2,053 research outputs found
Codebook-Based Beam Tracking for Conformal ArrayEnabled UAV MmWave Networks
Millimeter wave (mmWave) communications can potentially meet the high
data-rate requirements of unmanned aerial vehicle (UAV) networks. However, as
the prerequisite of mmWave communications, the narrow directional beam tracking
is very challenging because of the three-dimensional (3D) mobility and attitude
variation of UAVs. Aiming to address the beam tracking difficulties, we propose
to integrate the conformal array (CA) with the surface of each UAV, which
enables the full spatial coverage and the agile beam tracking in highly dynamic
UAV mmWave networks. More specifically, the key contributions of our work are
three-fold. 1) A new mmWave beam tracking framework is established for the
CA-enabled UAV mmWave network. 2) A specialized hierarchical codebook is
constructed to drive the directional radiating element (DRE)-covered
cylindrical conformal array (CCA), which contains both the angular beam pattern
and the subarray pattern to fully utilize the potential of the CA. 3) A
codebook-based multiuser beam tracking scheme is proposed, where the Gaussian
process machine learning enabled UAV position/attitude predication is developed
to improve the beam tracking efficiency in conjunction with the tracking-error
aware adaptive beamwidth control. Simulation results validate the effectiveness
of the proposed codebook-based beam tracking scheme in the CA-enabled UAV
mmWave network, and demonstrate the advantages of CA over the conventional
planner array in terms of spectrum efficiency and outage probability in the
highly dynamic scenarios
Polyketides from the Halotolerant Fungus Myrothecium sp. GS-17
Two new polyketides, myrothecol (1) and 5-hydroxy-3-methyl-4-(1- hydroxylethyl)-furan-2(5H)-one (2), were isolated from the fermentation broth of the halotolerant fungus Myrothecium sp. GS-17 along with three known compounds, 5-hydroxyl-3-[(1S)-1-hydroxyethyl]-4-methylfuran-2(5H)-one (3), 3,5-dimethyl-4- hydroxylmethyl-5-methoxyfuran-2(5H)-one (4), and 3,5-dimethyl-4-hydroxymethyl-5- hydroxyfuran-2(5H)-one (5). Compound 1 is the first natural occurring polyketide with a unique furylisobenzofuran skeleton. The structures of these compounds were established via extensive spectroscopic analyses including 1D-, 2D-NMR, HRESI-MS, and crystal X-ray diffraction analysis
Design and characterization of alkoxy-wrapped push–pull porphyrins for dye-sensitized solar cells
Three alkoxy-wrapped push–pull porphyrins were designed and synthesized for dye-sensitized solar cell (DSSC) applications. Spectral, electrochemical, photovoltaic and electrochemical impedance spectroscopy properties of these porphyrin sensitizers were well investigated to provide evidence for the molecular desig
Exploring natural therapy for chronic heart failure: experience in traditional Chinese medicine treatment before 2022
BackgroundTraditional Chinese medicine has great advantages in improving symptoms of CHF such as chest tightness, shortness of breath, and fatigue. In addition, some traditional Chinese medicines can be used as both medicine and food, which have good effects on the prevention and treatment of CHF patients at home.MethodA comprehensive search across China National Knowledge Infrastructure (CNKI), Wanfang, and Wei Pu (VIP) databases was conducted to retrieve pre-2022 literature related to CHF. After standardization, frequency analysis and Apriori algorithm were used to analyze these data.ResultAmong 626 effective medical records, Fuling, Huangqi, and Danshen are the most commonly used herbs; The medication for chest tightness is closely related to Tinglizi; The medication for palpitations is closely related to Guizhi, Fuzi, Zhigancao, and Wuweizi; The medication of fatigue and poor appetite is closely related to Huangqi and Baizhu; The medication for lower limb edema is closely related to Fuling and Tinglizi; The medication for coughing is closely related to the use of Tinglizi, Wuweizi, Kuxingren, and Sangbaipi; Insomnia is closely related to Suanzaoren and Dazao.ConclusionThe components in traditional Chinese medicine that have anti heart failure effects and reliable evidence can be potential candidates for drug discovery, while dietary therapeutic herbs such as Fuling, Huangqi, Danshen, and Zhigancao can be developed as health products
Observation of eight-photon entanglement
Using ultra-bright sources of pure-state entangled photons from parametric
down conversion, an eight-photon interferometer and post-selection detection,
we demonstrate the ability to experimentally manipulate eight individual
photons and report the creation of an eight-photon Schr\"odinger cat state with
an observed fidelity of .Comment: 6 pages, 4 figure
Epidemiologic characterization of 30 confirmed cases of human infection with avian influenza A(H7N9) virus in Hangzhou, China
BACKGROUND: We examined the clinical and epidemiological characteristics of 30 cases of human infection with avian influenza A(H7N9) virus in Hangzhou and investigated their external environments to provide evidence for contact tracing and disease prevention and control. METHODS: The cases confirmed from April 1 through May 1, 2013 were studied. Field epidemiologic surveys were conducted to collect the clinical and epidemiologic data. Case-related and environmental specimens were collected for etiologic detection. RESULTS: Thirty cases of human infection with avian influenza A(H7N9) virus were confirmed in Hangzhou from April 1 through May 1, 2013, including one pregnant woman and three deaths. The median age of the patients was 62 years (range: 38–86 years). Twenty-three of the patients were men (76.67%). The median duration between disease onset and occurrence of respiratory failure and confirmed diagnosis was 5 and 6 days, respectively. Maximum medical observation of 666 close contacts of the patients revealed no irregularity. Of 314 external environmental specimens, the overall positive detection rate of H7N9 nucleic acid was 28.98%. Eight districts of Hangzhou city had positive detections in the external environments, the highest rate being in Yuhang District (78.13%). Statistical analysis of the specimen collection locations indicates a significant difference between the case-linked locations and the non-case locations (χ( 2 ) = 16.563, p < 0.05) in terms of H7N9 viral nucleic acid detection rate. No epidemiologic link has been found among the 30 cases. CONCLUSIONS: Most of the infected were retired individuals aged 60 years or older. Men made the majority. The cases are sporadic at present, with no evidence of human-to-human transmission. Exposures to poultry and live poultry markets may be important sources of infection
A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III
We established a method on measuring the \dzdzb mixing parameter for
BESIII experiment at the BEPCII collider. In this method, the doubly
tagged events, with one decays to
CP-eigenstates and the other decays semileptonically, are used to
reconstruct the signals. Since this analysis requires good separation,
a likelihood approach, which combines the , time of flight and the
electromagnetic shower detectors information, is used for particle
identification. We estimate the sensitivity of the measurement of to be
0.007 based on a fully simulated MC sample.Comment: 6 pages, 7 figure
Revealing histological and morphological features of female reproductive system in tree shrew (Tupaia belangeri)
The tree shrew has been used as a primate animal model in neuroscience studies but it has only rarely been employed in the study of reproductive systems. This is mainly because we know very little about the histological features of reproductive organs of the tree shrew. In this study, we have systematically analyzed the histology of reproductive organs of tree shrew, in comparison with human organs. The uterus of female tree shrew is uterus biomes unicolis, which is connected with an enveloped ovary through a thin fallopian tube. Histologically, the fallopian tube consists of folded mucosa, muscularis and serosa. Like other mammalian animals, the different developmental stages (primordial, primary, secondary and Graafian follicles) of ovarian follicles including inner oocyte and outer granulosa cells are embedded in the cortex. The luminal endometrium, middle muscular myometrium and serosa constitute the wall of uterus of tree shrew. The uterine endometrium contains simple columnar ciliated cells and goblet cells, and there are rich uterine glands in underlying stroma. Furthermore, these glands of tree shrew are round and smaller during anestrus, and become much longer when they are in estrus. The uterine endometrium in younger animals was less developed when compared to a mature tree shrew. Compared to human uterine endometrium, the histological features of tree shrew are very similar, indicating that it could potentially be good primate animal model for studying the diseases in reproductive system
- …
