可监管的区块链匿名交易系统模型

针对现有区块链系统可追溯性与隐私保护难以兼顾的问题,设计了一种可监管的区块链匿名交易系统模型。首先,结合标识密码（IBC）和无证书公钥密码体制（CL-PKC）的优点,消除了单一IBC托管密钥带来的隐患,并在可保证安全条件下将用户交易标识与用户身份关联,从而保证了模型中的可监管性;其次,通过从网络层和应用层双层签名认证实现了隐私安全,既保证了用户交易内容和身份隐私的安全性,又确保权威机构能够根据异常交易进行追溯,从而为当下区块链匿名性和可监管性的兼容提供了一种新的思路;最后,把所提模型和自认证签名模型、多中心SM9模型及可追溯门罗币模型等进行对比,并通过计算机模拟仿真比较了所提模型和主流区块链模型的传输耗时。实验结果表明,所提模型在安全性和可追溯性上有较大优势;在相同软硬件环境下,多次传输相同大小信息时,所提模型的信息传输耗时比以太坊模型多168%,而长时间传输情况下效率差距不大;传输不同长度的信息时,所提模型的平均耗时要比以太坊模型多38%。     

IBC在LTE的认证与密钥协商中的应用

文章分析了当前无线互联网的现状以及LTE的特点,介绍了当前LTE标准中用户的身份认证和密钥协商过程,通过讨论当前基于对称密钥技术的协商过程不足,提出使用非对称密钥技术IBC进行身份认证和密钥协商,并具体分析了该系统的安全性。     

A 3‐in‐1 doping process for interdigitated back contact solar cells exploiting the understanding of co‐diffused dopant profiles by use of PECVD borosilicate glass in a phosphorus diffusion

Boron and phosphorus doping of crystalline silicon using a borosilicate glass (BSG) layer from plasma‐enhanced chemical vapor deposition (PECVD) and phosphorus oxychloride diffusion, respectively, is investigated. More specifically, the simultaneous and interacting diffusion of both elements through the BSG layer into the silicon substrate is characterized in depth. We show that an overlying BSG layer does not prevent the formation of a phosphorus emitter in silicon substrates during phosphorus diffusion. In fact, a BSG layer can even enhance the uptake of phosphorus into a silicon substrate compared with a bare substrate. From the understanding of the joint diffusion of boron and phosphorus through a BSG layer into a silicon substrate, a model is developed to illustrate the correlation of the concentration‐dependent diffusivities and the emerging diffusion profiles of boron and phosphorus. Here, the in‐diffusion of the dopants during diverse doping processes is reproduced by the use of known concentration dependences of the diffusivities in an integrated model. The simulated processes include a BSG drive‐in step in an inert and in a phosphorus‐containing atmosphere. Based on these findings, a PECVD BSG/capping layer structure is developed, which forms three different n⁺⁺−, n⁺− and p⁺−doped regions during one single high temperature process. Such engineered structure can be used to produce back contact solar cells. Copyright © 2016 John Wiley & Sons, Ltd.     

IBC/FEM Analysis of Electromagnetic Scatter of Cavities Coated with Layered Medium

The Leontovich impedance boundary condition (IBC) is combined with the edge-based finite element method (FEM) in this paper to analyze the electromagnetic (EM) scattering of cavities coated with a multilayered dielectric. The IBC on the surface of the medium and the boundary integral equation on the aperture of the cavity are transformed into the third boundary condition, and then the functional of the boundary value problem is obtained. The surface impedance of the layered dielectric is calculated by the generalized reflection coefficient; hence, the multireflection of the EM wave in the dielectric is involved. As a result, the IBC is improved. Numerical results are presented, which demonstrate that the presented IBC/FEM approach is accurate and convenient for the analysis of EM scattering of open-ended cavities coated with the dielectric. Translated from Journal of Nanjing University of Aeronautics and Astronautics, 2004, 36(1): 44–47 (in Chinese)     

Targeting Lipocalin-2 in Inflammatory Breast Cancer Cells with Small Interference RNA and Small Molecule Inhibitors

Inflammatory Breast Cancer (IBC) is an aggressive form of invasive breast cancer, highly metastatic, representing 2–4% of all breast cancer cases in the United States. Despite its rare nature, IBC is responsible for 7–10% of all breast cancer deaths, with a 5-year survival rate of 40%. Thus, targeted and effective therapies against IBC are needed. Here, we proposed Lipocalin-2 (LCN2)—a secreted glycoprotein aberrantly abundant in different cancers—as a plausible target for IBC. In immunoblotting, we observed higher LCN2 protein levels in IBC cells than non-IBC cells, where the LCN2 levels were almost undetectable. We assessed the biological effects of targeting LCN2 in IBC cells with small interference RNAs (siRNAs) and small molecule inhibitors. siRNA-mediated LCN2 silencing in IBC cells significantly reduced cell proliferation, viability, migration, and invasion. Furthermore, LCN2 silencing promoted apoptosis and arrested the cell cycle progression in the G0/G1 to S phase transition. We used in silico analysis with a library of 25,000 compounds to identify potential LCN2 inhibitors, and four out of sixteen selected compounds significantly decreased cell proliferation, cell viability, and the AKT phosphorylation levels in SUM149 cells. Moreover, ectopically expressing LCN2 MCF7 cells, treated with two potential LCN2 inhibitors (ZINC00784494 and ZINC00640089) showed a significant decrease in cell proliferation. Our findings suggest LCN2 as a promising target for IBC treatment using siRNA and small molecule inhibitors.     

23.2% laser processed back contact solar cell: fabrication,characterization and modeling

We describe the manufacturing process for interdigitated back contact back junction silicon solar cells based on laser processes, and present detailed results and analysis to our best cell efficiency of 23.24%. The manufacturing process features two laser doping steps, one for the boron doped emitter and one for the phosphorus doped back surface field. The saturation current densities of thermal oxide passivated laser doped regions are on par with furnace diffused silicon for high efficiency solar cells. Laser ablation locally defines the contact areas through the rear dielectric layer stack, and structures the rear aluminum metallization. The precision of the laser systems in conjunction with the optical setup yields line shaped doping traces with a width of 150 µm and a pitch below 500 µm. The measured optical and electrical properties of our solar cell agree well with 3D simulation results. The measured reflection, transmission, quantum efficiency and current voltage curves in dark and illuminated condition simultaneously agree well with simulation, based on the same data set, giving confidence in the result of a detailed free energy loss analysis. The bulk resistive and recombination losses are identified as the main loss contributors. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.     

Black Ultra-Thin Crystalline Silicon Wafers Reach the 4n2 Absorption Limit–Application to IBC Solar Cells

Cutting costs by progressively decreasing substrate thickness is a common theme in the crystalline silicon photovoltaic  industry for the last decades, since drastically thinner wafers would significantly reduce the substrate-related costs. In addition to the technological challenges concerning wafering and handling of razor-thin flexible wafers, a major bottleneck is to maintain high absorption in those thin wafers. For the latter, advanced light-trapping techniques become of paramount importance. Here we demonstrate that by applying state-of-the-art black-Si nanotexture produced by DRIE on thin uncommitted wafers, the maximum theoretical absorption (Yablonovitch's 4n² absorption limit), that is, ideal light trapping, is reached with wafer thicknesses as low as 40, 20, and 10 µm when paired with a back reflector. Due to the achieved promising optical properties the results are implemented into an actual thin interdigitated back contacted solar cell. The proof-of-concept cell, encapsulated in glass, achieved a 16.4% efficiency with an J_SC = 35 mA cm⁻², representing a 43% improvement in output power with respect to the reference polished cell. These results demonstrate the vast potential of black silicon nanotexture in future extremely-thin silicon photovoltaics.     

基于标识密码的双向认证的安全启动协议

传统安全启动(Secure boot)方案的认证环节是基于公钥基础设施(Public Key Infrastructure,PKI)体制实现,在设备数量剧增的情况下,证书的管理会增加系统复杂性,认证过程仅实现了单向认证,安全性不足。此外,由于选择了链式信任链,导致了在启动过程中的信任传递损失较大。针对上述问题,本文提出了一种基于标识密码(Identity-Based Encryption,IBC)体制的Secure boot方案,即IBCEB方案。该方案使用了IBC体制的国家标准SM9算法作为实现方法,实现了无证书的双向认证协议,并对信任链模型进行了优化,降低了信任传递的损失。在ZC706评估板上进行了测试,测试结果表明,设备在双向认证后成功启动,提高了系统的安全性。