Asymmetric Interference Research Articles

Distribution pattern of fluctuating wind pressures on cooling towers in grouped rectangular arrangement

The cooling towers in this study are in a typical grouped arrangement. Traditional research on grouped-tower interference effects usually emphasizes equivalent static wind loads and ignores quantitative definition of interference effects under aerodynamic load, especially those for fluctuating wind pressure distribution patterns. An eight-tower rectangular arrangement with various aerodynamic interference characteristics was selected as the research object on which a rigid-model synchronous-pressure-measurement wind-tunnel test was performed. Fluctuating time-variant pressures on the tower surfaces for different wind directions was obtained. In three typical incoming flow modes: “windward flow”, “crosswind flow” and “leeward flow”, the fluctuating wind pressure distribution around circumferential directions can be summarized as “V” type, “M” type, and half “V” + half “M” type. The interference patterns can be defined as “weak interference”, “asymmetric strong interference” or “symmetric strong interference”, according to which a 9-item fitting formula of fluctuating wind pressure is proposed and a recommended distribution is given. Interference involving aerodynamic correlation and spectra characters of distributed wind loads are further discussed, and a fitting expression of a specific point spectrum is given. The research strategies and conclusions on fluctuating wind pressure interference provide a loading mode reference for evaluating wind resistance design of similar groups of structures.

Asymmetric Scattering of Mirror-Symmetric Radiation from Nanostructures Coupled to Chiral Films

The interaction of radiation with chiral molecular films is not macroscopically invariant under mirror reflections and, accordingly, chiro-optical effects exist which affect the spatial symmetry of the radiation profile and which almost exclusively show up in the near field due to the large mismatch between molecule size and wavelength size. Here we prove that the scattering of a mirror-symmetric pair of plane waves by a nanowire lying on a chiral nanofilm is not mirror-symmetric with an angular dissymmetry factor that can be as large as a few tenths. Due to evanescent coupling, the nanowire efficiently experiences molecular chirality which produces a spatially asymmetric near field so that the self-consistent unbalanced excitation of nanowire photonic modes with opposite angular momenta yields asymmetric far-field interference. In addition to enriching the physical understanding of mirror symmetry breaking in chiral nanophotonics, our results could suggest ultra-efficient schemes for enantiomeric discrimination which is essential in biological chemistry and pharmacology.

High Sensitivity Fiber Refractive Index Sensors Based on Asymmetric Supermodes Interference in Tapered Four Core Fiber

We demonstrate high sensitivity fiber refractive index (RI) sensor based on asymmetric supermode interferences in tapered four core fiber (TFCF). To make TFCF-based RI sensors, the whitelight was launched into any one of the cores to define the excitation orientation and is called a vertex-core excitation scheme. When the four-core fiber (FCF) was gradually tapered, the four cores gathered closer and closer. Originally, the power coupling occurred between its two neighboring cores first and these three cores are grouped to produce supermodes. Subsequently, the fourth diagonal core enters the evanescent field overlapping region to excite asymmetric supermodes interferences. The output spectral responses of the two cores next to the excitation core are mutually in phase whereas the spectral responses of the diagonal core are in phase and out of phase to that of the excitation core at the shorter and longer wavelengths, respectively. Due to the lowest limitation of the available refractive index of liquids, the best sensitivity can be achieved when the tapered diameter is 10 μm and the best RI sensitivity S is 3249 nm/RIU over the indices ranging from 1.41–1.42. This is several times higher than that at other RI ranges due to the asymmetric supermodes.

Universal ultra-sensitive refractive index sensor based on an integrated SiO2 asymmetric Mach-Zehnder interference filter (AMZIF)

This paper proposes an integrated universal ultra-sensitive refractive index sensor that is applicable for many kinds of liquid. The sensor is SiO2 asymmetric Mach-Zehnder interference filter (AMZIF) with a reference window and a sensing window on different arms. The formula derivation shows that the sensitivity of AMZIF is directly proportional to the arm length, and its measurement range can be expanded by reducing the diffraction order. The sensor is fabricated using standard planar lightwave circuit (PLC) technology, and the tested sensitivity reaches 21193.3 nm per refractive index unit (nm/RIU). With appropriate reference material, the universal AMZIF sensor can measure the refractive index of any liquid whose refractive index is between 1.33 ∼ 1.45 and the sensitivity remains above 20000 nm/RIU.

Shared cognitive mechanisms involved in the processing of scene texture and scene shape.

Recent research has demonstrated that the parahippocampal place area represents both the shape and texture features of scenes, with the importance of each feature varying according to perceived scene category. Namely, shape features are predominately more diagnostic to the processing of artificial human–made scenes, while shape and texture are equally diagnostic in natural scene processing. However, to date little is known regarding the degree of interactivity or independence observed in the processing of these scene features. Furthermore, manipulating the scope of visual attention (i.e., globally vs. locally) when processing ensembles of multiple objects—stimuli that share a functional neuroanatomical link with scenes—has been shown to affect their cognitive visual representation. It remains unknown whether manipulating the scope of attention impacts scene processing in a similar manner. Using the well-established Garner speeded-classification behavioral paradigm, we investigated the influence of both feature diagnosticity and the scope of visual attention on potential interactivity or independence in the shape and texture processing of artificial human–made scenes. The results revealed asymmetric interference between scene shape and texture processing, with the more diagnostic feature (i.e., shape) interfering with the less diagnostic feature (i.e., texture), but not vice versa. Furthermore, this interference was attenuated and enhanced with more local and global visual processing strategies, respectively. These findings suggest that the scene shape and texture processing are mediated by shared cognitive mechanisms and that, although these representations are governed primarily via feature diagnosticity, they can nevertheless be influenced by the scope of visual attention.

Asymmetric coherent rainbows induced by liquid convection* *Project supported by the National Key Research and Development Program of China (Grant No. 2016YFA0301202) and the National Natural Science Foundation of China (Grant Nos. 11674311 and U20A20205)

Coherent rainbows can be formed by focusing white-light laser into liquids. They are bilaterally symmetric interference rings with various shapes. Such interference rings arise from the temperature distribution of the liquid induced by laser heating, i.e., thermal lens effect, which changes the refractive index locally and thus the optical path difference. The up–down asymmetry of the interference rings is caused by convection in the liquid. With the increase of the viscosity, the interference rings change their shape from oval to circular shape. After a shutter is opened and the laser shines into the liquid, the interference rings are circular at the beginning. As time goes on, they gradually turn into anoval shape. Let the liquid go a free-fall at the beginning, the interference rings remain circular. All the three experiments have confirmed that the asymmetric interference rings are due to convection in the liquid associated with thermal lens effect. We also numerically simulate the two-dimensional heat conduction with and without convection, whose results agree well with our experimental observations.

Multi-Layer Interference Alignment and GDoF of the K-User Asymmetric Interference Channel

In wireless networks, link strengths are often affected by some topological factors such as propagation path loss, shadowing and inter-cell interference. Thus, different users in the network might experience different link strengths. In this work we consider a K-user asymmetric interference channel, where the channel gains of the links connected to Receiver k are scaled with √{P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α_k</sup> }, k=1,2, ..., K, for 0 <; α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> ≤ α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ≤ ...≤ α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</sub> . For this setting, we show that the optimal sum generalized degrees-of-freedom (GDoF) is characterized as d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sum</sub> = Σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k=1</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</sup> α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sub> + α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</sub> -α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K-1</sub> /2 which matches the existing result d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sum</sub> = K/2 when α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> = α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> = ... = α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</sub> = 1. The achievability is based on multi-layer interference alignment, where different interference alignment sub-schemes are designed in different layers associated with specific power levels, and successive decoding is applied at the receivers. While the converse for the symmetric case only requires bounding the sum degrees-of-freedom (DoF) for selected two users, the converse for this asymmetric case involves bounding the weighted sum GDoF for selected J+2 users, with corresponding weights (2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</sup> , 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J-1</sup> , ..., 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> ), a geometric sequence with common ratio 2, for the first J users and with corresponding weights (1, 1) for the last two users, for J ∈ {1,2, ..., [log K/2]}.

Heterospecific pollination by an invasive congener threatens the native American bittersweet, Celastrus scandens

Invasive plants have the potential to interfere with native species’ reproductive success through a number of mechanisms, including heterospecific pollination and hybridization. This study investigated reproductive interactions between a native North American woody vine (American bittersweet, Celastrus scandens) and an introduced congener (oriental bittersweet, C. orbiculatus). The decline of C. scandens in the eastern portion of its range is coincident with the introduction and spread of C. orbiculatus, and the two species are known to hybridize. The relationship between proximity and floral production of conspecific and heterospecific males on fertilization and hybridization rates was measured at a field site in northwestern Indiana, USA where both species occur and reproduce. We found that the invasive vine had an extreme advantage in both male and female floral production, producing nearly 200 times more flowers per staminate plant and 65 times more flowers per pistillate plant than the native. Using nuclear microsatellite DNA markers we found that hybridization rates were asymmetric; 39% of the C. scandens seeds tested were hybrids, compared to only 1.6% of C. orbiculatus seeds. The asymmetric hybridization rates were likely not solely due to greater abundance of C. orbiculatus pollen because experimental hand crosses revealed that C. scandens had a higher rate (41%) of heterospecific fertilization than C. orbiculatus (2.4%). We previously reported that few hybrids were observed in the wild, and hybrids had greatly reduced fecundity. Thus, in our system, the threat posed by heterospecific pollen is not replacement by hybrids or introgression, but rather asymmetric reproductive interference. Reproductive interference extended to distances as great as 100 meters, thus, efforts to conserve the native species must reduce its exposure to C. orbiculatus over a relatively large spatial scale.

The Concept of space-time quanta in future technologies

The article discusses the possibility of using the technological advantages that appear in connection with the discovery of the physical essence of Time and new interpretation of the structure of space in the form of space-time quanta. One of the problems that can be successfully solved on the basis of the new physical model is the problem of establishing the true nature of gravity. The solution to this problem is directly related to the implementation of the idea of unsupported motion based on the interaction in a certain way of the created asymmetric interference structure of longitudinal waves with the natural structure of spatial frequencies.

Sorkin parameter for type-I spontaneous parametric down-conversion biphotons and matter waves

We propose experimental measurements of the logarithmic negativity, which quantifies quantum correlations using Gouy phase measurements in an asymmetric double-slit interference experiment for twin photons. This is possible because both quantities have analogous dependence with the spatial confinement by the slits and enables one to manipulate the portion of entanglement by the Gouy phase. In order to obtain those measurements, we need to work in a regime where the position correlations between particles are strong, therefore we investigate such correlations for biphotons. Since we would like to handle entanglement quantifiers through the Gouy phase, we analyze the Gouy phase difference for two entangled photons in an asymmetric double-slit interference experiment.

Behavioral dominance interactions between Nicrophorus orbicollis and N. tomentosus burying beetles (Coleoptera: Silphidae)

Asymmetric interference competition, where one species is behaviorally dominant over another, appears widespread in nature with the potential to structure ecological communities through trade-offs between competitive dominance and environmental tolerance. The details of how species interact and the factors that contribute to behavioral dominance, however, are poorly known for most species, yet such details are important for understanding when and why trade-offs occur. Here, we examine behavioral interactions between two species of burying beetles (Coleoptera: Silphidae) that compete for limited breeding resources (i.e., small vertebrate carcasses) in nature, to identify behaviors involved in interference competition and to test if large body size, species identity, or time of arrival best predict behavioral dominance among species. To test these ideas, we placed same-sex individuals of Nicrophorus orbicollis (early to mid-summer breeder) and N. tomentosus (late summer to fall breeder) into an enclosure together with a 25–30 g mouse carcass (Mus musculus). We then video-recorded all behaviors, including neutral and aggressive interactions, for 13 h per trial (N = 14 trials). For each interaction, we assigned a winner based on which beetle retained its position instead of fleeing or retained possession of the carcass; the overall behavioral dominant was determined as the individual that won the most interactions over the length of the trial. We found that large body size was the best predictor of behavioral dominance. In most interactions, N. orbicollis was larger and dominant over N. tomentosus; however, when N. tomentosus was larger they outcompeted smaller N. orbicollis, illustrating the importance of body size in aggressive contests. The order of arrival to the carcass (priority effects) did not predict behavioral dominance. The larger size and abundance of N. orbicollis in nature suggest a competitive asymmetry between the species, supporting the idea that N. orbicollis constrains the ability of N. tomentosus to breed earlier in the summer.

Ultra-compact low-loss variable-ratio 1×2 power splitter with ultra-low phase deviation based on asymmetric ladder-shaped multimode interference coupler.

We propose a novel optical 1×2 power splitter based on an asymmetric ladder-shaped multimode interference (MMI) coupler in silicon-on-insulator (SOI) which has an ultra-compact size of 3.3 µm×2.4 µm. A trapezoid with a small region is removed from the bottom left corner of the MMI coupler to achieve variable splitting ratio. The comparison with the asymmetric rectangular 1×2 splitter is numerically analyzed. By carefully optimizing the width of input taper, the proposed splitter shows a low phase deviation for the two output ports while keeping both of a low-loss performance and feasible splitting ratio. The simulated results show that the splitter can operate with an insertion loss less than 0.67 dB, a large range of splitting ratio from 50:50 to 11:89 and an ultra-low phase deviation less than 2.8° among the C band spectra.

Structured illumination microscopy based on asymmetric three-beam interference

Structured illumination microscopy (SIM) is a rapidly developing super-resolution technology. It has been widely used in various application fields of biomedicine due to its excellent two- and three-dimensional imaging capabilities. Furthermore, faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging. In this paper, a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed. An innovative time-series acquisition method is employed to halve the time required to obtain each raw image. A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time. Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image, the SIM setup proposed in this paper is 30% faster than the traditional spatial light modulator-SIM (SLM-SIM) in imaging each super-resolution image. The related theoretical derivation, hardware system, and verification experiment are elaborated in this paper. The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction, intercellular communication, and other biomedical fields.

Hyaenas and lions: how the largest African carnivores interact at carcasses

The study of the competitive interactions between predators has traditionally been approached within the context of predatory behavior. By using a quasi‐experimental, non‐intrusive approach, we go beyond the classical view that predators only compete for living prey and disentangle the mechanisms of exploitative and interference competition between two charismatic apex predators, lions Panthera leo and spotted hyaenas Crocuta crocuta, at carcasses other than their own kills. Carcasses of different sizes were monitored in two study areas of South Africa: one with both lions and hyaenas and the other with hyaenas only. We found evidence of both symmetric exploitative competition and asymmetric interference competition. Interactions were strongly conditioned by carcass size, and co‐occurrence was mostly recorded at large ungulate carcasses. Interference competition seemed to dominate interspecific interactions, with lions having preferential access. However, interference while feeding did not exert any cost on the subordinate hyaenas, in terms of amount of ingested food and consumption rate, probably thanks to the reward provided by large carcasses in the form of abundant carrion, the use of lions to detect carcasses, and spatiotemporal segregation at the carcass‐scale. Securing a diverse carrion supply in terms of carcass size, including megaherbivore carcasses, may favor the coexistence of the largest African carnivores, especially in small protected areas. Overall, our study reveals mechanisms related to both the food resource heterogeneity and the competitor behavior that allow the coexistence of strongly interacting species.

Insights into visual working memory precision at the feature- and object-level from a hemispheric encoding manipulation.

Mnemonic precision is an important aspect of visual working memory (WM). Here, we probed mechanisms that affect precision for spatial (size) and non-spatial (colour) features of an object, and whether these features are encoded and/or stored separately in WM. We probed precision at the feature-level-that is, whether different features of a single object are represented separately or together in WM-and the object-level-that is, whether different features across a set of sequentially presented objects are represented in the same or different WM stores. By manipulating whether stimuli were encoded by the left and/or right hemisphere, we gained further insights into how objects are represented in WM. At the feature-level, we tested whether recall fidelity for the two features of an object fluctuated in tandem from trial to trial. We observed no significant coupling under either central or lateralized encoding, supporting the claim of parallel feature channels at encoding. At the level of WM storage of a set of objects, we found asymmetric feature interference under central encoding, whereby an increase in colour load led to a decrease in size precision. When objects were encoded by a single hemisphere, however, we found largely independent feature stores. Precision for size was more resistant to interference from the size of another object under right-hemisphere encoding; by contrast, precision for colour did not differ across hemispheres, suggesting a more distributed WM store. These findings suggest that distinct features of a single object are represented separately but are then partially integrated during maintenance of a set of sequentially presented objects.

Experimental study on the corrosion behavior of X70 steel under asymmetric dynamic DC interference

AbstractThe corrosion behavior of X70 steel in simulated soil environment under asymmetric dynamic direct current (DC) interference was studied by immersion tests. The experimental results showed that the negatively asymmetric dynamic DC interference would induce localized corrosion. Under the same dynamic period of 160 ±80 s, when the negative half‐wave current density remained stable at −10 mA/cm2 and the positive half‐wave one decreased from 7 to 1 mA/cm2, the equivalent diameters of the localized corrosion zones became smaller and the steel samples demonstrated typical pitting corrosion morphologies. To further explore the effect of asymmetric dynamic DC interference on the localized corrosion behavior of carbon steel, a variety of experimental measurements were carried out including real‐time DC potential monitoring, in‐situ near‐surface pH measurements, cyclic voltammetry, and Mott–Schottky tests. It was found that the localized corrosion behavior was probably related to the breakdown of passive film formed on the metal surface exposed to negatively asymmetric DC current generated high pH conditions.

When and how much to neutralize interference? Balancing the benefits and cost of interference management

Interference management (IM) is essential to wireless communication systems, but it is also known to consume transmission resource such as power and degree of freedom, hence degrading users’ achievable spectral efficiency (SE). Therefore, it is important to select an appropriate IM method with optimal operating parameters so as to balance the benefits brought by and the cost of IM. Interference neutralization (IN) has recently been receiving considerable attention, with which a duplicate of interference of the same strength and opposite phase with respect to the original interfering signal is generated to neutralize the disturbance at the intended receiver. However, to the best of our knowledge, all existing IN schemes assume that interference is completely neutralized without accounting for their power consumption. To remedy this deficiency, we propose a novel scheme, called dynamic interference neutralization (DIN). By intelligently determining the appropriate portion of interference to be neutralized, we balance the transmitter’s power used for IN and the desired signal’s transmission. We then extend the proposed DIN to general cases where the numbers of interferences, desired data streams, as well as pico base stations and pico user equipments, are variables. Moreover, in addition to the design under asymmetric interference topology, the application of DIN in symmetric interference situation is also presented. Our in-depth analysis and simulation have shown that the proposed strategy can make better use of the transmit power than existing IM methods, hence enhancing users’ SE.

Cooperative NOMA for Downlink Asymmetric Interference Cancellation

This letter advances the non-orthogonal multiple access (NOMA) technique for cellular downlink co-channel interference mitigation, via exploiting the (limited) cooperation among base stations (BSs). Specifically, we consider a simplified but practically relevant scenario of two co-channel cells with asymmetric interference, i.e., only the user in one cell receives the strong interference from the BS in the other cell. To mitigate such interference, we propose a new cooperative NOMA scheme, where the interfered user's serving BS sends a superposed signal comprising both the desired message and the co-channel user's message (shared by the interfering BS). The co-channel user's signal is aimed to add constructively with the interfering BS's signal at the interfered user's receiver so that the combined interference with enhanced power can be effectively decoded and cancelled. This thus leads to a new problem on how to optimally allocate the transmit power for the two superposed messages. We provide the closed-form solution to this problem and investigate the conditions under which the performance of the proposed scheme is superior over the existing schemes.

Collapse of the Fano Resonance Caused by the Nonlocality of the Majorana State

One of the main features of the Majorana state, which attracts a considerable current interest to these excitations in solid-state systems, is related to its nonlocal character. It is demonstrated that the direct consequence of such nonlocality is the collapse of the Fano resonance manifesting itself in the conductance of an asymmetric interference device, the arms of which are connected by a one-dimensional topological superconductor. In the framework of the spinless model, it is shown that the predicted effect is associated with an increase in the multiplicity of the degeneracy of the zero-energy state of the structure arising at a specific case of the Kitaev model. Such an increase leads to the formation of a bound state in the continuum.

Asymmetric image encryption based on optical interference using modified error-reduction phase retrieval algorithm

In this paper, we propose an asymmetric interference based encryption (IBE) using a modified error-reduction phase retrieval algorithm (mERPRA) in a structure of optical interference. Unlike previously proposed IBE schemes, the ciphertext in our scheme has less pixels than the original image. What is more important, a plaintext-dependent private key can be retrieved by using mERPRA with a fixed amplitude constraint, which makes this IBE scheme asymmetric. As we know, except for equal modulus decomposition-based encryption schemes, this is the first time that asymmetric IBE is presented. Consequentially, our proposed IBE scheme gains enhanced security due to its asymmetry. Simulation results are demonstrated to prove the validity of this scheme.