National University of Defense Technology

About: National University of Defense Technology is a education organization based out in Changsha, China. It is known for research contribution in the topics: Radar & Synthetic aperture radar. The organization has 39430 authors who have published 40181 publications receiving 358979 citations. The organization is also known as: Guófáng Kēxuéjìshù Dàxué & NUDT.

High-Performance Few-layer Mo-doped ReSe2 Nanosheet Photodetectors

Abstract: Transition metal dichalcogenides (TMDCs) have recently been the focus of extensive research activity owing to their fascinating physical properties. As a new member of TMDCs, Mo doped ReSe2 (Mo:ReSe2) is an octahedral structure semiconductor being optically biaxial and highly anisotropic, different from most of hexagonal layered TMDCs with optically uniaxial and relatively high crystal symmetry. We investigated the effects of physisorption of gas molecule on the few-layer Mo:ReSe2 nanosheet based photodetectors. We compared the photoresponse of the as-exfoliated device with annealed device both in air or ammonia (NH3) environment. After annealing at sub-decomposition temperatures, the Mo:ReSe2 photodetectors show a better photoresponsivity (~55.5 A/W) and higher EQE (10893%) in NH3 than in air. By theoretical investigation, we conclude that the physisorption of NH3 molecule on Mo:ReSe2 monolayer can cause the charge transfer between NH3 molecule and Mo:ReSe2 monolayer, increasing the n-type carrier density of Mo:ReSe2 monolayer. The prompt photoswitching, high photoresponsivity and different sensitivity to surrounding environment from the few-layer anisotropic Mo:ReSe2 can be used to design multifunctional optoelectronic and sensing devices.

A Review of Routing Protocols for Mobile Ad Hoc Networks

Abstract: There are significant differences between wire networks and MANETs.MANETs have nodes with high mobility,limited bandwidth resources,and variable topology.Therefore,there is a need for new routing protocols,which solves all these drawbacks.Most routing protocols for MANETs do not take fairness into account.They tend to have a heavy burden on the hosts along the shortest path from a source to a destination.As a result,heavily loaded hosts may deplete power energy quickly,which will lead to network disconnections and failure of application sessions.There have been some methods of multipath routing to solve the question.In this paper,the progress of the multipath routing technique is surveyed,and various routing protocols are described and evaluated,which cover most types of multipath routing protocols,and then provide a comparison and discussion of their respective merits and drawbacks.Finally,the future research directions are outlined.

Analysis of 3 Algorithms for Syphilis Serodiagnosis and Implications for Clinical Management

Abstract: Background. Algorithms for the diagnosis of syphilis continue to be a source of great controversy, and numerous test interpretations have perplexed many clinicians. Methods. We conducted a cross-sectional study of 24 124 subjects to analyze 3 syphilis testing algorithms: traditional algorithm, reverse algorithm, and the European Centre for Disease Prevention and Control (ECDC) algorithm. Every serum sample was simultaneously evaluated using the rapid plasma reagin, Treponema pallidum particle agglutination, and chemiluminescence immunoassay tests. With the results of clinical diagnoses of syphilis as a gold standard, we evaluated the diagnostic accuracy of the 3 syphilis testing algorithms. The κ coefficient was used to compare the concordance between the reverse algorithm and the ECDC algorithm. Results. Overall, 2749 patients in our cohort were diagnosed with syphilis. The traditional algorithm had the highest negative likelihood ratio (0.24), a missed diagnosis rate of 24.2%, and only 75.81% sensitivity. However, both the reverse and ECDC algorithms had higher diagnostic efficacy than the traditional algorithm. Their sensitivity, specificity, and accuracy were 99.38%–99.85%, 99.98%–100.00%, and 99.93%–99.96%, respectively. Moreover, the overall percentage of agreement and κ value between the reverse and the ECDC algorithms were 99.9% and 0.996, respectively. Conclusions. Our research supported use of the ECDC algorithm, in which syphilis screening begins with atreponemal immunoassay that is followed by a second, different treponemal assay as a confirmatory test in highprevalence populations. In addition, our results indicated that nontreponemal assay is unnecessary for syphilis diagnosis but can be recommended for determining serological activity and the effect of syphilis treatment.

A Fast SINS Initial Alignment Scheme for Underwater Vehicle Applications

Abstract: To achieve high Strapdown Inertial Navigation System (SINS) alignment accuracy within a short period of time is still a challenging issue for underwater vehicles. In this paper, a new SINS initial alignment scheme aided by the velocity derived from Doppler Velocity Log (DVL) is proposed to solve this problem. In the stage of the coarse alignment, the velocity of DVL is employed to reduce the impact of the linear motion. With a backtracking framework, the fine alignment runs with the data recorded during the process of the coarse alignment and thus will speed up the overall alignment process. In addition, by using this new scheme, it is equivalent to length the alignment time for both coarse and fine alignments, so the accuracy of the alignments will be improved. In order to reduce the volume of the data that has to be recorded, a new model for SINS fine alignment is derived in the inertial reference frame which makes it feasible for real time applications. The experimental results are presented for both unaided static and in-motion alignment using DVL aiding. It is clearly shown that the proposed method meets the requirement of SINS alignment for underwater vehicles.