Direct imaging of SiO2 thickness variation on Si using modified atomic force microscope

Journal ArticleFabrication techniques of metal-oxide-semiconductor ~(MOS) transistors have been improved very rapidly during the last several decades. With this trend, scaling down of MOS transistors is necessary to improve the speed of circuits and the packing density of discrete devices. Both lateral and vertical dimensions of unit devices are reduced to ascertain better electrical characteristics of devices

Fungal diversity in chestnut galls induced by Dryocosmus kuriphilus from Basilicata Region (Southern Italy)

In recent years, the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus has been reported to have a high incidence in Italy and other Mediterranean basin countries. In 2021-2022, a study was undertaken in the Basilicata Region (Southern Italy) to investigate the relationship between the galls produced by ACGW on sweet chestnut (Castanea sativa Mill.) and fungal pathogens. In particular, the fungal diversity from green and necrotic galls collected from two important sweet chestnut sites (Melfi and Rionero in Vulture) was investigated. Nineteen fungal taxa were identified based on their morphological and molecular traits. In both localities, the most frequent species isolated from green and necrotic galls were Gnomoniopsis castaneae, Colletotrichum acutatum, and Pestalotiopsis sp. It is essential to understand the role played by the galls as an inoculum source for sweet chestnut fungal pathogens, particularly for G. castaneae, an emerging pathogen of which biology is still poorly understood. Findings from the present study stressed that the complex relationship between host-insect-microbial community needs to be elucidated to be able to control the pathogenic fungi and consequently maintain sweet chestnut trees' health as they play a key role in the local agriculture (horticulture, forestry) and subsidiary econom

No spin-localization phase transition in the spin-boson model without local field

We explore the spin-boson model in a special case, i.e., with zero local field. In contrast to previous studies, we find no possibility for quantum phase transition (QPT) happening between the localized and delocalized phases, and the behavior of the model can be fully characterized by the even or odd parity as well as the parity breaking, instead of the QPT, owned by the ground state of the system. Our analytical treatment about the eigensolution of the ground state of the model presents for the first time a rigorous proof of no-degeneracy for the ground state of the model, which is independent of the bath type, the degrees of freedom of the bath and the calculation precision. We argue that the QPT mentioned previously appears due to unreasonable treatment of the ground state of the model or of the infrared divergence existing in the spectral functions for Ohmic and sub-Ohmic dissipations.Comment: 5 pages, 1 figure. Comments are welcom

Fine structure of alpha decay in odd nuclei

Using an alpha decay level scheme, an explanation for the fine structure in odd nuclei is evidenced by taking into account the radial and rotational couplings between the unpaired nucleon and the core of the decaying system. It is stated that the experimental behavior of the alpha decay fine structure phenomenon is directed by the dynamical characteristics of the system.Comment: 8 pages, 3 figures, REVTex, submitted to Physical Review

Heterogeneous Federated Learning: State-of-the-art and Research Challenges

Federated learning (FL) has drawn increasing attention owing to its potential use in large-scale industrial applications. Existing federated learning works mainly focus on model homogeneous settings. However, practical federated learning typically faces the heterogeneity of data distributions, model architectures, network environments, and hardware devices among participant clients. Heterogeneous Federated Learning (HFL) is much more challenging, and corresponding solutions are diverse and complex. Therefore, a systematic survey on this topic about the research challenges and state-of-the-art is essential. In this survey, we firstly summarize the various research challenges in HFL from five aspects: statistical heterogeneity, model heterogeneity, communication heterogeneity, device heterogeneity, and additional challenges. In addition, recent advances in HFL are reviewed and a new taxonomy of existing HFL methods is proposed with an in-depth analysis of their pros and cons. We classify existing methods from three different levels according to the HFL procedure: data-level, model-level, and server-level. Finally, several critical and promising future research directions in HFL are discussed, which may facilitate further developments in this field. A periodically updated collection on HFL is available at https://github.com/marswhu/HFL_Survey.Comment: 42 pages, 11 figures, and 4 table

Contrast material–enhanced MRA overestimates severity of carotid stenosis, compared with 3D time-of-flight MRA

AbstractObjectiveNon–contrast-enhanced magnetic resonance angiography (MRA) carotid imaging with the time-of-flight (TOF) technique compares favorably with angiography, ultrasound, and excised plaques. However, gadolinium contrast-enhanced MRA (CE-MRA) has almost universally replaced TOF-MRA, because it reduces imaging time (25 seconds vs 10 minutes) and improves signal-to-noise ratio. In our practice we found alarming discrepancies between CE-MRA and TOF-MRA, which was the impetus for this study.Study designTo compare the two techniques, we measured stenosis, demonstrated on three-dimensional images obtained at TOF and CE-MRA, in 107 carotid arteries in 58 male patients. The measurements were made on a Cemax workstation equipped with enlargement and measurement tools. Measurements to 0.1 mm were made at 90 degrees to the flow channel at the area of maximal stenosis and distal to the bulb where the borders of the internal carotid artery lumen were judged to be parallel (North American Symptomatic Carotid Endarterectomy Trial criteria). Experiments with carotid phantoms were done to test the comtribution of imaging software to image quality.ResultsTwelve arteries were occluded. In the remaining 95 arteries, compared with TOF-MRA, CE-MRA demonstrated a greater degree of stenosis in 42 arteries, a lesser degree of stenosis in 14 arteries, and similar (±5%) stenosis in 39 arteries (P = .02, χ2 analysis). The largest discrepancies were arteries with 0% to 70% stenosis. In those arteries in which CE-MRA identified a greater degree of stenosis than shown with TOF-MRA, mean increase was 21% for 0% to 29% stenosis, 36% for 30% to 49% stenosis, and 38% for of 50% to 69% stenosis. The carotid phantom experiments showed that the imaging parameters of CE-MRA, particularly the plane on which frequency encoding gradients were applied, reduced signal acquisition at the area of stenosis.ConclusionsCollectively these data demonstrate that CE-MRA parameters must be retooled if the method is to be considered reliable for determination of severity of carotid artery stenosis. CE-MRA is an excellent screening technique, but only TOF-MRA should be used to determine degree of carotid artery stenosis

Review of SIS Experimental Results on Strangeness

>A review of meson emission in heavy ion collisions at incident energies around 1 -- 2 $A\cdot$GeV is presented. It is shown how the shape of the spectra and the various particle yields vary with system size, with centrality and with incident energy. A statistical model assuming thermal and chemical equilibrium and exact strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features. Emphasis is put onto the study of $K^+$ and $K^-$ emission. In the framework of this statistical model it is shown that the experimentally observed equality of $K^+$ and $K^-$ rates at threshold corrected energies $\sqrt{s} - \sqrt{s_{th}}$ is due to a crossing of two excitation functions. Furthermore, the independence of the $K^+$ to $K^-$ ratio on the number of participating nucleons observed between 1 and 10 $A\cdot$GeV is consistent with this model. The observed flow effects are beyond the scope of this model.Comment: 10 pages, 9 figures, Strangeness 2000, V International Conference on Strangeness in Quark Matter, July, 2000, Berkeley, Californi

Implementation of quantum gates and preparation of entangled states in cavity QED with cold trapped ions

We propose a scheme to perform basic gates of quantum computing and prepare entangled states in a system with cold trapped ions located in a single mode optical cavity. General quantum computing can be made with both motional state of the trapped ion and cavity state being qubits. We can also generate different kinds of entangled states in such a system without state reduction, and can transfer quantum states from the ion in one trap to the ion in another trap. Experimental requirement for achieving our scheme is discussed.Comment: To appear in J. Opt.