Short Devices Research Articles

Organic Salt Buffer Layer Enables High‐Performance NiOx‐Based Inverted Perovskite Solar Cells

The merits of a low‐cost fabrication process, suitable band structure, excellent wettability to perovskite precursor, and outstanding stability ensure NiOx as a hole transport material with beneficial characteristics to construct high‐performance perovskite solar cells (PSCs). However, direct contact between perovskite and NiOx causes delamination and chemical instability and thus results in poor carrier transport and short device lifespan. Here, we propose a solution for this issue by introducing an organic salt additive 4‐(trifluoromethyl) benzylammonium formate (TFMBAFa) in the perovskite precursor to passivate perovskite film and NiOx@(2‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl) ethyl) phosphonic acid (Me‐2PACz) composited hole transport layer (HTL), and thus construct a buffer layer between perovskite‐HTL interface. The effective diminishing of NiOx/perovskite interfacial reactions and defects results in enhanced carrier transport. Consequently, the target device achieves simultaneous improvements in power conversion efficiency (24.2%), storage stability (T100 > 1400 h), thermal stability (T80 > 1000 h), and operational stability (T70 > 850 h), where T100, T80, and T70 refer to the retention of 100%, 80%, and 70% of initial PCE, respectively. This work provides an effective strategy to advance the performance of NiOx‐based inverted PSCs.

Positive Effects of Guanidinium Salt Post-Treatment on Multi-Cation Mixed Halide Perovskite Solar Cells.

As one of the most promising photovoltaic technologies, perovskite solar cells (PSCs) exhibit high absorption coefficients, tunable bandgaps, large carrier mobilities, and versatile fabrication techniques. Nevertheless, the commercialization of the technology is hindered by poor material stability, short device lifetimes and the scalability of fabrication techniques. To address these technological drawbacks, various strategies have been explored, with one particularly promising approach involving the formation of a low-dimensional layer on the surface of the three-dimensional perovskite film. In this work, we demonstrate the use of guanidinium tetrafluoroborate, CH6BF4N3, (GATFB) as a post-treatment step to enhance the performance of PSCs. Compared with the control sample, the application of GATFB improves the film surface topology, reduces surface defects, suppresses non-radiative recombination, and optimizes band alignment within the device. These positive effects reduce recombination losses and enhance charge transport in the device, resulting in PSCs with an open-circuit voltage (VOC) of 1.18 V and a power conversion efficiency (PCE) of 19.7%. The results obtained in this work exhibit the potential of integrating low-dimensional structures in PSCs as an effective approach to enhance the overall device performance, providing useful information for further advancement in this rapidly evolving field of photovoltaic technology.

Single layer dual hollow core antiresonant fiber based polarization beam splitters

To confront the growing challenges of integrated photonics, optical devices need to be compact in size to integrate them in communication networks where a polarization beam splitter device may play a crucial role. In this regard, hollow core antiresonant fibers have garnered significant attention as a versatile platform, for achieving efficient polarization splitting, owing to their promising characteristics. In this article, traditional and available multilayer complex cladding geometry, in dual hollow core antiresonant fiber, is simplified to single layer arrangement and created efficient polarization beam splitters device. First, we introduced a splitter with single layer cladding geometry that simultaneously presents a short device length of 2.24 cm and an ultra-wide bandwidth of 415 nm, with an extinction ratio exceeding 20 dB. This bandwidth also encompasses widely used communication wavelengths of 1.31μm and 1.55μm. Moreover, a careful investigation of geometrical dimensions, nesting, and conjoined tubes inclusion suggests that the device structure having two horizontal nested elements has an excellent splitting performance with a concise splitter length of 2.06 cm and an ultra-wide bandwidth of 465 nm, covering most telecom bands. Notably, the splitters have the highest extinction ratio of around 140 dB at 1.55μm, along with an effective single mode performance. Therefore, the claimed single layer polarization splitters might be an attractive candidate for the integration of optical devices in communication systems.

Strategies for hollow cathode command in short electrodynamics tether-based deorbit devices

Heaterless hollow cathodes are a promising solution for reaching a good cathodic contact in electrodynamic tether systems. However, these cathodes cannot keep the plasma discharge if the electric current IC is below a threshold Imin. If the tether is short, and to save power and expellant, an appropriate command strategy is needed to ensure that the cathode is triggered in conditions satisfying IC>Imin. This study investigates four command strategies, including two fully autonomous approaches (one based on satellite position and the other on local plasma density) and two strategies involving ground segment access, differing in command generation location (ground segment and on-board computer). The success rates of the four strategies were studied though numerical simulation and for the specific scenario of the E.T.PACK demonstration mission. The results demonstrate that, as compared to continuous operation of the hollow cathode, the proposed strategies reduce propellant wastage by a factor between 5 and 10. The strategy requiring ground segment access and with the onboard computer making the command decision has the highest success rate (94%). Among the autonomous configurations, the strategy based solely on local plasma density achieves the highest success rate (69%). Additionally, the impact of sensor accuracy on success rates was assessed via Monte Carlo analysis. The command strategy relying on plasma density measurement is the most sensitivity strategy, with a 10% decrease in success rate due to sensor uncertainty.

Effects of Trigger Method on Fire Propagation during the Thermal Runaway Process in Li-ion Batteries

Abstract Lithium-ion batteries are prone to fire hazards due to the possibility of thermal runaway propagation. During battery product development and subsequent safety tests for design validation and safety certification, the thermal runaway onset is triggered by various test methods such as nail penetration, thermal ramp, or external short circuit. This failure initiation method affects the amount of heat contributions and the composition of gas generations. This study compares two such trigger methods, external heating and using a thermally-activated internal short circuit device (ISCD). The effects of the trigger method on total heat generation are experimentally investigated within 18650 cylindrical cells at single cell level as well as at multiple cell configuration level. The severity of failure was observed to be worse for cells with ISCDs at single cell level, whereas quite the opposite results were observed at multiple cell configuration level. A preliminary numerical analysis was performed to better understand the battery safety performance with respect to thermal runaway trigger methods and heat transfer conditions.

What Can we Learn from Nonequilibrium Response of a Strange Metal?

We critically address the recent experiment by L. Chen et al. [Science 382, 907 (2023)] on nonequilibrium transport and noise in a strange metal YbRh2Si2 patterned into the nanowire shape. In the long device, resistivity, differential resistance and current noise data seem to be consistent allowing us to extract electron–phonon coupling and the temperature dependence of electron–phonon scattering length. The obtained values can be reconciled with the experimental data for the short device only assuming the significant contact resistance. We discuss its possible origin as due to the current redistribution between YbRh2Si2 and its gold covering, and reveal that this redistribution contact resistance should be proportional to the YbRh2Si2 resistivity. We also discuss some subtleties of the noise measurements. Overall, neglecting electron–phonon energy relaxation even in the shortest devices is arguable so that the observed shot noise suppression can hardly be attributed to the failure of quasiparticle concept.

Understanding the effects of annealing induced structural transformations on the UVC absorbance and other optical properties of RF sputter deposited Ga2O3 thin films

Gallium oxide (Ga2O3) is a transparent material with high absorption in the UVC region of the electromagnetic spectrum and hence is a very important candidate in the field of short wavelength optical device fabrication. A proper understanding of the different optical parameters is necessary for developing more efficient coatings and devices. In this work, changes in the optical behavior of Ga2O3 thin films due to post-deposition annealing (at temperatures 300 °C–900 °C) are discussed in detail. Structural, surface morphological and compositional modifications of the films are identified using the x-ray diffractometer, scanning electron microscopy and x-ray photoelectron spectrometer techniques, respectively. At 900 °C, a highly stable monoclinic β phase of Ga2O3 is obtained. The optical transmittance spectra acquired using UV–Vis spectroscopy indicate an improved UVC absorbance of the β-Ga2O3 films with an excellent visible transmittance (>80%). The structural transformation from amorphous to crystalline β-Ga2O3 phase and the associated reduction in defect density is found to modify other optical attributes, like the bandgap energy, Urbach energy, dispersion parameters, etc.

Asymmetric dual-core liquid crystal channel-based tunable mode converter

In this work, a higher order-to-fundamental mode converter is reported and analyzed based on an asymmetric dual channel waveguide (ADC-WG) on silicon. In the reported structure, one of the two waveguides is infiltrated with nematic liquid crystal (NLC) material to add temperature tunability while the other one is a solid BK7 waveguide. The modal characteristics are obtained using the full vectorial finite difference method (FVFDM). In addition, the structural parameters and optical characteristics of the employed materials are investigated to achieve good wavelength selectivity with a short device length (LD). Thus, a compact mode converter that can work at different wavelengths including the telecommunication wavelength i.e., 1.55 μm with LD ~ 482.31 μm and a low crosstalk of − 19.86 dB is presented. To prove the thermal tunability of the suggested mode converter, its operation is tested through a temperature range between 20 and 35 °C and the results show that the mode conversion process is achieved at each temperature with different phase matching wavelengths (λPMW) but with quite similar coupling length (LC). The proposed device can therefore be effectively utilized in integrated photonic circuits.

Establishment and application of a rapid molecular diagnostic platform for the isothermal visual amplification of group B Streptococcus based on recombinase polymerase.

With growing concerns about Group B streptococcal (GBS) infections and their adverse effects on perinatal pregnancies, including infection, premature delivery, neonatal septicemia, and meningitis, it is urgent to promote GBS screening at all pregnancy stages. The purpose of this study is to establish a device-independent, fast, sensitive, and visual GBS detection method. Taking advantage of the characteristics of the recombinase polymerase isothermal amplification (RPA), the activity of the nfo nuclease cleavage base analog (tetrahydrofuran, THF) site, and the advantages of visual reading of the lateral flow chromatography strip (LFS), a GBS detection method was developed. This method focused on the conservative region of the Christie-Atkins-Munch-Petersen factor encoded by the cfb gene, a virulence gene specific to GBS. Two forward primers, two biotin-labeled reverse primers, and one fluorescein isothiocyanate (FITC)-labeled and C3spacer-blocked probe were designed. The study involved optimizing the primer pair and probe combination, determining the optimal reaction temperature and time, evaluating specificity, analyzing detection limits, and testing the method on 87 vaginal swabs from perinatal pregnant women. The results showed that the visual detection method of GBS-RPA-LFS, using the cfb-F1/R2/P1 primer probe, could detect GBS within 15 min at the temperature ranging from 39°C to 42°C. Furthermore, the method specifically amplified only GBS, without cross-reacting with pathogens like Lactobacillus iners, Lactobacillus crispatus, Candida albicans, Listeria monocytogenes, Yersinia enterocolitica, Klebsiella Pneumoniae, Enterobacter cloacae, Citrobacter freundii, Vibrio alginolyticus, Vibrio parahaemolyticus, Salmonella typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa, or Trichomonas vaginalis. It could detect a minimum of 100 copies per reaction. In clinical 98 samples of vaginal swabs from pregnant women, the agreement rate between the GBS-RPA-LFS method and TaqMan real-time fluorescence quantification method was 95.92%. In conclusion, this study successfully established a combined RPA and LFS GBS in situ detection platform, with short reaction time, high sensitivity, high specificity, portability, and device independence, providing a feasible strategy for clinical GBS screening.

Improved Hole Extraction and Band Alignment via Interface Modification in Hole Transport Material‐Free Ag/Bi Double Perovskite Solar Cells

Within one decade, lead halide perovskite solar cells have reached power conversion efficiencies (PCEs) compatible with that of silicon solar cells. While in the beginning, they suffered from short device lifetimes, those have also been strongly improved over time. However, their content of toxic lead still poses a risk of environmental pollution and human health on exposure. The double perovskite (DP) Cs2AgBiBr6 offers the potential to be a lead‐free alternative light‐harvesting material. Herein, the fabrication of hole transport material (HTM)‐free Cs2AgBiBr6‐based solar cells is presented, in which the DP surface is modified via a n‐butylammonium posttreatment to create a 2D/3D mixed interface. Additionally, the commonly utilized metal electrode and HTM are substituted with a carbon black back electrode (CBE) consisting of up‐cycled biowaste. Through the 2D/3D interface modification, charge recombination is suppressed, and band alignment is improved at the perovskite/CBE interface. Additionally, density functional theory calculations reveal that an increasing 2D modification thickness enhances the probability for holes in Cs2AgBiBr6 to be located close to the perovskite/CBE interface, further supporting their extraction. Overall, the PCE of the HTM‐free solar cells is improved through the implementation of a low‐cost and end‐of‐waste fabrication strategy.

Heat conductance of the quantum Hall bulk.

The quantum Hall effect is a prototypical realization of a topological state of matter. It emerges from a subtle interplay between topology, interactions and disorder1-9. The disorder enables the formation of localized states in the bulk that stabilize the quantum Hall states with respect to the magnetic field and carrier density3. Still, the details of the localized states and their contribution to transport remain beyond the reach of most experimental techniques10-31. Here we describe an extensive study of the bulk's heat conductance. Using a novel 'multiterminal' short device (on a scale of 10 µm), we separate the longitudinal thermal conductance, [Formula: see text] (owing to the bulk's contribution), from the topological transverse value [Formula: see text] by eliminating the contribution of the edge modes24. When the magnetic field is tuned away from the conductance plateau centre, the localized states in the bulk conduct heat efficiently ([Formula: see text]), whereas the bulk remains electrically insulating. Fractional states in the first excited Landau level, such as the [Formula: see text] and [Formula: see text], conduct heat throughout the plateau with a finite [Formula: see text]. We propose a theoretical model that identifies the localized states as the cause of the finite heat conductance, agreeing qualitatively with our experimental findings.

Variance of Alpha Angle with Use of Intramedullary Guide – Long or Short Intramedullary Alignment Guide (IAG)

Introduction: Total Knee Replacement is common surgery to treat osteoarthritis in present day. This is important to restore the daily activities of living and at times it also helps to patients to go further with daily activities of earning in their old age. This surgery also reduces the burden of old people in the society. With advancements in TKR surgery, every aspect of alignment of prosthesis needs to be measured to determine acceptability of implant. Further this can help in refinement to improve the movement and acceptance of implant, better patient satisfaction. Aim: We here by propose null hypothesis that use of long or short Intramedullary Alignment Guide (IAG) during the distal femur cut cannot influence the alpha angle of femur. Materials and Methods: This is a radiological evaluation study done in BIRRD (T) Hospital. All the patients admitted into BIRRD for TKR in unit III were evaluated pre operatively. Surgery was performed by different surgeons based upon their training and using of IAG (short or long). There were no indications for use of short or long IAG. This is totally based on surgeon preference on using. Later alpha angle was measured post operatively. Observation and Results: A total of 243 patients were included into the study. Data was collected based the surgeons experience and preference in use of long and short IAG device. There were 96 and 147 patients were long and short IAG devices used respectively. It was found that alpha angle of 93.6o (+ 2.7) and 93.4o (+ 3.04) respectively with long and short IAG. Conclusion: We found that there is no significant statistical difference in alpha angle with use of long and short IAG during femur cuts in TKR. Hence null hypothesis is accepted.

Successive Interference Analysis for 5G System at Mid-Band and High-Band Frequency

This research study focuses on the impact of interference on different 5G system parameters such as modulation techniques (64-QAM, 256-QAM), channel models (AWGN, Rayleigh, and Rician), and MIMO (multiple input, multiple output) in terms of Bit Error Rate (BER). After the analysis of interference for each parameter, an analysis of interference by Short Range Devices (SRDs) on the 5G system network on the downlink channel is done. Finally, successive interference cancellation (SIC) for a 5G Non-Orthogonal Multiple Access (NOMA) system with Power Division Multiplexing (PDM) is applied. A 5G NOMA has higher spectral efficiency as compared to an Orthogonal Frequency Division Multiple Access (OFDMA), so it can fulfil the needs of the Internet of Things (IoT). SIC is implemented using PDM, where each user is assigned a certain power factor and generates a signal, the generated signal is superimposed and the New-Radio (NR) transmitter that transmits the superimposed signal. Finally, the signal is detected with and without SIC on the access side with SRDs as an interferer. After simulation and analysis of different 5G system parameters, it is found that the BER is decreased with an increase in the MIMO and is more applicable to the higher order modulation. With the SIC, the BER for the NOMA users decreased as compared to OFDMA users. The power coefficients for the stronger signal user (user 1) and weaker signal user (user 2) are 0.25 and 0.75 respectively.

PERcutaneous transhepatic CHOLangioscopy using a new single-operator short cholangioscope (PERCHOL): European feasibility study.

A new short device for percutaneous endoscopic cholangioscopy was recently developed. However, feasibility and safety has not yet been evaluated. The aim of this study was to assess clinical success, technical success, and adverse events (AEs). This observational multicenter retrospective study included all patients who underwent percutaneous cholangioscopy using a short cholangioscope between 2020 and 2022. The clinical success, defined as the complete duct clearance or obtaining at least one cholangioscopy-guided biopsy, was assessed. The histopathological accuracy, technical success, and the AE rate were also evaluated. Fifty-one patients (60 ± 15 years, 45.1% male) were included. The majority of patients had altered anatomy (n = 40, 78.4%), and biliary stones (n = 34, 66.7%) was the commonest indication. The technique was predominantly wire-guided (n = 44, 86.3%) through a percutaneous sheath (n = 36, 70.6%) following a median interval of 8.5 days from percutaneous drainage. Cholangioscopy-guided electrohydraulic lithotripsy was performed in 29 cases (56.9%), combined with a retrieval basket in eight cases (27.6%). The clinical success was 96.6%, requiring a median of one session (range 1-3). Seventeen patients (33.3%) underwent cholangioscopy-guided biopsies. There were four (7.8%) cholangioscopy-related AEs (cholangitis and peritonitis). Overall, the technical success and AE rates were 100% and 19.6%, respectively, in a median follow-up of 7 months. Percutaneous endoscopic cholangioscopy with a new short device is effective and safe, requiring a low number of sessions to achieve duct clearance or accurate histopathological diagnosis.

Integration of a Custom-Made Fenestration to Simplify Acute Reno-Visceral In Situ Aortic Repair.

To illustrate the technique of antegrade in situ laser fenestration (ISLF) on a predesign custom-manufactured stent-graft with single reinforced fenestration for use in emergency endovascular repair of complex abdominal aortic aneurysms (AAAs). A short custom-made device (CMD) fenestrated graft was predesigned with a single preloaded 8 mm strut-free fenestration at 12 o'clock position. A modified preloaded system was used to allow unilateral access from the distal port if necessary. After bilateral percutaneous femoral access, the graft was deployed under fusion guidance with the CMD fenestration matching the superior mesenteric artery (SMA) origin and immediately bridged as per standard technique. The aneurysm was then excluded with a bifurcated device. A large steerable sheath was used to allow for sequential antegrade laser in situ fenestration and stenting of the renal arteries. Single-vessel customized short fenestrated grafts for the SMA and antegrade in situ laser renal fenestrations are technically feasible for repair of acute complex AAAs even after previous infrarenal reconstruction. It could become an off-the-shelf solution to limit aortic coverage and reno-visceral ischemia, even in patients with a narrow aortic diameter at the renal level. Single-vessel precustomized short fenestrated grafts for the SMA combined with renal artery antegrade ISLF can be a feasible option for the acute repair of patients with complex aneurysms and a narrow aortic diameter at the reno-visceral segment. It may limit aortic coverage and reno-visceral ischemic time and also be applicable after previous infrarenal endovascular aneurysm repair (EVAR).

Use of the Occlutech pmVSD Device for Hybrid Closure of a Large Mid-Muscular Ventricular Septal Defect in a Small Infant Born With Hypoplastic Aortic Arch.

We describe the perventricular device closure of a large mid-muscular ventricular septal defect (VSD) in a 2.9 kg infant born with hypoplastic aortic arch and VSD using an Occlutech perimembranous occluder. In this case, the anatomy required a short low-profile device and hence a perimembranous occluder was used. To our knowledge, this is the first described use of this device for hybrid closure of a muscular VSD and the application of this technique in a patient <3 kg.

Rapid Production of Nanoscale Liposomes Using a 3D-Printed Reactor-In-A-Centrifuge: Formulation, Characterisation, and Super-Resolution Imaging.

Nanoscale liposomes have been extensively researched and employed clinically for the delivery of biologically active compounds, including chemotherapy drugs and vaccines, offering improved pharmacokinetic behaviour and therapeutic outcomes. Traditional laboratory-scale production methods often suffer from limited control over liposome properties (e.g., size and lamellarity) and rely on laborious multistep procedures, which may limit pre-clinical research developments and innovation in this area. The widespread adoption of alternative, more controllable microfluidic-based methods is often hindered by complexities and costs associated with device manufacturing and operation, as well as the short device lifetime and the relatively low liposome production rates in some cases. In this study, we demonstrated the production of liposomes comprising therapeutically relevant lipid formulations, using a cost-effective 3D-printed reactor-in-a-centrifuge (RIAC) device. By adjusting formulation- and production-related parameters, including the concentration of polyethylene glycol (PEG), temperature, centrifugation time and speed, and lipid concentration, the mean size of the produced liposomes could be tuned in the range of 140 to 200 nm. By combining selected experimental parameters, the method was capable of producing liposomes with a therapeutically relevant mean size of ~174 nm with narrow size distribution (polydispersity index, PDI ~0.1) at a production rate of >8 mg/min. The flow-through method proposed in this study has potential to become an effective and versatile laboratory-scale approach to simplify the synthesis of therapeutic liposomal formulations.

The evaluation of the influence of Gaussian noise, harmonic type noise and combined noise to short range wireless devices

Modern short-range wireless devices are widely used for data transmission and / or control actions in various radio engineering and information-measuring networks. Such a device in the process of use is in the conditions of a potential violation of the permissible type, which limits the possibilities of their application. The aim of the work is to evaluate the Gaussian noise, harmonic type noise and combined noise on short-range wireless devices using pseudo-random frequency conversion and frequency ripple. An estimate of the influence of various types of noise on the named wireless devices is obtained, as well as the dependence of the average error probability on the signal-to-noise and signal-to-interference ratios. It is shown that devices in which the frequency span between channels is continuously changing have the highest noise immunity, and this is also typical for devices with the highest signal-to-noise ratio. The increase in the noise immunity of devices increases with the size of the signal alphabet. It is shown that the noise immunity of the device when exposed to combined noise, which is a superposition of noise and a harmonic signal, differs little when exposed to one of the named noises. It is noted that the use of binary block codes increases the noise immunity of the device. In the course of the work, practically significant results were obtained, which make it possible to evaluate the noise immunity of these devices for various values of the signal-to-noise and signal-to- interference ratios, as well as the size of the signal alphabet. The results obtained can be used in the construction and analysis of wireless devices operating in the unlicensed bands below 1 GHz.

Effect of Total Dose Irradiation on Parasitic BJT in 130 nm PDSOI MOSFETs.

In this work, the effects of total dose irradiation on the parasitic bipolar junction transistor (BTJ) in 130 nm PDSOI MOSFETs were investigated. The experimental results demonstrate that irradiation-induced oxide-trap charges can modify the E-B junction barrier, and thereby make the common-emitter gain β0 of the parasitic BJT in NMOS device increase, while decreasing it in a PMOS device. Additionally, irradiation-generated oxide-trap charges in shallow trench isolation (STI) elevate the surface electrostatic potential of the gate above the STI sidewall, thus providing an additional channel from the emitter to the collector. Moreover, these charges may generate parasitic reverse conductive paths at the STI/Si interface under high dose irradiation, thereby enhancing the leakage current in the front gate channel and diminishing the significance of the parasitic BJT. Under irradiation, the electric field intensity difference between two biases leads to higher β0 of the parasitic BJT in PG-biased devices than in ON-biased ones. Furthermore, the lifting effect of irradiation on β0 increases in wide or short channel irradiated devices, which can be explained using simulations and an emitter current crowding effect model.

Healthcare-Associated Infections Caused by Mycolicibacterium neoaurum.

Mycolicibacterium neoaurum is a rapidly growing mycobacterium and an emerging cause of human infections. M. neoaurum infections are uncommon but likely underreported, and our understanding of the disease spectrum and optimum management is incomplete. We summarize demographic and clinical characteristics of a case of catheter-related M. neoaurum bacteremia in a child with leukemia and those of 36 previously reported episodes of M. neoaurum infection. Most infections occurred in young to middle-aged adults with serious underlying medical conditions and commonly involved medical devices. Overall, infections were not associated with severe illness or death. In contrast to other mycobacteria species, M. neoaurum was generally susceptible to multiple antimicrobial drugs and responded promptly to treatment, and infections were associated with good outcomes after relatively short therapy duration and device removal. Delays in identification and susceptibility testing were common. We recommend using combination antimicrobial drug therapy and removal of infected devices to eradicate infection.