Gate-Tunable Tunneling Resistance in Graphene/Topological Insulator Vertical Junctions

Graphene-based vertical heterostructures, particularly stacks incorporated with other layered materials, are promising for nanoelectronics. The stacking of two model Dirac materials, graphene and topological insulator, can considerably enlarge the family of van der Waals heterostructures. Despite well understanding of the two individual materials, the electron transport properties of a combined vertical heterojunction are still unknown. Here we show the experimental realization of a vertical heterojunction between Bi2Se3 nanoplate and monolayer graphene. At low temperatures, the electron transport through the vertical heterojunction is dominated by the tunneling process, which can be effectively tuned by gate voltage to alter the density of states near the Fermi surface. In the presence of a magnetic field, quantum oscillations are observed due to the quantized Landau levels in both graphene and the two-dimensional surface states of Bi2Se3. Furthermore, we observe an exotic gate-tunable tunneling resistance under high magnetic field, which displays resistance maxima when the underlying graphene becomes a quantum Hall insulator

Noncoherent Spatial/Spectral Optical CDMA System With Two-Dimensional Perfect Difference Codes

[[abstract]]A dynamic optical code division multiple access (DOCDMA) communication system is proposed for high-bandwidth communication systems. An implementation of the system is proposed based on a fast tunable optical filter (TOF) in each encoder and decoder. This technique actively modulates the central wavelength of a TOF according to a functional code at the transmitter during the bit period before the transmission of the data. The system is modeled and analyzed taking into account multiple access interference (MAI), thermal noise, and phase-induced intensity noise (PIIN). The performance of this system is compared to that of a spectral amplitude coding system that uses either a Hadamard code or a modified quadratic congruence (MQC) code. The results show that the proposed DOCDMA system reduces the PIIN effect on the performance of the system and improves the bit error rate (BER) performance at a large number of users. Furthermore, it is found that when the effective power is large enough, the MAI becomes the main factor that limits system performance, whereas when the effective power is relatively low, both thermal noise and PIIN become the main limiting factors with thermal noise having the main influence.[[notice]]補正完畢[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙本[[booktype]]電子

THE IMPACT OF SOCIAL PSYCHOLOGICAL FACTORS ON THE RELATIONSHIP QUALITY OF FACEBOOK USERS

Armed with the great potential for business value and social networking, social media have generated great interests in academia and practice. Rare studies investigated the impact of social psychological factors on the usage of Facebook and the formation of quality relationship. The objective of this paper is to examine the key social psychological factors to better explain the formation of quality relationship. Our proposed theoretical model combined the theories of social influence, social identity, and social presence to capture the essences of the relationship quality between users and Facebook. We conducted a survey to collect data and empirically test our proposed model. Overall, our findings provide theoretical insights to explain the influence of social psychological factors on the usage of Facebook and quality relationship. These findings also help practitioners to plan marketing strategies in better utilize social network sites

In-silico design of novel 4-aminoquinolinyl analogs as potential anti-malaria agents using quantitative structure– activity relationships and ADMET approach

Purpose: To design and screen for potential anti-malaria agents based on a series of 4-aminoquinolinyl analogues.Methods: Molecular fingerprint analysis was used for molecular partitioning of training and test sets. Acquired training sets were used for CoMFA and CoMSIA model construction after good alignment was achieved. Partial least squares analysis combined with external validation were used for  model evaluation. Deep analysis of acquired contour maps was performed to summarize the substituent property requirements for further rational molecular design. Using the chosen models, activity prediction and subsequent ADMET investigation were performed to discover novel designed  compounds with the desired properties.Results: Three different set partitions for model establishment were obtained using fingerprint-based selection. Partition 02 offered an optimal CoMFA model (r2 = 0.964, q2 = 0.605 and r2pred = 0.6362) and the best CoMSIA model (r2 = 0.955, q2 = 0.585 and r2 pred = 0.6403). Based on contour map analysis, a series of compounds were designed for activity prediction. Two of the compounds (wmx09, wmx25) were chosen for their ideal predicted biological activities. Subsequent ADMET investigation indicated that these compoundss have acceptable drug-like characteristics.Conclusion: The screening reveals that compounds wmx09 and wmx25 have strong potential as antimalaria agents. Keywords: Malaria, 4-Aminoquinolinyl, Molecular fingerprint, QSAR, ADME

Shoupa: An AI System for Early Diagnosis of Parkinson's Disease

Parkinson's Disease (PD) is a progressive nervous system disorder that has affected more than 5.8 million people, especially the elderly. Due to the complexity of its symptoms and its similarity to other neurological disorders, early detection requires neurologists or PD specialists to be involved, which is not accessible to most old people. Therefore, we integrate smart mobile devices with AI technologies. In this paper, we introduce the framework of our developed PD early detection system which combines different tasks evaluating both motor and non-motor symptoms. With the developed model, we help users detect PD punctually in non-clinical settings and figure out their most severe symptoms. The results are expected to be further used for PD rehabilitation guidance and detection of other neurological disorders.Comment: 2 pages, 1 figure, accepted by IEEE/ACM CHASE 2022 (Poster Presentation