Graphene-based nanosheets (GNS) have been studied for use in electrochemical energy storage devices. A deeper understanding about the system is required for achieving enhanced power output and high ...energy storage. The effects of sulfur doping on the electrochemical properties of GNS are studied for their use as an anode material in lithium-ion batteries. Sulfur doping in GNS contributes to the high specific capacity by providing more lithium storage sites due to Faradaic reactions. In addition, superior rate performance of sulfur-doped GNS (S-GNS) is achieved through the improved electrical conductivity of S-GNS (1743 S m super(-1)), which is two orders of magnitude higher than that of GNS (32 S rrr super(1)). In addition, good cyclic stability of S-GNS is maintained even after 500 cycles at a high current density of 1488 mA g super(-1) (4 C).
In this paper, a new single-stage half-bridge (HB) resonant <inline-formula><tex-math notation="LaTeX">LLC </tex-math></inline-formula> converter additionally employing one resonant capacitor and two ...relays with one package is proposed, compared with a single-stage HB <inline-formula><tex-math notation="LaTeX">LLC</tex-math></inline-formula> converter. Moreover, a center-tapped transformer is replaced with a coupled transformer. Since the proposed converter changes the turns ratio of the coupled transformer using a relay according to low- or high-input-voltage range, it can decrease the range of its needed voltage gain. It means that the proposed converter can be designed with large transformer magnetizing inductance compared with the conventional single-stage HB <inline-formula> <tex-math notation="LaTeX">LLC</tex-math></inline-formula> converter. As a result, the primary conduction and turn-off losses are reduced. Moreover, in low input voltage range, it has smaller total primary wire resistance of the transformer due to parallel connection of the coupled transformer, which decreases its conduction loss. In addition, additionally employed small-sized components can be inserted to the conventional system. To confirm the operation, features, and validity of the proposed converter, universal input with low line and high line and 16.5 V/60 W output laboratory prototype targeting laptop adapters with wide-input-voltage range is built and tested.
Background: Permanent pacemaker (PPM) implantation has been identified as a risk factor for morbidity and mortality after Fontan operation. This study investigated the factors associated with ...outcomes in patients with Fontan physiology who underwent PPM implantation.Methods and Results: We retrospectively reviewed 508 patients who underwent Fontan surgery at Asan Medical Center between September 1992 and August 2022. Of these patients, 37 (7.3%) received PPM implantation. Five patients were excluded, leaving 32 patients, of whom 11 were categorized into the poor outcome group. Poor outcomes comprised death, heart transplantation, and “Fontan failure”. Clinical, Fontan procedure-related, and PPM-related factors were compared between the poor and good outcome groups. Ventricular morphology, Fontan procedure-associated factors, pacing mode, high ventricular pacing rate, and time from first arrhythmia to PPM implantation did not differ significantly between the 2 groups. However, the poor outcome group exhibited a significantly longer mean paced QRS duration (P=0.044). Receiver operating characteristic curve analysis revealed a paced QRS duration cut-off value of 153 ms with an area under the curve of 0.73 (P=0.035).Conclusions: A longer paced QRS duration was associated with poor outcomes, indicating its potential to predict adverse outcomes among Fontan patients.
Global climate change accompanied by continuous increases in atmospheric carbon dioxide (CO2) concentration and temperature affects the growth and yield of important crops. The present study ...investigated the effect of elevated temperature and CO2 concentrations on the growth, yield, and photosynthesis of potato (Solanum tuberosum L. cv. Superior) crops using Korean Soil-Plant-Atmosphere-Research chambers that allow the regulation of temperature and CO2 concentration under daylight conditions. Based on the average temperature from 1991 to 2010 in the Jeonju area, South Korea, potato plants were exposed to four different conditions: ambient weather (400 μmol mol-1, aCaT), elevated temperature (+4°C, aCeT), elevated CO2 concentration (800 μmol mol-1, eCaT), and concurrently elevated CO2 concentration and temperature (eCeT). Under aCeT conditions, the temperature exceeded the optimal growth temperature range towards the late growth phase that decreased stomatal conductance and canopy net photosynthetic rate and subsequently reduced biomass and tuber yield. Stomatal conductance and chlorophyll concentration were lower under eCaT conditions than under aCaT conditions, whereas late-growth phase biomass and tuber yield were greater. Compared to other conditions, eCeT yielded a distinct increase in growth and development and canopy net photosynthetic rate during tuber initiation and bulking. Consequently, biomass and canopy net photosynthesis increased, and tuber yield increased by 20.3%, which could be attributed to the increased tuber size, rather than increased tuber number. Elevated CO2 reduced chlorophyll, magnesium, and phosphorus concentrations; reducing nitrogen concentration (by approximately 39.7%) increased the C:N ratio. The data indicate that future climate conditions will likely change nutrient concentration and quality of crops. The present study shows that while elevated temperature may negatively influence the growth and yield of potato crops, especially towards the late-growth phase, the concurrent and appropriate elevation of CO2 and temperature could promote balanced development of source and sink organs and positively effect potato productivity and quality.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Due to climate change, soil moisture may increase, and outflows could become more frequent, which will have a considerable impact on crop growth. Crops are affected by soil moisture; thus, soil ...moisture prediction is necessary for irrigating at an appropriate time according to weather changes. Therefore, the aim of this study is to develop a future soil moisture (SM) prediction model to determine whether to conduct irrigation according to changes in soil moisture due to weather conditions. Sensors were used to measure soil moisture and soil temperature at a depth of 10 cm, 20 cm, and 30 cm from the topsoil. The combination of optimal variables was investigated using soil moisture and soil temperature at depths between 10 cm and 30 cm and weather data as input variables. The recurrent neural network long short-term memory (RNN-LSTM) models for predicting SM was developed using time series data. The loss and the coefficient of determination (R
) values were used as indicators for evaluating the model performance and two verification datasets were used to test various conditions. The best model performance for 10 cm depth was an R
of 0.999, a loss of 0.022, and a validation loss of 0.105, and the best results for 20 cm and 30 cm depths were an R
of 0.999, a loss of 0.016, and a validation loss of 0.098 and an R
of 0.956, a loss of 0.057, and a validation loss of 2.883, respectively. The RNN-LSTM model was used to confirm the SM predictability in soybean arable land and could be applied to supply the appropriate moisture needed for crop growth. The results of this study show that a soil moisture prediction model based on time-series weather data can help determine the appropriate amount of irrigation required for crop cultivation.
Background:Implantable cardioverter-defibrillator (ICD) therapy is important for the prevention of sudden cardiac death, but data on clinical outcomes of ICD therapy in Asian pediatric patients are ...scarce. The aim of this Korean multicenter study was to evaluate the current state and elucidate the clinical outcomes of ICD therapy in children.Methods and Results:Data from 5 pediatric cardiology centers were retrospectively collected from 2007 to 2019. Altogether, 99 patients were enrolled (mean age 13.9±4.1 years). The most common underlying disease was a primary electrical disease (56%). An ICD was implanted for primary prevention in 19%. Appropriate shock occurred in 44% of patients at a median of 1.6 years after implantation. There was no significant difference in the appropriate shock rate between patients with primary and secondary prevention indications (32% vs. 48%, respectively). A total of 33 patients (33%) experienced inappropriate shock, which was associated with primary electrical disease and follow-up duration on multivariate analysis. 17% of patients had ICD-related complications.Conclusions:The utilization rate of ICD for primary prevention was still low in the pediatric population in Korea, but there was a substantial rate of appropriate shock in these patients. Efforts to increase ICD usage to save the lives of high-risk patients and reduce the incidence of inappropriate shock are required.
In this paper, a simple control method of the half-bridge (HB) LLC converter with one additional switch and capacitor in the primary side is proposed for wide-input-voltage applications with the ...hold-up time conditions. At nominal input, since the proposed method enables the HB LLC converter to operate with large transformer magnetizing inductance, it can reduce the conduction and switch turn-off losses in the primary side, which makes it highly efficient. On the other hand, during the hold-up time, since the proposed method increases the resonant capacitance by turning on one additional switch, the HB LLC converter can obtain high-voltage gain. To confirm the validity of the HB LLC converter with the proposed method, a 325-385 V input and 56 V/350 W output laboratory prototype is built and tested.
For a fixed graph H, the reconfiguration problem for H‐colorings (ie, homomorphisms to H) asks: given a graph G and two H‐colorings φ and ψ of G, does there exist a sequence f0,…,fm of H‐colorings ...such that f0=φ, fm=ψ, and fi(u)fi+1(v)∈E(H) for every 0≤i<m and uv∈E(G)? If the graph G is loop‐free, then this is the equivalent to asking whether it possible to transform φ into ψ by changing the color of one vertex at a time such that all intermediate mappings are H‐colorings. In the affirmative, we say that φ reconfigures to ψ. Currently, the complexity of deciding whether an H‐coloring φ reconfigures to an H‐coloring ψ is only known when H is a clique, a circular clique, a C4‐free graph, or in a few other cases which are easily derived from these. We show that this problem is PSPACE‐complete when H is an odd wheel. An important notion in the study of reconfiguration problems for H‐colorings is that of a frozen H‐coloring; that is, an H‐coloring φ such that φ does not reconfigure to any H‐coloring ψ such that ψ≠φ. We obtain an explicit dichotomy theorem for the problem of deciding whether a given graph G admits a frozen H‐coloring. The hardness proof involves a reduction from a constraint satisfaction problem which is shown to be nondeterministic polynomial time NP‐complete by establishing the nonexistence of a certain type of polymorphism.
Background:Percutaneous atrial septal defect (ASD) closure is the treatment of choice for patients with a suitable ASD anatomy; however, the procedural characteristics and outcomes in children aged ...<6 years are unclear. The feasibility and safety of percutaneous ASD closure in children aged <6 years was evaluated and the predictors of procedural failure and challenging cases were identified.Methods and Results:Patients from a single center between 2006 and 2018 (n=407) were retrospectively evaluated. There were 265 (65.1%) female patients. The median age at the time of the procedure and ASD size were 3.4 (0.9–5.9) years and 13.3 (3.8–27.0) mm, respectively. Medical records and echocardiographic images were analyzed. A challenging case was indicated by the use of non-conventional techniques. The procedure was completed in 399 patients (98.0%). Post-procedural acute complications occurred in 5 patients, including 1 with device embolization. Two patients underwent surgical device removal. During the follow up (30.3 3.6–140.8 months), aggravated mitral regurgitation occurred in 5 patients. A multivariate logistic regression revealed large-sized ASD as a predictor of procedural failure (odds ratio=1.828, 95% confidence interval: 1.139–2.934, P=0.012) and challenging cases (odds ratio=1.371, 95% confidence interval: 1.180–1.593, P<0.001).Conclusions:Percutaneous ASD closure is feasible and safe in children aged <6 years; however, patients with large-sized ASD are at high risk of procedural failure and becoming a challenging case.
Interferometric synthetic aperture radar (InSAR) denosing is an essential processing step in deformation measurement and topography reconstruction. A noisy InSAR phase image gives rise to the phase ...unwrapping difficulties and even results in the degradation on various final products of InSAR. To address this issue, we develop a compressive sensing (CS)-based InSAR phase denoising technique in this paper. Since the spectrum of InSAR phase image is usually sparse in two-dimensional frequency domain, the estimation of sensing dictionary matrix of linear system between the InSAR phase signal and its spectrum in the pursuit of sparsity is considered for InSAR phase denoising. The optimization problem derived by signal parameterization approach is effectively carried out by estimating the basis function that is closely analogous to the strongest signal component in the spectrum of InSAR phase image. The proposed method is effectively capable of eliminating noise and preserving detailed fringe information of InSAR. In the end, simulations and experimental results demonstrate that the proposed scheme outperforms other conventional InSAR phase denoising methods.
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