-InGaAs DCFET amplifier using BCB coplanar waveguide technology

A K-band (20 GHz) monolithic amplifier was developed and fabricated by adopting a low-/spl kappa/ benzocyclobutene (BCB) coplanar waveguide (CPW) line and InGaP-InGaAs doped-channel HFETs (DCFETs). This monolithic microwave integrated circuit (MMIC) utilizes a high impedance BCB CPW microstrip line (Z/sub 0/=70 /spl Omega/) for the biasing circuits, and a Z/sub 0/=50 /spl Omega/ line for the RF signal transmission. The low dielectric constant characteristic of the BCB interlayer is beneficial for a common-ground bridge process, which reduces the parasitics. The calculated loss tan/spl delta/ is 0.036 for the BCB at 20 GHz. The one-stage MMIC amplifier achieves an S/sub 21/ of 5 dB at 20 GHz, which is the first demonstration of the K-band InGaP-InGaAs DCFET monolithic circuit.     

Targeting PSEN1 by lnc-CYP3A43-2/miR-29b-2-5p to Reduce β Amyloid Plaque Formation and Improve Cognition Function

Presenilin-1 (PSEN1) is a crucial subunit within the γ-secretase complex and regulates β-amyloid (Aβ) production. Accumulated evidence indicates that n-butylidenephthalide (BP) acts effectively to reduce Aβ levels in neuronal cells that are derived from trisomy 21 (Ts21) induced pluripotent stem cells (iPSCs). However, the mechanism underlying this effect remains unclear. This article aims to investigate the possible mechanisms through which BP ameliorates the development of Alzheimer’s disease (AD) and verify the effectiveness of BP through animal experiments. Results from RNA microarray analysis showed that BP treatment in Ts21 iPSC-derived neuronal cells reduced long noncoding RNA (lncRNA) CYP3A43-2 levels and increased microRNA (miR)-29b-2-5p levels. Bioinformatics tool prediction analysis, biotin-labeled miR-29b-2-5p pull-down assay, and dual-luciferase reporter assay confirmed a direct negative regulatory effect for miRNA29b-2-5p on lnc-RNA-CYP3A43-2 and PSEN1. Moreover, BP administration improved short-term memory and significantly reduced Aβ accumulation in the hippocampus and cortex of 3xTg-AD mice but failed in miR-29b-2-5p mutant mice generated by CRISP/Cas9 technology. In addition, analysis of brain samples from patients with AD showed a decrease in microRNA-29b-2-5p expression in the frontal cortex region. Our results provide evidence that the LncCYP3A43-2/miR29-2-5p/PSEN1 network might be involved in the molecular mechanisms underlying BP-induced Aβ reduction.