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排序方式： 共有1038条查询结果，搜索用时 15 毫秒
101.
Jingxing Wu Sailin Liu Yaser Rehman Taizhong Huang Jiachang Zhao Qinfen Gu Jianfeng Mao Zaiping Guo 《Advanced functional materials》2021,31(27):2010832
Sulfides are promising anode candidates because of their relatively large theoretical discharge/charge specific capacity and pretty small volume changes, but suffers from sluggish kinetics and structural instability upon cycling. Phase engineering can be designed to overcome the weakness of the electrochemical performance of sulfide anodes. By choosing nickel sulfides (α-NiS, β-NiS, and NiS2) supported by reduced graphene oxide (rGO) as model systems, it is demonstrated that the nickel sulfides with different crystal structures show different performances in both sodium-ion and potassium-ion batteries. In particular, the α-NiS/rGO display superior stable capacity (≈426 mAh g−1 for 500 cycles at 500 mA g−1) and exceptional rate capability (315 mAh g−1 at 2000 mA g−1). The combined density functional theory calculations and experimental studies reveal that the hexagonal structure is more conducive to ion absorption and conduction, a higher pseudocapacitive contribution, and higher mechanical ability to relieve the stress caused by the volume changes. Correspondingly, the phase engineered nickel sulfide coupled with the conducting rGO network synergistically boosts the electrochemical performance of batteries. This work sheds light on the use of phase engineering as an essential strategy for exploring materials with satisfactory electrochemical performance for sodium-ion and potassium-ion batteries. 相似文献
102.
In the present numerical study, the combined effect of temperature-dependent thermal conductivity, linear thermal radiation, and magnetic effect on shear-thinning tangent hyperbolic fluid past a sensor surface has been studied. After converting the modelled partial differential equations into ordinary differential equations by using similarity transformation, the system of equations is tackled with the aid of the shooting method. The influence of important parameters on the fluid motion and energy distribution is displayed graphically and analyzed in detail. The presented simulations depict that a significant rise in fluid velocity is noticed for an enhancement in the magnetic parameter while an opposite trend is observed for the temperature distribution. Moreover, the skin friction coefficient decreases as the squeezed flow index is increased. 相似文献
103.
S. Adeel M. Saeed A. Abdullah F. Rehman M. Salman M. Kamran 《Journal of Natural Fibers》2018,15(4):517-526
The role of radiations in textile processing is gaining attention due to its low cost, energy effectiveness and eco-friendly process. This study is concerned with the improvement in modulation of microwave assisted vat dyeing of cellulosic fiber. It was found that radiation treatment of both cotton fabric and dye solution for 1 min gives good color strength, while for redox reaction, 2.5 g of NaHSO3, 2 mL of CH3COOH, and 1.5 mL of H2O2 are the optimized conditions which show it is a cost-effective tool. Good color strength was obtained at 65 °C for 1 h dyeing using 50 mL of optimal solution in dye bath at pH 9. Finally, ISO standards for color fastness to light, washing, rubbing and perspiration were applied at 0.5–2.5% of shade at optimal conditions which showed that microwave treatment has enhanced the color characteristics. Hence, the technique can successfully and easily be employed for surface modification of fabric for good quality dyeing with various classes of dyes. 相似文献
104.
Muhammad Ali Raza Ling Yang Feng Wopke van der Werf Gao Ren Cai Muhammad Hayder Bin Khalid Nasir Iqbal Muhammad Jawad Hassan Tehseen Ahmad Meraj Muhammd Naeem Imran Khan Sana ur Rehman Muhammad Ansar Mukhtar Ahmed Feng Yang Wenyu Yang 《Food and Energy Security》2019,8(3)
Planting arrangements affect radiation use efficiency (RUE) and competitiveness of intercrop species in intercropping systems. Here, we reveal that narrow‐wide‐row planting arrangement in maize‐soybean relay‐intercropping system increases the dry matter and competitiveness of soybean, increased the RUE of maize and soybean, and compensates the yield loss of maize by substantially increasing the yield of soybean. In this field study, maize was planted with soybean in different planting arrangements (P1, 20:180, P2, 40:160; P3, 60:140, and P4, 80:120) of relay intercropping, all the relay‐intercropping treatments were compared with sole crops of maize (SM) and soybean (SS). Results showed that P1 improved the total RUE 3.26 g/MJ (maize RUE + soybean RUE) of maize and soybean in relay‐intercropping system. Compared to P4, treatment P1 increased the soybean competition ratio (CR) values (by 55%) but reduced the maize CR values (by 29%), which in turn significantly improved the yield of soybean by maintaining the maize yield. Generally, in P1, soybean produced 82% of SS yield, and maize produced 88% of SM yield, and it achieved the land equivalent ratio of 1.7. These results suggest that by maintaining the appropriate planting distances between maize and soybean we can improve the competitiveness and yield of intercrop species in relay‐intercropping system. 相似文献
105.
In this work, the optical, film formation, morphological and the magnetic properties of a novel type of nanocomposite system, composed of polystyrene (PS) latex and core‐shell superparamagnetic nanoparticles (SP‐MNPs), is presented. The film formation and optical properties were examined by UV‐vis technique, morphological changes by scanning electron microscopy and magnetic properties studied using vibrating sample magnetometer (VSM) as a function of SP‐MNPs content. A series of mixtures were prepared by mixing of PS latex dispersion with different amount of SP‐MNPs in the range of (0–100 wt%). PS/SP‐MNPs films were then prepared from these mixtures on glass substrates using drop casting method. After drying, film was separately annealed at elevated temperatures between 100°C and 250°C. In order to monitor film formation process, transmittance of these composites was measured after each annealing step as a function of SP‐MNPs content. It was found that below a critical SP‐MNPs content, PS percolates into the SP‐MNPs hard phase and forms an interconnected network upon annealing. However, above this critical value, PS latexes were no longer film forming at all temperatures. Besides, composite films showed superparamagnetic behaviors. The saturation magnetization (Ms) first increased and reached to 0.014 emu/cm3 at 50 wt% SP‐MNPs, then decreased to 0.010 emu/cm3 with increasing SP‐MNPs content. The maximum value of Ms was approximately 0.020 emu/cm3 and was obtained for the 85 wt% SP‐MNPs content film. These results indicated that the optical, film formation and magnetic properties of PS/SP‐MNPs composite films can be readily tuned by varying SP‐MNPs content. POLYM. COMPOS., 40:1018–1033, 2019. © 2018 Society of Plastics Engineers 相似文献
106.
Abdul Rehman Yasin Muhammad Ashraf Aamer Iqbal Bhatti Ali Arshad Uppal 《Asian journal of control》2019,21(4):2074-2086
The rising cost of fossil fuels, their high depleting rate and issues regarding environmental pollution have brought the attention of the researchers towards renewable energy technologies. Different renewable energy resources like wind turbines, fuel cells and solar cells are connected to DC micro grid through controllable power electronic converters. In presence of these diverse generation units, robust controllers are required to ensure good power quality and to regulate grid voltage. This paper presents a sliding mode control based methodology to address the above mentioned challenges. The proposed technique keeps the switching frequency constant so that electromagnetic compatibility (EMC) issues can be solved with conventional filter design. Parallel operation of converter in DC micro gird is considered. Chattering reduction and power quality improvement by harmonic cancellation is proposed. A scaled down hardware for unregulated 11.5 V to 17.5 V input and 24V output is designed and tested. The experimental results show good performance of the controller under different loads and uncertain input voltage conditions. Moreover, the results show the robustness of the closed loop system to sudden variations in load conditions. Furthermore, a significant improvement in power quality is achieved by harmonic cancellation of chattering in the output of the converters. 相似文献
107.
108.
Kashif Iqbal Asfandyar Khan Danmei Sun Munir Ashraf Abdur Rehman Faiza Safdar 《纺织学会志》2019,110(4):625-638
Phase change materials (PCMs) are widely being used in thermal energy storage systems for solar engineering, building materials, heat pumps, spacecraft, and in textile field especially smart and technical textiles. There are large numbers of organic and inorganic PCMs that possess a wide range of melting and solidifying temperature which attracts researcher’s attention for their applications in different fields. This review paper summarizes the investigation and analysis of the available organic and inorganic PCMs, different encapsulating techniques, characterization techniques, incorporation into fiber and pad application on textiles with practical applications in the field of smart textiles. 相似文献
109.
Zeliha Uur Ayd&#x;n Neslihan Büra Keskin Taha
zyürek 《Microscopy research and technique》2019,82(6):856-860
The purpose of this study was to evaluate and compare the effect of Reciproc Blue (RPCB), XP‐endo Shaper (XPS), and WaveOne Gold (WOG) single‐files on dentinal microcrack formation using micro‐computed tomography (micro‐CT). Twenty‐four mesial roots (24 mesio‐buccal and 24 mesio‐lingual canals) of mandibular molar teeth were prepared using RPCB, XPS, and WOG files (n = 8/each group). The samples were scanned with micro‐CT in the pre‐ and post‐preparation. Then, before preparation and after preparation cross‐sectional images of the teeth were evaluated to detect the presence of microcracks. For each group, the number of microcracks was calculated as a percentage rate. The data were statistically analyzed using McNemar at 5% significance level (p < .05). Dentinal microcracks were observed in 25.99% (2,103 of 7,813), 31.99% (2,482 of 7,758), and 36.66% (2,836 of 7,731) of cross‐sectional images of the XPS, WOG, and RPCB groups, respectively. In all the groups, all the dentinal microcracks seen in the post‐treatment cross‐sectional images were present in the corresponding pre‐treatment images. Within the limitations of this study, the XPS, WOG, and RPCB files did not cause new dentinal microcrack formation or propagation of existing dentinal microcracks. 相似文献
110.
Naveed Abbas Tanzila Saba Amjad Rehman Zahid Mehmood Nadeem Javaid Muhammad Tahir Naseer Ullah Khan Khawaja Tehseen Ahmed Roaider Shah 《Microscopy research and technique》2019,82(7):1198-1214
Malaria is a serious worldwide disease, caused by a bite of a female Anopheles mosquito. The parasite transferred into complex life round in which it is grown and reproduces into the human body. The detection and recognition of Plasmodium species are possible and efficient through a process called staining (Giemsa). The staining process slightly colorizes the red blood cells (RBCs) but highlights Plasmodium parasites, white blood cells and artifacts. Giemsa stains nuclei, chromatin in blue tone and RBCs in pink color. It has been reported in numerous studies that manual microscopy is not a trustworthy screening technique when performed by nonexperts. Malaria parasites host in RBCs when it enters the bloodstream. This paper presents segmentation of Plasmodium parasite from the thin blood smear points on region growing and dynamic convolution based filtering algorithm. After segmentation, malaria parasite classified into four Plasmodium species: Plasmodium falciparum, Plasmodium ovale, Plasmodium vivax, and Plasmodium malaria. The random forest and K‐nearest neighbor are used for classification base on local binary pattern and hue saturation value features. The sensitivity for malaria parasitemia (MP) is 96.75% on training and testing of the proposed approach while specificity is 94.59%. Beside these, the comparisons of the two features are added to the proposed work for classification having sensitivity is 83.60% while having specificity is 94.90% through random forest classifier based on local binary pattern feature. 相似文献