Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline

A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L⁻¹ was obtained and the detection limit was 0.17 μmol L⁻¹. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.     

High-Tg porous polyimide films with low dielectric constant derived from spiro-(adamantane-2,9′(2′,7′-diamino)-fluorene)

Porous polyimide (PI) films with low dielectric constants and excellent thermal properties have been a pressing demand for the next generation of high-performance, miniature, and ultrathin microelectronic devices. A series of novel porous PI films containing fluorenyl-adamantane groups were prepared successfully via thermolysis of poly(ethylene glycol) (PEG) added in the PI matrix. The cross-sectional morphologies of porous PI films showed closed pores with diameters ranging from 135 to 158 nm, which were uniform and regular in shape without interconnectivity. These porous PI films exhibited excellent thermal properties with a glass-transition temperature at 376 °C whereas the 5% weight loss temperature in air excess of 405 °C due to enhanced rigidity afforded by fluorenyl-adamantane groups. Accompanied by thermolysis content of PEG increasing from 0 to 20 wt %, the density of porous PI films decreased, and the corresponding porosity grew significantly from 0 to 11.48%. Depending on porosity, the dielectric constant and dielectric loss of porous PI films significantly declined from 2.89 to 2.37 and from 0.050 to 0.021, respectively. These excellent properties benefit the as-prepared porous PI films for application as interlayer dielectrics, integrated circuit chips, or multichip modules in microelectronic fields. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47313.     

海上稠油油田蒸汽吞吐产量确定新方法

针对目前蒸汽吞吐产量预测模型假设条件简单、普适性差等问题,一般采用测试法和类比法综合确定海上稠油油田蒸汽吞吐初期产量。由于目前海上油田通常只开展常规测试,无法直接获得热采开发初期产量。笔者提出海上稠油油田蒸汽吞吐初期产量确定新方法,建立蒸汽吞吐相对于常规开发的初期产量倍数预测模型,通过蒸汽吞吐产量倍数,将常规测试确定的产量转化为蒸汽吞吐产量。研究表明,蒸汽吞吐初期产量倍数主要受储集层渗透率、原油黏度、注入强度、蒸汽干度等因素影响,利用正交试验设计和多元回归等方法,建立海上稠油油田蒸汽吞吐初期产量倍数与油藏地质参数及注入参数之间的非线性预测模型,该模型经实际生产数据验证,预测误差小于5%,可靠性高,能够为海上稠油油田蒸汽吞吐初期产量的确定提供依据。     

具有底水边界的水平井压力不稳态特征分析及认识

根据水平井三维渗流特征，在底水油藏情形仍假定顶面为不渗透隔层所封闭，底部则是恒压边界，水平井渗流表现为早期径向流以及稳定流动期，由此进行常规试井分析。以TKxxDH井为例，通过水平井的静压、压恢试井资料结果的对比分析，阐述了不稳定试井资料的应用，为此类油藏油井模型的选择及效果评价提供了可借签的经验。     

大牛地气田气井无阻流量的确定方法研究

大牛地气田气井试井大多采用一点法，由于气层渗透性差，测试时间短，流压很难达到稳定，计算的无阻流量往往偏高，且无法获得正确的产能方程。通过气田多口井修正等时试井数据进行统计分析，获得了一点法试井在不同生产时间下计算无阻流量的经验公式；利用气田修正等时试井的二项式方程系数曰，计算惯性阻力系数并经过曲线回归处理获得了经验关系式，很好地解决了一点法试井计算产能方程的问题。     

Uplink Scheduling in CDMA Packet-Data Systems

Uplink scheduling in wireless systems is gaining importance due to arising uplink intensive data services (ftp, image uploads etc.), which could be hampered by the currently in-built asymmetry in favor of the downlink. In this work, we propose and study algorithms for efficient uplink packet-data scheduling in a CDMA cell. The algorithms attempt to maximize system throughput under transmit power limitations on the mobiles assuming instantaneous knowledge of user queues and channels. However no channel statistics or traffic characterization is necessary. Apart from increasing throughput, the algorithms also improve fairness of service among users, hence reducing chances of buffer overflows for poorly located users. The major observation arising from our analysis is that it is advantageous on the uplink to schedule “strong” users one-at-a-time, and “weak” users in larger groups. This contrasts with the downlink where one-at-a-time transmission for all users has shown to be the preferred mode in much previous work. Based on the optimal schedules, we propose less complex and more practical approximate methods, both of which offer significant performance improvement compared to one-at-a-time transmission, and the widely acclaimed Proportional Fair (PF) algorithm, in simulations. When queue content cannot be fed back, we propose a simple modification of PF, Uplink PF (UPF), that offers similar improvement. Hereafter, we refer to users with low recieved power at the base even when transmitting at peak transmit power as “weak” users, and the strongly recieved users at the base as “strong” users. Krishnan Kumaran is currently a member of the Complex Systems Modeling section in the Corporate Strategic Research of ExxonMobil Corp., Clinton, NJ. Formerly, he was a Member of Technical Staff in the Mathematics of Networks and Systems Research Department at Bell Labs in Murray Hill, NJ, where his research interests were in modeling, analysis and simulation of design, resource management and scheduling issues in telecommunication networks. Lijun Qian is an assistant professor in the Department of Electrical Engineering at Prairie View A&M University. He received his B.S. from Tsinghua University in Beijing, M.S. from Technion-Israel Institute of Technology, and Ph.D. from WINLAB, Rutgers University, all in electrical engineering. Before joining PVAMU, he was a researcher at Networks and Systems Research Department of Bell Labs in Murray Hill, NJ. His major research interests are in wireless communications and networking technologies, especially in radio resource management, protocol design, TCP/RLP optimization and MPLS traffic engineering.     

分组密码算法芯片验证

介绍了分组密码算法芯片验证的流程、内容和方法,详细介绍了分组密码算法芯片的验证技术——测试基准。     

结构化编程实现Sniffer

随着各高校校园网络规模的不断扩大和各种应用的急剧增加,各种新的网络问题也在不断出现。Sniffer是网络管理员进行网络管理的有效工具,可以有效地对网络进行实时监控,及时发现网络中存在的各种问题。本文首先介绍了Sniffer的工作原理,其次给出了实现Sniffer功能的编程流程图,并用C语言给出了编程所需的关键代码。     

共面波导(CPW)馈电单极子天线的设计与研究

给出一种工作于900MHz的共面波导(CPW)馈电单极子天线的设计。该单极子天线以共面波导的中心导带为辐射单极子，以中心导带两边的金属导体作反射板，结构简单紧凑。但是由于天线与共面波导之间缺少有效的隔离，造成天线性能受共面波导尺寸的影响较严重。本文通过模拟计算和实验测量详细分析了共面波导尺寸的变化对天线性能的影响，给出了结合共面波导尺寸设计的工作在900MHz的单极子天线结构数据。