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- 저자 : Jianrui Zhang (검색결과 3 건)
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Yuan Xie,Yanjun Li,Jiqiu Wen,Xue Li,Zhe Zhang,Jianrui Li,Yan’e Zhao,Peng Wang,Jun Zhang,Ying Tian,Long Jiang Zhang,Guang Ming Lu 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2
Objective: To determine the feasibility of reduced field-of-view diffusion-weighted imaging (rFOV DWI) with multi-b values to detect functional variability in transplanted kidneys. Materials and Methods: Using a 3T MRI scanner, multi-b rFOV DWI of transplanted kidney or native kidney was performed in 40 renal transplantation recipients and 18 healthy volunteers. The patients were stratified, according to an estimated glomerular filtration rate (eGFR): Group 1, eGFR ≥ 60 mL/min/1.73 m2; Group 2, eGFR ≥ 30 mL/min/1.73 m2 and < 60 mL/min/1.73 m2; Group 3, eGFR < 30 mL/min/1.73 m2. Total apparent diffusion coefficient (ADCT), perfusion-free ADC (ADCD) and perfusion fraction (FP) of kidneys were calculated and compared among the four groups. Correlations between the imaging results and eGFR were assessed. Results: All volunteers had eGFR ≥ 60 mL/min/1.73 m2, while 16, 16, and 8 patients were included in Groups 1, 2, and 3, respectively. In the renal cortex, ADCT was higher in Group 1 ([1.65 ± 0.13] x 10-3 mm2/s) than Group 3 ([1.44 ± 0.11] x 10-3 mm2/s) (p < 0.05), and the inter-group differences of FP values were significant (all p < 0.05) (0.330 ± 0.024, 0.309 ± 0.019, 0.278 ± 0.033, and 0.250 ± 0.028 for control group, Groups 1, 2, and 3, respectively). Renal cortical ADCT, ADCD, FP, and renal medullary ADCT and FP correlated positively with eGFR (r = 0.596, 0.403, 0.711, 0.341, and 0.323, respectively; all p < 0.05). When using 0.278 as the cutoff value, renal cortical FP had a sensitivity of 97.1% and a specificity of 66.7% for predicting decreased renal function. Conclusion: Multi-b rFOV DWI presents transplanted kidneys with high resolution, which is a promising functional tool for non-invasively monitoring function of transplanted kidneys.
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( Jianrui Fan ),( Xinru Zhao ),( Wencan Wang ),( Shengsuo Cai ),( Lijuan Zhang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.4
Using directional antennas in wireless Ad hoc networks has many superiorities, including reducing interference, extending transmission range, and increasing space division multiplexing. However, directional transmission introduces two problems: deafness and directional hidden terminals problems. We observe that these problems result in saturation throughput disparity among the competing flows in directional CSMA/CA based Ad hoc networks and bring challenges for modeling the saturation throughput of the flows. In this article, we concentrate on how to model and analyze the saturation throughput disparity of different flows in directional CSMA/CA based Ad hoc networks. We first divide the collisions occurring in the transmission process into directional instantaneous collisions and directional persistent collisions. Then we propose a four-dimensional Markov chain to analyze the transmission state for a specific node. Our model has three different kinds of processes, namely back-off process, transmission process and freezing process. Each process contains a certain amount of continuous time slots which is defined as the basic time unit of the directional CSMA/CA protocols and the time length of each slot is fixed. We characterize the collision probabilities of the node by the one-step transition probability matrix in our Markov chain model. Accordingly, we can finally deduce the saturation throughput for each directional data stream and evaluate saturation throughput disparity for a given network topology. Finally, we verify the accuracy of our model by comparing the deviation of analytical results and simulation results.
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Xiaocui Han,Jianrui Zhang,Cheng Yue,Jinhui Pang,Haibo Zhang,Zhenhua Jiang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.91 No.-
The gas separation of polymers of intrinsic microporosity (PIMs) was enhanced by incorporatingbipyrimidine (bpy) into the polymer (PIM-bpy-x) through the polycondensation of a novel tetraphenyl-bipyrimidine monomer. The structures of PIM-bpy-x were investigated with 1H NMR and FT-IR. Becauseof the excellent heat resistance imparted by the tetraphenyl-bipyrimidine unit, PIM-bpy-x displayedbetter thermal stability than did PIM-1. These polymers displayed large Brunauer-Emmett-Teller (BET)surface areas, ranging from 656 to 728 m2 g 1. The BET surface area of PIM-bpy-5 was 728 m2 g 1, whichwas similar to that of PIM-1 (774 m2 g 1). PIM-bpy-x exhibited excellent gas separation performance. PIM-bpy-5 showed the highest CO2 permeability (5141 barrer), which was much higher than that of PIM-1 (4234 barrer). The increase in CO2 permeability is due to the affinity between the N-rich bipyrimidineunits and CO2. Furthermore, PIM-bpy-x also showed greater resistance to aging than did PIM-1. All of theabove indicate that introducing bipyrimidine units into the polymers can enhance the gas separationperformance of PIMs.
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