Perceived stress among staff in Saudi Arabian dental colleges before and after an accreditation process: A cross-sectional study

BACKGROUND Accreditation processes are extensively employed to guarantee the quality of higher education institutions.However,this process can potentially generate a stressful atmosphere for staff,thus impacting their ability to perform optimally under pressure.AIM To examine the knowledge of the National Commission for Academic Assessment and Accreditation(NCAAA)and its effects on perceived stress among dental college staff before and after the program accreditation process.METHODS The present cross-sectional questionnaire-based study included 300 employees from three dental colleges.The same employees had to fill out the questionnaire 1 mo after the NCAAA process.RESULTS Approximately 51.33%of the included employees believed that NCAAA is essential to attract quality students to join the program before and after the program.A total of 44.67%felt that their stress was high before,and 31.33%had low stress levels before and after NCAAA.These findings were statistically significant(P≤0.05).CONCLUSION NCAAA raised the prestige of the institution and specific programmes and increased prospects to attract better students,staff,and money,according to the employees.In addition to their needed teaching,research,and other service responsibilities,this work requires a tremendous amount of faculty effort and may cause them stress.

Peer pressure and academic stress among junior high school students:a cross-sectional study

Objective:The objective of the study was to explore the connection between peer pressure and academic stress among junior high school students.Methods:This descriptive correlational study was conducted to investigate the link between perceived peer pressure and academic stress.The study involved a total of 525 adolescents,aged 14-19 years,drawn from 6 public junior high schools(PJHS)in Padang,Indonesia,using purposive sampling.Academic stress and perceived peer pressure were assessed using the Educational Stress Scale for Adolescents(ESSA)and the Perceived Peer Pressure Scale(PPPS).Results:The findings indicated significant variations in stress levels among students in different grade levels(7th,8th,and 9th grades)(P<0.05),while there were no noteworthy differences in peer pressure across these grade levels(P>0.05).Additionally,there was a positive correlation observed between perceived peer pressure and academic stress(r=0.14,P<0.05).Furthermore,multiple regression analyses,incorporating demographic variables and perceived peer pressure as independent factors,yielded statistically significant results(adjusted R^(2)=0.082,F=4.33,P<0.001).Notably,peer pressure had a direct impact on academic stress among adolescents,with class level and parents’educational background mediating the relationship between academic stress and adolescent behavioral problems.Conclusions:These findings underscore the importance of addressing both external and internal factors at the individual,family,school,and societal levels to enhance adolescents’psychological resilience and mitigate problem behaviors.

Optimization Design of the Multi-Layer Cross-Sectional Layout of An Umbilical Based on the GA-GLM

Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with multi-layers.The layout of these components directly affects manufacturing,operation and storage performances of the umbilical.For the multi-layer cross-sectional layout design of the umbilical,a quantifiable multi-objective optimization model is established according to the operation and storage requirements.Considering the manufacturing factors,the multi-layering strategy based on contact point identification is introduced for a great number of functional components.Then,the GA-GLM global optimization algorithm is proposed combining the genetic algorithm and the generalized multiplier method,and the selection operator of the genetic algorithm is improved based on the steepest descent method.Genetic algorithm is used to find the optimal solution in the global space,which can converge from any initial layout to the feasible layout solution.The feasible layout solution is taken as the initial value of the generalized multiplier method for fast and accurate solution.Finally,taking umbilicals with a great number of components as examples,the results show that the cross-sectional performance of the umbilical obtained by optimization algorithm is better and the solution efficiency is higher.Meanwhile,the multi-layering strategy is effective and feasible.The design method proposed in this paper can quickly obtain the optimal multi-layer cross-sectional layout,which replaces the manual design,and provides useful reference and guidance for the umbilical industry.

Association between triglyceride-glucose index and colorectal polyps:A retrospective cross-sectional study

BACKGROUND Colorectal polyps(CPs)are frequently occurring abnormal growths in the colorectum,and are a primary precursor of colorectal cancer(CRC).The triglyceride-glucose(TyG)index is a novel marker that assesses metabolic health and insulin resistance,and has been linked to gastrointestinal cancers.AIM To investigate the potential association between the TyG index and CPs,as the relation between them has not been documented.METHODS A total of 2537 persons undergoing a routine health physical examination and colonoscopy at The First People's Hospital of Kunshan,Jiangsu Province,China,between January 2020 and December 2022 were included in this retrospective cross-sectional study.After excluding individuals who did not meet the eligibility criteria,descriptive statistics were used to compare characteristics between patients with and without CPs.Logistic regression analyses were conducted to determine the associations between the TyG index and the prevalence of CPs.The TyG index was calculated using the following formula:Ln[triglyceride(mg/dL)×glucose(mg/dL)/2].The presence and types of CPs was determined based on data from colonoscopy reports and pathology reports.RESULTS A nonlinear relation between the TyG index and the prevalence of CPs was identified,and exhibited a curvilinear pattern with a cut-off point of 2.31.A significant association was observed before the turning point,with an odds ratio(95% confidence interval)of 1.70(1.40,2.06),P<0.0001.However,the association between the TyG index and CPs was not significant after the cut-off point,with an odds ratio(95% confidence interval)of 0.57(0.27,1.23),P=0.1521.CONCLUSION Our study revealed a curvilinear association between the TyG index and CPs in Chinese individuals,suggesting its potential utility in developing colonoscopy screening strategies for preventing CRC.

Wideband radar cross-section reduction by a double-layer-plasma-based metasurface

Reduction of the radar cross-section(RCS) is the key to stealth technology. To improve the RCS reduction effect of the designed checkerboard metasurface and overcome the limitation of thinlayer plasma in RCS reduction technology, a double-layer-plasma-based metasurface—composed of a checkerboard metasurface, a double-layer plasma and an air gap between them—was investigated. Based on the principle of backscattering cancellation, we designed a checkerboard metasurface composed of different artificial magnetic conductor units;the checkerboard metasurface can reflect vertically incident electromagnetic(EM) waves in four different inclined directions to reduce the RCS. Full-wave simulations confirm that the doublelayer-plasma-based metasurface can improve the RCS reduction effect of the metasurface and the plasma. This is because in a band lower than the working band of the metasurface, the RCS reduction effect is mainly improved by the plasma layer. In the working band of the metasurface,impedance mismatching between the air gap and first plasma layer and between first and second plasma layers cause the scattered waves to become more dispersed, so the propagation path of the EM waves in the plasma becomes longer, increasing the absorption of the EM waves by the plasma. Thus, the RCS reduction effect is enhanced. The double-layer-plasma-based metasurface can be insensitive to the polarization of the incoming EM waves, and can also maintain a satisfactory RCS reduction band when the incident waves are oblique.

Cross-section distortion and springback characteristics of double-cavity aluminum profile in force controlled stretch-bending

3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.

Dyslipidemia in Adults with Type 2 Diabetes in a Rural Community in Ganadougou, Mali: A Cross-Sectional Study

Dyslipidemia is a disorder where abnormally lipid concentrations circulate in the bloodstream. The disorder is common in type 2 diabetics (T2D) and is linked with T2D comorbidities, particularly cardiovascular disease. Dyslipidemia in T2D is typically characterized by elevated plasma triglyceride and low high-density lipoprotein cholesterol (HDL-C) levels. There is a significant gap in the literature regarding dyslipidemia in rural parts of Africa, where lipid profiles may not be captured through routine surveillance. This study aimed to characterize the prevalence and demo-graphic profile of dyslipidemia in T2D in the rural community of Ganadougou, Mali. We performed a cross-sectional study of 104 subjects with T2D in Ganadougou between November 2021 and March 2022. Demographic and lipid profiles were collected through cross-sectional surveys and serological analyses. The overall prevalence of dyslipidemia in T2D patients was 87.5% (91/104), which did not differ by sex (P = .368). High low-density lipoprotein cholesterol (LDL-C) was the most common lipid abnormality (78.9%, [82/104]). Dyslipidemia was associated with age and hypertension status (P = .013 and.036, respectively). High total and high LDL-C parameters were significantly associated with hypertension (P = .029 and .006, respectively). In low-resource settings such as rural Mali, there is a critical need to improve infrastructure for routine dyslipidemia screening to guide its prevention and intervention approaches. The high rates of dyslipidemia observed in Gandadougou, consistent with concomitant increases in cardiovascular diseases in Africa suggest that lipid profile assessments should be incorporated into routine medical care for T2D patients in African rural settings.

Prediction of(n,2n)reaction cross-sections of long-lived fission products based on tensor model

Interest has recently emerged in potential applications of(n,2n)reactions of unstable nuclei.Challenges have arisen because of the scarcity of experimental cross-sectional data.This study aims to predict the(n,2n)reaction cross-section of long-lived fission products based on a tensor model.This tensor model is an extension of the collaborative filtering algorithm used for nuclear data.It is based on tensor decomposition and completion to predict(n,2n)reaction cross-sections;the corresponding EXFOR data are applied as training data.The reliability of the proposed tensor model was validated by comparing the calculations with data from EXFOR and different databases.Predictions were made for long-lived fission products such as^(60)Co,^(79)Se,^(93)Zr,^(107)P,^(126)Sn,and^(137)Cs,which provide a predicted energy range to effectively transmute long-lived fission products into shorter-lived or less radioactive isotopes.This method could be a powerful tool for completing(n,2n)reaction cross-sectional data and shows the possibility of selective transmutation of nuclear waste.

An Analysis of the Lifestyle and Mental Health Status of Adult People Living in Dhaka City: A Cross-Sectional Study in Post COVID-19 Era

Introduction: The Novel Coronavirus or COVID-19 affected all the megacities of the world and made the mental health and lifestyle of people paralyzed. According to different studies, such difficulties were different in scale in different cities depending on the demographic attributes of the people. This phenomenon has created the essence of the current study to examine the health conditions in terms of their mental health, lifestyle, and demographic attributes during and immediate past of the COVID-19 era. Method: It was a cross-sectional study covering the people of Dhaka City Corporation. For this purpose, a multistage sampling method was applied, under which the respondents were selected randomly and a self-administered structured questionnaire was used to collect data. The questionnaire was developed based on the DASS 21, as it was suitable to measure the components of mental health in the form of depression, anxiety, and stress. Descriptive analysis and cross-tabulation were applied to find out the association between dependent and independent variables, whereas, a chi-square test was performed to examine the hypothesis. Finally, multivariate analysis was done to find out the risk factors. Three logistic regression models were developed for three dependent variables. Result: The findings of the analysis revealed that the lifestyle of people had severely influenced the components of their mental health conditions during and immediate past of COVID-19 in the Dhaka City Corporation, which varies to some extent depending on the demographic attributes of those. Conclusion: The above findings are statistically significant enough to conclude about the essence of taking preventive measures regarding mental health issues in the future. However, the limitations of this study-keeping it within the urban areas and the educated people, have also created the venue for future researchers to move with their research endeavors in the rural areas nationwide and thus generalize the results.

Mental health and insomnia problems in healthcare workers after the COVID-19 pandemic:A multicenter cross-sectional study

BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and insomnia.These problems can persist for a long period,even after the pandemic.However,less is known about this topic.AIM To analyze mental health,insomnia problems,and their influencing factors in HCWs after the COVID-19 pandemic.METHODS This multicenter cross-sectional,hospital-based study was conducted from June 1,2023 to June 30,2023,which was a half-year after the end of the COVID-19 emergency.Region-stratified population-based cluster sampling was applied at the provincial level for Chinese HCWs.Symptoms such as anxiety,depression,and insomnia were evaluated by the Generalized Anxiety Disorder-7,Patient Health Questionnaire-9,and Insomnia Severity Index.Factors influencing the symptoms were identified by multivariable logistic regression.RESULTS A total of 2000 participants were invited,for a response rate of 70.6%.A total of 1412 HCWs[618(43.8%)doctors,583(41.3%)nurses and 211(14.9%)nonfrontline],254(18.0%),231(16.4%),and 289(20.5%)had symptoms of anxiety,depression,and insomnia,respectively;severe symptoms were found in 58(4.1%),49(3.5%),and 111(7.9%)of the participants.Nurses,female sex,and hospitalization for COVID-19 were risk factors for anxiety,depression,and insomnia symptoms;moreover,death from family or friends was a risk factor for insomnia symptoms.During the COVID-19 outbreak,most[1086(76.9%)]of the participating HCWs received psychological interventions,while nearly all[994(70.4%)]of them had received public psychological education.Only 102(7.2%)of the HCWs received individual counseling from COVID-19.CONCLUSION Although the mental health and sleep problems of HCWs were relieved after the COVID-19 pandemic,they still faced challenges and greater risks than did the general population.Identifying risk factors would help in providing targeted interventions.In addition,although a major proportion of HCWs have received public psychological education,individual interventions are still insufficient.

Patterns of Infertility and Abortion in Saudi Arabia: A Cross-Sectional Study

Background: Infertility and abortion are significant reproductive health concerns globally, impacting individuals' well-being and healthcare systems. In Saudi Arabia, cultural, social, and religious factors influence perceptions and management of these issues, necessitating research to understand the patterns and associated factors. Study Aim: This cross-sectional study aimed to investigate the patterns of infertility and abortion among 458 women in Saudi Arabia, focusing on demographic profiles, reproductive histories, medical conditions, and lifestyle factors. Methodology: Participants were recruited from healthcare facilities, and data on age, BMI, reproductive history, medical conditions, assisted reproduction methods, and lifestyle behaviors were collected. Statistical analyses, including chi-square tests, were conducted to examine associations between variables. Results: The majority of participants were aged 30 - 39 years (47.4%), with 76.9% experiencing secondary infertility. Among those with offspring (76.9%), 31% reported using assisted reproduction methods, primarily ovarian stimulators (54.2%). Abortion history was reported by 39.5% of participants. Significant associations were found between age and infertility type (X2 = 5.8, p = 0.054), having offspring and infertility type (X2 = 458.0, p = 0.001), menstrual irregularity and infertility type (X2 = 11.4, p = 0.001), and abortion history and delayed fertility (X2 = 10.4, p = 0.001). Conclusion: Our study reveals significant associations between demographic, medical, and lifestyle factors with infertility patterns and abortion history among Saudi women. These findings emphasize the need for tailored interventions addressing medical conditions, age-related factors, and access to reproductive healthcare services.

Theoretical analysis of the double-differential cross-sections of neutron,proton,deuteron,^(3)He,andαfor the p+^(6) Li reaction

Based on the unified Hauser–Feshbach and exciton model,which can describe the particle emission processes between discrete energy levels with energy,angular momentum,and parity conservations,a statistical theory of light nucleus reaction(STLN)is developed to calculate the double-differential cross-sections of the outgoing neutron and light charged particles for the proton-induced^(6) Li reaction.A significant difference is observed between the p+^(6) Li and p+^(7) Li reactions owing to the discrepancies in the energy-level structures of the targets.The reaction channels,including sequential and simultaneous emission processes,are analyzed in detail.Taking the double-differential cross-sections of the outgoing proton as an example,the influence of contaminations(such as^(1) H,^(7)Li,^(12)C,and^(16)O)on the target is identified in terms of the kinetic energy of the first emitted particles.The optical potential parameters of the proton are obtained by fitting the elastic scattering differential cross-sections.The calculated total double-differential cross-sections of the outgoing proton and deuteron at E_(p)=14 MeV agree well with the experimental data for different outgoing angles.Simultaneously,the mixed double differential cross-sections of^(3) He andαare in good agreement with the measurements.The agreement between the measured data and calculated results indicates that the two-body and three-body breakup reactions need to be considered,and the pre-equilibrium reaction mechanism dominates the reaction processes.Based on the STLN model,a PLUNF code for the p+^(6) Li reaction is developed to obtain an ENDF-6-formatted file of the double-differential cross-sections of the nucleon and light composite charged particles.

Adolescents’perceived stress of COVID-19 and self-compassion in Saudi Arabia:A cross-sectional study

Objectives Worldwide,the COVID-19 pandemic has significantly impacted mental health challenges for adolescent populations.The current study aims to examine the levels of perceived stress of COVID-19 and self-compassion and their relationship among adolescents in Saudi Arabia.Methods This study employed a cross-sectional online survey of adolescents from secondary schools in Asir,Saudi Arabia.Instruments that we distributed online included the modified Perceived Stress Scale(PSS-10)and the Self-Compassion Scale(SCS),in addition to demographic and health-related questions.A total of 500 adolescents completed the survey.Results Adolescents in the study reported an average moderate perceived stress level of 18.6(SD=6.67)and an average moderate self-compassion level of 3.22(SD=0.53).A significant correlation is also found between the two variables(r=−0.460,P<0.001).This negative correlation indicates that lower levels of perceived stress are significantly correlated with higher levels of self-compassion.Conclusion The study results show that the perceived stress of COVID-19 is inversely correlated with self-compassion in Saudi adolescents.Further research is needed to explore how to enhance adolescents’self-compassion.School nurses’role should be given full play in this area.

First Born Double Differential Cross-Section for Ionization of H (3d) by Incident Electron Impact

Double differential cross section (DDCS) of First-Born approximation is calcu-lated for the ionization of metastable 3d-state hydrogen atoms by electron impact energy at 150 eV and 250 eV. A multiple scattering theory is applied in the present study. The present results are compared with the other related the-oretical results for the ionization of hydrogen atoms from different metastable states and ground-state experimental results. The findings demonstrate a strong qualitative agreement with the existing results. The obtained results have an extensive scope for further study of such an ionization process.

A Cross-Sectional Study on The Prevalence of Anemia in Maintenance Hemodialysis and Peritoneal Dialysis Patients and Its Related Factors

Objective:To study the prevalence of anemia,the proportion of hemoglobin(Hb)levels,the treatment methods,and the influencing factors of Hb levels in maintenance hemodialysis(MHD)and peritoneal dialysis patients.Methods:In this study,602 patients with maintenance hemodialysis and continuous ambulatory peritoneal dialysis were enrolled from December 2020 to December 2022 in our hospital,and their medical records were collected and summarized.The main contents included the patient’s gender,age,primary disease,dialysis duration,dialysis method,the use of erythropoietic stimulating agents(ESA),intravenous iron,and laboratory tests.A Hb index exceeding 110 g/L was set as the standard for the prevalence of anemia.Results:The rate of anemia in patients undergoing blood purification was 83%.The proportion of ESA use was 84.1%,and the proportion of iron use was 76.7%,of which the proportion of intravenous iron used was 17.0%,and the proportion of folic acid used was 28.3%.Conclusion:The incidence of anemia in MHD patients was relatively high,with a low proportion of patients reaching the standard Hb levels.Risk factors include albumin(ALB)levels,iron storage,white blood cells,C-reactive protein,cholesterol,etc.Nutritional support,iron supplementation,and prevention of micro-inflammatory reactions can effectively promote the improvement of Hb indicators in dialysis patients to prevent anemia.

Exploring Work-Related Stress and Coping Strategies among Omani Nurses Working in Tertiary Governmental Hospitals at Muscat: A Cross-Sectional Study

Introduction: Work-related stress has become a global issue in the nursing workplace, with about 9.20% - 68.0% of nurses globally experiencing stress. Conversely, work-related stress ranges between 20% and 40% in nursing. Other researchers noted that 35.1% of nurses globally experienced elevated stress levels. Stress can damage well-being and lead to coping, which can, directly and indirectly, improve well-being through a perceived state. Nurses need coping mechanisms to manage their stress levels and maintain stability. Coping mechanisms can vary greatly depending on a nurse’s culture and background. Numerous findings indicate that managing stress is more critical than the cause of stress and that the more successful a stress-management approach, the less damage stress brings. Objective: In response to this, it is necessary to explore Omani nurses’ stress level and their coping strategies working in tertiary governmental hospitals in Muscat. Methods: The sample size for this study was 383 Omani nurses, with a 100% response rate. This study used a descriptive cross-sectional design from 15 October 2020 to 30 November 2020. Samples were selected through proportionate population sampling (PPS) from the five selected tertiary hospitals. Data were collected by self-administered questionnaires using a perceived stress scale and Ways of Coping. A simple random sample within a stratum (each hospital admitting ward) was done to identify the study participants. The sample size for this study was 383 Omani nurses, with a 100% response rate. Results: About 83.3% of participants had a moderate perceived level of stress with an overall mean perceived stress level of 18.46 ± 4.52. The most common sources of perceived stress are feeling nervous and “stressed” in the last month (2.30 ± 0.95). According to the ways of coping strategies, nurses seemed to be resorting to more “planful problem” (mean = 11.04) and least was seeking social support (mean = 9.67). Conclusion: This study highlighted the work-related stress level of staff nurses, explored their ways of coping and determined the relationship between work-related stress levels and methods of coping. The key finding of this study was that the frequency of stress reported by nurses was high enough to suggest that their stress levels were significant, given the demanding nature of their profession that requires maximum attention. Additionally, nurses seemed to resort to more planful problem-solving mechanisms to deal with their stressful situations than other coping strategies.

Psychosocial Risk Factors and Stress in an Oil Company in the Republic of the Congo: A Cross-Sectional Study

Introduction: Occupational stress is a significant health concern in the work-place, constituting a prevalent psychosocial risk. Due to its specific nature, the oil industry is perceived as a high psychosocial risk zone. This study aimed to correlate the perceived stress level with the identified psychosocial risk factors (PSRFs) among employees of an oil company in Congo-Brazzaville. Materials and Methods: This was an analytical cross-sectional study conducted between July and September 2021 among employees of an oil company. They were recruited during their routine medical check-ups. Data were collected using the Perceived Stress Scale (PSS10) and the Copenhagen Psychosocial Questionnaire (COPSOQ), respectively to assess stress and identify PSRFs. Results: Out of the sample, 203 workers were included. The majorities were males (81.3%), and the average age of participants was 39.5 ± 9.62 years. The frequency of perceived stress was 39.4%, and 40% of the workers were exposed to at least 3 PSRFs. A positive correlation was observed between perceived stress and workload (r = 0.37, p Conclusion: The study revealed that employees of this company exhibited a high level of stress. The detrimental impact of certain PSRFs was highlighted. A multidisciplinary intervention appears imperative to address these inherent risks in their professional environment.

Perceived stress and coping capacities among frontline healthcare workers of AIIMS during COVID-19 pandemic:A cross-sectional study

Objective:To assess perceived stress and coping capacity of frontline health workers from AIIMS during COVID-19 pandemic.Methods:This cross-sectional study conducted from May to July 2021 enrolled 694 participants.An online questionnaire based on Google Forms was developed to collect the data.Participants were assessed using the validated Perceived Stress Scale and the Coping Resources Inventory Scale.Results:The age of participants were 27(23-52)years old.The majority of respondents(73.5%)felt moderately stressed.Of the 694 participants,83.0%of the 576 participants had average stress management skills.Sex,marital status,and profession were significantly associated with perceived stress.In addition,marital status and profession were significantly associated with coping capacity.Conclusions:The majority of participants have moderate stress levels and average coping skills.Frontline healthcare workers have to maintain mental and physical health.Achieving this requires early screening and stress management for healthcare workers.

Prediction models of the ionization coefficient and ionization cross-section based on multi-layer molecular parameters

Prediction models were proposed to estimate the reduced Townsend ionization coefficient and ionization cross-section.A shape function of the reduced Townsend ionization coefficient curves was derived from the ionization collision probability model.The function had three parameters:the first ionization potential energy,A_(α),and B_(α).A_(α)and B_(α)were related to the molecule symmetry and size.The polarization of molecules could characterize the molecule symmetry.The multi-layer molecular cross-section(MMCS)was proposed to describe the contributions of electrons and molecule radius on different molecule surfaces to collisions.A prediction model of the ionization cross-section was also proposed based on Aα.The molecule parameters were calculated by the Becke3–Lee–Yang–Parr(B3LYP)method and the 6–311G**basis set.We used available data of 30 and 23 gases,respectively,to build the prediction models of reduced Townsend ionization coefficients and ionization cross-sections.The relationships between the molecular parameters Aαand Bαand the ionization cross-section were built up via nonlinear fittings.The determination coefficients R^(2)of Aα,Bα,and the ionization cross-section were 0.877,0.887,and 0.838,respectively.The results showed that the accuracy of models was positively correlated with the molecule symmetry and reduced electric field.This was mainly related to the accuracy of the MMCS model in predicting Aα.The MMCS model needed to be improved to describe the collision direction selectivity caused by the molecule asymmetry.Under a high reduced electric field,that error of Aαhad less influence on the prediction results.However,the prediction results for single atoms with high symmetry were poor.This may be due to the absolute error of the model close to single atoms’reduced Townsend ionization coefficients.The models could provide the basis for gas insulation prediction and discharge calculations,especially for symmetric molecules under a high electric field.

Direct measurement of an energy-dependent single-event-upset cross-section with time-of-flight method at CSNS

To predict the soft error rate for applications, it is essential to study the energy dependence of the single-event-upset(SEU) cross-section. In this work, we present a direct measurement of the SEU cross-section with the Back-n white neutron source at the China Spallation Neutron Source. The measured cross section is consistent with the soft error data from the manufacturer and the result suggests that the threshold energy of the SEU is about 0.5 Me V, which confirms the statement in Iwashita’s report that the threshold energy for neutron soft error is much below that of the(n, α) cross-section of silicon.In addition, an index of the effective neutron energy is suggested to characterize the similarity between a spallation neutron beam and the standard atmospheric neutron environment.