Spectroscopic Observation and Modeling of Photonic Modes in CeO2 Nanocubes

Photonic modes in dielectric nanostructures, e.g., wide gap semiconductor like CeO2 (ceria), has potential for various applications such as light harvesting and information transmission. To fully understand the properties of such phenomenon in nanoscale, we applied electron energy-loss spectroscopy (EELS) in scanning transmission electron microscope (STEM) to detect such modes in a well-defined ceria nanocube. Through spectra and mapping, we demonstrated a geometrical difference of mode excitation. By comparing various spectra taken at different location relative to the cube, we also showed the transmission properties of the mode. To confirm our observation, we performed EELS simulation with finite-element dielectric calculations in COMSOL Multiphysics. We also revealed the origin of the modes through the calculation. We purposed a simple analytical model to estimate the energy of photonic modes as well. In all, this work gave a fine description of the photonic modes' properties in nanostructures, while demonstrating the advantage of EELS in characterizing optical phenomena in nanoscale

Time-Optimal Control for High-Order Chain-of-Integrators Systems with Full State Constraints and Arbitrary Terminal States

Time-optimal control for high-order chain-of-integrators systems with full state constraints and arbitrary given terminal states remains a challenging problem in the optimal control theory domain, yet to be resolved. To enhance further comprehension of the problem, this paper establishes a novel notation system and theoretical framework, successfully providing the switching manifold for high-order problems in the form of switching law. Through deriving properties of switching laws on signs and dimension, this paper proposes a definite condition for time-optimal control. Guided by the developed theory, a trajectory planning method named the manifold-intercept method (MIM) is developed. The proposed MIM can plan time-optimal jerk-limited trajectories with full state constraints, and can also plan near-optimal higher-order trajectories with negligible extra motion time. Numerical results indicate that the proposed MIM outperforms all baselines in computational time, computational accuracy, and trajectory quality by a large gap

A New Species of the Asian Toad Genus Megophrys sensu lato(Amphibia: Anura: Megophryidae) from Guizhou Province, China

We describe a new species of the genus Megophrys sensu lato from Guizhou Province, China. Molecular phylogenetic analyses based on mitochondrial DNA and nuclear DNA sequences all strongly supported the new species as an independent lineage in Megophrys (Panophrys) clade. The new species is distinguished from its congeners by a combination of the following morphological characteristics: (1) small body size with SVL < 38.8 mm in male and SVL < 42.3 mm in female; (2) vomerine teeth absent; (3) tongue not notched behind; (4) a small horn-like tubercle at the edge of each upper eyelid; (5) tympanum distinctly visible, rounded; (6) two metacarpal tubercles in hand; (7) relative finger lengths: II < I < V < III; (8) toes with rudimentary webbing at bases; (9) heels overlapping when thighs are positioned at right angles to the body; (10) tibiotarsal articulation reaching the level between tympanum to eye when leg stretched forward; (11) an internal single subgular vocal sac in male; (12) in breeding male, the nuptial pads with black nuptial spines on the dorsal bases of the first and second fingers

Improved Side Channel Cube Attacks on PRESENT

The paper presents several improved side channel cube attacks on PRESENT based on single bit leakage model. Compared with the previous study of Yang et al in CANS 2009 [30], based on the same model of single bit leakage in the 3rd round, we show that: if the PRESENT cipher structure is unknown, for the leakage bit 0, 32-bit key can be recovered within $2^{7.17}$ chosen plaintexts; if the cipher structure is known, for the leakage bit 4,8,12, 48-bit key can be extracted by $2^{11.92}$ chosen plaintexts, which is less than $2^{15}$ in [30]; then, we extend the single bit leakage model to the 4th round, based on the two level “divide and conquer” analysis strategy, we propose a sliding window side channel cube attack on PRESENT, for the leakage bit 0, about $2^{15.14}$ chosen plaintexts can obtain 60-bit key; in order to obtain more key bits, we propose an iterated side channel cube attack on PRESENT, about $2^{8.15}$ chosen plaintexts can obtain extra 12 equivalent key bits, so overall $2^{15.154}$ chosen plaintexts can reduce the PRESENT-80 key searching space to $2^{8}$; finally, we extend the attack to PRESENT-128, about $2^{15.156}$ chosen plaintexts can extract 85 bits key, and reduce the PRESENT-128 key searching space to $2^{43}$. Compared with the previous study of Abdul-Latip et al in ASIACCS 2011 [31] based on the Hamming weight leakage model, which can extract 64-bit key of PRESENT-80/128 by $2^{13}$ chosen plaintexts, our attacks can extract more key bits, and have certain advantages over [31]

A new species of the odorous frog genus Odorrana (Amphibia, Anura, Ranidae) from southwestern China

The genus Odorrana is widely distributed in the mountains of East and Southeastern Asia. An increasing number of new species in the genus have been recognized especially in the last decade. Phylogenetic studies of the O. schmackeri species complex with wide distributional range also revealed several cryptic species. Here, we describe a new species in the species complex from Guizhou Province of China. Phylogenetic analyses based on mitochondrial DNA indicated the new species as a monophyly clustered into the Odorrana clade and sister to O. schmackeri, and nuclear DNA also indicated it as an independent lineage separated from its related species. Morphologically, the new species can be distinguished from its congeners based on a combination of the following characters: (1) having smaller body size in males (snout-vent length (SVL) <43.3 mm); (2) head longer than wide; (3) dorsolateral folds absent; (4) tympanum of males large and distinct, tympanum diameter twice as long as width of distal phalanx of finger III; (5) two metacarpal tubercles; (6) relative finger lengths: II < I < IV < III; (7) tibiotarsal articulation reaching to the level between eye to nostril when leg stretched forward; (8) disks on digits with circum-marginal grooves; (9) toes fully webbed to disks; (10) the first subarticular tubercle on fingers weak; (11) having white pectoral spinules, paired subgular vocal sacs located at corners of throat, light yellow nuptial pad on the first finger in males

Design and realization of a 3-K cryostat for a 10-cm ultrastable silicon cavity

Crystalline optical cavities operating at cryogenic temperatures provide a promising route for realizing the next generation of ultrastable lasers with extremely low thermal noise floor. However, it remains challenging to realize a closed-cycle cryostat for cooling a relatively long cavity to very low temperatures. Here we report on the design and experimental realization of a cryostat operating continuously at 3.1 K for an ultrastable 10-cm silicon cavity. Based on a combination of active temperature control and passive thermal damping, we realize at 3.1 K a two-second temperature instability of 6 × 10−8 K for the cavity. By implementing separate supporting structures for the cryocooler and the sample chamber, we realize vibration control on the 1 × 10−7g level at one second in each spatial direction, where g is the gravitational acceleration. With all these features, our cryostat can support an ultrastable silicon cavity with instability near its fundamental thermal noise floor at averaging time of 1–50 s. With proper upgrading, our platform holds promise for realizing ultrastable lasers with 3 × 10−17 or better frequency stability, which will in turn enable numerous studies on precision metrology and quantum many-body physics

Ambipolar ferromagnetism by electrostatic doping of a manganite

Complex-oxide materials exhibit physical properties that involve the interplay of charge and spin degrees of freedom. However, an ambipolar oxide that is able to exhibit both electron-doped and hole-doped ferromagnetism in the same material has proved elusive. Here we report ambipolar ferromagnetism in LaMnO3, with electron–hole asymmetry of the ferromagnetic order. Starting from an undoped atomically thin LaMnO3 film, we electrostatically dope the material with electrons or holes according to the polarity of a voltage applied across an ionic liquid gate. Magnetotransport characterization reveals that an increase of either electron-doping or hole-doping induced ferromagnetic order in this antiferromagnetic compound, and leads to an insulator-to-metal transition with colossal magnetoresistance showing electron–hole asymmetry. These findings are supported by density functional theory calculations, showing that strengthening of the inter-plane ferromagnetic exchange interaction is the origin of the ambipolar ferromagnetism. The result raises the prospect of exploiting ambipolar magnetic functionality in strongly correlated electron systems

Thermal Conductivity of Nanocrystalline Nickel

The grain-size dependences of thermal conductivity and electrical resistivity of polycrystalline and nanocrystalline nickel were measured by the flash method and four-point probe method, respectively. Nanocrystalline nickel was made by the pulsed-current electrodeposition process, while polycrystalline nickel was commercially available Ni 200 in annealed condition. The grain sizes of the materials examined ranged from 28 nanometers to 57 micrometers. Noticeable changes in thermal conductivity and electrical resistivity with grain size were observed in particular for samples with grain sizes less than 100 nm. These results can be explained on the basis of the rapid increase in the intercrystalline grain boundary and triple junction volume fractions at very small grain sizes. The relationship between thermal conductivity and electrical resistivity of nanocrystalline nickel follows the classic Wiedemann-Franz law.MAS

Toward an Optimal Selection of Constraints for Terrestrial Reference Frame (TRF)

Given that the observations from current space geodetic techniques do not carry all the necessary datum information to realize a Terrestrial Reference System (TRS), and each of the four space geodetic techniques has limits, for instance: Very Long Baseline Interferometry (VLBI) ignores the center of mass and satellite techniques lack the TRS orientation, additional constraints have to be added to the observations. This paper reviews several commonly used constraints, including inner constraints, internal constraints, kinematic constraints, and minimum constraints. Moreover, according to their observation equations and normal equations, the similarities and differences between them are summarized. Finally, we discuss in detail the influence of internal constraints on the scale of VLBI long-term solutions. The results show that there is a strong correlation between the scale parameter and the translation parameter introduced by the combination model at the Institut National de l&rsquo;Information G&eacute;ographique et Foresti&egrave;re (IGN), and internal constraints force these two groups of parameters to meet certain conditions, which will lead to the coupling of scale and translation parameters and disturbing the scale information in VLBI observations. The minimum or kinematic constraints are therefore the optimum choices for TRF