A 16-Mb MRAM featuring bootstrapped write drivers

A 16-Mb magnetic random access memory (MRAM) is demonstrated in 0.18-/spl mu/m three-Cu-level CMOS with a three-level MRAM process adder. The chip, the highest density MRAM reported to date, utilizes a 1.42/spl mu/m/sup 2/ 1-transistor 1-magnetic tunnel junction (1T1MTJ) cell, measures 79 mm/sup 2/ and features a /spl times/16 asynchronous SRAM-like interface. The paper describes the cell, architecture, and circuit techniques unique to multi-Mb MRAM design, including a novel bootstrapped write driver circuit. Hardware results are presented.     

Novel polymeric aromatic lithium sulfonylimides as salts for polymer electrolytes

Three new polymeric aromatic lithium sulfonylimides were used as salts in high molecular weight poly(ethylene oxide) (PEO) electrolytes. Their conductivity and electrochemical stability behaviors were investigated. The electrolytes with lithium poly[4,4′‐(hexafluoroisopropylidene)diphenoxy]sulfonylimide (LiPHFIPSI) showed a better conductive performance compared with the other two lithium salts. The best conductivity was obtained for PEO/LiPHFIPSI EO/Li = 16 (1.90 × 10^?4 S/cm at 60°C). Thermal analysis indicated that the salts effectively decreased the crystallinity of PEO. Moreover, the electrolytes also had good electrochemical stability and their oxidative potential was to 5.5 V versus Li/Li⁺. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1802–1805, 2002     

Bone replacement in head and neck surgery: a biocompatible alternative

BACKGROUND: Defects in the skull have presented difficult reconstructive problems. Recently glass-ionomer cement and preformed. implants have been used to repair bony defects in the skull base and in cranio-facial surgery. Three patients are reported to illustrate possible applications for this new material. METHODS: Ionocap cement and Ionoroc-skull standardized implants have been used. The cement is available as a two component blister pack. When mixed and blended a gel is produced which can be worked for approximately 5 min before hardening. It can then be contoured and drilled to the required shape. The resultant material is biocompatible and biostable, is non-toxic and permanently bonds to bone with no increase in temperature or shrinkage. RESULTS: The material has been used to fill the temporal defect left by transplantation of the temporalis muscle for oral reconstruction, the anterior and lateral walls of the maxilla and following craniofacial resection, the posterior wall of the frontal sinus and anterior skull base. CONCLUSIONS: Three patients with different reconstructive problems have been presented to illustrate the use of an alloplastic material that has a tensile strength similar to bone and firmly adheres to it. The material was found to be safe and easy to use. All three patients have now been followed for 12 months with no adverse affects.     

Substitution of the human beta-spectrin promoter for the human agamma-globin promoter prevents silencing of a linked human beta-globin gene in transgenic mice

During development, changes occur in both the sites of erythropoiesis and the globin genes expressed at each developmental stage. Previous work has shown that high-level expression of human beta-like globin genes in transgenic mice requires the presence of the locus control region (LCR). Models of hemoglobin switching propose that the LCR and/or stage-specific elements interact with globin gene sequences to activate specific genes in erythroid cells. To test these models, we generated transgenic mice which contain the human Agamma-globin gene linked to a 576-bp fragment containing the human beta-spectrin promoter. In these mice, the beta-spectrin Agamma-globin (betasp/Agamma) transgene was expressed at high levels in erythroid cells throughout development. Transgenic mice containing a 40-kb cosmid construct with the micro-LCR, betasp/Agamma-, psibeta-, delta-, and beta-globin genes showed no developmental switching and expressed both human gamma- and beta-globin mRNAs in erythroid cells throughout development. Mice containing control cosmids with the Agamma-globin gene promoter showed developmental switching and expressed Agamma-globin mRNA in yolk sac and fetal liver erythroid cells and beta-globin mRNA in fetal liver and adult erythroid cells. Our results suggest that replacement of the gamma-globin promoter with the beta-spectrin promoter allows the expression of the beta-globin gene. We conclude that the gamma-globin promoter is necessary and sufficient to suppress the expression of the beta-globin gene in yolk sac erythroid cells.     

高温超导红外探测器的电极工艺探讨

介绍了高温超导红外探测器电极材料的选择和制备。选用先蒸、后蒸金，再合金化的电极工艺。芯片装配成器件后，器件性能稳定，膜层牢固，接触电阻小。     

Synthesis and antitumor evaluation of 2,5-disubstituted-indazolo[4, 3-gh]isoquinolin-6(2H)-ones (9-aza-anthrapyrazoles)

The synthesis and antitumor evaluation of 2, 5-disubstituted-indazolo[4,3-gh]isoquinolin-6(2H)-ones (9-aza-APs) are described. The key intermediates in the synthesis are benz[g]isoquinoline-5,10-diones which are substituted at positions 6 and 9 with groups of different nucleofugacity for SNAr displacements. The initial displacement of fluoride by a substituted hydrazine leads to the pyrazole analogues. Substitution of the remaining leaving group by an amine or BOC-protected amines leads to the 9-aza-APs 12. These analogues were converted into their maleate or hydrochloride salts 13. In two cases, namely, 13x and 13z, sidearm buildup was also employed in the synthetic pathway. In vitro evaluation of 9-aza-APs against the human colon tumor cell line LoVo uncovered for most of the compounds a cytotoxic potency lower than that of DuP-941 or mitoxantrone and comparable to that of doxorubicin. Only analogues 13c, 13n, and 13ff were as cytotoxic as DuP-941. Interestingly, while DuP-941 was highly cross-resistant in the LoVo cell line resistant to doxorubicin (LoVo/Dx), the 9-aza-APs carrying a distal lipophilic tertiary amine moiety in both chains were capable of overcoming the MDR resistance induced in this cell line. The 9-aza-APs show outstanding in vivo antitumor activity against both systemic P388 murine leukemia and MX-1 human mammary carcinoma transplanted in nude mice. At their optimal dosages, congeners 13a-c, 13f, 13n, 13q, 13x, and 13dd were highly effective against P388 leukemia with T/C% of 200-381, while the T/C% value of DuP-941 was 147. In the MX-1 tumor model, 24 compounds elicited percentages of tumor weight inhibitions (TWI) ranging from 50% to 99%. Congeners 13d, 13k, 13l, 13x, 13z, and 13ee emerged as the most effective ones, with TWI% 96, simliar to that of DuP-941 (TWI% = 95). On the basis of their efficacy profile in additional experimental tumors and lack of cardiotoxicity in preclinical models, two congeners have surfaced as potential clinical candidates.     

ConcurrentC语言在分布式系统上的一种高效实现

本文介绍了ＣｏｎｃｕｒｒｅｎｔＣ语言在一分布式系统上的实现。该实现使用了不同于预编译法的编译器的构造方法，同时将Ｃｏｎｃｕｒｒｅｎｔ Ｃ语言中的进程实现为ＵＮＩＸ进程中的用户级线索，是ＣｏｎｃｕｒｒｅｎｔＣ语言在分布式系统上的一种高效实现。