Artificial Synapse Based on a δ-FAPbI3/Atomic-Layer-Deposited SnO2 Bilayer Memristor.

Halide perovskite-based resistive switching memory (memristor) has potential in an artificial synapse. However, an abrupt switch behavior observed for a formamidinium lead triiodide (FAPbI3)-based memristor is undesirable for an artificial synapse. Here, we report on the δ-FAPbI3/atomic-layer-deposited (ALD)-SnO2 bilayer memristor for gradual analogue resistive switching. In comparison to a single-layer δ-FAPbI3 memristor, the heterojunction δ-FAPbI3/ALD-SnO2 bilayer effectively reduces the current level in the high-resistance state. The analog resistive switching characteristics of δ-FAPbI3/ALD-SnO2 demonstrate exceptional linearity and potentiation/depression performance, resembling an artificial synapse for neuromorphic computing. The nonlinearity of long-term potentiation and long-term depression is notably decreased from 12.26 to 0.60 and from -8.79 to -3.47, respectively. Moreover, the δ-FAPbI3/ALD-SnO2 bilayer achieves a recognition rate of ≤94.04% based on the modified National Institute of Standards and Technology database (MNIST), establishing its potential in an efficient artificial synapse.

The Role of Collective Group Orientation and Social Norms on Physical Distancing Behaviors for Disease Prevention.

To reduce the impact of communicable diseases like COVID-19, collective action is required and likely to be susceptible to normative influence as well as whether people are more or less collectively oriented. We extend the theory of normative social behavior (TNSB) to account for group orientation and predict the relationships between social norms and physical distancing behaviors. Using a rolling cross-sectional design during 17 weeks of the pandemic, a national sample of US residents from 20 states (N = 8,778) participated in the study. The findings show that perceived descriptive norms, injunctive norms, and group orientation are significantly associated with physical distancing. The descriptive norm-behavior relationship and injunctive norm-behavior relationship are moderated by group orientation and the other predicted moderators in the TNSB. The findings extend the TNSB and highlight the need to understand social norms and group orientation in formative research for health communication campaigns designed to promote prevention behaviors.

Medial Epicondyle Fracture in Children and Its Association with Increased Carrying Angle.

Background: This study aimed to evaluate the injury mechanism of medial epicondylar fractures in children and adolescents and its association with increased carrying angle (CA) as a predisposing factor. Materials and Methods: We evaluated 37 patients with medial epicondylar fractures who were surgically treated at our institution. Medical records and plain radiographs were reviewed to determine the mechanism of injury and the humerus-elbow-wrist angle (HEWA) and CA of the uninjured arm. To evaluate the effect of coronal alignment on specific fracture type, we compared the CA and HEWA of the 23 patients with medial epicondylar fracture who were injured by falling onto an outstretched hand (group I) with age- and sex-matched controls of 23 patients who had sustained extension-type supracondylar fractures (group II). Results: The mean age at injury was 11.7 ± 2.8 years (range, 5 to 16 years). Of the 37 patients, 23 (62.2%) recalled the injury mechanism as falling onto an outstretched hand and 10 patients (27.0%) were injured while arm wrestling, and in one patient (2.7%), the injury was associated with elbow dislocation. In the case-matched analysis, the mean HEWA of group I was 13.1 ± 2.8° (range, 7.1° to 19.8°) and the mean CA was 17.7 ± 2.7° (range, 13.0° to 22.2°). These angles were significantly increased in group I (p=0.003 and p=0.001, respectively). Conclusion: Falling onto an outstretched hand is the most common injury mechanism in patients with medial epicondylar fractures, and these fractures are associated with an increased CA.

Prevalence of Vitamin D Deficiency in Children with Fractures: Before and during the COVID-19 Outbreak.

Background: Although it is generally agreed that vitamin D is important for bone health, the role of vitamin D in preventing fractures in children and adolescents remains unclear. Therefore, this study aimed to investigate the prevalence of vitamin D deficiency and insufficiency in healthy Korean children with fractures. Our secondary aim was to compare serum vitamin D levels before and during the coronavirus disease 2019 (COVID-19) outbreak. Methods: We evaluated 334 patients with fractures who were surgically treated at our institution between 2018 and 2019 before the onset of COVID-19 (group I). In addition, we collected data on the serum 25(OH)D levels of 210 patients who visited our pediatric department for evaluation of short stature (group II) and the serum 25(OH)D levels of the patients with fractures during the COVID-19 pandemic period (group III). A serum 25(OH)D level of <20 ng/mL was considered deficient, between 20 and 32 ng/mL was insufficient, and ≥32 ng/mL was considered sufficient. Results: The mean age was 8.1 ± 3.5 years in group I, 8.2 ± 3.7 years in group II, and 8.6 ± 3.5 years in group III. The prevalence of vitamin D deficiency was 53.0% in group I and 32.9% in group II. The mean serum 25(OH)D level was lower in group I than in group II (20.0 ± 7.3 ng/ml vs. 23.2 ± 6.9 ng/ml, p < 0.001). The mean serum 25(OH)D level of younger patients (<10 years) in group III was lower than that of the younger patients in the prepandemic period (21.4 ± 7.2 ng/mL vs. 19.2 ± 6.8 ng/mL, p=0.037). Conclusions: We observed a high prevalence of vitamin D deficiency/insufficiency in children with fractures who required surgical treatment. During the COVID-19 pandemic, the serum vitamin D levels became even lower, especially in younger children.

A Comprehensive Evaluation of Possible RNSS Signals in the S-Band for the KPS.

Recently, the Korean government has announced a plan to develop a satellite-based navigation system called the Korean Positioning System (KPS). When designing a new Radio Navigation Satellite Service (RNSS) signal, the use of the S-band has emerged as an alternative to avoiding signal congestion in the L-bands, and South Korea is considering using the S-band with the L-bands. Therefore, this study proposed possible S-band signal candidates and evaluated their performance, such as the radio frequency (RF) compatibility, spectral efficiency, ranging performance, and receiver complexity. Several figures-of-merit (FoMs) were introduced for quantitative performance evaluation for each candidate. Each FoM was calculated using an analytical equation by considering the signal design parameters, such as the center frequency, modulation scheme, and chip rate. The results showed that the outstanding candidate signal was different depending on the signal performance of interest and the reception environments. Therefore, we discuss and summarize the signal performance analysis results considering the whole FoMs together. Under the assumptions given in this paper, the binary phase shift keying (BPSK)(1), sine-phased binary offset carrier (BOCs)(5,2), and BPSK signals were superior for the spectral efficiency, ranging performance, and receiver complexity, respectively.

The Moderating Role of Self-construal in Culturally Reflected Fear Appeals.

Scholars have long investigated fear appeals as a way to improve persuasive messages, yet we still lack understanding regarding the role of cultural orientation in relation to fear appeals. In the current study, we investigate how individual self-construal influences responses to culturally reflected fear appeals in the context of smoking cessation. Using a 2 (reference type: self-reference versus other-reference) x 2 (smoking cessation program: individual program versus group program) experimental design, this study found that self-construal moderates the effects of reference type on perceived threat and perceived threat to freedom. In addition, main effects of self-construal on perceived threat to freedom and self-efficacy are observed. Theoretical and practical implications of findings are discussed.

The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears.

BACKGROUND: The natural course of and risk factors for tear progression in full-thickness rotator cuff tears (FTRCTs) have not been clarified yet. The study's purpose was to retrospectively evaluate tear progression in FTRCTs by using magnetic resonance imaging (MRI) and to identify risk factors that are relevant to such tear progression. METHODS: Between June 2010 and September 2019, a total of 345 patients with FTRCTs who had been diagnosed via MRI were treated conservatively. Of these, 48 patients who underwent post-treatment follow-up MRI were retrospectively enrolled. Tear progression was defined as significant when the tear size increased by >5 mm. RESULTS: The mean MRI follow-up duration was 22 ± 14 months (range, 12-65 months). Among the 48 patients (mean age, 69 years; range, 53-81), 26 (54%) and 20 (41%) showed medial-lateral (M-L) and anterior-posterior (A-P) tear progression on MRI follow-up. Multivariate analysis revealed that MRI follow-up duration (P = .011), diabetes mellitus (P = .017), and infraspinatus muscle atrophy (P = .011) were independent risk factors for tear progression in the A-P plane. A high critical shoulder angle (P = .011) and supraspinatus (P = .024) and infraspinatus (P = .020) muscle atrophy were risk factors associated with M-L tear progression. CONCLUSION: Among the assessed patients, a considerable number of FTRCTs increased in size during the follow-up period. Severe infraspinatus muscle atrophy was the independent risk factor for exacerbation of A-P and M-L tear progression.

Nitric oxide- induced AtAO3 differentially regulates plant defense and drought tolerance in Arabidopsis thaliana.

BACKGROUND: Exposure of plants to different environmental insults instigates significant changes in the cellular redox tone driven in part by promoting the production of reactive nitrogen species. The key player, nitric oxide (NO) is a small gaseous diatomic molecule, well-known for its signaling role during stress. In this study, we focused on abscisic acid (ABA) metabolism-related genes that showed differential expression in response to the NO donor S-nitroso-L-cysteine (CySNO) by conducting RNA-seq-based transcriptomic analysis. RESULTS: CySNO-induced ABA-related genes were identified and further characterized. Gene ontology terms for biological processes showed most of the genes were associated with protein phosphorylation. Promoter analysis suggested that several cis-regulatory elements were activated under biotic and/or abiotic stress conditions. The ABA biosynthetic gene AtAO3 was selected for validation using functional genomics. The loss of function mutant atao3 was found to differentially regulate oxidative and nitrosative stress. Further investigations for determining the role of AtAO3 in plant defense suggested a negative regulation of plant basal defense and R-gene-mediated resistance. The atao3 plants showed resistance to virulent Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000) with gradual increase in PR1 gene expression. Similarly, atao3 plants showed increased hypersensitive response (HR) when challenged with Pst DC3000 (avrB). The atgsnor1-3 and atsid2 mutants showed a susceptible phenotype with reduced PR1 transcript accumulation. Drought tolerance assay indicated that atao3 and atnced3 ABA-deficient mutants showed early wilting, followed by plant death. The study of stomatal structure showed that atao3 and atnced3 were unable to close stomata even at 7 days after drought stress. Further, they showed reduced ABA content and increased electrolyte leakage than the wild-type (WT) plants. The quantitative polymerase chain reaction analysis suggested that ABA biosynthesis genes were down-regulated, whereas expression of most of the drought-related genes were up-regulated in atao3 than in WT. CONCLUSIONS: AtAO3 negatively regulates pathogen-induced salicylic acid pathway, although it is required for drought tolerance, despite the fact that ABA production is not totally dependent on AtAO3, and that drought-related genes like DREB2 and ABI2 show response to drought irrespective of ABA content.

WRKYs, the Jack-of-various-Trades, Modulate Dehydration Stress in Populus davidiana-A Transcriptomic Approach.

Populus davidiana, native to Korea and central Asian countries, is a major contributor to the Korean forest cover. In the current study, using high-throughput RNA-seq mediated transcriptome analysis, we identified about 87 P. davidiana WRKY transcription factors (PopdaWRKY TFs) that showed differential expression to dehydration stress in both sensitive and tolerant cultivars. Our results suggested that, on average, most of the WRKY genes were upregulated in tolerant cultivars but downregulated in sensitive cultivars. Based on protein sequence alignment, P. davidiana WRKYs were classified into three major groups, I, II, III, and further subgroups. Phylogenetic analysis showed that WRKY TFs and their orthologs in Arabidopsis and rice were clustered together in the same subgroups, suggesting similar functions across species. Significant correlation was found among qRT-PCR and RNA-seq analysis. In vivo analysis using model plant Arabidopsis showed that atwrky62 (orthologous to Potri.016G137900) knockout mutants were significantly sensitive to dehydration possibly due to an inability to close their stomata under dehydration conditions. In addition, a concomitant decrease in expression of ABA biosynthetic genes was observed. The AtHK1 that regulates stomatal movement was also downregulated in atwrky62 compared to the wild type. Taken together, our findings suggest a regulatory role of PopdaWRKYs under dehydration stress.

Suicide rates across income levels: Retrospective cohort data on 1 million participants collected between 2003 and 2013 in South Korea.

BACKGROUND: The relation of income and socioeconomic status with suicide rates remains unclear. Most previous studies have focused on the relationship between suicide rates and macroeconomic factors (e.g., economic growth rate). Therefore, we aimed to identify the relationship between individuals' socioeconomic position and suicide risk. METHODS: We analyzed suicide mortality rates across socioeconomic positions to identify potential trends using observational data on suicide mortality collected between January 2003 and December 2013 from 1,025,340 national health insurance enrollees. We followed the subjects for 123.5 months on average. Socioeconomic position was estimated using insurance premium levels. To examine the hazard ratios of suicide mortality in various socioeconomic positions, we used Cox proportional hazard models. RESULTS: We found that the hazard ratios of suicide showed an increasing trend as socioeconomic position decreased. After adjusting for gender, age, geographic location, and disability level, Medicaid recipients had the highest suicide hazard ratio (2.28; 95% CI, 1.87-2.77). Among the Medicaid recipients, men had higher hazard ratios than women (2.79; 95% CI, 2.17-3.59 vs. 1.71; 95% CI, 1.25-2.34). Hazard ratios also varied across age groups. The highest hazard ratio was found in the 40-59-year-old group (3.19; 95% CI, 2.31-4.43), whereas the lowest ratio was found in those 60 years and older (1.44; 95% CI, 1.09-1.87). CONCLUSIONS: Our results illuminate the relationship between socioeconomic position and suicide rates and can be used to design and implement future policies on suicide prevention.

Nitric oxide and S-nitrosoglutathione function additively during plant immunity.

Nitric oxide (NO) is emerging as a key regulator of diverse plant cellular processes. A major route for the transfer of NO bioactivity is S-nitrosylation, the addition of an NO moiety to a protein cysteine thiol forming an S-nitrosothiol (SNO). Total cellular levels of protein S-nitrosylation are controlled predominantly by S-nitrosoglutathione reductase 1 (GSNOR1) which turns over the natural NO donor, S-nitrosoglutathione (GSNO). In the absence of GSNOR1 function, GSNO accumulates, leading to dysregulation of total cellular S-nitrosylation. Here we show that endogenous NO accumulation in Arabidopsis, resulting from loss-of-function mutations in NO Overexpression 1 (NOX1), led to disabled Resistance (R) gene-mediated protection, basal resistance and defence against nonadapted pathogens. In nox1 plants both salicylic acid (SA) synthesis and signalling were suppressed, reducing SA-dependent defence gene expression. Significantly, expression of a GSNOR1 transgene complemented the SNO-dependent phenotypes of paraquat resistant 2-1 (par2-1) plants but not the NO-related characters of the nox1-1 line. Furthermore, atgsnor1-3 nox1-1 double mutants supported greater bacterial titres than either of the corresponding single mutants. Our findings imply that GSNO and NO, two pivotal redox signalling molecules, exhibit additive functions and, by extension, may have distinct or overlapping molecular targets during both immunity and development.

Real-time sonoelastography in the diagnosis of rotator cuff tendinopathy.

BACKGROUND: Real-time sonoelastography can be used to assess tissue elasticity. The present study evaluated the relationship between tendon stiffness on sonoelastography and the magnetic resonance imaging (MRI) tendinosis grade in patients with rotator cuff tendinopathy. METHODS: The study included 39 patients with chronic pain and no history of trauma or rotator cuff tear. The supraspinatus tendons were graded according to MRI findings (grade 0, normal; grade 1, mild tendinosis; grade 2, moderate tendinosis; grade 3, marked tendinosis), and the subcutaneous fat-to-tendon (Fat/T) and gel pad-to-tendon (Pad/T) strain ratios were assessed. We used the trend test to analyze the relationship of the MRI grade with the Fat/T strain ratio and the Pad/T strain ratio. RESULTS: Of the 39 patients, 9 had grade 0, 17 had grade 1, 12 had grade 2, and 1 had grade 3 tendinosis. The mean real-time elastography Fat/T and Pad/T strain ratios were 2.92 ± 2.13 and 20.77 ± 21.78 in patients with grade 0 tendinosis, 4.08 ± 4.09 and 21.78 ± 17.16 in patients with grade 1 tendinosis, 13.48 ± 10.19 and 83.00 ± 48.26 in patients with grade 2 tendinosis, and 12.3 ± 0.00 and 16.58 ± 0.00 in patients with grade 3 tendinosis, respectively. The Fat/T and Pad/T strain ratios were positively associated with the MRI grade (P <.001). CONCLUSION: The MRI tendinosis grade is associated with stiffness assessed using sonoelastography in patients with rotator cuff tendinopathy. Therefore, sonoelastography might be a useful diagnostic tool for supraspinatus tendinopathy. LEVEL OF EVIDENCE: Level III; Diagnostic Study.

Does size difference in allogeneic cancellous bone granules loaded with differentiated autologous cultured osteoblasts affect osteogenic potential?

We study the efficacy of bone regeneration by using two differently sized allogeneic cancellous bone granules loaded with autologous cultured osteoblasts in a rabbit model. Critical-sized bone defects of the radial shaft were made in 40 New Zealand White rabbits. Small allogeneic bone granules (150-300 µm in diameter) loaded with cultured differentiated autologous osteoblasts were implanted into one forearm (SBG group) and large bone granules (500-710 µm) loaded with osteoblasts were implanted into the forearm of the other side (LBG group). Radiographic evaluations were performed at 3, 6, 9 and 12 weeks and histology and micro-CT image analysis were carried out at 6 and 12 weeks post-implantation. On radiographic evaluation, the LBG group showed a higher bone quantity index at 3 and 6 weeks post-implantation (P < 0.05) but statistical significance was lost at 9 and 12 weeks. The progression of biological processes of the SBG group was faster than that of the LBG group. On micro-CT image analysis, the LBG group revealed a higher total bone volume and surface area than the SBG group at 6 weeks (P < 0.05) but the difference decreased at 12 weeks and was without statistical significance. Histological evaluation also revealed faster progression of new bone formation and maturation in the SBG group. Thus, the two differently sized allogeneic bone granules loaded with co-cultured autologous osteoblasts show no differences in the amount of bone regeneration, although the SBG group exhibits faster progression of bone regeneration and remodeling. This method might therefore provide benefits, such as a short healing time and easy application in an injectable form, in a clinical setting.

Accurate Evaluation of Electro-Thermal Performance in Silicon Nanosheet Field-Effect Transistors with Schemes for Controlling Parasitic Bottom Transistors.

The electro-thermal performance of silicon nanosheet field-effect transistors (NSFETs) with various parasitic bottom transistor (trpbt)-controlling schemes is evaluated. Conventional punch-through stopper, trench inner-spacer (TIS), and bottom oxide (BOX) schemes were investigated from single-device to circuit-level evaluations to avoid overestimating heat's impact on performance. For single-device evaluations, the TIS scheme maintains the device temperature 59.6 and 50.4 K lower than the BOX scheme for n/pFETs, respectively, due to the low thermal conductivity of BOX. However, when the over-etched S/D recess depth (TSD) exceeds 2 nm in the TIS scheme, the RC delay becomes larger than that of the BOX scheme due to increased gate capacitance (Cgg) as the TSD increases. A higher TIS height prevents the Cgg increase and exhibits the best electro-thermal performance at single-device operation. Circuit-level evaluations are conducted with ring oscillators using 3D mixed-mode simulation. Although TIS and BOX schemes have similar oscillation frequencies, the TIS scheme has a slightly lower device temperature. This thermal superiority of the TIS scheme becomes more pronounced as the load capacitance (CL) increases. As CL increases from 1 to 10 fF, the temperature difference between TIS and BOX schemes widens from 1.5 to 4.8 K. Therefore, the TIS scheme is most suitable for controlling trpbt and improving electro-thermal performance in sub-3 nm node NSFETs.

Effect of the Hammett substituent constant of para-substituted benzoic acid on the perovskite/SnO2 interface passivation in perovskite solar cells.

It is critical to design bifunctional passivation molecules to simultaneously passivate the charge transport layer and perovskite layer at the charge transport layer/perovskite interface in perovskite solar cells (PSCs). In this study, we investigate the effect of para-substituted benzoic acid with different Hammett constants (σ) on the photovoltaic performance of PSCs. Two passivation molecules 4-aminomethylbenzoic acid (4-AMBA) and 4-sulfamoylbenzoic acid (4-SABA) are used to passivate the SnO2 surface with carboxylic acid and the perovskite with para-substituent electron-donating -CH2NH2 (σ = ca. -0.02) and electron-withdrawing -SO2NH2 (σ = ca. +0.60). Compared with non-passivated PSC, the passivation improves the power conversion efficiency (PCE) mainly due to the increased open-circuit voltage (VOC) and fill factor (FF), where the -SO2NH2 substituent is better in improving the photovoltaic performance than the -CH2NH2 one. The trap density is more reduced and the charge extraction ability is more improved by 4-SABA than by 4-AMBA, which indicates that the weak electron-withdrawing nature of a para-substituent such as -SO2NH2 is better for the passivation of the bottom perovskite than a weak electron-donating -CH2NH2 substituent. Consequently, the passivation with 4-SABA enhances the PCE from 22.27% to 23.64%, along with improved long-term stability. This work highlights for the first time the role of the Hammett constant in the surface passivation of PSCs.

Climate change belief systems across political groups in the United States.

Beliefs and attitudes form the core of public opinion about climate change. Network analysis can reveal the structural configuration of these beliefs and attitudes. In this research, we utilize a belief system framework to identify key psychological elements, track change in the density of these belief systems over time and across political groups, and analyze the structural heterogeneity of belief systems within and between political groups in the United States. Drawing on fifteen waves of nationally representative survey data from 2010 to 2021 (N = 16,742), our findings indicate that worry about climate change is the most central psychological element. Interestingly, we find that among politically unaffiliated individuals, the connections between psychological elements have strengthened over time, implying an increase in the consistency of belief systems within this group. Despite the political polarization in beliefs about climate change between Republicans and Democrats, our findings reveal that the ways these two groups organize and structure climate change beliefs systems are not markedly different compared to those of other groups. These findings provide theoretical and practical insights for climate change experts and communicators.

Degassing 4-tert-Butylpyridine in the Spiro-MeOTAD Film Improves the Thermal Stability of Perovskite Solar Cells.

The organic molecular 2,2',7,7'-tetrakis(4,4'-dimethoxy-3-methyldiphenylamino)-9,9'-spirobifluorene (Spiro-MeOTAD) is known as a typical hole transport material in the development of an all-solid-state perovskite solar cell (PSC). Spiro-MeOTAD requires additives of lithium bifurflimide (LiTFSI) and 4-tert-butylpyridine (tBP) to increase the conductivity and solubility for enhancing the photovoltaic performance of PSCs. However, those additives have an adverse effect on the thermal stability. We report on the origin of instability of additive-containing Spiro-MeOTAD at 85 °C and the methodology to solve the thermal instability. We have found that the interaction of LiTFSI with the underneath perovskite surface facilitated by diffusive tBP is responsible for thermal degradation. Degasification of tBP from the Spiro-MeOTAD film is found to be the key to achieving thermally stable PSCs, where the optimal degassing process achieves 90% of the initial power conversion efficiency (PCE) at 85 °C after 1000 h.

Improving the classification accuracy for IR spectroscopic diagnosis of stomach and colon malignancy using non-linear spectral feature extraction methods.

Non-linear feature extraction methods, neighborhood preserving embedding (NPE) and supervised NPE (SNPE), were employed to effectively represent the IR spectral features of stomach and colon biopsy tissues for classification, and improve the classification accuracy for diagnosis of malignancy. The motivation was to utilize the NPE and SNPE's capability of capturing non-linear spectral behaviors by simultaneously preserving local relationships in order that minute spectral differences among classes would be effectively recognized. NPE and SNPE derive an optimal embedding feature such that the local neighborhood structure can be preserved in reduced spaces (variables). The IR spectra collected from stomach and colon tissues were represented by several new variables through NPE and SNPE, and also by using the principal component analysis (PCA). Then, the feature-extracted variables were subsequently classified into normal, adenoma and cancer tissues by using both k-nearest neighbor (k-NN) and support vector machine (SVM), and the resulting accuracies were compared with each other. In both cases, the combination of SNPE-SVM provided the best classification performance, and the accuracy was substantially improved compared to when PCA-SVM was used. Overall results demonstrate that NPE and SNPE could be potential feature-representation strategies useful in biomedical diagnosis based on vibrational spectroscopy where effective recognition of minute spectral differences is critical.

A plasma-based pressure pulse generator for simulating pellet-cladding mechanical interaction during reactivity-initiated accident.

This paper describes the characteristics of a plasma-based pressure pulse generator and its potential use as a simulator for studying pellet-cladding mechanical interaction (PCMI) during reactivity-initiated accidents (RIAs). In this device, a transient pressure pulse is generated by rapid heating and expansion of hot, dense plasma inside a nuclear fuel cladding. Thus, the parameters of a pressure pulse, such as peak pressure and pressure rise-rate, can be controlled by modifying the electrical parameters of a pulse discharge circuit. The pulse discharge circuit utilizes a capacitor bank comprising several energy storage capacitors connected in parallel and a high-power solid-state switch. A pressure loading system is attached as a load to the pulse discharge circuit. The power and energy delivered to the load are calculated by measuring the voltage and current waveforms at one end of the loading system. A piezoelectric sensor is connected at the other end of the loading system to simultaneously measure the pressure pulse inside the cladding tube. Preliminary experiments are carried out with a stainless-steel tube to characterize the performance of the device as well as with a pre-hydrided ZIRLO™ cladding tube to demonstrate the potential of the device as a simulator for studying the failure characteristics of the cladding as a result of an RIA. The high pressurization rate of the device is expected to offer unique advantages for studying the PCMI mechanism.

Atomic layer deposition of SnO2 using hydrogen peroxide improves the efficiency and stability of perovskite solar cells.

Low-temperature processed SnO2 is a promising electron transporting layer in perovskite solar cells (PSCs) due to its optoelectronic advantage. Atomic layer deposition (ALD) is suitable for forming a conformal SnO2 layer on a high-haze substrate. However, oxygen vacancy formed by the conventional ALD process using H2O might have a detrimental effect on the efficiency and stability of PSCs. Here, we report on the photovoltaic performance and stability of PSCs based on the ALD-SnO2 layer with low oxygen vacancies fabricated via H2O2. Compared to the ALD-SnO2 layer formed using H2O vapors, the ALD-SnO2 layer prepared via H2O2 shows better electron extraction due to a reduced oxygen vacancy associated with the highly oxidizing nature of H2O2. As a result, the power conversion efficiency (PCE) is enhanced from 21.42% for H2O to 22.34% for H2O2 mainly due to an enhanced open-circuit voltage. Operational stability is simultaneously improved, where 89.3% of the initial PCE is maintained after 1000 h under an ambient condition for the H2O2-derived ALD SnO2 as compared to the control device maintaining 72.5% of the initial PCE.