Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repellency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer‐by‐layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale surface structures that are further surface‐functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid interface that repels water, low‐surface‐tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparticles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. The LbL process is conceptually simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non‐fouling materials. 相似文献
The network interconnection and its regulation consist in solving the following dilemma: increase competition and preserve the universal service through access charges, which symbolizes today institutional organization within the telecommunication industry. This paper presents some of the economic and social factors that drive the interconnection policies namely ona (open network architecture) in the United States, or onp (open network provision) in Europe. In the first section, we list some social and economical issues related to open network policies. In the second section, we study the different answers brought up by the regulator through alternative interconnection price formulas. In conclusion, we discuss the stakes and risks of interconnection, while the technological evolution of network introduces intelligent software in switching équipement and implements the tremendous abilities of the digital broadband networks. 相似文献
This work explores the possibility of achieving low side lobes in a circular ring array by adopting a new field-synthesis technique. The control of the unit (or element) pattern is used to overcome the phase problem associated with the field synthesis of circular ring array described in the text 相似文献
Many materials, upon fracturing, emit electrons (exo-electrons) by a process called fracto-emission. For a substance or mixture that can deflagrate or detonate upon impact or friction, these exo-electrons may contribute to the initiation of deflagration or detonation. Some materials, such as p-type semiconductors, can absorb exo-electrons and, as used as additives, can reduce the impact or friction sensitivity of propellants or explosives. It was found that the addition of 1% p-type silicon powder did decrease the impact sensitivity of a propellant consisting of ammonium perchlorate in a polybutadiene matrix, but did not reduce the impact sensitivity of powdered cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), and pentaerythritol trinitrate (PETN). 相似文献
Journal of Computer Virology and Hacking Techniques - With macOS increasing popularity, the number, and variety of macOS malware are rising as well. Yet, very few tools exist for dynamic analysis... 相似文献
Edge caching has received much attention as a promising technique to overcome the stringent latency and data-hungry challenges in the future generation wireless networks. Meanwhile, full-duplex (FD) transmission can potentially double the spectral efficiency by allowing a node to receive and transmit at the same frequency band simultaneously. In this paper, we investigate the delivery time performance of a cache-aided FD system, in which an edge node, operates in FD mode, serves users via wireless channels and is equipped with a cache memory. Firstly, we derive a closed-form expression for the average delivery time by taking into account the uncertainties of both backhaul and access wireless channels. The derived analysis allows the examination of the impact of key parameters, e.g., cache size and transmit power. Secondly, a power optimization problem is formulated to minimize the average delivery time. To deal with the non-convexity of the formulated problem, we propose an iterative optimization algorithm based on the bisection method. Finally, numerical results are presented to demonstrate the effectiveness of the proposed algorithm. A significant delivery time reduction is achieved by the proposed optimization compared to the FD reference and half-duplex counterpart.
High resolution n.m.r. spectroscopy, involving the technique of cross-polarization, along with magicangle spinning, was used in the structural characterization of eight kerogens of different origins, selected to represent the three types of kerogens (types I–III evolution paths). The influence of cross-polarization dynamics on the sensitivity of the method and the ratio of individual fractions in the spectrum was studied in more detail. It is suggested that an analysis of the influence of the mixing time is necessary prior to definitive characterization of any sample. Good separation of signals in aliphatic, aromatic, and carboxylic regions was achieved. The general correlation between the 13C n.m.r. structural characteristics and the classification based on ultimate analysis of the kerogens (types I–III, van Krevelen atomic H/C vs. O/C diagrams) was found to be satisfactory. The structural features of kerogens derived from 13C n.m.r. analysis agreed quite well with characteristics constituting the above mentioned classification. The 13C n.m.r. method used in this paper may be considered promising in the classification of kerogens. 相似文献
The mechanical properties are presented for a series of discontinuous fiber-reinforced thermoplastic composites made with random-in-plane fiber orientation. The matrix and fiber materials were chosen to provide a wide range of strength, modulus, ductility and adhesive properties. In many cases strong, rigid, yet tough composites were fabricated. Strength levels of over 20,000 psi and modulus values over 1,000,000 psi were reached in several systems reinforced with short Kevlar-49 and graphite fibers. A strong dependence of composite strength and modulus on fiber strength and modulus was noted indicating good transfer of load from matrix to reinforcement. Fiber efficiency factors for modulus and strength were calculated for the experimental composite systems and averaged 0.19 and 0.11 respectively. Data were analyzed using basic composite theory. Properties of the experimental composites could not be predicted from constituent properties. 相似文献
The quenching of a SHS sample under conditions of intense heat removal from the outer surface was investigated numerically. A two-step reaction was considered. The reaction proceeds in the reginmes of blending, control, and takeoff. It was established that in the control and takeoff regimes a significant amount of an intermediate phase is fixed during quenching. In the blending regime the relative fraction of the intermediate product in the quenched sample is small. It is shown that the method of quenching with an impacting water jet can be used to investigate phase-and structure-formation processes during SHS.Minsk Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 4, pp. 76–82, July–August, 1992. 相似文献