First synthesis of dioxadithiaporphycene with a benzene ring fused onto the double bond

Dioxadithiaporphycenes 5 and 5′ were synthesized by using the Suzuki cross-coupling and McMurry coupling reactions as the key steps. This approach provided an access to the first dioxadithiaporphycene derivative 15 with a benzene ring fused onto the double bond.     

Phase change memory alloys: GST cell array characterization using picosecond ultrasonics

Phase change random access memory alloys (PRAM or PCM) are a class of non-volatile memory that is thought as viable alternatives to flash memory technology or to supplement other memory technologies depending on the end applications and its key performance requirements. Ge₂Sb₂Te₅ alloy (GST) is the most widely used chalcogenide material for PCM application, and has many unique properties, including strong temperature-dependent film properties, low thermal conductivity, and high electrical resistivity. Picosecond ultrasonics was used to make non-contact, non-destructive measurements of GST films on blanket wafers and directly on product wafers. On-product wafer measurements were made on various via array (0.5 μm and 1 μm between cell edges with CD size from 250 to 800 nm). Measurements have shown excellent correlation to cross-section SEM and were consistent with CMP polish times for both blanket and pattern wafer measurement. Excellent repeatability based on extensive measurements demonstrates the capability and reliability of picosecond ultrasonic technology. Picosecond ultrasonic measurements also provide rapid characterization across the whole wafer at production-worthy throughputs.     

变速率调制解调器的DSP实现

介绍了一种较为简单的抗干扰方式－－降低信息速率，分析了当系统采用该方式时系统误码率、误分组概率及信道利用率的提高并给出了仿真结果，最后介绍了如何用数字信号处理芯片Ｃ５０实现了可变速率的调制解调器。     

A diode-pumped, self-starting, all-solid-state self-mode-locked Cr:LiSGAF laser

In this paper, a self-starting, diode-pumped self-mode-locked Cr:LiSGAF laser, which produced a stable pulse train of 45 fs duration with about 20 mW-average power at the repeated rate of 90 MHz, was presented. Self-mode-locked operation can be obtained whether there is the semiconductor saturable absorber mirror (SESAM) in the Cr:LiSGAF laser cavity or not, and with the SESAM in the cavity, the self-mode-locked operation could self-start. The shortest pulses, as short as 38 fs, which were not very stable, were obtain with the SESAM in the cavity.     

Novel chiral thiazoline‐containing N―O ligands in the asymmetric addition of diethylzinc to aldehydes: substituent effect on the enantioselectivity

Several novel chiral thiazoline primary and tertiary alcohols were easily synthesized from commercially available l ‐cysteine in three steps and with high yield. These ligands were subsequently applied to the asymmetric addition of diethylzinc (Et₂Zn) to various aldehydes. Products with S configuration were obtained when thiazoline‐containing tertiary alcohol ligands were used as catalysts. The primary alcohol induced corresponding products with R configuration in 68% enantiomeric excess, which was a higher value relative to other N―O ligands possessing a primary alcohol unit in the literature. Furthermore, a plausible transition state model was proposed to explain the observed enantioselectivities. Copyright © 2012 John Wiley & Sons, Ltd.     

Luminescent sensitization and blue shift emission of Ir(ppy)2(VPHD) by copolymerization with MMA

Ir(ppy)₂(VPHD) (ppy=2-phenyl pyridine, VPHD=6-(4-vinylphenyl)-2,4-hexanedione) was copolymerized with methyl methacrylate (MMA). The copolymer had high quantum yield of 52.3±0.5% in dilute ethyl acetate solution, and the yield increased around 45% than that of the iridium monomer. The maximum emission peaks for the copolymers shifted from 515 to 489 nm while the iridium complex content was less than 0.005 mol% in the feed. The blue emission at 489 nm and the green emission at 520 nm were analyzed by Lorenz function. They are attributed to ¹MLCT and ³MLCT emissions, respectively.     

Biologically Active Iridoids from Hedyotis diffusa

Two new iridoids, 10‐O‐benzoyl‐6′‐O‐α‐L ‐arabino(1→6)‐β‐D ‐glucopyranosylgeniposidic acid ( 1 ), deacetyl‐6‐ethoxyasperulosidic acid methyl ester ( 2 ), along with 14 other known iridoids, were isolated from the whole plant of Hedyotis diffusa Willd. Their structures were determined on the basis of spectroscopic analysis. The short‐term‐memory‐enhancement activities of compounds 1, 7 – 9, 11 , and 13 were evaluated on an Aβ transgenic drosophila model.