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991.
Raviteja Kammari Vijaya Sankara Rao Pasupureddi 《International Journal of Circuit Theory and Applications》2020,48(2):198-213
In this work, a robust, low-power, widely linear multiphase clock generation and multiplying delay-locked loop (MPCG-MDLL) architecture is realized, using a new differential charge-mode delay element circuit topology. The heart of any MPCG-MDLL architecture is the delay element, and hence, the characteristics of the delay element influence the overall performance of the MPCG-MDLL, in terms of its specifications such as peak-to-peak jitter, lock range, delay range, control voltage range, and power consumption. The proposed eight-phase MPCG-MDLL along with the charge-mode delay element outperforms the conventional MPCG-MDLLs that deploy delay elements such as a current-starved inverter (CSI), wide-range CSI, triply controlled delay cell, digital-controlled delay element, and the like. The eight-phase MPCG-MDLL along with the new charge-mode delay element circuit topology is implemented in 1.2-V, 65-nm CMOS technology. The performance results show that the eight-stage delay line has a delay range from 640 to 960 ps over the rail-to-rail control voltage range. The implemented MPCG-DLL is robust over process, voltage, and temperature (PVT) corners and exhibits a lock range of 400 MHz and a peak-to-peak jitter of less than 60 fs for all the DLL output phases and peak-to-peak jitter of 0.54 and 1.24 ps for the synthesized 5-GHz clocks for an input reference clock frequency of 1.25 GHz. The MPCG-MDLL consumes 4.74 mW of power and occupies an area of 0.017 mm2. 相似文献
992.
Badugu Prudhvi Nadh Boddapati Taraka Phani Madhav Munuswamy Siva Kumar Tirunagari Anilkumar Manikonda Venkateswara Rao Poluri Venkata Vijay Kishore 《International Journal of Numerical Modelling》2020,33(6):e2757
This article presents the design of low-profile single band antenna on flexible substrate material. The proposed antenna is designed on the polyimide substrate with overall size of 30 mm × 30 mm × 0.2 mm. The designed antenna operates in the frequency range of 5.71 to 5.99 GHz with impedance bandwidth of 4.8% and covers the Industrial Scientific Medical band for medical body area network applications. The antenna is enabled by placing artificial magnetic conductor (AMC) with two by two array elements under the ground plane. The AMC structure acts as an isolation for the ground plane and main radiator to reduce back radiation. Compared with literature in the wearable antenna designs, the proposed antenna is compact in structure with high gain of 8.31 dBi with AMC-backed structure. The specific absorption rate values are observed by placing the antenna on the three-layered human body model and the observed values are 1.26 and 0.72 W/Kg without AMC and with AMC, respectively. The obtained values are in conjunction with ICNIRP standards, that is, 2 W/Kg should be averaged over 10 g of tissue. The proposed antenna can be used for the smart clothing and wearable electronics applications. 相似文献
993.
为了探究米香型白酒小曲发酵酒醅微生物群落演绎与理化因子的相关性,分别测定发酵第0,1,2,3,4,5,6,7,8,15,22,29,36,43,50,64,94天的理化指标和微生物群落变化情况。结果表明,在发酵阶段,pH值呈先减小后增加再减小的趋势,发酵结束后pH值约为4.1,总酸则呈逐渐增加的趋势。淀粉含量在发酵前期迅速被水解消耗,发酵后期趋于平缓;还原糖含量在发酵0~2 d内呈增加趋势,在第2天达到最大值约为180.14 g/L,在2~15 d内被微生物利用,其含量迅速降低。在发酵前期(0~3 d)未产生酒精度,发酵22 d时,酒精度达到最大值为9.5°,而发酵后期酒精度降低;总酚含量则随着发酵时间的延长呈现上升趋势,最终发酵结束后含量为375.63 mg GAE/L。在发酵过程中,变形菌门和厚壁菌门为主要优势菌门,主要优势菌属是肠杆菌属、泛菌属、片球菌属和乳球菌属。主坐标分析结果显示:所有样品在PCoA图上分为6个集群,由冗余分析(RDA)可知乳球菌属,假单胞菌属和片球菌属与总酸呈正相关性,泛菌属、阪崎肠杆菌属、肠杆菌属和克雷伯菌属与总酸呈负相关,而泛菌属、阪崎肠杆菌属、肠杆菌属和克雷伯菌属与pH值、淀粉和还原糖呈正相关,且总酸对优势菌属的影响力最大,pH值、淀粉和还原糖对优势菌属的影响较为相似。 相似文献
994.
ABSTRACTThis work investigates the effect of adding Cerium oxide nanoparticles at different proportions (30, 60 and 90?ppm) to Calophyllum inophyllum methyl ester and diesel blends (20% CI methyl ester and 80% diesel) in a four-stroke single-cylinder diesel engine. Addition of nanoparticles is a strategy to reduce emission and to improve the performance of the biodiesel. Modified fuels are introduced into the engine by admitting exhaust gas recirculation (EGR) at a rate of 10% and 20% so as to reduce nitrogen oxide (NOX) emissions from biodiesel and diesel blends. Results revealed a significant reduction in emissions (CO, NOX, HC and Smoke) at a 10% EGR rate. However, brake thermal efficiency is reduced with an increase in brake-specific fuel consumption at higher EGR rates. Hence, it is observed that 10% EGR rate is an effective method to control the emission of biodiesel and diesel blends without compromising much on engine efficiency. 相似文献
995.
ABSTRACTInjection timing (IT) is a vital factor among different injection parameters which governs the emissions and performance factors of the engine. This work portrays the effect of IT on cerium oxide nanoparticle doped Waste Cooking Palm Oil biodiesel and diesel blends. The doping is made at 30, 60 and 90?ppm. The modified fuels are introduced in reducing IT of 19°, 21° and 23°bTDC. 1500?rpm engine is made use in this study. Results revealed a significant reduction in emissions (CO, NOX, HC and Smoke) at IT?=?23°bTDC. Furthermore, performance (BSFC, BTE) is improved for fuel blends at IT?=?23°bTDC. 相似文献
996.
Sreedhar Kollem Katta Rama Linga Reddy Duggirala Srinivasa Rao 《International journal of imaging systems and technology》2020,30(4):1271-1293
Medical image processing is typically performed to diagnose a patient's brain tumor prior to surgery. In this study, a technique in denoising and segmentation was developed to improve medical image processing. The proposed approach employs multiple modules. In the first module, the noisy brain tumor image is transformed into multiple low- and high-pass tetrolet coefficients. In the second module, multiple low-pass tetrolet coefficients are applied through a modified transform-based gamma correction method. Generalized cross-validation is used on multiple high-pass tetrolet coefficients to obtain the best threshold value. In the third module, all enhanced coefficients are applied to the partial differential equation method. In the final module, the denoised image is applied to Atanassov's intuitionistic fuzzy set histon-based fuzzy clustering method with centroid optimization using an elephant herding method. Accordingly, the tumor part is segmented from the nontumor part in the magnetic resonance imaging brain images. The method was assessed in terms of peak signal-to-noise ratio, mean square error, specificity, sensitivity, and accuracy. The experimental results showed that the suggested method is superior to traditional methods. 相似文献
997.
Haibo Bi Xusheng Wang Haili Liu Yonglin He Weijian Wang Wenjun Deng Xinlei Ma Yushu Wang Wei Rao Yuqiao Chai Hui Ma Rui Li Jitao Chen Yapei Wang Mianqi Xue 《Advanced materials (Deerfield Beach, Fla.)》2020,32(16):2000074
Aqueous energy-storage systems have attracted wide attention due to their advantages such as high security, low cost, and environmental friendliness. However, the specific chemical properties of water induce the problems of narrow electrochemical stability window, low stability of water–electrode interface reactions, and dissolution of electrode materials and intermediate products. Therefore, new low-cost aqueous electrolytes with different water chemistry are required. The nature of water depends largely on its hydroxyl-based hydrogen bonding structure. Therefore, the super-concentrated hydroxyl-rich sugar solutions are designed to change the original hydrogen bonding structure of water. The super-concentrated sugars can reduce the free water molecules and destroy the tetrahedral structure, thus lowering the binding degree of water molecules by breaking the hydrogen bonds. The ionic electrolytes based on super-concentrated sugars have the expanded electrochemical stability window (up to 2.812 V), wide temperature adaptability (–50 to 80 °C), and fair ionic conductivity (8.536 mS cm−1). Aqueous lithium-, sodium-, potassium-ion batteries and supercapacitors using super-concentrated sugar-based electrolytes demonstrate an excellent electrochemical performance. The advantages of ultralow cost and high universality enable a great practical application potential of the super-concentrated sugar-based aqueous electrolytes, which can also provide great experimental and theoretical assistance for further research in water chemistry. 相似文献
998.
Zhipeng Shao Hongguang Meng Xiaofan Du Xiuhong Sun Peiliang Lv Caiyun Gao Yi Rao Chen Chen Zhipeng Li Xiao Wang Guanglei Cui Shuping Pang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(30):2001054
The stability issue is still one of the main limitations of the commercialization of perovskite photovoltaics. The mixed cation FAxCs1−xPbI3 has shown great promise owing to its improved thermal and moisture stability. However, the study of FAxCs1−xPbI3 is concentrated on formamidine (FA)-rich perovskite, whereas cesium (Cs)-rich FAxCs1−xPbI3 perovskites are barely studied due to the inevitable phase separation when Cs > 30 mol%. Here, a Cs4PbI6-mediated method is developed to synthesize Cs-rich FAxCs1−xPbI3 perovskites. It is demonstrated that Cs4PbI6 intermediate phase has a low Cs cation diffusion barrier and therefore offers a fast ion exchange with the preformed FA-rich perovskite phase to finally form the Cs-rich FAxCs1−xPbI3 perovskite. The results indicate that ≈15% alloying with organic FA cations can sufficiently stabilize the perovskite phase with excellent phase and UV-irradiation stability. The FA0.15Cs0.85PbI3 perovskite solar cells achieve a champion power conversion efficiency of 17.5%, showing the great potential of Cs-based perovskites for efficient and stable solar cells. 相似文献
999.
ABSTRACTTargeted photoacoustic imaging using exogenous contrast agents can potentially improve early detection of breast cancer, even at significant depths inside the breast. In this study, computer simulations were performed to compare the photoacoustic performance of 11 different near-infrared (NIR) dyes for detecting tumours deep inside the breast tissue. It was observed that the three high performing NIR dyes produced at least two-fold contrast enhancement of a spherical breast tumour embedded at 4?cm depth inside the breast than those of the corresponding endogenous contrast agents. These three selected dyes were employed to visualize small blood vessels deep inside the breast tissue. Although methylene blue provided the best contrast in visualizing tumour blood vessels at depths beyond 3?cm, considering other factors such as availability of suitable targeting agent, indocyanine green at 800?nm may be preferred over all other dyes for deep breast imaging applications. 相似文献
1000.
Graphitic porous carbon sheets (GPCS), which were synthesized at a low temperature of 900°C by KOH chemical activation technique, possess a specific surface area of 1246 m2 g-1 with high pore volume. The size of the pores varied in micro-mesopore regions and exhibited three-dimensional sheet-like morphology composed of multilayered graphene sheets with an inter planar distance of 0.360 nm. The GPCS material was tested as anode for Li-ion battery (LIB) application in half cell mode (vs Li+/Li). The fabricated GPCS electrode shows excellent electrochemical properties in comparison with commercial graphite such as a high discharge specific capacity of 1022 mA h g-1 after 10 cycles at 100 mA g-1 and excellent specific capacity retention of 170 mA h g-1 at a very high current rate of 8000 mA g-1 and also retains a high capacity of 541 mA h g-1 after 250 cycles at 500 mA g-1, which suggests that GPCS material can be a promising electrode for LIB application. A brief comparison with commercial graphite and various carbonaceous materials from literature demonstrated that the GPCS electrode was potential material for high rate LIBs. 相似文献