Toward a scalable, silicon-based quantum computing architecture

Advances in quantum devices have brought scalable quantum computation closer to reality. We focus on the system-level issues of how quantum devices can be brought together to form a scalable architecture. In particular, we examine promising silicon-based proposals. We discover that communication of quantum data is a critical resource in such proposals. We find that traditional techniques using quantum SWAP gates are exponentially expensive as distances increase and propose quantum teleportation as a means to communicate data over longer distances on a chip. Furthermore, we find that realistic quantum error-correction circuits use a recursive structure that benefits from using teleportation for long-distance communication. We identify a set of important architectural building blocks necessary for constructing scalable communication and computation. Finally, we explore an actual layout scheme for recursive error correction, and demonstrate the exponential growth in communication costs with levels of recursion, and that teleportation limits those costs.     

High affinity hormone binding to the extracellular N-terminal exodomain of the follicle-stimulating hormone receptor is critically modulated by exoloop 3

The human follicle-stimulating hormone receptor (FSH-R) consists of two distinct domains of >330 amino acids, the N-terminal extracellular exodomain and membrane-associated endodomain. The exodomain alone binds hormone with high affinity, whereas the endodomain is the site of receptor activation. Coordination of these two domains is essential for successful hormone action but little is known about their functional and structural relationship. In this communication, we report that exoloop 3 of FSH-R constrains follicle-stimulating hormone binding to the exodomain. When the FSH-R exodomain was prepared by truncating its endodomain, the hormone binding affinity of the exodomain was slightly improved, compared with the wild type receptor. The binding affinity was further improved by >3-fold when the exodomain was attached to the membrane-associated domain of CD8. These results suggest that the FSH-R endodomain attenuates hormone binding at the exodomain. As a first step to test this hypothesis, the 11 amino acids except Ala589 of exoloop 3 were individually substituted with Ala. Ala substitution for Leu583 or Ile584 improved the hormone binding affinity by 4-6-fold while totally abolishing cAMP induction, indicating an inverse relationship. The Ala substitution for Lys580 or Pro582 had a similar trend but to a lesser extent. This significant improvement in the binding affinity suggests that the four residues at the N-terminal region of exoloop 3 interact with the exodomain and constrain the hormone binding in the wild type receptor. This effect is specific since substitutions for other than the 4 residues did not improve the hormone binding affinity. Computer modeling shows that the 4 residues can be positioned on one side of exoloop 3. This result and the apparent inverse relationship of hormone binding and cAMP induction suggest that these two essential functions may work against each other. Therefore, hormone binding might be compromised to preserve cAMP inducibility while maintaining a reasonably high, but below maximum, binding affinity.     

Non-peptidic HIV protease inhibitors: C2-symmetry-based design of bis-sulfonamide dihydropyrones

Potent, non-peptidic, dihydropyrone sulfonamide HIV protease inhibitors have been previously described. Crystallographic analysis of dihydropyrone sulfonamide inhibitor/HIV protease complexes suggested incorporation of a second, C2 symmetry-related sulfonamide group. Selected bis-sulfonamide dihydropyrone analogues display high HIV protease inhibitory activity.     

Characterization of proton-exchanged optical waveguides in ZnO:LiNbO3

We report the first demonstration of proton-exchanged optical planar waveguides in x-cut and z-cut LiNbO₃ doped with 6 mol% ZnO using adipic acid as proton source. These waveguides exhibit a graded index profile which can be modeled by a linear step function with a surface index increase of 0.135 and 0.14 for x-cut and z-cut waveguides, respectively. The diffusion constant D_o and the activation energy Q are characterized optically to be 1.64×10⁹ μm²/h and 88.8 KJ/mol for x-cut waveguides, and 1.478×10⁹ μm²/h and 91.25 KJ/mol for z-cut waveguides, respectively. The diffusion rate along the z-axis is slower than that along the x-axis, whereas the surface index increase on z-cut waveguides is larger than that on x-cut waveguides.     

Motion based object tracking with mobile camera

An efficient algorithm which detects and tracks a moving object is proposed. The global motion energy caused by camera movement is eliminated by finding the maximal matching position with the cross-correlation value between two consecutive frames using the spiral scanning technique. The region of a moving object is segmented exactly by combining the results of the temporal derivatives and edge map from one image, and the actual centroid of the moving object is determined as the mid-point of the cumulative distribution of the projection profile of the region     

由对硝基苯甲醚制备对氨基苯甲醚的工艺研究

以硫磺和氢氧化钠为原料,制备多硫化钠,然后用多硫化钠还原对硝基苯甲醚合成对氨基苯甲醚。第一步反应在90℃下回流1h,硫磺的转化率可达100%;第二步反应在110℃下回流8h,对氨基苯甲醚的收率为96%,纯度为99%,副产品硫代硫酸钠的收率为92%,纯度为98%。     

Miscibility of some hydroxyl-containing polymers with poly(acetonyl methacrylate), poly(tetrahydropyranyl-2-methacrylate), and poly(cyclohexyl methacrylate)

Poly(tetrahydropyranyl-2-methacrylate) (PTHPMA) was found to be miscible with Poly(vinyl phenol) (PVPH), Poly(hydroxy ether of bisphenol A) (Phenoxy), and Poly(styrene-co-allyl alcohol) (PSAA). However, Poly(cyclohexyl methacrylate) (PCHMA) is immiscible with all these three hydroxyl-containing polymers. Poly(acetonyl methacrylate) (PACMA) was found to be miscible with PVPH but immiscible with Phenoxy and PSAA. Miscible PTHPMA-Phenoxy blends showed lower critical solution temperature behavior.     

神经网络在电路诊断中的应用

目的：阐述了目前电路基于数据库技术和人工智能专家系统及神经网络原理的故障诊断系统。方法：将所记录的模糊症状输入到系统中，通过模糊运算后，运用神经网络学习算法来寻找故障类型。结果：介绍了人工神经网络技术在电路诊断中的应用，并给出系统故障诊断软件的设计，结论：所用专家系统和神经网络相结合的方法改进电子电路故障诊断是可行的。     

水电厂设备故障诊断系统实时数据库的一种简捷实现

实时数据库及时准确地从现场获取数据并有效地组织和管理，是水电厂 设备故障诊断系统进行故障诊断的首要条件。文中在分析了现有的实时数据库实现方法后， 用C++ Builder 5.0和SQL Server 7.0完成了实时数 据库实现的一种简洁方法，它不但能够满足工程需要，而且具有关系数据库所具有的一切强 大的数据库管理和维护功能，实现也很简单，极大地节省了实时数据库开发的人力和物力。 实验表明，该方法是可行的。