Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 131
Filtrar
1.
Chemphyschem ; : e202400312, 2024 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-39004605

RESUMO

Developing highly superior precious-metal-free electrocatalysts for oxygen reduction reaction (ORR) are challenging and great significance. In this study, it is reported that an efficient ORR catalysts with N and S co-doped carbon nanotubes anchored to copper (Cu) nanoclusters by mechanical grinding and high temperature heat treatment. The obtained Cu-S1-N-C electrocatalysts exhibited a high ORR performance with an onset potential (Eonest) of 0.989 V and a half-wave potential (E1/2) of 0.905 V (vs. RHE) in alkaline electrolyte, which was superior to that of commercial Pt/C catalyst. In contrast to N doping alone, the defect structures and active species of the catalysts were optimized by precise modulation of S-atom doping, and moreover, the introduction of S-atoms provided more thiophene-sulfur active sites. This study provides an innovative idea for designing excellent ORR catalysts.

2.
China CDC Wkly ; 6(19): 418-423, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38854752

RESUMO

What is already known on this topic?: In China, there is limited data available on the use and coverage of the non-program, combined diphtheria, tetanus toxoid, acellular pertussis adsorbed, inactivated poliovirus and haemophilus influenzae type b (DTaP-IPV/Hib) pentavalent vaccine, and its role as a substitute for the separately administered standalone program vaccines. What is added by this report?: We evaluated the use and coverage of the pentavalent vaccine in nine provincial-level administrative divisions (PLADs) spanning eastern, central, and western China from 2019 to 2021. Initial use and coverage were low, but demonstrated annual growth albeit with regional and urban-rural discrepancies. The pentavalent vaccine was increasingly substituted for standalone vaccines over the course of this period. What are the implications for public health practice?: Parents in China are increasingly opting to replace the standard program vaccines with voluntarily purchased combination vaccines, particularly the pentavalent vaccine. The development of combination vaccines should thus be promoted in China, as it could enhance utilization and coverage rates, and decrease the economic burden.

3.
China CDC Wkly ; 6(19): 413-417, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38854753

RESUMO

What is already known on this topic?: There is a lack of comprehensive data on the coverage of the human papillomavirus (HPV) vaccine in China. The limited published literature hampers our ability to accurately assess the current situation. What is added by this report?: This study aimed to determine the rates of HPV vaccine coverage based on data from the electronic vaccination registry reported to the China Immunization Information System between 2017 and 2022. While there was an increase in HPV vaccine coverage each year, the overall coverage remained below the optimal level. What are the implications for public health practice?: This study presents evidence of low HPV vaccine coverage when administered outside of a national immunization program. Therefore, it is recommended that the HPV vaccine be included in the National Immunization Program in order to meet the 2030 WHO target of achieving 90% vaccination coverage for girls by the age of 15.

4.
China CDC Wkly ; 6(16): 344-349, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38736467

RESUMO

Introduction: Detecting poliovirus infections proves to be highly challenging due to their asymptomatic nature and infectious potential, highlighting the crucial importance of effective detection methods in the context of polio eradication efforts. In many countries, including China, the primary approach for identifying polio outbreaks has been through acute flaccid paralysis (AFP) surveillance. In this study, we conducted an evaluation spanning three decades (1993-2022) to assess the effectiveness of AFP surveillance in China. Methods: Data on all AFP cases identified since 1993 and national-level AFP surveillance system quality indicators aligned with the World Health Organization (WHO) standards were collected for analysis. The quality indicators assess surveillance sensitivity, completeness, timeliness of detection notification, case investigation, and laboratory workup. Surveillance sensitivity is determined by the non-polio AFP (NPAFP) detection rate among children under 15 years of age. Results: Between 1993 and 2022, a total of 150,779 AFP cases were identified and reported. Within this pool, surveillance identified 95 cases of wild poliovirus (WPV) and 24 cases due to vaccine-derived poliovirus. From 1995 onwards, the detection rate of NPAFP cases consistently adhered to the WHO and national standards of ≥1 case per 100,000, falling between 1.38 and 2.76. Starting in 1997, all timeliness indicators consistently achieved the criteria of 80%, apart from the consistency in meeting standards set for the rate of positive specimens sent to the national laboratory. Conclusions: AFP surveillance has been instrumental in China's accomplishment of maintaining a polio-free status. The ongoing adherence to key performance indicators, ensuring sensitivity and prompt specimen collection, demonstrates that AFP surveillance is proficient in detecting poliovirus in China. As we move into the post-eradication phase, AFP surveillance remains crucial for the sustained absence of polioviruses in the long term.

5.
Sensors (Basel) ; 24(9)2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38732966

RESUMO

This paper presents an in-depth analysis of the oscillation phenomenon occurring in multi-chip parallel automotive-grade power modules under short-circuit conditions and investigates three suppression methods. We tested and analyzed two commercial automotive-grade power modules, one containing two chips and the other containing a single chip, and found that short-circuit gate oscillations were more likely to occur in multi-chip parallel packaged modules than in single-chip packaged modules. Through experimental and simulation analyses, we observed that gate oscillations were mainly caused by the interaction between internal parasitic parameters of the module and the external drive circuit, and we found that high drive resistance and low common emitter inductance between parallel chips could effectively suppress gate voltage oscillations. We also analyzed the two mainstream suppression schemes, increasing the drive gate resistance and placing the drive capacitors in parallel. Unfortunately, we found that these suppression schemes were not ideal solutions because both schemes changed the switching characteristics of the power module. As an alternative, we propose a simple and effective solution that involves adding parallel connections between the parallel chips. Simulation calculations showed that this optimized method reduced the emitter inductance between parallel chips in the upper bridge arm by about 30% and in the lower bridge arm by 35%. Through short-circuit experiments conducted at different DC bus voltages, it has been verified that the new optimized solution effectively resolves gate oscillation issues without affecting the switching characteristics of the power module.

6.
J Imaging Inform Med ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750186

RESUMO

OBJECTIVES: To preoperatively predict the high expression of Ki67 and positive pituitary transcription factor 1 (PIT-1) simultaneously in pituitary adenoma (PA) using three different radiomics models. METHODS: A total of 247 patients with PA (training set: n = 198; test set: n = 49) were included in this retrospective study. The imaging features were extracted from preoperative contrast-enhanced T1WI (T1CE), T1-weighted imaging (T1WI), and T2-weighted imaging (T2WI). Feature selection was performed using Spearman's rank correlation coefficient and least absolute shrinkage and selection operator (LASSO). The classic machine learning (CML), deep learning (DL), and deep learning radiomics (DLR) models were constructed using logistic regression (LR), support vector machine (SVM), and multi-layer perceptron (MLP) algorithms. The area under the receiver operating characteristic (ROC) curve (AUC), sensitivity, specificity, accuracy, negative predictive value (NPV) and positive predictive value (PPV) were calculated for the training and test sets. In addition, combined with clinical characteristics, the best CML and the best DL models (SVM classifier), the DL radiomics nomogram (DLRN) was constructed to aid clinical decision-making. RESULTS: Seven CML features, 96 DL features, and 107 DLR features were selected to construct CML, DL and DLR models. Compared to CML and DL model, the DLR model had the best performance. The AUC, sensitivity, specificity, accuracy, NPV and PPV were 0.827, 0.792, 0.800, 0.796, 0.800 and 0.792 in the test set, respectively. CONCLUSIONS: Compared with CML and DL models, the DLR model shows the best performance in predicting the Ki67 and PIT-1 expression in PAs simultaneously.

7.
iScience ; 27(5): 109697, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38680665

RESUMO

The inheritance of recurrent patellar dislocation (RPD) is known, but the susceptible gene remains unidentified. Here, we performed the first whole exome sequencing (WES) cohort study to identify the susceptible genes. The results showed eight genes were associated with this disease. Notably, the carboxypeptidase D (CPD) gene showed the highest relevance based on its gene function and tissue expression. Single-cell sequencing results indicate that the CPD gene is involved in the pathophysiological process of RPD through granulocytes. Implicated pathways include nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and Wnt/ß-catenin signaling, potentially influencing CPD's role in RPD pathogenesis. This study identified the susceptible gene and investigates the potential pathogenesis of RPD, which provided a new prospect for the understanding of RPD. Besides, it would offer the theoretical basis for disease prevention and genetic counseling.

8.
BMC Cancer ; 24(1): 521, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38658858

RESUMO

BACKGROUND: Emerging evidence suggests that the gut microbiota is associated with various intracranial neoplastic diseases. It has been observed that alterations in the gut microbiota are present in gliomas, meningiomas, and pituitary neuroendocrine tumors (Pit-NETs). However, the correlation between gut microbiota and craniopharyngioma (CP), a rare embryonic malformation tumor in the sellar region, has not been previously mentioned. Consequently, this study aimed to investigate the gut microbiota composition and metabolic patterns in CP patients, with the goal of identifying potential therapeutic approaches. METHODS: We enrolled 15 medication-free and non-operated patients with CP and 15 healthy controls (HCs), conducting sequential metagenomic and metabolomic analyses on fecal samples to investigate changes in the gut microbiota of CP patients. RESULTS: The composition of gut microbiota in patients with CP compared to HCs show significant discrepancies at both the genus and species levels. The CP group exhibits greater species diversity. And the metabolic patterns between the two groups vary markedly. CONCLUSIONS: The gut microbiota composition and metabolic patterns in patients with CP differ significantly from the healthy population, presenting potential new therapeutic opportunities.


Assuntos
Craniofaringioma , Fezes , Microbioma Gastrointestinal , Neoplasias Hipofisárias , Humanos , Craniofaringioma/metabolismo , Masculino , Feminino , Adulto , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/microbiologia , Fezes/microbiologia , Pessoa de Meia-Idade , Estudos de Casos e Controles , Adulto Jovem , Adolescente , Metabolômica/métodos , Metagenômica/métodos , Metaboloma
9.
J Appl Psychol ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38619475

RESUMO

Employees' responses to diversity initiatives are critical to understand the effectiveness of such initiatives. However, prior research has largely considered the isolated effects of specific favorable or unfavorable employee responses (e.g., support or resistance) from a variable-centered perspective. This prior focus overlooks the potential (a) coexistence of more complex configurations of cognitive, affective, and behavioral response types within individuals and (b) the existence of subpopulations of employees who may respond both favorably and unfavorably, thus displaying ambivalence. To address these shortcomings, we build on the tripartite response model and adopt a person-centered approach to shed light on a more comprehensive spectrum of employees' responses to diversity initiatives. Using latent profile analysis, our results across three studies reveal (Study 1, n = 605) and replicate (Study 2, n = 503 and Study 3, n = 514) four distinct response types: excited supporters, calm compliers, torn shapers, and discontent opponents. Furthermore, using time-lagged data from Study 3, we provide initial insights into relevant person and situation predictors of profile membership and show how employees across profiles differ on work-related outcomes that can be functional or dysfunctional for their organization. Taken together, we aim to initiate a conversation on the complex nature of responses to diversity initiatives within the diversity management literature and call for more research, specifically on ambivalent responses. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

10.
Sci Transl Med ; 16(735): eadh9751, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38381849

RESUMO

Osteoarthritis (OA) is a chronic joint disease characterized by progressive degeneration of articular cartilage. A challenge in the development of disease-modifying drugs is effective delivery to chondrocytes. The unique structure of the joint promotes rapid clearance of drugs through synovial fluid, and the dense and avascular cartilage extracellular matrix (ECM) limits drug penetration. Here, we show that poly(lactide-co-glycolic acid) nanoparticles coated in chondrocyte membranes (CM-NPs) were preferentially taken up by rat chondrocytes ex vivo compared with uncoated nanoparticles. Internalization of the CM-NPs was mediated primarily by E-cadherin, clathrin-mediated endocytosis, and micropinocytosis. These CM-NPs adhered to the cartilage ECM in rat knee joints in vivo and penetrated deeply into the cartilage matrix with a residence time of more than 34 days. Simulated synovial fluid clearance studies showed that CM-NPs loaded with a Wnt pathway inhibitor, adavivint (CM-NPs-Ada), delayed the catabolic metabolism of rat and human chondrocytes and cartilage explants under inflammatory conditions. In a surgical model of rat OA, drug-loaded CM-NPs effectively restored gait, attenuated periarticular bone remodeling, and provided chondroprotection against cartilage degeneration. OA progression was also mitigated by CM-NPs-Ada in a canine model of anterior cruciate ligament transection. These results demonstrate the feasibility of using chondrocyte membrane-coated nanoparticles to improve the pharmacokinetics and efficacy of anti-OA drugs.


Assuntos
Cartilagem Articular , Nanopartículas , Osteoartrite , Ratos , Animais , Cães , Humanos , Condrócitos/metabolismo , Osteoartrite/tratamento farmacológico , Osteoartrite/metabolismo , Articulação do Joelho , Cartilagem Articular/metabolismo
11.
J Appl Psychol ; 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38284993

RESUMO

Despite gossip research's predominant focus on gossipers and gossip targets, existing theoretical views and the limited yet important empirical studies converge to suggest that gossip benefits its recipients. Our research builds on conservation of resources theory to shift this consensus by examining the negative effects of supervisor-directed gossip on recipients. We theorize that hearing negative supervisor-directed gossip triggers both cognition- and affect-focused rumination, which consume resources, and we develop a research question around the moderating role of hearing positive supervisor-directed gossip. Furthermore, we propose that the aforementioned effects have cascading implications for recipients' work behaviors the following day. In a 15-day experience sampling investigation of 122 workers, we found that on days when employees hear negative gossip about the supervisor, they are more likely to engage in cognition- and affect-focused rumination, and hearing positive supervisor-directed gossip strengthens these positive relationships. In addition, we found that cognition- and affect-focused rumination lead to poor sleep quality and diminished next-morning vitality, which in turn results in reduced work engagement and supervisor-directed organizational citizenship behavior. We conclude by discussing the implications and future directions of our work. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

12.
Sensors (Basel) ; 24(2)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38257704

RESUMO

With the rapid development of novel energy vehicles, power generation, photovoltaics, and other industries, power electronic devices have gained considerable attention. Insulated-gate bipolar transistors (IGBTs) have been widely used in those fields. With the emergence of intelligent manufacturing concepts such as Germany's "Industry 4.0" and China's "Made in China 2025", conventional manufacturing which needs to be upgraded with higher efficiency and yield is rapidly pivoting toward digitalization and intelligence. The digital twin methodology has been extensively used in various industries for constructing virtual models of physical entities, facilitating real-time data interconnection to reduce costs and improve efficiency. This study proposes a modular intelligent IGBT production line based on the digital twin. Real-time data are transmitted from a physical line to a digital line for storage and analysis. The digital line is visualized, and an intelligent management platform containing multiple functions is developed. Additionally, a process simulation database is established to obtain the optimal process parameters. Numerous quality issues that can arise during each process of IGBT packaging are addressed using a problem-solving approach based on the digital twin methodology. Consequently, this digital-twin-based IGBT intelligent production line effectively enhances yield rates and efficiency. IGBT modules with various packaging forms such as ACF, ACE, and ACD are manufactured.

14.
J Appl Psychol ; 109(1): 99-114, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37561477

RESUMO

The fast-changing work environment has created growing hindrances to employee daily goal pursuits and rendered it not uncommon for employees to leave work with unachieved daily work goals. The significant ramifications of unachieved goals on employee well-being and performance thus call for more research efforts to understand how employees respond to unsatisfactory goal progress (e.g., goal-performance discrepancy [GPD]). Interestingly, two paradoxical theoretical perspectives exist on this matter, with the self-regulation perspective suggesting an adaptive feedback loop (i.e., GPD on a given day eventually reduces next-day GPD), whereas the self-focused cognition perspective suggesting a maladaptive feedback loop (i.e., GPD on a given day eventually exacerbates next-day GPD). Taking a temporal lens to integrate these two perspectives, we conducted a daily diary study to map out the self-regulatory cognition mechanisms (i.e., anticipatory thinking) and self-focused cognition mechanisms (i.e., rumination) underlying the feedback loops, and identify employee temporal focus (future and past focuses) as critical cross-level boundary conditions to explain why some react to daily GPD adaptively, whereas others maladaptively. Based on 485 daily reports from 100 work professionals, we revealed that daily GPD at work resulted in reduced next-day GPD via increased after-work anticipatory thinking. Meanwhile, daily GPD also resulted in aggravated next-day GPD via increased after-work rumination. Moreover, employee future focus mitigated the maladaptive cycle, whereas employee past focus hindered the adaptive cycle. Our study thus provides important theoretical and empirical insights into employee goal-pursuit process. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Assuntos
Emprego , Objetivos , Humanos , Cognição
15.
Environ Sci Pollut Res Int ; 31(1): 857-870, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38032529

RESUMO

Sulfate radical (SO4•-)-based advanced oxidation processes (AOPs) from sulfite activation have recently received attention for abatement of microorganic pollutants in the aquatic environments. Trace-level Co(II) has been demonstrated to be effective for promoting sulfite activation (simplified as the Co(II)/sulfite system) and the corresponding radical formation, yet this process is challenged by the limited valence inter-transformation of Co(II)/Co(III). In order to enhance this valence inter-transformation, a novel Co(II)/HPO42-/sulfite system is developed in this work, because HPO42-, as a typical radical scavenging agent, has the advantage of complexing with Co(II) without quenching effect. In this work, complexation of Co(II) with HPO42- can regulate the electronic structure of Co(II), accelerate electron transfer, and promote valence inter-transformation of Co(II)/Co(III) during the sulfite activation process. The Co(II)/HPO42-/sulfite system exhibits superior iohexol abatement performance under circumneutral conditions. For pH 8.0 and Co(II) dose of 1 µM, the iohexol abatement efficiency is as high as 98%, which is considerably higher than that of the Co(II)/sulfite system (50%). SO4•- is identified as the predominant reactive radical contributing to iohexol abatement. The presence of HPO42- broadens the pH adaptability of the Co(II)/sulfite system for iohexol abatement. In addition, the coexisting Cl- exerts an inhibitory effect on iohexol abatement while the other cations and anions show negligible effect. The Co(II)/HPO42-/sulfite system displays good reusability and adaptability towards various organic pollutants. This study highlights the important role of complexation of Co(II) with HPO42- in sulfite activation and provides a feasible idea for abatement of the microorganic pollutants.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Iohexol , Cobalto , Fosfatos , Oxirredução , Sulfitos/química , Poluentes Químicos da Água/química
16.
Cancer Cell Int ; 23(1): 258, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37919754

RESUMO

BACKGROUND: Metastasis is still a major cause of poor pathological outcome and prognosis in esophageal squamous cell carcinoma (ESCC) patients. NUAK1 has been reported highly expressed in many human cancers and is associated with the poor prognosis of cancer patients. However, the role of NUAK1 and its underlying signaling mechanism in ESCC metastasis remain unclear. METHODS: Expression of NUAK1 in ESCC was detected by real-time quantitative RT-PCR (qRT-PCR), Western blotting and immunohistochemical staining. MTT, colony formation, wound-healing and transwell assays were used to determine the role NUAK1 in vitro. Metastasis was evaluated by use of an experimental pulmonary metastasis model in BALB/c-nu/nu mice. The mechanisms were assessed by using coimmunoprecipitation, immunofluorescence and dual-luciferase reporter gene experiments. RESULTS: NUAK1 was highly expressed in ESCC tissues compared with the adjacent normal esophageal epithelial tissues. Moreover, the elevated expression of NUAK1 positively correlated with tumor invasion depth, lymph node metastasis, pathological TNM stage, and poor survival in ESCC patients. Further experiments showed that NUAK1 overexpression did not change the cell viability and colony formation of ESCC cells, while remarkably promoted the migration and invasion in vitro and experimental pulmonary metastasis in vivo. Mechanistically, NUAK1 enhanced the transcription level of Slug, which enhanced the migratory and invasive capability of ESCC cells. Consistently, silencing Slug almost completely diminished the migration and invasion of NUAK1-overexpressing ESCC cells. Further studies demonstrated that NUAK1 upregulated the transcription activity of Slug through activating the JNK/c-Jun pathway. CONCLUSION: These results demonstrated that NUAK1 promoted the metastasis of ESCC cells through activating JNK/c-Jun/Slug signaling, indicating NUAK1 is a promising therapeutic target for metastatic ESCC.

17.
Org Lett ; 25(48): 8727-8732, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38029372

RESUMO

The 1,3-rearrangement of allylic derivatives has rarely been reported, except for allylic alcohols. Herein, we describe an iridium-catalyzed 1,3-rearrangement of readily available allylic ethers to access the difficultly prepared allylic ethers with a large steric hindrance. The developed method shows a broad substrate scope and could be used in the late-stage modification of several natural products. In addition, a possible reaction pathway is also provided on the basis of the control experiments.

18.
J Orthop Surg Res ; 18(1): 656, 2023 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-37667363

RESUMO

BACKGROUND: The aim of this study was to comprehensively evaluate the short-term clinical efficacy and safety of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) versus minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of lumbar degenerative diseases by meta-analysis. METHODS: A computer-based search of PubMed, Embase, Web of Science, Cochrane Database, China National Knowledge Infrastructure (CNKI), Wanfang Database, and Chinese Science and Technology Journal Database (VIP) was conducted from the inception of the each database to April 2023. The searched literature was then screened according to strict inclusion and exclusion criteria. The critical data were extracted and analyzed using Review Manager software5.4.1. Pooled effects were calculated on the basis of data attributes by mean difference (MD) or odds ratio (OR) with 95% confidence interval (CI). The Newcastle-Ottawa Scale was used to assess the quality of the studies. RESULTS: A total of 13 studies and 949 patients met the inclusion criteria for this meta-analysis, 445 in the UBE-LIF group and 504 in the MIS-TLIF group. UBE-TLIF was superior to MIS-TLIF in terms of intraoperative blood flow, postoperative drainage flow, duration of hospital stay, VAS score for low back pain and ODI score, but the operative time was longer than MIS-TLIF group. There were no significant differences between the two groups in terms of total complication rate, modified Macnab grading criteria, fusion rate, VAS score of leg pain, lumbar lordosis, intervertebral disk height. CONCLUSION: Both UBE-TLIF and MIS-TLIF are effective surgical modalities for the treatment of degenerative lumbar spine diseases. They have similar treatment outcomes, but UBE-TLIF has the advantages of less intraoperative blood loss, shorter postoperative hospital stay, and faster recovery. TRIAL REGISTRATION: This study has been registered at INPLASY.COM (No. INPLASY202320087).


Assuntos
Vértebras Lombares , Fusão Vertebral , Animais , Humanos , Endoscopia/efeitos adversos , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/efeitos adversos , Fusão Vertebral/efeitos adversos , Resultado do Tratamento
19.
Micromachines (Basel) ; 14(9)2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37763858

RESUMO

There is an increasing demand for the use of automotive sensors where complex working environments may easily lead to failure. Wire pull and shear test models based on finite-element analysis are established to evaluate their reliability by investigating the failure mode and mechanism of gold wire bonding. The effect of shear force position and pull force position on failure is also analyzed. The bonding failure was verified by experiments, which is consistent with the simulation result. The results show that: (1) The three-dimensional quantitative modeling reveals the process of bonding delamination and stress concentration. (2) The bonding-slip method (BSM) is adopted in the gold ball detaching process. The concept of three states, including deformation accumulation, cracking, and disengagement, was put forward to reveal the interface stress evolution trend according to the shear testing results. The results indicate that in the interface, the stress in the deformation accumulation state decreases from the tensile side (or compression side) to the center, and the stress in the cracking and disengagement states reduces gradually from the tensile side to the edge. When the interface is completely separated, the failed shear force concentrates on 42 g. The concept and theory proposed in this work can effectively reveal the failure mechanism of bonding interface and help to establish a new failure criterion.

20.
Sci Total Environ ; 902: 166072, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37544443

RESUMO

Isotopic methodologies have gained prominence in investigating the composition of plant water sources; however, concerns regarding their suitability and reliability in diverse environments have emerged in recent years. This study presents a comparative analysis of root, soil, and liquid water (precipitation, dew, and groundwater) samples obtained from a desert steppe using isotope ratio infrared spectrometry (IRIS) and isotope ratio mass spectrometry (IRMS). The objective was to evaluate the applicability of these techniques in discerning the water sources of Stipa breviflora, a shallow-rooted herbaceous plant species. Additionally, we explored the root water uptake characteristics and water use strategy of S. breviflora. Our findings indicate that the IRIS method had more enriched values of D compared to the IRMS method across all samples, while no discernible pattern was observed for 18O. Notably, the differences observed among all samples exceeded the instruments' accuracies. Moreover, an unexpected occurrence was noted, whereby both D and 18O values in the root water were more enriched than in any of the considered water sources, rendering identification of the plant water sources unattainable. By conducting a re-analysis of more refined soil layer samples, we discovered that S. breviflora exhibits the ability to absorb and utilize water sources in close proximity to the soil surface. It further suggested that the shallow-rooted herbaceous plants in desert steppes can exploit small rainfalls, frequently overlooked in their ecological importance. Considering the distinctive soil and plant characteristics of desert steppes, we recommend adopting IRMS methods in conjunction with refined surface soil sampling for isotopic analysis aiming to identify water sources of shallow-rooted herbaceous plants. This study provides novel insights into assessing the suitability of isotopic techniques for analyzing plant water sources, while enhancing our understanding of water use strategies and environmental adaptation mechanisms employed by shallow-rooted herbaceous plants within xerophytic grassland ecosystems.


Assuntos
Ecossistema , Água , Água/análise , Reprodutibilidade dos Testes , Plantas/química , Solo/química , Isótopos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...