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71.
A low‐cost and easy‐to‐fabricate microchip remains a key challenge for the development of true point‐of‐care (POC) diagnostics. Cellulose paper and plastic are thin, light, flexible, and abundant raw materials, which make them excellent substrates for mass production of POC devices. Herein, a hybrid paper–plastic microchip (PPMC) is developed, which can be used for both single and multiplexed detection of different targets, providing flexibility in the design and fabrication of the microchip. The developed PPMC with printed electronics is evaluated for sensitive and reliable detection of a broad range of targets, such as liver and colon cancer protein biomarkers, intact Zika virus, and human papillomavirus nucleic acid amplicons. The presented approach allows a highly specific detection of the tested targets with detection limits as low as 102 ng mL?1 for protein biomarkers, 103 particle per milliliter for virus particles, and 102 copies per microliter for a target nucleic acid. This approach can potentially be considered for the development of inexpensive and stable POC microchip diagnostics and is suitable for the detection of a wide range of microbial infections and cancer biomarkers.  相似文献   
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73.
A 2D/2D heterojunction of black phosphorous (BP)/graphitic carbon nitride (g‐C3N4) is designed and synthesized for photocatalytic H2 evolution. The ice‐assisted exfoliation method developed herein for preparing BP nanosheets from bulk BP, leads to high yield of few‐layer BP nanosheets (≈6 layers on average) with large lateral size at reduced duration and power for liquid exfoliation. The combination of BP with g‐C3N4 protects BP from oxidation and contributes to enhanced activity both under λ > 420 nm and λ > 475 nm light irradiation and to long‐term stability. The H2 production rate of BP/g‐C3N4 (384.17 µmol g?1 h?1) is comparable to, and even surpasses that of the previously reported, precious metal‐loaded photocatalyst under λ > 420 nm light. The efficient charge transfer between BP and g‐C3N4 (likely due to formed N? P bonds) and broadened photon absorption (supported both experimentally and theoretically) contribute to the excellent photocatalytic performance. The possible mechanisms of H2 evolution under various forms of light irradiation is unveiled. This work presents a novel, facile method to prepare 2D nanomaterials and provides a successful paradigm for the design of metal‐free photocatalysts with improved charge‐carrier dynamics for renewable energy conversion.  相似文献   
74.
75.
Wireless Personal Communications - This paper presents a least squares channel estimation (LSCE) in the UpLink transmission for a Massive MIMO systems in 5G wireless communications, combined with...  相似文献   
76.
In this paper, we propose an efficient privacy-preserving energy consumption scheme with updating certificates, called EPEC, for secure smart grid communications. Specifically, the proposed EPEC scheme consists of four phases: gateways initialization, party registration, privacy-preserving energy consumption, and updating certificates. Based on the bilinear pairing, the identity-based encryption, and the strategy of updating certificates, EPEC can achieve data privacy, gateway privacy, and is robust to data replay attack, availability attack, modification attack, man-in-the-middle attack, and Sybil attack. Through extensive performance evaluations, we demonstrate the effectiveness of EPEC in terms of transmission delay performance at the HAN gateway and average delivery ratio, by implementing three types of curves including, the Barreto–Naehrig curve with modulus 256 bits, the Kachisa–Schaefer–Scott curve with modulus 512 bits, and the Barreto–Lynn–Scott curve with modulus 640 bits.  相似文献   
77.
Mohamed  Marwa F.  Nassar  Hamed 《Wireless Networks》2020,26(4):2423-2432
Wireless Networks - In order to save on the energy expended by a sensor node in its communications with the sink, forecasting-based frameworks have recently been proposed. Those frameworks...  相似文献   
78.
Most radar targets are complex objects and produce a wide variety of reflections. An important class of targets is represented by the so-called moderately fluctuating Rayleigh targets, which, when illuminated by a coherent pulse train, return a train of correlated pulses with a correlation coefficient in the range 0<ρ<1 (intermediate between SWII and SWI models). The detection of this type of fluctuating targets is therefore of great interest. On the other hand, the CFAR detection is one of the desirable features for radar receivers. Because of the simplicity of cell-averaging (CA detectors in their implementation, they are commonly used in modern radar systems to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain an approximately constant rate of false alarm. In this paper, we analyze the performance of these detectors for the case where the radar receiver postdetection integrates M square-law detected pulses and the signal fluctuation obeys chi-square statistics with two degrees of freedom. These detectors include the mean-level ML), the greatest-of (GO) and the smallest-of (SO) schemes. In these processors, the estimation of the noise power levels from the leading and the trailing reference windows is based on the CA technique. Exact formulas for the detection probabilities are derived, in the absence as well as in the presence of spurious targets. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the chi-square fluctuation model with two degrees of freedom. Swerling's well known fluctuation models I and II represent the cases where the signal is completely correlated and completely decorrelated, respectively, from pulse to pulse. Probability of detection curves are presented for the chi-square family of fluctuations, including the Swerling cases I and II. The ML detector has the best homogeneous performance, the SO processor has the best multiple-target performance, while the GO scheme does not offer any merits neither in the absence nor in the presence of outlying targets.  相似文献   
79.
Glaucoma is a disease characterized by damaging the optic nerve head, this can result in severe vision loss. An early detection and a good treatment provided by the ophthalmologist are the keys to preventing optic nerve damage and vision loss from glaucoma. Its screening is based on the manual optic cup and disc segmentation to measure the vertical cup to disc ratio (CDR). However, obtaining the regions of interest by the expert ophthalmologist can be difficult and is often a tedious task. In most cases, the unlabeled images are more numerous than the labeled ones.We propose an automatic glaucoma screening approach named Super Pixels for Semi-Supervised Segmentation “SP3S”, which is a semi-supervised superpixel-by-superpixel classification method, consisting of three main steps. The first step has to prepare the labeled and unlabeled data, applying the superpixel method and bringing in an expert for the labeling of superpixels. In the second step, We incorporate prior knowledge of the optic cup and disc by including color and spatial information. In the final step, semi-supervised learning by the Co-forest classifier is trained only with a few number of labeled superpixels and a large number of unlabeled superpixels to generate a robust classifier. For the estimation of the optic cup and disc regions, the active geometric shape model is used to smooth the disc and cup boundary for the calculation of the CDR. The obtained results for glaucoma detection, via an automatic cup and disc segmentation, established a potential solution for glaucoma screening. The SP3S performance shows quantitatively and qualitatively similar correspondence with the expert segmentation, providing an interesting tool for semi-automatic recognition of the optic cup and disc in order to achieve a medical progress of glaucoma disease.  相似文献   
80.
Circuit techniques are presented for increasing the voltage swing of BiCMOS buffers through active charging and discharging using complementary bipolar drivers. These BiCMOS circuits offer near rail-to-rail output voltage swing, higher noise margins, and higher speed of operation at scaled-down power supply voltages. The circuits are simulated and compared to BiCMOS and CMOS buffers. The comparison shows that the conventional BiCMOS and the complementary BiCMOS buffers are efficient for power supply voltages greater than 3V and that if the power supply voltage is scaled down (<3 V) and the load capacitance is large (>1 pF), the complementary BiCMOS buffers would be the most suitable choice. They provide high speed and low delay to load sensitivity and high noise margins. The first implementation is favorable near a 2.5-V power supply for its smaller area  相似文献   
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