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Effect of Bogie Cavity End Wall Inclination on Flow Field and Aerodynamic Noise in the Bogie Region of High-Speed Trains
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作者 Jiawei Shi Jiye Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期2175-2195,共21页
Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically s... Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically studied.First,the simulation is conducted based on a simplified cavity-bogie model,including five cases with different inclination angles of the front and rear walls of the cavity.By comparing and analyzing the flow field and acoustic results of the five cases,the influence of the regularity and mechanism of the bogie cavity end wall inclination on the flow field and the aerodynamic noise of the bogie region are revealed.Then,the noise reduction strategy determined by the results of the simplified cavity-bogie model is applied to a three-car marshaling train model to verify its effectiveness when applied to the real train.The results reveal that the forward inclination of the cavity front wall enlarges the influence area of shear vortex structures formed at the leading edge of the cavity and intensifies the interaction between the vortex structures and the front wheelset,frontmotor,and front gearbox,resulting in the increase of the aerodynamic noise generated by the bogie itself.The backward inclination of the cavity rear wall is conducive to guiding the vortex structures flow out of the cavity and weakening the interaction between the shear vortex structures and the cavity rear wall,leading to the reduction of the aerodynamic noise generated by the bogie cavity.Inclining the rear end wall of the foremost bogie cavity of the head car is a feasible aerodynamic noise reduction measure for high-speed trains. 展开更多
关键词 BOGIE cavity flow aerodynamic noise end wall inclination
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End-group modulation of phenazine based non-fullerene acceptors for efficient organic solar cells with high open-circuit voltage
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作者 Yahui Zhang Yafeng Li +7 位作者 Ruixiang Peng Yi Qiu Jingyu Shi Zhenyu Chen Jinfeng Ge Cuifen Zhang Zheng Tang Ziyi Ge 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期461-468,I0011,共9页
Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increa... Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(Pz IC-4H,Pz IC-4F,Pz IC-4Cl,Pz IC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied.Synergetic photophysical and morphological analyses revealed that the PM6:Pz IC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6:Pz IC-4F as the active layer exhibited a PCE of 16.48%with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 e V,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs. 展开更多
关键词 Organic solar cells Non-fullerene acceptor PHENAZINE Central core end group
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Molecular packing tuning via chlorinated end group enables efficient binary organic solar cells over 18.5%
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作者 Yafeng Li Zhenyu Chen +1 位作者 Xingzheng Yan Ziyi Ge 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期196-203,共8页
Designing novel nonfullerene acceptors(NFAs)is of vital importance for the development of organic solar cells(OSC).Modification on the side chain and end group are two powerful tools to construct efficient NFAs.Here,b... Designing novel nonfullerene acceptors(NFAs)is of vital importance for the development of organic solar cells(OSC).Modification on the side chain and end group are two powerful tools to construct efficient NFAs.Here,based on the high-performance L8BO,we selected 3-ethylheptyl to substitute the inner chain of 2-ethylhexyl,obtaining the backbone of BON3.Then we introduced different halogen atoms of fluorine and chlorine on 2-(3-oxo-2,3-dihydro-1Hinden-1-ylidene)malononitrile end group(EG)to construct efficient NFAs named BON3-F and BON3-Cl,respectively.Polymer donor D18 was chosen to combine with two novel NFAs to construct OSC devices.Impressively,D18:BON3-Cl-based device shows a remarkable power conversion efficiency(PCE)of 18.57%,with a high open-circuit voltage(V_(OC))of 0.907 V and an excellent fill factor(FF)of 80.44%,which is one of the highest binary PCE of devices based on D18 as the donor.However,BON3-F-based device shows a relatively lower PCE of 17.79%with a decreased FF of 79.05%.The better photovoltaic performance is mainly attributed to the red-shifted absorption,higher electron and hole mobilities,reduced charge recombination,and enhanced molecular packing in the D18:BON3-Cl films.Also,we performed stability tests on two binary systems;the D18:BON3-Cl and D18:BON3-F devices maintain 88.1%and 85.5%of their initial efficiencies after 169 h of storage at 85°C in an N2-filled glove box,respectively.Our work demonstrates the importance of selecting halogen atoms on EG and provides an efficient binary system of D18:BON3-Cl for further improvement of PCE. 展开更多
关键词 binary organic solar cell chlorinated end group molecular packing
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End-of-Pregnancy Monitoring at CHUMEFJE through the Functional Investigation Centre (FIC) in 2022
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作者 Ulysse Pascal Minkobame Zaga Minko Opheelia Makoyo Komba +5 位作者 Pamphile Assoumou Obiang Anouchka Mewie Lendzinga Elsy Ntsame Mezui Irenee Edzo Mvono Jacques Albert Bang Ntamack Jean François Meye 《Open Journal of Obstetrics and Gynecology》 2024年第1期186-192,共7页
Introduction: The end of pregnancy is a high-risk period for both mother and foetus. Rigorous monitoring can prevent complications before delivery. Materials and Method: We conducted a descriptive cross-sectional obse... Introduction: The end of pregnancy is a high-risk period for both mother and foetus. Rigorous monitoring can prevent complications before delivery. Materials and Method: We conducted a descriptive cross-sectional observational study. It took place in the delivery room of the Teacher hospital Mother and Child of Jeanne Ebori Fondation from the 01 October 2020 to 01 October 2021. All patients followed at the Functional Investigation Centre (FIC) of the CHUMEFJE and who gave birth in that same hospital were included. Data were collected on the basis of pregnancy diaries, the fic register and delivery room registers. They were analysed using SPSS Statistical Software. Results: During the period of our study, 4086 parturients arrived in the delivery room. Of these, 150 were followed up at the FIC, giving a prevalence of 3.7%. The majority of parturients (48%) had only one prenatal contact. 6 (4%) patients underwent pelvic scans, and 4 (2.6%) presented with a narrowed pelvis. A vaginal delivery was performed in 80% of cases, and of the caesarean sections, 9 (30%) could be scheduled. The maternal prognosis was marred by one post-partum complication of hypertension, and newborns with poor adaptation to life outside the womb accounted for 3.3% of cases. Conclusion: The Functional Investigation Centre makes it possible to detect anomalies at the end of pregnancy with a view to better planning of delivery. 展开更多
关键词 FOLLOW-UP end of Pregnancy Scheduled Caesarean Section Prognosis
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Prognostic value of neutrophil-to-lymphocyte ratio in end-stage liver disease:A meta-analysis
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作者 Xiang-Hao Cai Yun-Ming Tang +4 位作者 Shu-Ru Chen Jia-Hui Pang Yu-Tian Chong Hong Cao Xin-Hua Li 《World Journal of Hepatology》 2024年第3期477-489,共13页
BACKGROUND The neutrophil-to-lymphocyte ratio(NLR)is commonly utilized as a prognostic indicator in end-stage liver disease(ESLD),encompassing conditions like liver failure and decompensated cirrhosis.Nevertheless,som... BACKGROUND The neutrophil-to-lymphocyte ratio(NLR)is commonly utilized as a prognostic indicator in end-stage liver disease(ESLD),encompassing conditions like liver failure and decompensated cirrhosis.Nevertheless,some studies have contested the prognostic value of NLR in ESLD.AIM To investigate the ability of NLR to predict ESLD.METHODS Databases,such as Embase,PubMed,Web of Science,Cochrane Library,China National Knowledge Infrastructure,Weipu,and Wanfang,were comprehensively searched to identify studies published before October 2022 assessing the prognostic ability of NLR to predict mortality in patients with ESLD.Effect sizes were calculated using comprehensive meta-analysis software and SATAT 15.1.RESULTS A total of thirty studies involving patients with end-stage liver disease(ESLD)were included in the evaluation.Among the pooled results of eight studies,it was observed that the Neutrophil-to-Lymphocyte Ratio(NLR)was significantly higher in non-survivors compared to survivors(random-effects model:standardized mean difference=1.02,95%confidence interval=0.67-1.37).Additionally,twenty-seven studies examined the associations between NLR and mortality in ESLD patients,reporting either hazard ratios(HR)or odds ratios(OR).The combined findings indicated a link between NLR and ESLD mortality(randomeffects model;univariate HR=1.07,95%CI=1.05-1.09;multivariate HR=1.07,95%CI=1.07-1.09;univariate OR=1.29,95%CI=1.18-1.39;multivariate OR=1.29,95%CI=1.09-1.49).Furthermore,subgroup and meta-regression analyses revealed regional variations in the impact of NLR on ESLD mortality,with Asian studies demonstrating a more pronounced effect.CONCLUSION Increased NLR in patients with ESLD is associated with a higher risk of mortality,particularly in Asian patients.NLR is a useful prognostic biomarker in patients with ESLD. 展开更多
关键词 Neutrophil-to-lymphocyte ratio end stage liver diseases PROGNOSIS META-ANALYSIS MORTALITY
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Regulatory role of peroxynitrite in advanced glycation end products mediated diabetic cardiovascular complications
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作者 Asis Bala 《World Journal of Diabetes》 SCIE 2024年第3期572-574,共3页
The Advanced Glycation End Products(AGE)binding with its receptor can increase reactive oxygen species(ROS)generation through specific signaling mediators.The effect of superoxide(O2-)and O2-mediated ROS and reactive ... The Advanced Glycation End Products(AGE)binding with its receptor can increase reactive oxygen species(ROS)generation through specific signaling mediators.The effect of superoxide(O2-)and O2-mediated ROS and reactive nitrogen species depends on their concentration and location of formation.Nitric oxide(NO)has anti-inflammatory and anticoagulant properties and a vasodilation effect,but NO can be deactivated by reacting with O_(2)^(-).This reaction between NO and O2-produces the potent oxidant ONOO−.Therefore,ONOO-'s regulatory role in AGEs in diabetic cardiovascular complications must considered as a regulator of cardiovascular complications in diabetes. 展开更多
关键词 DIABETES Cardiovascular complication Advanced glycation end products Reactive oxygen species Reactive nitrogen species PEROXYNITRITE
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High glucose reduces Nrf2-dependent cRAGE release and enhances inflammasome-dependent IL-1βproduction in monocytes:the modulatory effects of EGCG
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作者 Chi-Hao Wu Yin-Hsuan Chang +2 位作者 Chin-Lin Hsu Sheng-Yi Chen Gow-Chin Yen 《Food Science and Human Wellness》 SCIE CSCD 2024年第3期1531-1542,共12页
Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms un... Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms underlying sRAGE remain unclear.In this study,THP-1 monocytes were cultured in normal glucose(NG,5.5 mmol/L)and high glucose(HG,15 mmol/L)to investigate the effects of diabetesrelevant glucose concentrations on sRAGE and interleukin-1β(IL-1β)secretion.The modulatory effects of epigallocatechin gallate(EGCG)in response to HG challenge were also evaluated.HG enhanced intracellular reactive oxygen species(ROS)generation and RAGE expression.The secretion of sRAGE,including esRAGE and cRAGE,was reduced under HG conditions,together with the downregulation of a disintegrin and metallopeptidase 10(ADAM10)and nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation.Mechanistically,the HG effects were counteracted by siRAGE and exacerbated by siNrf2.Chromatin immunoprecipitation results showed that Nrf2 binding to the ADAM10 promoter and HG interfered with this binding.Our data reinforce the notion that RAGE and Nrf2 might be sRAGE-regulating factors.Under HG conditions,the treatment of EGCG reduced ROS generation and RAGE activation.EGCG-stimulated cRAGE release was likely caused by the upregulation of the Nrf2-ADAM10 pathway.EGCG inhibited HG-mediated NLRP3 inflammasome activation at least partly by stimulating sRAGE,thereby reducing IL-1βrelease. 展开更多
关键词 Epigallocatechin gallate(EGCG) INFLAMMASOME Nuclear factor erythroid 2-related factor 2(Nrf2) Receptor for advanced glycation end products(RAGE) Soluble RAGE(sRAGE)
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Bilateral pericapsular end nerve blocks for steroid-induced avascular necrosis following COVID-19 infection requiring bilateral total hip replacement
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作者 Somita Christopher Sweety Dutta Thota Venkata Sanjeev Gopal 《World Journal of Anesthesiology》 2024年第1期1-8,共8页
BACKGROUND Osteonecrosis or avascular necrosis(AVN)of the hip was one of the dreaded complications of coronavirus disease 2019(COVID-19),which emerged in patients who received steroid therapy.Corticosteroids have been... BACKGROUND Osteonecrosis or avascular necrosis(AVN)of the hip was one of the dreaded complications of coronavirus disease 2019(COVID-19),which emerged in patients who received steroid therapy.Corticosteroids have been a mainstay in the treatment protocol of COVID-19 patients.Popular corticosteroid drugs used in patients suffering from COVID-19 were intravenous(IV)or oral dexamethasone,methylprednisolone or hydrocortisone.The use of such high doses of corticost-eroids has shown very positive results and has been lifesaving in many cases.Still,long-term consequences were drug-induced diabetes,osteoporosis,Cushing syndrome,muscle wasting,peripheral fat mobilization,AVN,hirsutism,sleep disturbances and poor wound healing.A significant number of young patients were admitted for bilateral total hip replacements(THR)secondary to AVN following steroid use for COVID-19 treatment.AIM To assess the efficacy of bilateral pericapsular end nerve group(PENG)blocks in patients posted for bilateral THR post-steroid therapy after COVID-19 infection and assess the time taken to first ambulate after surgery.METHODS This prospective observational study was conducted between January 2023 and August 2023 at Care Hospitals,Hyderabad,India.Twenty young patients 30-35 years of age who underwent bilateral THR were studied after due consent over 8 months.All the patients received spinal anaesthesia for surgery and bilateral PENG blocks for postoperative analgesia.RESULTS The duration of surgery was 2.5 h on average.Seventeen out of twenty patients(85%)had a Visual Analog Score(VAS)of less than 2 and did not require any supplementation.One patient was removed from the study,as he required re-exploration.The remaining two patients had a VAS of more than 8 and received IV morphine post-operatively as a rescue analgesic drug.Fifteen out of seventeen patients(88.2%)could be mobilized 12 h after the procedure.CONCLUSION Osteonecrosis or AVN of the hip was one of the dreaded complications of COVID-19,which surfaced in patients who received steroid therapy requiring surgical intervention.Bilateral PENG block is an effective technique to provide post-operative analgesia resulting in early mobilization and enhanced recovery after surgery. 展开更多
关键词 Avascular necrosis Pericapsular end nerve group block ANALGESIA Hip replacement COVID-19 STEROIDS
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六味地黄丸介导RAGE抑制MMP-2/MMP-9对Aβ_(1-40)损伤bEnd.3细胞紧密连接蛋白的影响
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作者 丁蕊 袁永 +3 位作者 贾亚泉 高爱社 张振强 宋军营 《中成药》 CAS CSCD 北大核心 2024年第2期424-430,共7页
目的探讨六味地黄丸对β淀粉样蛋白1-40(Aβ_(1-40))损伤的小鼠脑微血管内皮细胞(bEnd.3)的保护作用及其机制。方法采用CCK8法检测Aβ_(1-40)和六味地黄丸含药血清(MSLDP)对细胞活性的影响,筛选合适的作用浓度。将bEnd.3细胞分为对照组... 目的探讨六味地黄丸对β淀粉样蛋白1-40(Aβ_(1-40))损伤的小鼠脑微血管内皮细胞(bEnd.3)的保护作用及其机制。方法采用CCK8法检测Aβ_(1-40)和六味地黄丸含药血清(MSLDP)对细胞活性的影响,筛选合适的作用浓度。将bEnd.3细胞分为对照组、Aβ_(1-40)组、MSLDP+Aβ_(1-40)组和MSLDP组,采用Western blot检测低密度脂蛋白相关蛋白1(LRP1)、晚期糖基化终末产物受体(RAGE)、基质金属蛋白酶2(MMP-2)、MMP-9、闭锁小带蛋白-1(ZO-1)、脑源性神经营养因子(BDNF)蛋白表达,免疫荧光检测LRP1、RAGE、ZO-1表达;再将bEnd.3细胞分为对照组、Aβ_(1-40)组、FPS-ZM1(RAGE抑制剂)+Aβ_(1-40)组和FPS-ZM1+Aβ_(1-40)+MSLDP组,Western blot检测RAGE、MMP-9、MMP-2、ZO-1蛋白表达。结果Aβ_(1-40)呈剂量依赖性降低bEnd.3细胞活性(P<0.01),MSLDP对Aβ_(1-40)损伤的细胞活性具有保护作用(P<0.05,P<0.01),因此选择10μmol/L Aβ_(1-40)和10%MSLDP进行后续实验。与对照组比较,Aβ_(1-40)组RAGE、MMP-2、MMP-9蛋白表达升高(P<0.01),LRP1、ZO-1、BDNF蛋白表达降低(P<0.05,P<0.01),并且LRP1、ZO-1荧光强度降低(P<0.01),RAGE荧光增强(P<0.01);与Aβ_(1-40)组比较,MSLDP组RAGE、MMP-2、MMP-9蛋白表达和RAGE荧光强度降低(P<0.05,P<0.01),而LRP1、ZO-1、BDNF蛋白表达和LRP1、ZO-1荧光强度升高(P<0.05,P<0.01)。与Aβ_(1-40)组比较,Aβ_(1-40)+FPS-ZM1组MMP-2、MMP9、RAGE蛋白表达降低(P<0.05,P<0.01),ZO-1蛋白表达升高(P<0.05);Aβ_(1-40)+FPS-ZM1+MSLDP组MMP-2、MMP9、RAGE蛋白表达降低(P<0.01),ZO-1蛋白表达升高(P<0.01),FPS-ZM1和MSLDP联合使用的效果更佳。结论六味地黄丸能够保护Aβ_(1-40)损伤的脑微血管内皮的细胞紧密连接,减轻血脑屏障障碍,保护神经血管单元防治阿尔茨海默病,可能通过调节RAGE途径抑制MMP-2/MMP-9途径实现。 展开更多
关键词 六味地黄丸 阿尔茨海默病 脑微血管内皮细胞 β淀粉样蛋白1-40(Aβ_(1-40)) 晚期糖基化终末产物受体(RAGE) 基质金属蛋白酶家族(MMPs)
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Investigation of Student Nurses’Attitudes towards End-of-Life Care and Their Influencing Factors
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作者 Lei Peng Jingxian Wang +1 位作者 Jia Wang Qiangqiang Liu 《Open Journal of Nursing》 2024年第5期183-191,共9页
Background: This cross-sectional investigative study aimed to determine student nurses’ attitudes towards end-of-life care. Methods: This study used a descriptive research design with stratified sampling to survey st... Background: This cross-sectional investigative study aimed to determine student nurses’ attitudes towards end-of-life care. Methods: This study used a descriptive research design with stratified sampling to survey student nurses enrolled in one of four nursing colleges in China from January 2023 to December 2023. Student nurses’ general demographic and prior related information, attitudes towards death and attitudes towards end-of-life care were determined using a general information questionnaire, the Death Attitude Profile—Revised scale and the Professional End-of-Life Attitude Scale (PEAS), respectively. Results: The total PEAS score was 122.91 ± 16.123. Significant differences were noted in the attitude towards end-of-life care scores according to sources of end-of-life care knowledge (P Conclusions: Student nurses lacked an optimistic attitude towards end-of-life care, which was influenced by differences in the sources of end-of-life care knowledge. 展开更多
关键词 Nursing Students end-of-Life Care ATTITUDE
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Building Custom Spreadsheet Functions with Python: End-User Software Engineering Approach
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作者 Tamer Bahgat Elserwy Atef Tayh Nour El-Din Raslan +1 位作者 Tarek Ali Mervat H. Gheith 《Journal of Software Engineering and Applications》 2024年第5期246-258,共13页
End-user computing empowers non-developers to manage data and applications, enhancing collaboration and efficiency. Spreadsheets, a prime example of end-user programming environments widely used in business for data a... End-user computing empowers non-developers to manage data and applications, enhancing collaboration and efficiency. Spreadsheets, a prime example of end-user programming environments widely used in business for data analysis. However, Excel functionalities have limits compared to dedicated programming languages. This paper addresses this gap by proposing a prototype for integrating Python’s capabilities into Excel through on-premises desktop to build custom spreadsheet functions with Python. This approach overcomes potential latency issues associated with cloud-based solutions. This prototype utilizes Excel-DNA and IronPython. Excel-DNA allows creating custom Python functions that seamlessly integrate with Excel’s calculation engine. IronPython enables the execution of these Python (CSFs) directly within Excel. C# and VSTO add-ins form the core components, facilitating communication between Python and Excel. This approach empowers users with a potentially open-ended set of Python (CSFs) for tasks like mathematical calculations, statistical analysis, and even predictive modeling, all within the familiar Excel interface. This prototype demonstrates smooth integration, allowing users to call Python (CSFs) just like standard Excel functions. This research contributes to enhancing spreadsheet capabilities for end-user programmers by leveraging Python’s power within Excel. Future research could explore expanding data analysis capabilities by expanding the (CSFs) functions for complex calculations, statistical analysis, data manipulation, and even external library integration. The possibility of integrating machine learning models through the (CSFs) functions within the familiar Excel environment. 展开更多
关键词 end-User Software Engineering Custom Spreadsheet Functions (CSFs)
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Theory of Flexural Shear, Bending and Torsion for a Thin-Walled Beam of Open Section
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作者 David W. A. Rees Abdelraouf M. Sami Alsheikh 《World Journal of Mechanics》 2024年第3期23-53,共31页
Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under trans... Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under transverse shear and axial torsional loading are each considered theoretically. These analyses involve the location of the shear centre at which transverse shear forces when applied do not produce torsion. This centre, when taken to be coincident with the centre of twist implies an equivalent reciprocal behaviour. That is, an axial torsion applied concentric with the shear centre will twist but not bend the beam. The respective bending and shear stress conversions are derived for each action applied to three aluminium alloy extruded channel sections mounted as cantilevers with a horizontal principal axis of symmetry. Bending and shear are considered more generally for other thin-walled sections when the transverse loading axes at the shear centre are not parallel to the section = s centroidal axes of principal second moments of area. The fixing at one end of the cantilever modifies the St Venant free angular twist and the free warping displacement. It is shown from the Wagner-Kappus torsion theory how the end constrained warping generates an axial stress distribution that varies with the length and across the cross-section for an axial torsion applied to the shear centre. It should be mentioned here for wider applications and validation of the Vlasov theory that attendant papers are to consider in detail bending and torsional loadings applied to other axes through each of the centroid and the web centre. Therein, both bending and twisting arise from transverse shear and axial torsion applied to each position being displaced from the shear centre. Here, the influence of the axis position upon the net axial and shear stress distributions is to be established. That is, the net axial stress from axial torsional loading is identified with the sum of axial stress due to bending and axial stress arising from constrained warping displacements at the fixing. The net shear stress distribution overlays the distributions from axial torsion and that from flexural shear under transverse loading. Both arise when transverse forces are displaced from the shear centre. 展开更多
关键词 Thin Wall Theory Cantilever Beam Open Channel Section Principal Axes Flexure Transverse Shear TORSION Shear Centre Shear Flow WARPING Fixed-end Constraint
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Numerical Analysis of a Spiral-groove Dry-gas Seal Considering Micro-scale Effects 被引量:12
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作者 WANG Bing ZHANG Huiqiang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第1期146-153,共8页
A dry-gas seal system is a non-contact seal technology that is widely used in different industrial applications.Spiral-groove dry-gas seal utilizes fluid dynamic pressure effects to realize the seal and lubrication pr... A dry-gas seal system is a non-contact seal technology that is widely used in different industrial applications.Spiral-groove dry-gas seal utilizes fluid dynamic pressure effects to realize the seal and lubrication processes,while forming a high pressure gas film between two sealing faces due to the deceleration of the gas pumped in or out.There is little research into the effects and the influence on seal performance,if the grooves and the gas film are at the micro-scale.This paper investigates the micro-scale effects on spiral-groove dry-gas seal performance in a numerical solution of a corrected Reynolds equation.The Reynolds equation is discretized by means of the finite difference method with the second order scheme and solved by the successive-over-relaxation(SOR) iterative method.The Knudsen number of the flow in the sealing gas film is changed from 0.005 to 0.120 with a variation of film depth and sealing pressure.The numerical results show that the average pressure in the gas film and the sealed gas leakage increase due to micro-scale effects.The open force is enlarged,while the gas film stiffness is significantly decreased due to micro-scale effects.The friction torque and power consumption remain constant,even in low sealing pressure and spin speed conditions.In this paper,the seal performance at different rotor face spin speeds is also described.The proposed research clarifies the micro-scale effects in a spiral-groove dry-gas seal and their influence on seal performance,which is expected to be useful for the improvement of the design of dry-gas seal systems operating in the slip flow regime. 展开更多
关键词 micro-scale effect spiral-groove dry-gas seal numerical analysis Reynolds equation
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Recent Advances in Computational Simulation of Macro-,Meso-,and Micro-Scale Biomimetics Related Fluid Flow Problems 被引量:5
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作者 Y. Y. Yan 《Journal of Bionic Engineering》 SCIE EI CSCD 2007年第2期97-107,共11页
Over the last decade, computational methods have been intensively applied to a variety of scientific researches and engineering designs. Although the computational fluid dynamics (CFD) method has played a dominant r... Over the last decade, computational methods have been intensively applied to a variety of scientific researches and engineering designs. Although the computational fluid dynamics (CFD) method has played a dominant role in studying and simulating transport phenomena involving fluid flow and heat and mass transfers, in recent years, other numerical methods for the simulations at meso- and micro-scales have also been actively applied to solve the physics of complex flow and fluid-interface interactions. This paper presents a review of recent advances in multi-scale computational simulation of biomimetics related fluid flow problems. The state-of-the-art numerical techniques, such as lattice Boltzmann method (LBM), molecular dynamics (MD), and conventional CFD, applied to different problems such as fish flow, electro-osmosis effect of earthworm motion, and self-cleaning hydrophobic surface, and the numerical approaches are introduced. The new challenging of modelling biomimetics problems in developing the physical conditions of self-clean hydrophobic surfaces is discussed. 展开更多
关键词 biomimetics computational simulation macro- meso- micro-scale HYDROPHOBIC SURFACES
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Discharge characteristics of a needle-to-plate electrode at a micro-scale gap 被引量:7
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作者 王荣刚 季启政 +3 位作者 张桐恺 夏清 张宇 欧阳吉庭 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第5期126-130,共5页
To understand the discharge characteristics under a gap of micrometers,the breakdown voltage and current–voltage curve are measured experimentally in a needle-to-plate electrode at a microscale gap of 3–50 μm in ai... To understand the discharge characteristics under a gap of micrometers,the breakdown voltage and current–voltage curve are measured experimentally in a needle-to-plate electrode at a microscale gap of 3–50 μm in air.The effect of the needle radius and the gas pressure on the discharge characteristics are tested.The results show that when the gap is larger than 10 μm,the relation between the breakdown voltage and the gap looks like the Paschen curve;while below 10 μm,the breakdown voltage is nearly constant in the range of the tested gap.However,at the same gap distance,the breakdown voltage is still affected by the pressure and shows a trend similar to Paschen's law.The current–voltage characteristic in all the gaps is similar and follows the trend of a typical Townsend-to-glow discharge.A simple model is used to explain the non-normality of breakdown in the micro-gaps.The Townsend mechanism is suggested to control the breakdown process in this configuration before the gap reduces much smaller in air. 展开更多
关键词 needle-to-plate electrode micro-scale gap gas breakdown
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Fabrication of micro-scale gratings for moiré method with a femtosecond laser 被引量:2
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作者 Gaosheng Yan Jianguo Zhu +2 位作者 Yanlong Huang Wenfen Hao Yanjie Li 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2016年第4期171-175,共5页
Fabrication of micro gratings using a femtosecond laser exposure system is experimentally investigated for the electron moire method. Micro holes and lines are firstly etched for parameter study. Grating profile is th... Fabrication of micro gratings using a femtosecond laser exposure system is experimentally investigated for the electron moire method. Micro holes and lines are firstly etched for parameter study. Grating profile is theoretically optimized to form high quality moire patterns. For a demonstration, a parallel grating is fabricated on a specimen of quartz glass. The minimum line width and the distance between two adjacent lines are both set to be 1 μm, and the frequency of grating is 500 lines/ram. The experimental results indicate that the quality of gratings is good and the relative error of the gratings pitch is about 1.5%. Based on molte method, scanning electron microscope (SEM) moire patterns are observed clearly, which manifests that gratings fabricated with the femtosecond laser exposure is suitable for micro scale deformation measurement. 展开更多
关键词 micro-scale grating Femtosecond laser Moire method
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次线性期望空间下END列Jamison型加权和的几乎处处收敛性 被引量:1
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作者 刘伦义 吴群英 《吉林大学学报(理学版)》 CAS 北大核心 2023年第4期808-814,共7页
利用截尾的方法,考虑次线性期望空间下广义负相依(END)随机变量序列Jamison型加权和的几乎处处收敛问题,得到了次线性期望空间下END随机变量序列Jamison型加权和的几乎处处收敛性.将概率空间下END随机变量序列Jamison型加权和的几乎处... 利用截尾的方法,考虑次线性期望空间下广义负相依(END)随机变量序列Jamison型加权和的几乎处处收敛问题,得到了次线性期望空间下END随机变量序列Jamison型加权和的几乎处处收敛性.将概率空间下END随机变量序列Jamison型加权和的几乎处处收敛拓展到了次线性期望空间下,推广了Jamison定理. 展开更多
关键词 次线性期望 几乎处处收敛 Jamison型加权和 end随机变量序列 截尾
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Micro-scale Dispersion of Air Pollutants over an Urban Setup in a Coastal Region 被引量:1
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作者 Srikanth Madala A.N.V. Satyanarayana V. Krishna Prasad 《Open Journal of Air Pollution》 2012年第2期51-58,共8页
The dispersion is mainly governed by wind field and depends on the planetary boundary layer (PBL) dynamics. Accurate representation of the meteorological weather fields would improve the dispersion assessments. In urb... The dispersion is mainly governed by wind field and depends on the planetary boundary layer (PBL) dynamics. Accurate representation of the meteorological weather fields would improve the dispersion assessments. In urban areas representation of wind around the obstacles is not possible for the pollution dispersion studies using Gaussian based modeling studies. It is widely accepted that computational fluid dynamics (CFD) tools would provide reasonably good solution to produce the wind fields around the complex structures and other land scale elements. By keeping in view of the requirement for the micro-scale dispersion, a commercial CFD model PANACHE with PANEPR developed by Fluidyn is implemented to study the micro-scale dispersion of air pollution over an urban setup at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam a coastal station in the east coast of India under stable atmospheric conditions. Meso-scale module of the PANACHE model is integrated with the data generated at the site by IGCAR under RRE (Round Robin Exercise) program to develop the flow fields. Using this flow fields, CFD model is integrated to study the micro-scale dispersion. Various pollution dispersion scenarios are developed using hypothetical emission inventory during stably stratified conditions to understand the micro-scale dispersion over different locations of coastal urban set up in the IGCAR region of Kalpakkam. 展开更多
关键词 CFD PBL MESO-SCALE micro-scale DISPERSION
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Micro-scale FEM Calculation of Concrete Temperature during Production and Casting
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作者 朱振泱 LIU Yi +5 位作者 ZHANG Guoxin WU Congcong WANG Zhenhong LIU Youzhi ZHANG Lei YANG Ning 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第1期113-120,共8页
A micro-scale finite element method(FEM) was proposed to precisely calculate the heat conduction between mortar and aggregate, and thus to accurately predict the non-uniformity of concrete pouring temperature. The con... A micro-scale finite element method(FEM) was proposed to precisely calculate the heat conduction between mortar and aggregate, and thus to accurately predict the non-uniformity of concrete pouring temperature. The concrete temperature field during vibration was also precisely calculated by accurate description of heat absorption characteristics of different parts of concrete when vibration. Based on the above method, the prediction model was used to predict the pouring temperature of a practical engineering. The comparison between actual results and simulated values shows that this method can be adopted to accurately predict the non-uniformity of concrete pouring temperature and the influence of mechanized vibration on concrete pouring temperature, and thus accurately predict pouring temperature. The control of casting temperature is crucial for preventing concrete fracture. The study provides a new method for predicting the pouring temperature of concrete structures, which has great practical value in engineering application. 展开更多
关键词 concrete POURING TEMPERATURE micro-scale FINITE-ELEMENT TEMPERATURE prediction
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Advanced glycation end products:Key mediator and therapeutic target of cardiovascular complications in diabetes 被引量:1
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作者 Savita Bansal Archana Burman Asok Kumar Tripathi 《World Journal of Diabetes》 SCIE 2023年第8期1146-1162,共17页
The incidence of type 2 diabetes mellitus is growing in epidemic proportions and has become one of the most critical public health concerns.Cardiovascular complications associated with diabetes are the leading cause o... The incidence of type 2 diabetes mellitus is growing in epidemic proportions and has become one of the most critical public health concerns.Cardiovascular complications associated with diabetes are the leading cause of morbidity and mortality.The cardiovascular diseases that accompany diabetes include angina,myocardial infarction,stroke,peripheral artery disease,and congestive heart failure.Among the various risk factors generated secondary to hyperglycemic situations,advanced glycation end products(AGEs)are one of the important targets for future diagnosis and prevention of diabetes.In the last decade,AGEs have drawn a lot of attention due to their involvement in diabetic pathophysiology.AGEs can be derived exogenously and endogenously through various pathways.These are a nonhomogeneous,chemically diverse group of compounds formed nonenzymatically by condensation between carbonyl groups of reducing sugars and free amino groups of protein,lipids,and nucleic acid.AGEs mediate their pathological effects at the cellular and extracellular levels by multiple pathways.At the cellular level,they activate signaling cascades via the receptor for AGEs and initiate a complex series of intracellular signaling resulting in reactive oxygen species generation,inflammation,cellular proliferation,and fibrosis that may possibly exacerbate the damaging effects on cardiac functions in diabetics.AGEs also cause covalent modifications and cross-linking of serum and extracellular matrix proteins;altering their structure,stability,and functions.Early diagnosis of diabetes may prevent its progression to complications and decrease its associated comorbidities.In the present review,we recapitulate the role of AGEs as a crucial mediator of hyperglycemia-mediated detrimental effects in diabetes-associated complications.Furthermore,this review presents an overview of future perspectives for new therapeutic interventions to ameliorate cardiovascular complications in diabetes. 展开更多
关键词 Type 2 diabetes mellitus Cardiovascular complications HYPERGLYCEMIA Advanced glycation end products Reactive oxygen species Oxidative stress endothelial cells Receptor of advanced glycation end products Anti-advanced glycation end products strategies
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