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Simulation of 1D Topological Phases in Driven Quantum Dot Arrays
摘要： We propose a driving protocol which allows us to use quantum dot arrays as quantum simulators for 1D topological phases. We show that by driving the system out of equilibrium, one can imprint bond order in the lattice (producing structures such as dimers, trimers, etc.) and selectively modify the hopping amplitudes at will. Our driving protocol also allows for the simultaneous suppression of all the undesired hopping processes and the enhancement of the necessary ones, enforcing certain key symmetries which provide topological protection. In addition, we have discussed its implementation in a 12-QD array with two interacting electrons and found correlation effects in their dynamics, when configurations with different number of edge states are considered.
关键词： hopping amplitudes,topological protection,quantum dot arrays,correlation effects,1D topological phases,driving protocol,bond order
更新于2025-09-11 14:15:04
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Flexible Management of WDM-PON Using AMCC for 5G Radio Access Networks
摘要： This paper overviews flexible management functions of WDM-PON using an auxiliary management and control channel and introduces wavelength allocation, adjustment as use-cases.
关键词： Optical access networks for post 5G mobile service,Future high capacity and long-reach access networks including WDM-PON, OFDM-PON, TWDM-PON,Access Network and Subsystem,Optical access network architecture, design, protection, and management
更新于2025-09-11 14:15:04
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A comparative study of surface characterization and corrosion performance properties of laser surface modified biomedical grade nitinol
摘要： Laser melting and quick solidification of shape memory alloy surfaces promise to explore the multifunctional capabilities required for enhanced biocompatibility of different implantable medical devices. Before subsequent bio-trial, understanding of the effect of cooling rate vis-à-vis laser fluence on surface characteristics and corrosion protection performance is essential before designing a tailor-made biocompatible surface for various implantable devices. The current study systematically investigates the effect of laser fluence on physical, mechanical and chemical surface characteristics along with corrosion protection performance of the modified surface as compared to bare Nitinol surface. Various phases were prominent on the top surface, namely nickel and titanium-rich phase along with different nickel-titanium intermetallics and nano-structure of titanium oxide, based on varying melting pool recirculation time and cooling rate with laser fluence energy. At low laser fluence up to 4 J/mm2, no significant melting pool were formed and only transformation to the martensitic phase of Nitinol took place on the top surface, which seemed to be highly too much corrosion-prone under simulated body fluid. At moderate laser fluence of 6–8 J/mm2, mostly titanium-rich phases are prominent on the surfaces on account of optimum recirculation of melting pool and subsequent surfacing out of comparably light phase of titanium. Titanium-rich phases on top surface exhibit superior corrosion resistance as compared to all other samples including bare nitinol. However, titanium oxide nano-particles-reinforced martensitic structure is formed under high laser fluence due to over recirculation of molten pool. The modulus of elasticity also varied from 10 to 110 GPa based on top surface formation under different fluence levels, and thus this process can act as a tailor-made controllable pre-treatment process over the traditional coating processes.
关键词： Corrosion protection performance,Laser melting and re-solidification,Surface characteristics,Nitinol surface modification
更新于2025-09-11 14:15:04
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PATIENT DOSE IN DIGITAL RADIOGRAPHY UTILISING BMI CLASSIFICATION
摘要： Dose audit is important towards optimisation of patients’ radiation protection in diagnostic radiography. In this study, the effect of the body mass index (BMI) on radiation dose received by 1869 adult patients undergoing chest, abdomen, lumbar spine, kidneys and urinary bladder (KUB) and pelvis radiography in an X-ray room with a digital radiography system was investigated. Patients were categorised into three groups (normal, overweight and obese) based on the BMI values. The patients’ entrance surface air kerma (ESAK) and the effective dose (ED) were calculated based on the X-ray tube output, exposure parameters and technical data, as well as utilising appropriate conversion coefficients of the recorded kerma area product (KAP) values. The local diagnostic reference levels (LDRLs) were established at the 75th percentile of the distribution of ESAK and KAP values. Statistically, a significant increase was found in ESAK, KAP and ED values, for all examinations, both for overweight and obese patients compared to normal patients (Mann–Whitney test, p < 0.0001). Regarding the gender of the patients, a statistically significant increase was found in the dose values for male patients compared to female patients, except for the chest LAT examinations (Mann–Whitney test, p = 0.06). The percentage increase for chest PA, chest LAT, abdomen AP, lumbar spine AP, lumbar spine LAT, pelvis AP and KUB AP in overweight patients was 75%, 100%, 136%, 130%, 70%, 66% and 174% for median ESAK, 67%, 81%, 135%, 134%, 85%, 63% and 172% for median KAP, as well as 89%, 54%, 146%, 138%, 82%, 57% and 183% for median ED values, respectively. For obese patients, the corresponding increases were 200%, 186%, 459%, 345%, 203%, 150% and 785% for median ESAK, 200%, 185%, 423%, 357%, 227%, 142% and 597% for median KAP, as well as 222%, 156%, 446%, 363%, 218%, 136% and 625% for median ED. The corresponding LDRLs for overweight patients were 0.17 mGy, 1.21 mGy, 3.74 mGy, 7.70 mGy, 7.99 mGy, 4.07mGy, 5.03 mGy and 0.13 Gy cm2, 0.69 Gy cm2, 2.35 Gy cm2, 2.10 Gy cm2, 2.59 Gy cm2, 2.13 Gy cm2, 2.49 Gy cm2 in terms of ESAK and KAP values, respectively, while in the case of obese patients were 0.28 mGy, 1.82 mGy, 7.26 mGy, 15.10 mGy, 13.86 mGy, 6.89 mGy, 13.40 mGy and 0.21 Gy cm2, 1.10 Gy cm2, 4.68 Gy cm2, 4.01 Gy cm2, 4.80 Gy cm2, 3.27 Gy cm2, 6.02 Gy cm2, respectively. It can be concluded that overweight and obese patients received a significantly increased radiation dose. Careful adjustment of imaging protocols is needed for these patients to reduce patient dose, while keeping the image quality at an acceptable level. Additional studies need to be conducted for these patient groups, that could further contribute to the development of radiation protection culture in diagnostic radiography.
关键词： BMI,diagnostic reference levels,patient dose,radiation protection,digital radiography
更新于2025-09-10 09:29:36
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An Experimental Demonstration of Short Circuit Protection of SiC Devices
摘要： An experimental demonstration of an effective short circuit protection scheme for SiC MOSFETs is presented in this paper. Measurements of the static characteristics of the SiC device before and after the short circuit events were obtained to evince that the device remained in good health. An ultra-fast short circuit protection scheme is implemented given the observed lower short-circuit withstand of present SiC devices. It is shown that the integrity of the SiC device was protected after one-hundred short circuit events.
关键词： Short-Circuit,MOSFET,Silicon Carbide,Protection,SiC,Wide band-gap
更新于2025-09-10 09:29:36
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Untersuchungen zum ganzj?hrigen W?rmeschutz an Varianten eines kombinierten Dachaufbaus mit Photovoltaik und Begrünung
摘要： Investigation of the year-round thermal buffering effect of a combined green roof with photovoltaics. Research projects on the possible synergies of green roof (GR) and photovoltaics (PV) carried out a decade ago. Today, this combination is well known for its advantages to achieve better yields, through the cooling process of evapotranspiration of the plants, the simultaneous use of the GR’s advantages and very good thermal properties. All previous studies on combinations PV+green-roof in the literature focus on PV optimization, PV yield and PV temperatures. Within the scope of the research project ?GrünPlusSchule@Ballungszentrum“ in Vienna, different combinations of PV+greening (fa?ade and/or roof) were tested. This article presents temperature measurement results of PV+green-roofs and its comparison to a normal extensive GR. Exciting results were founded: the combination PV+GR works as a year-round thermal buffer.
关键词： Green roof,Winter thermal protection,Summer thermal insulation,PV+green roofs-combination,Photovoltaics
更新于2025-09-10 09:29:36
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Enhanced Electrochemical Stability of TiO <sub/>2</sub> -Protected, Al-doped ZnO Transparent Conducting Oxide Synthesized by Atomic Layer Deposition
摘要： Transparent, conductive coatings on porous, three-dimensional materials are often used as the current collector for photoelectrode designs in photoelectrochemical applications. These structures allow for improved light trapping and absorption in chemically-synthesized, photoactive overlayers while minimizing parasitic absorption in the current collecting layer. Atomic layer deposition (ALD) is particularly useful for fabricating transparent conducting oxides (TCOs) like Sn-doped In2O3 (ITO) and Al-doped ZnO (AZO) for structured materials because the deposition is specific to exposed surfaces. Unlike line-of-site deposition methods (evaporation, spray pyrolysis, sputtering), ALD can access the entire complex interface to make a conformal transparent conductive layer. While ITO and AZO can be grown by ALD, they are intrinsically soluble in the acidic and basic environments common for electrochemical applications like water splitting. To take advantage of the unique characteristics of ALD in these applications, is important to develop strategies for fabricating TCO layers with enhanced chemical stability. Ultra-thin coatings of stable materials can be used to protect otherwise unstable electrochemical interfaces while maintaining the desired function. Here, we describe experiments to characterize the chemical and electrochemical stability of ALD-deposited AZO TCO thin films protected by a 10nm TiO2 overlayer. The addition of a TiO2 protection layer is demonstrated to improve the chemical stability of AZO by orders of magnitude compared to unprotected, yet otherwise identically prepared AZO films. The electrochemical stability is enhanced accordingly in both acidic and basic environments. We demonstrate that TiO2-protected AZO can be used as a TCO for both the cathodic hydrogen evolution (HER) and anodic water oxidation (OER) half-reactions of electrochemical water splitting in base and for HER in acid when the appropriate electrocatalysts are added. As a result, we show that ALD can be used to synthesize a chemically stable TCO heterostructure, expanding the range of materials and electrochemical environments available for building complex photoelectrode architectures.
关键词： Water splitting,Transparent conducting oxides,Atomic layer deposition,Electrochemical stability,Al-doped ZnO,TiO2 protection layer
更新于2025-09-10 09:29:36
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[IEEE 2018 International CET Conference on Control, Communication, and Computing (IC4) - Thiruvananthapuram, India (2018.7.5-2018.7.7)] 2018 International CET Conference on Control, Communication, and Computing (IC4) - Reversible and Secure False Color Based Image Privacy Protection with Color Palette Generation
摘要： In many areas, visual privacy needs the protection, especially in video surveillance. Video surveillance is considered as an important solution for the security and safety issues in public places, since it monitors behaviour, activities, or other changing information. Its usage is increased in today’s world which affects individual’s privacy. There comes the need of visual privacy protection in video surveillance. Local servers can not store and analyze this large amount of data from the surveillance camera. So usage of cloud servers can solve this problem. But there is a chance to acquire these data by unauthorized parties. Different schemes for data hiding are present, which reversibly encrypts this data. But such systems need to do the detection of sensitive regions either by using a computer vision module or manually which increases complexity and reduces reliability. So two fully reversible privacy protection schemes for images using false coloring can be used. First scheme is more generic i.e., it is ?exible with other privacy protection schemes and the next scheme is fully based on false colors. These schemes are independent of region-of-interest (ROI) detection and can be applied to the whole image. So the user can escape from the complex ROI detection. A color palette generation method is also added with these schemes which increases the security.
关键词： k-means clustering,scrambling,pixelation,ROI,blurring,privacy protection,false coloring
更新于2025-09-10 09:29:36
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Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment
摘要： Introduction: To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods: Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and na?ve human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results: In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion: As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer’s edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers’ edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients.
关键词： X-ray equipment type test,Radiation protection,Edge determination,Light field indicator,Diagnostic X-ray
更新于2025-09-10 09:29:36
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A comparative path establishment study on routing performance of MLR WDM optical networks
摘要： In this paper, we investigate the effect of path establishment method priorities over routing performance in mixed line rate (MLR) wavelength division multiplexed (WDM) optical networks. The survivable routing with rate and wavelength assignment (SRRWA) problem is presented and an efficient shared backup path protection solution is proposed. We prepared detailed simulation scenarios with all possible prioritizations and observed their performances. The simulation results show that assigning higher priority to single hop methods as compared with multi‐hop methods yields better performance. In both methods, it has been observed that assigning higher priority to grooming reduces the communication cost and the traffic blocking ratio while enhancing the resource utilization.
关键词： MLR,survivable communication,rate and wavelength assignment (RRWA),optical WDM networks,traffic grooming,shared backup protection,routing
更新于2025-09-10 09:29:36