Wireless Personal Communications - Electroencephalography (EEG) is a technique of Electrophysiology used in a wide variety of scientific studies and applications. Inadequately, many commercial... 相似文献
In this paper, we introduce variability of syntactic phrases and propose a new retrieval approach reflecting the variability of syntactic phrase representation.
With variability measure of a phrase, we can estimate how likely a phrase in a given query would appear in relevant documents and control
the impact of syntactic phrases in a retrieval model. Various experimental results over different types of queries and document
collections show that our retrieval model based on variability of syntactic phrases is very effective in terms of retrieval
performance, especially for long natural language queries. 相似文献
The therapeutic use of interferon (IFN)-alpha administered as adjuvant medication in chronic schizophrenia was investigated. Natural leukocyte IFN-alpha was given to 9 long-term hospitalized chronic schizophrenic patients daily as subcutaneous injection of 3 million units 5 times a week. The trial followed a placebo-controlled double-blind crossover design. Each treatment period lasted for 8 weeks with a 2-week washout period in between. IFN-alpha did not prove to be beneficial for the total group of patients. Yet, 3 patients improved during the IFN-alpha drug period. The clinical improvement was seen as better social competence and less affective tension in the ward surroundings. 相似文献
Summary An expression is presented which relates the experimentally observed melting point depression in crystallizable, compatible polymer blends to changes in lamellar thickness and thermodynamic considerations.Considering a given crystallization temperature, this relationship suggests that one should observe a depressed blend melting point, despite an increase in lamellar thickness over the pure crystallizable material.Possible explanations for the melting point elevation observed in some compatible blends are discussed. 相似文献
Fabricating thermoelectric generators (TEGs) using the screen‐printing process has advantages, including mass production, device scalability, and system applicability. However, the thick film formed through the process typically has low film density, and reduced performance, because of the presence of pores in the film created by the vaporization of the resin during high‐temperature annealing. During the soldering process used for thermoelectric module fabrication, the printed solder infiltrates into the screen‐printed electrodes through the micropores in the electrodes, causing cracks of the electrode film and an increase in resistivity. In this paper, an ultraviolet radiation (UV)‐curable process for screen‐printed electrodes is reported. The paste for the electrodes is synthesized by mixing Ag flakes that can be cured at low temperature with a UV resin. Scanning electron microscope images show that the UV‐curing process significantly reduces pores and thereby results in a smooth‐surfaced electrode layer. The film density after crystallization is also enhanced. TEGs composed of 72 couples with UV‐curable Ag electrodes generate a high power density of ≈6.69 mW cm?2 at a temperature difference of 25 °C; the device resistance is ≈0.75 Ω, and the figure of merit of the device is recorded to be 0.57, which is the highest among the printed TEGs. 相似文献
As filtering policies are getting larger and more complex, packet filtering at firewalls needs to keep low delays. New firewall architectures are needed to enforce security and meet the increasing demand for high-speed networks. Two main architectures exist for parallelization, data-parallel and function-parallel firewalls. In the first, packets are distributed across a set of identical firewalls that implement the entire policy. In the second, each firewall implements a subset of the policy with a fewer number of rules, but the packets have to be duplicated and processed by all the firewalls. This paper proposes a new architecture function-parallel with pre-processing that combines the advantages of both architectures. The proposed architecture has the advantage of not duplicating the data, so that the processing time can be significantly reduced. Moreover, our architecture enables stateful inspection of packets, which is necessary to prevent multiple types of attacks. The performances of this architecture have been proven to be scalable for large security policies.
Narrow-bandgap mixed Pb-Sn perovskite solar cells (PSCs) have great feasibility for constructing efficient all-perovskite tandem solar cells, in combination with wide-bandgap lead halide PSCs. However, the power conversion efficiency of mixed Pb-Sn PSCs still lags behind lead-based counterparts. Here, additive engineering using ionic imidazolium tetrafluoroborate (IMBF4) is proposed, where the imidazolium (IM) cation and tetrafluoroborate (BF4) anion efficiently passivate defects at grain boundaries and improve crystallinity, simultaneously relaxing lattice strain, respectively. Defect passivation is achieved by the chemical interaction between the IM cation and the positively charged under-coordinated Pb2+ or Sn2+ ions, and lattice strain relaxation is realized by lattice expansion with the intercalation of BF4 anions into the perovskite lattice. As a result, the synergistic effects of the cation and anion in the IMBF4 additive greatly enhance the optoelectronic performance of half-mixed Pb-Sn perovskites, leading to much longer carrier lifetimes. The best-performing half-mixed Pb-Sn PSC shows an efficiency above 19% with negligible hysteresis, while retaining over 90% of its initial efficiency after 1000 h in a nitrogen-filled glovebox and showing a lifetime to 80% degradation of 53.5 h under continuous illumination. 相似文献
Until now, the theory, methodology of investigations, and interpretation of thermometry data have been most completely developed for single-phase (oil, water, or gas) flows in formations. However, multiphase (oil+gas, oil+water, and oil+water+gas) flows in formations are more common in practice. This is primarily typical for fields featuring a high value of gas factor and saturation pressure, as well as for cases of formation tests at low values of bottom-hole pressure. Analysis of actual thermograms under these conditions has shown that the earlier-developed techniques for the cases of single-phase flows in the formation and the well cannot be applied here.This paper presents research data on the influence of the adiabatic and Joule-Thomson effects and the heat of fluid degassing on temperature field in porous medium. 相似文献
In an effort to investigate the effect of the crystalline morphology of a poly(butylene terephthalate) (PBT) phase on the toughening of PBT/epoxy blends, the blends, having different degrees of perfectness of the PBT crystalline phase, were prepared by blending PBT and epoxy at various temperatures ranging from 200 to 240 °C. As the blending temperature decreases, the degree of perfectness of the PBT crystalline phase increases as a result of the increase of crystal growth rate. For PBT/epoxy blends, the change in crystalline morphology induced by processing may be the most important cause for the dependency of the fracture energy on blending temperatures. It has been found that PBT phases with a well-developed Maltese cross are most effective for epoxy toughening. This dependency reveals the occurrence of a phase transformation toughening mechanism. Also, the higher relative enhancement of fracture energy of a higher molecular weight epoxy system is further indirect evidence for a phase transformation toughening mechanism. Some other toughening mechanisms observed from the fracture surfaces, such as crack bifurcation, crack bridging, and ductile fracture of PBT phases, have been found to also be affected by the blending temperatures. 相似文献