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Diameter Variations of Irregular Fibers under Different Tensions
Deng, Chuanming,Wang, Lijing,Wang, Xungai The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.6
The cross-section area of animal fibers varies along the fiber length, and this geometrical irregularity has a major impact on the mechanical properties of those fibers. In practice fibers are often subjected to tensile stresses during processing and application, which may change fiber cross-section area. It is thus necessary to examine geometrical irregularity of fibers under tension. In this study, scoured animal fibers were subjected to different tensile loading using a Single Fiber Analyzer (SIFAN) instrument. The 3D images of the fiber specimens were first constructed, and then along-fiber diameter irregularities of the specimens were analyzed for different levels of tensile loading. The changes in effective fineness of the fiber specimens were also discussed. The results indicate that for the wool fibers examined, there is considerable discrepancy in the fiber diameter results obtained from the commonly used single scan along fiber length and that from multiple scans at different rotational angles, and that the diameter variation along fiber length increases as fiber tension increases. The results also show that when diameter reduction treatments are applied to wool by stretching, the reduced average fiber diameter is associated with an increase in both within-fiber and between-fiber diameter variations. So in terms of effective fineness, the change is much smaller than the difference between the average diameters of the parent and treated wool. These results have significant implications for improving the accuracy of fiber diameter measurement and evaluation.
Margin Adaptive Optimization in Multi-User MISO-OFDM Systems under Rate Constraint
Wei, Chuanming,Qiu, Ling,Zhu, Jinkang The Korea Institute of Information and Commucation 2007 Journal of communications and networks Vol.9 No.2
In this paper, we focus on the total transmission power minimization problem for downlink beamforming multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems while ensuring each user's QoS requirement. Although the linear integer programming (LIP) solution we formulate provides the performance upper bound of the margin adaptive (MA) optimization problem, it is hard to be implemented in practice due to its high computational complexity. By regarding each user's equivalent channel gain as approximate independent values and using iterative descent method, we present a heuristic MA resource allocation algorithm. Simulation results show that the proposed algorithm efficiently converges to the local optimum, which is very close to the performance of the optimal LIP solution. Compared with existing space division multiple access (SDMA) OFDM systems with or without adaptive resource allocation, the proposed algorithm achieves significant performance improvement by exploiting the frequency diversity and multi-user diversity in downlink multiple-input single-output (MISO) OFDM systems.
Ning ShuYa,Wu Yuan,Wu ChuanMing,Zhang YiFan,Luo MeiTing,Wang XinYe,Wang DongDong 한국물리학회 2022 Current Applied Physics Vol.39 No.-
TADF-sensitizing-fluorescence (TSF) strategy suffered a disturbing energy loss causing by the T1 states of fluorescence dopant (FD) due to its low T1-state energy and forbidden of radiative transition. In this manuscript, we used TCTA/PO-T2T planar heterojunction (PHJ) interface as exciton generation zone and adjacent PO-T2T layer doped with rubrene as fluorescence emission zone, achieved the maximum EQE and CE of 8.3% and 26.1 cd A-1, respectively for rubrene-based device. Our experiments show the necessary PO-T2T thickness doped with rubrene is 15 nm and thicker doping layer over 15 nm would destroy device efficiency. It was further found that the exciplex exciton begin to decay within the time of 4 nm diffusion distance in PO-T2T layer and most of exciplex excitons were restrained in TCTA/PO-T2T heterojunction interface in PHJ device. The about 1.1 eV barrier for hole injection from TCTA to PO-T2T and bad hole-transporting capability of PO-T2T made exciple exciton only generate on this interface. Thus, even if the rubrene doped PO-T2T layer is right after the TCTA layer, FD in PO-T2T layer are well separated to the exciplex excitons in TCTA/PO-T2T interface, overcoming T1 energy loss caused by FD. Our approach provides a beneficial path towards overcome energy loss causing by the T1 states of FD in TSF-OLEDs based on exciplex as TADF sensitizer.
Song Rao,Wu Xiaojia,Liu Huan,Guo Dajing,Tang Lin,Zhang Wei,Feng Junbang,Li Chuanming 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.1
Objective: To improve the N biomarker in the amyloid/tau/neurodegeneration system by radiomics and study its value for predicting cognitive progression in individuals with mild cognitive impairment (MCI). Materials and Methods: A group of 147 healthy controls (HCs) (72 male; mean age ± standard deviation, 73.7 ± 6.3 years), 197 patients with MCI (114 male; 72.2 ± 7.1 years), and 128 patients with Alzheimer’s disease (AD) (74 male; 73.7 ± 8.4 years) were included. Optimal A, T, and N biomarkers for discriminating HC and AD were selected using receiver operating characteristic (ROC) curve analysis. A radiomics model containing comprehensive information of the whole cerebral cortex and deep nuclei was established to create a new N biomarker. Cerebrospinal fluid (CSF) biomarkers were evaluated to determine the optimal A or T biomarkers. All MCI patients were followed up until AD conversion or for at least 60 months. The predictive value of A, T, and the radiomics-based N biomarker for cognitive progression of MCI to AD were analyzed using Kaplan-Meier estimates and the log-rank test. Results: The radiomics-based N biomarker showed an ROC curve area of 0.998 for discriminating between AD and HC. CSF Aβ42 and p-tau proteins were identified as the optimal A and T biomarkers, respectively. For MCI patients on the Alzheimer’s continuum, isolated A+ was an indicator of cognitive stability, while abnormalities of T and N, separately or simultaneously, indicated a high risk of progression. For MCI patients with suspected non-Alzheimer’s disease pathophysiology, isolated T+ indicated cognitive stability, while the appearance of the radiomics-based N+ indicated a high risk of progression to AD. Conclusion: We proposed a new radiomics-based improved N biomarker that could help identify patients with MCI who are at a higher risk for cognitive progression. In addition, we clarified the value of a single A/T/N biomarker for predicting the cognitive progression of MCI.