M2M energy saving strategy in 5G millimeter wave system

Telecommunication Systems - Machine to Machine technology has a broad application prospect in the 5G network, but there is a bottleneck in the energy consumption of intelligent devices powered by...     

低GWP制冷剂在热泵行业的应用分析

随着世界各国对于环境问题的日益关注,热泵行业中的R22制冷剂产品已经开始逐步降低使用,主流制冷剂R134a、R410A等已经被列入受控物质范围,使用更低GWP的制冷剂成为热泵行业可持续发展的重要支撑.针对现有热泵行业的三大主流细分领域高温热泵、普通热泵、低温环境热泵,分别对各个领域的低GWP制冷剂的应用情况进行分析,提出未来中期和长期的可能发生的冷媒替换形势.同时对R290和CO2两种典型的适用于热泵行业的天然制冷剂进行探讨,分析其未来发展趋势.开发适应于我国国情又能在国际竞争中处于优势的全新低GWP制冷剂(包括天然制冷剂)的热泵产品或将成为行业后续发展方向.     

Surface wettability and flow properties of non-metallic pipes in laminar flow

In this paper, three liquids flowing in five pipes with the same inner diameter of 14 mm were studied to determine the relationship between the surface wettability and flow properties in laminar flow(Re b 2000). This was motivated by oilfield observations of increased pressure drops in non-metallic pipes compared to those in metal pipes,which was contrary to expectations. A new expression for the frictional coefficient that considers the Reynolds number and contact angle θ in laminar flow for non-metallic pipes was proposed based on the experimental results of single-phase flow using dimension and regression analyses. The solutions of the anomalous phenomenon were proposed from the perspectives of the pipe diameter, contact-angle difference, and the compatibility between flexible composite pipe and JLHW105 oil according to the new formula. The surprising finding was that the surface wettability could control the frictional resistance by the critical contact angle(39.9°) obtained at the same Reynolds number. If 0° b θ≤ 39.9°, the frictional coefficient increased as the contact angle increased. In contrast, if 39.9° b θ b 180°,the frictional coefficient decreased with increasing contact angle. The influences of the pipe diameter and contactangle difference on the pressure drop difference of JLHW105 oil showed an inversely proportional relation. A series of materials and liquids were tested. The selection of pipe material for transporting a given fluid can be based on the contact angle, surface tension, and critical limit of the contact angle obtained. The research results are expected to provide some guidelines for the selection of the appropriate pipe material for a given set of fluids.     

PCN-Fe(III)-PTX nanoparticles for MRI guided high efficiency chemo-photodynamic therapy in pancreatic cancer through alleviating tumor hypoxia

As nanomedicine-based clinical strategies have continued to develop, the possibility of combining chemotherapy and singlet oxygen-dependent photodynamic therapy (PDT) to treat pancreatic cancer (PaC) has emerged as a viable therapeutic modality. The efficacy of such an approach, however, is likely to be constrained by the mechanisms of drug release and tumor oxygen levels. In the present study, we developed an Fe(III)-complexed porous coordination network (PCN) which we then used to encapsulate PTX (PCN-Fe(III)-PTX) nanoparticles (NPs) in order to treat PaC via a combination of chemotherapy and PDT. The resultant NPs were able to release drug in response to both laser irradiation and pH changes to promote drug accumulation within tumors. Furthermore, through a Fe(III)-based Fenton-like reaction these NPs were able to convert H₂O₂ in the tumor site to O₂, thereby regulating local hypoxic conditions and enhancing the efficacy of PDT approaches. Also these NPs were suitable for use as a T₁-MRI weighted contrast agent, making them viable for monitoring therapeutic efficacy upon treatment. Our results in both cell line and animal models of PaC suggest that these NPs represent an ideal agent for mediating effective MRI-guided chemotherapy-PDT, giving them great promise for the clinical treatment of PaC.

     

冰下单载波水声通信试验研究

北极地区战略地位的提高促进了极区各种应用的快速发展，冰下水声通信成为其中一个热点问题。为了研究冰下单载波水声通信性能，在黄海冰区开展冰下试验。重点分析了内嵌锁相环的多通道判决反馈均衡(Multi-channelDecision Feedback Equalization, M-DFE)技术在冰下水声通信中抗多途时延的能力，研究比较了改进比例归一化最小均方(Improved Proportional normalized Least Mean Square, IPNLMS)算法和递归最小二乘(Recursive Least Squares,RLS)算法的均衡性能。试验结果表明IPNLMS和RLS都能克服信道多途效应带来的影响。在牺牲计算复杂度的前提下，RLS具有更好的均衡效果，M-DFE在冰下环境中能够有效消除码间干扰。     

日本煤炭清洁利用及对我国的启示

1日本煤炭利用现状 二战后，煤炭对日本经济的恢复和发展起到了重要作用。20世纪60年代的能源革命，石油开始取代煤炭成为日本的主要能源，在1973年，石油在一次能源供给中的比重高达77％。但由于20世纪70年代爆发了2次石油危机，煤炭又重新在世界范围内受到关注，国际能源机构又重新提倡大力促进煤炭的生产和利用。日本为了改善其脆弱的能源供给结构，也把煤炭作为代替石油的能源放在了重要的位置，希望能够加大利用的力度。     

矿井煤与瓦斯突出危险性模糊综合评价方法研究

采用模糊综合评价方法建立模糊数学模型，对矿井煤与瓦斯突出危险性进行分析。在矿山地质调查的基础上，建立矿井煤与瓦斯突出危险性数据库，针对矿山开采与矿山安全的关系建立数学模型，在单一因素评价的基础上进行多因素的模糊综合评价，为矿山安全生产和科学决策提供依据。     

典型红粘土与膨胀土的对比试验研究

通过室内试验对广西贵港红粘土、湖北荆门弱膨胀土与中膨胀土的物理力学性质指标、原状样脱湿过程中的强度变化、击实样泡水前后强度变化以及脱湿吸湿性能等方面进行了对比试验研究。结果表明：3种土原状样脱湿过程中的强度指标在土体裂隙性与基质吸力双重因素的作用下表现出完全不同的变化规律；由于红粘土与膨胀土膨胀性能上的差异，不同含水量的击实样泡水后的干密度峰值与加州承载比(CBR)峰值所对应的原击实样含水量比最优含水量有不同程度的增大；土体因矿物成分的差异而表现出明显不同的脱湿、吸湿速率。广西贵港红粘土与荆门膨胀土虽然在一些物理力学指标上具有相似之处，但其力学特性与水敏性特征具有明显的差异，在实际工程中应给予充分重视。