High Speed and High Efficiency Travelling Wave Single-Photon Detectors Embedded in Nanophotonic Circuits

Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics

A Single-Photon Imager Based on Microwave Plasmonic Superconducting Nanowire

Detecting spatial and temporal information of individual photons by using single-photon-detector (SPD) arrays is critical to applications in spectroscopy, communication, biological imaging, astronomical observation, and quantum-information processing. Among the current SPDs1,detectors based on superconducting nanowires have outstanding performance2, but are limited in their ability to be integrated into large scale arrays due to the engineering difficulty of high-bandwidth cryogenic electronic readout3-8. Here, we address this problem by demonstrating a scalable single-photon imager using a single continuous photon-sensitive superconducting nanowire microwave-plasmon transmission line. By appropriately designing the nanowire's local electromagnetic environment so that the nanowire guides microwave plasmons, the propagating voltages signals generated by a photon-detection event were slowed down to ~ 2% of the speed of light. As a result, the time difference between arrivals of the signals at the two ends of the nanowire naturally encoded the position and time of absorption of the photon. Thus, with only two readout lines, we demonstrated that a 19.7-mm-long nanowire meandered across an area of 286 {\mu}m * 193 {\mu}m was capable of resolving ~590 effective pixels while simultaneously recording the arrival times of photons with a temporal resolution of 50 ps. The nanowire imager presents a scalable approach to realizing high-resolution photon imaging in time and space

Evolutionary Sequence Modeling for Discovery of Peptide Hormones

There are currently a large number of “orphan” G-protein-coupled receptors (GPCRs) whose endogenous ligands (peptide hormones) are unknown. Identification of these peptide hormones is a difficult and important problem. We describe a computational framework that models spatial structure along the genomic sequence simultaneously with the temporal evolutionary path structure across species and show how such models can be used to discover new functional molecules, in particular peptide hormones, via cross-genomic sequence comparisons. The computational framework incorporates a priori high-level knowledge of structural and evolutionary constraints into a hierarchical grammar of evolutionary probabilistic models. This computational method was used for identifying novel prohormones and the processed peptide sites by producing sequence alignments across many species at the functional-element level. Experimental results with an initial implementation of the algorithm were used to identify potential prohormones by comparing the human and non-human proteins in the Swiss-Prot database of known annotated proteins. In this proof of concept, we identified 45 out of 54 prohormones with only 44 false positives. The comparison of known and hypothetical human and mouse proteins resulted in the identification of a novel putative prohormone with at least four potential neuropeptides. Finally, in order to validate the computational methodology, we present the basic molecular biological characterization of the novel putative peptide hormone, including its identification and regional localization in the brain. This species comparison, HMM-based computational approach succeeded in identifying a previously undiscovered neuropeptide from whole genome protein sequences. This novel putative peptide hormone is found in discreet brain regions as well as other organs. The success of this approach will have a great impact on our understanding of GPCRs and associated pathways and help to identify new targets for drug development

A Strategic Thinking of the Issues in Cost Management of FB Real Estate Company

摘要 论文结合FB房地产公司开发项目遇到的主要问题：如何选择项目开发的成本管理战略以获取成本竞争优势？成本管理效果不佳的问题：如成本核算数据不准确不能及时反映项目产品的成本状况、项目开发预算与实际支出差异大、产品的成本与利润不清楚、项目间成本不可比、成本管理不能及时对市场变化进行调整和企业利润被侵蚀的成本失控问题如何解决？怎么对异地项目开发进行成本控制及风险管理？怎样创新管理针对房地产成本管理的疑难问题展开战略分析研究，通过对解决问题的相关因素分析得出解决方案，在某项目开发中进行应用取得成功以验证其可行性。 论文以某项目开发针对成本管理中存在的疑难问题，以企业成本战略管理方法的“五力分析法...Abstract This article is mainly focused on the following topics of FB Real Estate Company: how to obtain the competitive advantage of project management by carrying on effective cost management strategies? How to change the situation of ineffective cost management, such as the data can't reflect the cost of the project accurately and there is a huge gap between the project's budget and actual...学位：工商管理硕士院系专业：管理学院高级经理教育中心（EMBA项目）_高级管理人员工商管理硕士(EMBA)学号：X200715612

Superconducting single photon detectors integrated with diamond nanophotonic circuits

Photonic quantum technologies promise to repeat the success of integrated nanophotonic circuits in non-classical applications. Using linear optical elements, quantum optical computations can be performed with integrated optical circuits and thus allow for overcoming existing limitations in terms of scalability. Besides passive optical devices for realizing photonic quantum gates, active elements such as single photon sources and single photon detectors are essential ingredients for future optical quantum circuits. Material systems which allow for the monolithic integration of all components are particularly attractive, including III-V semiconductors, silicon and also diamond. Here we demonstrate nanophotonic integrated circuits made from high quality polycrystalline diamond thin films in combination with on-chip single photon detectors. Using superconducting nanowires coupled evanescently to travelling waves we achieve high detection efficiencies up to 66 % combined with low dark count rates and timing resolution of 190 ps. Our devices are fully scalable and hold promise for functional diamond photonic quantum devices.Comment: 28 pages, 5 figure

Analysis and Suggestions for Business Model of eBayEachnet

EBAY易趣网和淘宝网是目前中国电子商务中经常被提及的两个对手。2002年时，EBAY易趣曾经一枝独秀，但在淘宝网和拍拍网的竞争下，迅速丧失市场领先地位，市场份额逐步缩小，并终于与TOM集团有限公司下属的TOM在线成立了合营公司。 本文主要运用翁君奕教授的《商业模式创新》理论，以合营公司的成立为研究截止时间，尝试揭示、分析、解释EBAY易趣商务模式针对中国大陆市场而言存在的不足之处，并提出实现转机的若干建议。全文共分五章，分别如下： 第一章主要介绍论文写作的背景和研究意义所在，以及研究理论和框架。 第二章针对EBAY易趣商务模式，按照商业模式创新理论的层次，从商务模式环境、商务模式要素、...eBayEachnet and Taobao are main competitors in China’s E-commerce. eBayEachnet just took the lead in as earlier as year 2002, however, it was overwhelmed by Taobao and Paipai gradually, the leading was lost and the share market diminished very soon, as a result, it incorporated with Tom Online, a filial of Tom group limited company.Bearing in mind the theory of <Business Models Innovatio...学位：工商管理硕士院系专业：管理学院工商管理教育中心（MBA中心）_工商管理硕士(MBA)学号：20041523

Proteinuria in cyclosporine-treated renal transplant recipients.

10.1097/00007890-199001000-00008Transplantation49135-4