Filters compatible with isomorphism testing

Like the lower central series of a nilpotent group, filters generalize the connection between nilpotent groups and graded Lie rings. However, unlike the case with the lower central series, the associated graded Lie ring may share few features with the original group: e.g. the associated Lie ring can be trivial or arbitrarily large. We determine properties of filters such that every isomorphism between groups is induced by an isomorphism between graded Lie rings.     

Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis

The direct 2‐deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2‐deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2‐deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2‐deoxyglycosylation of amide groups using a newly designed Brønsted acid catalyst under mild conditions. Through mechanistic investigations, we discovered that the amide group can inhibit acid catalysts, and the inhibition has made the 2‐deoxyglycosylation reaction difficult. Diffusion‐ordered two‐dimensional NMR spectroscopy analysis implied that the 2‐chloroazolium salt catalyst was less likely to form aggregates with amides in comparison to other acid catalysts. The chlorine atom and the extended π‐scaffold of the catalyst played a crucial role for this phenomenon. This relative insusceptibility to inhibition by amides is more responsible for the catalytic activity than the strength of the acidity.     

Compiler compatible 5.66 Mb/mm2 8T 1R1W register file in 14 nm FinFET technology

1-read/1-write (1R1W) register file (RF) is a popular memory configuration in modern feature rich SoCs requiring significant amount of embedded memory. A memory compiler is constructed using the 8T RF bitcell spanning a range of instances from 32 b to 72 Kb. An 8T low-leakage bitcell of 0.106 μm² is used in a 14 nm FinFET technology with a 70 nm contacted gate pitch for high-density (HD) two-port (TP) RF memory compiler which achieves 5.66 Mb/mm² array density for a 72 Kb array which is the highest reported density in 14 nm FinFET technology. The density improvement is achieved by using techniques such as leaf-cell optimization (eliminating transistors), better architectural planning, top level connectivity through leaf-cell abutment and minimizing the number of unique leaf-cells. These techniques are fully compatible with memory compiler usage over the required span. Leakage power is minimized by using power-switches without degrading the density mentioned above. Self-induced supply voltage collapse technique is applied for write and a four stack static keeper is used for read Vmin improvement. Fabricated test chips using 14 nm process have demonstrated 2.33 GHz performance at 1.1 V/25 °C operation. Overall V_min of 550 mV is achieved with this design at 25 °C. The inbuilt power-switch improves leakage power by 12x in simulation. Approximately 8% die area of a leading 14 nm SoC in commercialization is occupied by these compiled RF instances.     

基于FPGA的ASI信号接收与发送的实现

提出了一种用FPGA芯片代替Cypress公司的CY78933和CY78923芯片来实现ASI信号接收与发送的方案，详细阐述了DVB—ASI接口的硬件组成与FPGA实现，该接口符合DVB—ASI的接口规范，可实现270Mbps的信号传输，已经得到实际运用。     

微机械可调谐滤波器的研制

利用 Ga As/Al Ga As分布反馈 Bragg反射镜在 Ga As衬底上制作了一个微机械的调谐滤波器 .该器件在 7V调谐电压下调谐范围达28nm     

Congruence criteria for finite subsets of complex projective and complex hyperbolic spaces

We investigate congruence classes and direct congruence classes of m-tuples in the complex projective space ℂP ⁿ . For direct congruence one allows only isometries which are induced by linear (instead of semilinear) mappings. We establish a canonical bijection between the set of direct congruence classes of m-tuples of points in ℂP ⁿ and the set of equivalence classes of positive semidefinite Hermitean m×m-matrices of rank at most n+1 with 1's on the diagonal. As a corollary we get that the direct congruence class of an m-tuple is uniquely determined by the direct congruence classes of all of its triangles, provided that no pair of points of the m-tuple has distance π/2. Examples show that the situation changes drastically if one replaces direct congruence classes by congruence classes or if distances π/2 are allowed. Finally we do the same kind of investigation also for the complex hyperbolic space ℂH ⁿ . Most of the results are completely analogous, however, there are also some interesting differences. Received: 15 January 1996     

Numerical methods for finding multiple eigenvalues of matrices depending on parameters

Summary. Let be a square matrix dependent on parameters and , of which we choose as the eigenvalue parameter. Many computational problems are equivalent to finding a point such that has a multiple eigenvalue at . An incomplete decomposition of a matrix dependent on several parameters is proposed. Based on the developed theory two new algorithms are presented for computing multiple eigenvalues of with geometric multiplicity . A third algorithm is designed for the computation of multiple eigenvalues with geometric multiplicity but which also appears to have local quadratic convergence to semi-simple eigenvalues. Convergence analyses of these methods are given. Several numerical examples are presented which illustrate the behaviour and applications of our methods. Received December 19, 1994 / Revised version received January 18, 1996