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Food intolerance and sensitivity are associated with features of fibromyalgia in a self-selected community population
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作者 Ella Thomson Harriet Beer +2 位作者 Laura Ryan Edward Philcox Clive Kelly 《Food and Health》 2023年第4期8-15,共8页
Introduction:People are now presenting with chronic musculoskeletal pain at a younger age,and many of them fulfil criteria for fibromyalgia.We have recently shown a strong association between fibromyalgia symptoms and... Introduction:People are now presenting with chronic musculoskeletal pain at a younger age,and many of them fulfil criteria for fibromyalgia.We have recently shown a strong association between fibromyalgia symptoms and autistic traits in a self-selected community population,with the relationship mediated in part by the presence of hypermobility.Many respondents also described food sensitivities and intolerances.This study explores the relationships between food issues and fibromyalgia symptoms in this population.Methods:We adopted a nonexperimental,correlational design and collected data from a volunteer sample of 442 adults(aged 18–60)who completed online self-report questionnaires assessing each of fibromyalgia symptoms(ACR criteria),autistic traits(RAADS score)and hypermobility(Beighton’s test).Subjects were also asked to record any food sensitivities,allergies,or intolerances,along with their consequences.Correlation analyses and linear regressions were used to test the relationships between these features and each of fibromyalgia,autistic traits and hypermobility.We analysed the data with parametric and non-parametric techniques to assess the significance and power of relationships,and the potential mediating effect of food-related symptoms in the correlation between fibromyalgia features and autistic traits.Results:Our self-selected community population had a mean age of 24 years and was 77%female.The self-reported prevalence of fibromyalgia,autistic traits and hypermobility was 40%,65%and 44%respectively.Hypermobile individuals showed a high prevalence of autistic traits,reaching 79%among females and 88%among males.Half of all subjects reported food sensitivity and 31%reported food intolerance.The incidence of food-related symptoms was higher among subjects who met criteria for fibromyalgia than those who reported autistic traits or hypermobility.Food sensitivity and food intolerance were both more significantly associated with fibromyalgia(r=0.24,P>0.001 and r=0.38,P>0.001)than with autistic traits(r=0.172,P>0.01 and r=0.148,P>0.01).Discussion:This community study provides evidence for an association between features of fibromyalgia and reported food intolerance and sensitivity.Although self-selected,the findings in our predominantly young population suggest that gluten and lactose consumption may be associated with higher levels of musculoskeletal pain.The study population commonly reported that avoidance of gluten and/or lactose containing foods reduced symptoms.Dietary adjustment may merit further investigation as a therapeutic modality for some patients with fibromyalgia. 展开更多
关键词 FIBROMYALGIA food intolerance food sensitivity AUTISM HYPERMOBILITY
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Modeling and Testing of Hydrodynamic Damping Model for a Complex-shaped Remotely-operated Vehicle for Control 被引量:6
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作者 Cheng Chin Michael Lau 《Journal of Marine Science and Application》 2012年第2期150-163,共14页
In this paper,numerical modeling and model testing of a complex-shaped remotely-operated vehicle(ROV) were shown.The paper emphasized the systematic modeling of hydrodynamic damping using the computational fluid dyn... In this paper,numerical modeling and model testing of a complex-shaped remotely-operated vehicle(ROV) were shown.The paper emphasized the systematic modeling of hydrodynamic damping using the computational fluid dynamic software ANSYS-CFXTM on the complex-shaped ROV,a practice that is not commonly applied.For initial design and prototype testing during the developmental stage,small-scale testing using a free-decaying experiment was used to verify the theoretical models obtained from ANSYS-CFXTM.Simulation results are shown to coincide with the experimental tests.The proposed method could determine the hydrodynamic damping coefficients of the ROV. 展开更多
关键词 remotely-operated vehicle hydrodynamic damping ANSYS-CFXTM MODELING simulation
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Oral manifestations of hepatitis C virus infection 被引量:4
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作者 Marco Carrozzo Kara Scally 《World Journal of Gastroenterology》 SCIE CAS 2014年第24期7534-7543,共10页
Extrahepatic manifestations (EHMs) of hepatitis C virus (HCV) infection can affect a variety of organ systems with significant morbidity and mortality. Some of the most frequently reported EHM of HCV infection, involv... Extrahepatic manifestations (EHMs) of hepatitis C virus (HCV) infection can affect a variety of organ systems with significant morbidity and mortality. Some of the most frequently reported EHM of HCV infection, involve the oral region predominantly or exclusively. Oral lichen planus (OLP) is a chronic inflammatory condition that is potentially malignant and represents cell-mediated reaction to a variety of extrinsic antigens, altered self-antigens, or super antigens. Robust epidemiological evidence support the link between OLP and HCV. As the virus may replicate in the oral mucosa and attract HCV-specific T lymphocytes, HCV may be implicated in OLP pathogenesis. Sj&#x000f6;gren syndrome (SjS) is an autoimmune exocrinopathy, characterized by dryness of the mouth and eyes and a multitude of other systemic signs and symptoms. SjS patients have also an increased risk of non-Hodgkin lymphoma. Patients with chronic hepatitis C do frequently have histological signs of Sj&#x000f6;gren-like sialadenitis with mild or even absent clinical symptoms. However, it is still unclear if HCV may cause a disease mimicking SjS or it is directly responsible for the development of SjS in a specific subset of patients. Oral squamous cell carcinoma is the most common oral malignant tumour and at least in some part of the world could be linked to HCV. 展开更多
关键词 Hepatitis C virus Lichen planus Oral lichen planus Sjogren’ s syndrome SIALADENITIS Oral squamous cell carcinoma
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Mutifactorial analysis of risk factors for reduced bone mineral density in patients with Crohn’s disease 被引量:2
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作者 Sarah A Bartram Robert T Peaston +3 位作者 David J Rawlings David Walshaw Roger M Francis Nick P Thompson 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第35期5680-5686,共7页
AIM: To determine the prevalence of osteoporosis in a cohort of patients with Crohn’s disease (CD) and to identify the relative significance of risk factors for osteoporosis. METHODS: Two hundred and fifty-eight unse... AIM: To determine the prevalence of osteoporosis in a cohort of patients with Crohn’s disease (CD) and to identify the relative significance of risk factors for osteoporosis. METHODS: Two hundred and fifty-eight unselected patients (92 M, 166 F) with CD were studied. Bone mineral density (BMD) was measured at the lumbar spine and hip by dual X-ray absorptiometry. Bone formation was assessed by measuring bone specific alkaline phosphatase (BSAP) and bone resorption by measuring urinary excretion of deoxypyridinoline (DPD) and N-telopeptide (NTX). RESULTS: Between 11.6%-13.6% patients were osteoporotic (T score < -2.5) at the lumbar spine and/or hip. NTX levels were significantly higher in the patients with osteoporosis (P < 0.05) but BSAP and DPD levels were not significantly different. Independent risk factors for osteoporosis at either the lumbar spine or hip were a low body mass index (P < 0.001), increasing corticosteroid use (P < 0.005), and male sex (P < 0.01). These factors combined accounted for 23% and 37% of the reduction in BMD at the lumbar spine and hip respectively. CONCLUSION: Our results confirm that osteoporosis is common in patients with CD and suggest that increased bone resorption is the mechanism responsible for thebone loss. However, less than half of the reduction in BMD can be attributed to risk factors such as corticosteroid use and low BMI and therefore remains unexplained. 展开更多
关键词 Crohn's disease OSTEOPOROSIS OSTEOPENIA Bone mineral density
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Magnetic Barkhausen Noise Profile Analysis: Effect of Excitation Field Strength and Detection Coil Sensitivity in Case Carburized Steel 被引量:2
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作者 Mohamed Mehemed Blaow Brian A. Shaw 《Materials Sciences and Applications》 2014年第5期258-266,共9页
The sensitivity of magnetic Barkhausen noise (MBN) profile to changes in the excitation field strength and the number of turns of the detection coil was investigated in inhomogeneous material. Generally, the 0.5 mm ca... The sensitivity of magnetic Barkhausen noise (MBN) profile to changes in the excitation field strength and the number of turns of the detection coil was investigated in inhomogeneous material. Generally, the 0.5 mm case depth EN 36 steel specimen shows a double peak profile indicative of inhomogeneity through the detected depth the magnetized landscape. Various excitation field amplitudes were applied to the specimen and the induced MBN emission was analyzed for each magnetizing current. Excitation field at the lowest level induced an MBN emission of two peaks of equivalent heights. The first peak occurs at lower field than the second peak in the magnetization period. As the excitation field increased, the height of both peaks increased but the second peak increased in a higher rate than that of the first peak. Beyond certain excitation level, both peaks began to saturate and no increase in the MBN intensity was observed with increased excitation field strength. However, peak position and the number of Barkhausen events, indicated linearly as a function of the applied field strength. The experiment also establishes that the number of turns in the detection coil is important parameter which controls the height of the first peak. Low field peak height increases as the number of turn of the detection coil increases. The results indicate that the potential difference applied to the electromagnet and the sensitivity of the detection coil, determine the MBN profile characteristics. 展开更多
关键词 EXCITATION Field EN 36 STEEL MBN Profile INHOMOGENEITY Detection COIL ELECTROMAGNET Potential DIFFERENCE
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Regulation of Power Conversion in Fuel Cells
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作者 ZHANG J. K. Scott 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第4期466-469,共4页
Here we report a regulation about power conversion in fuel cells. This regulation is expressed as that total power produced by fuel cells is always proportional to the square of the potential difference between the \{... Here we report a regulation about power conversion in fuel cells. This regulation is expressed as that total power produced by fuel cells is always proportional to the square of the potential difference between the \{equilibrium\} potential and work potential. With this regulation we deduced fuel cell performance equation which can describe the potential vs.the current performance curves, namely, polarization curves of fuel cells with three power source parameters: equilibrium potential E_0; internal resistance R; and power conversion coefficient K. The concept of the power conversion coefficient is a new criterion to evaluate and compare the characteristics and capacity of different fuel cells. The calculated values obtained with this equation agree with practical performance of different types of fuel cells. 展开更多
关键词 Fuel cell Power conversion coefficient Internal resistance PERFORMANCE POTENTIAL
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Stem cells derived from testis show promise for treating a wide variety of medical conditions
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作者 Karim Nayemia 《Cell Research》 SCIE CAS CSCD 2007年第11期895-897,共3页
The continuation of the spermatogenic process through-out life relies on a proper regulation of self-renewal and differentiation ofgermline testis stem cells, the spermatogonial stem cells. These are single cells situ... The continuation of the spermatogenic process through-out life relies on a proper regulation of self-renewal and differentiation ofgermline testis stem cells, the spermatogonial stem cells. These are single cells situated on the basal membrane of the seminiferous epithelium. Only 0.03% of all germ cells are spermatogonial stem cells (SSCs) [1-3]. To maintain spermatogenesis, the processes of self-renewal and differentiation of S SCs must be precisely regulated by intrinsic gene expression in the stem cells and extrinsic signals, including soluble factors or adhesion molecules from the surrounding microenvironment, the stem cell niche. 展开更多
关键词 干细胞 睾丸 医学条件 治疗
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Characterization of H^+ and HCO_3^- transporters in CFPAC-1 human pancreatic duct cells
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作者 ZoltánRakonczayJr AmyFearn +4 位作者 PéterHegy MichaelAGray BarryEArgent PéterHegyi Imre Boros 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第6期885-895,共11页
AIM: To characterize H^+ and HCO3^- transporters in polarized CFPAC-1 human pancreatic duct cells, which were derived from a cystic fibrosis patient with the AF508 CFTR mutation. METHODS: CFPAC-1 cells were seeded ... AIM: To characterize H^+ and HCO3^- transporters in polarized CFPAC-1 human pancreatic duct cells, which were derived from a cystic fibrosis patient with the AF508 CFTR mutation. METHODS: CFPAC-1 cells were seeded at high density onto permeable supports and grown to confluence. The cells were loaded with the pH-sensitive fluorescent dye BCECF, and mounted into a perfusion chamber, which allowed the simultaneous perfusion of the basolateral and apical membranes. Transmembrane base flux was calculated from the changes in intracellular pH and the buffering capacity of the cells. RESULTS: Our results showed differential permeability to HCO3^+/CO2 at the apical and basolateral membranes of CFPAC-1 cells. Na^+/HCO3^- co-transporters (NBCs) and Cl^-/HCO3^- exchangers (AEs) were present on the basolateral membrane, and Na+/H+ exchangers (NHEs) on both the apical and basolateral membranes of the cells. Basolateral HCO3 uptake was sensitive to variations of extracellular K^+ concentration, the membrane permeable carbonic anhydrase (CA) inhibitors acetazolamide (100 μmol/L) and ethoxyzolamide (100 μmol/L), and was partially inhibited by H2-DIDS (600 μmol/L). The membrane-impermeable CA inhibitor 1-N-(4-sulfamoylphenylethyl)-2,4,6-trimethylpyridine perchlorate did not have any effect on HCO3^- uptake.The basolateral AE had a much higher activity than that in the apical membrane, whereas there was no such difference with the NHE under resting conditions. Also, 10 μmol/L forskolin did not significantly influence Cl^-/HCO3^- exchange on the apical and basolateral membranes. The administration of 250 μmol/L H2-DIDS significantly inhibited the basolateral AE. Amiloride (300 μmol/L) completely inhibited NHEs on both membranes of the cells. RT-PCR revealed the expression of pNBC1, AE2, and NHE1 mRNA. CONCLUSION: These data suggest that apart from the lack of CFTR and apical Cl^-/HCO3^- exchanger activity, CFPAC-1 cells express similar H^+ and HCO3^- transporters to those observed in native animal tissue. 展开更多
关键词 CFPAC-1 Pancreatic duct cells HCO3^- Intracellular pH
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DETECTION OF INCIPIENT DEFECTS IN A GEARBOX BY DEMODULATION OF MESHING VIBRATION SIGNATURE
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作者 Luo Zhusan Fawcet t J N 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第1期57-63,共7页
This paper presents an investigation into the detection of incipient fatigue cracks in a gearbox.On the basis of modulation theory,a signal processing technique is proposed in the paper to isolate irregular signals fr... This paper presents an investigation into the detection of incipient fatigue cracks in a gearbox.On the basis of modulation theory,a signal processing technique is proposed in the paper to isolate irregular signals from complex vibration signals,and to obtain the amplitude and phase modulation functions without use of any tachometers or frequency multiplier.It has been shown that this signal processing method is useful for enhancement of the signal containing the fault features and effective in the detection of incipient defects in the gearbox. 展开更多
关键词 GEAR failure diagnosis signal processing gear transmission
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Effect of Soaking Pre-Treatment on Reactive Extraction/<i>in situ</i>Transesterification of <i>Nannochloropsis occulata</i>for Biodiesel Production
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作者 Kamoru A. Salam Sharon B. Velasquez-Orta Adam P. Harvey 《Journal of Sustainable Bioenergy Systems》 2017年第4期149-164,共16页
Microalgal phospholipid bilayer contributes to the molar excesses of methanol and high acid concentration required in reactive extraction to achieve high fatty acid methyl ester (FAME) yield. This study reports an inv... Microalgal phospholipid bilayer contributes to the molar excesses of methanol and high acid concentration required in reactive extraction to achieve high fatty acid methyl ester (FAME) yield. This study reports an investigation into the effects of pre-soaking Nannochloropsis occulata in methanol at 600:1 and 1000:1 methanol to oil molar ratios prior to acid-catalyzed in situ transesterification at 8.5:1 and 15:1 H2SO4 to oil molar ratios on the FAME yield. The results showed that the pre-soaked Nannochloropsis occulata produced a higher FAME yield at the two tested methanol to oil molar ratios and acid concentrations than the un-soaked, resulting in a reduction in methanol volume and acid concentration. A maximum FAME yield of 98.4% ± 1.3% was obtained for the pre-soaked Nannochloropsis occulata at 1000:1 methanol to oil molar ratio and 15:1 H2SO4 to oil molar ratio. Both the phosphorus mass balance and conversion of the isolated phospholipids into FAME revealed that pre-soaking solubilizes the phospholipid bilayer to some degree, and contributes to an increased FAME yield. 展开更多
关键词 Pre-Soaking MICROALGAE Cell Disruption Glycerol TRANSESTERIFICATION in situ TRANSESTERIFICATION (Reactive Extraction)
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In Situ Transesterification of Wet Marine and Fresh Water Microalgae for Biodiesel Production and Its Effect on the Algal Residue
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作者 Kamoru A. Salam Sharon B. Velasquez-Orta Adam P. Harvey 《Journal of Sustainable Bioenergy Systems》 2016年第2期17-30,共14页
This article reports a high yielding technique of synthesizing zirconium dodecyl sulphate (“ZDS”) for in situ transesterification of Nannochloropsis occulata and Chlorella vulgaris for fatty acid methyl ester (FAME)... This article reports a high yielding technique of synthesizing zirconium dodecyl sulphate (“ZDS”) for in situ transesterification of Nannochloropsis occulata and Chlorella vulgaris for fatty acid methyl ester (FAME) production. ZDS produced a significantly higher FAME yield in N. occulata than in C. vulgaris (p = 0.008). The varying performance of ZDS in the two species could be due to their different cell wall chemistries. Sodium dodecyl sulphate (SDS) in H2SO4 for FAME enhancement from the two species was also studied. Treatment with SDS in H2SO4 increased the FAME production rate in both species. Residual protein content after the in situ transesterification in C. vulgaris and N. occulata reduced respectively by 6.5% and 10%. The carbohydrate content was reduced by 71% in C. vulgaris and 65% in N. occulata. The water tolerance of the process when using H2SO4, with or without SDS, was evaluated by hydrating the two species with 10% - 30% distilled water (w/w dry algae). The FAME concentration began to diminish only at 30% water content in both species. Furthermore, the presence of a small amount of water in the biomass or methanol increased the lipid extraction efficiency, improving the FAME yield, rather than inhibiting the reaction. 展开更多
关键词 Biodiesel (Fatty Acid Methyl Ester) Cell Wall In Situ Transesterification SURFACTANT Surfactant Catalyst Wet Microalgae
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An Evaluation of R134a and R245fa as the Working Fluid in an Organic Rankine Cycle Energized from a Low Temperature Geothermal Energy Source
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作者 S. Masheiti B. Agnew S. Walker 《Journal of Energy and Power Engineering》 2011年第5期392-402,共11页
The characteristics of an organic Rankin cycle designed to operate with a low temperature geothermal source and constant temperature cooling water supplied from freshwater ponds typical to those found near Waddan City... The characteristics of an organic Rankin cycle designed to operate with a low temperature geothermal source and constant temperature cooling water supplied from freshwater ponds typical to those found near Waddan City in the Al Jufrah region of Libya were examined. Two working fluids were examined and it was concluded that the most suitable for this application was R-245fa. The off design performance of the organic Rankine cycle was examined and it was shown that the cycle is controlled by the performance of the condenser which is cooling water side temperature limited. 展开更多
关键词 Low-temperature resources IPSEpro organic Rankine cycle (ORC) R-245fa R-134a.
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生物标志化合物与相关的全球变化 被引量:57
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作者 谢树成 梁斌 +4 位作者 郭建秋 易轶 R.P.Evershed D.Maddy F.M.Chambers 《第四纪研究》 CAS CSCD 北大核心 2003年第5期521-528,共8页
在各种地质体中广泛分布的生物标志化合物在全球变化研究中有着广泛应用 ,特别是在海洋和湖泊沉积物中 ,研究工作已涉及到古植被、古温度、古降水量、古大气CO2 浓度和古季风等的恢复。文章介绍利用气相色谱仪、气相色谱 -质谱联用仪、... 在各种地质体中广泛分布的生物标志化合物在全球变化研究中有着广泛应用 ,特别是在海洋和湖泊沉积物中 ,研究工作已涉及到古植被、古温度、古降水量、古大气CO2 浓度和古季风等的恢复。文章介绍利用气相色谱仪、气相色谱 -质谱联用仪、气相色谱 -热转换 -同位素比质谱仪分析了一个长 40cm泥炭岩芯 (约 2 2 2年 )的生物标志化合物的分布及其单体氢同位素。结果显示 ,不管是生物标志化合物的分布 ,还是其单体稳定同位素特征都记载了气候 (温度 )的变化。正构脂肪酸的碳优势指数 (CPI值 )、正构烷烃C2 3/C31 比值、正构烷烃C2 展开更多
关键词 生物标志化合物 分子化石 化学化石 有机质演化 单体稳定同位素
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戒烟与复吸影响因素及戒烟者健康状况分析 被引量:35
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作者 钱军程 饶克勤 +3 位作者 高军 Julia Critchley 汤胜蓝 蔡敏 《中国卫生统计》 CSCD 北大核心 2009年第2期150-153,共4页
目的揭示戒烟水平、戒烟与复吸原因、成功戒烟的影响因素及与其健康状况的关系,为在中国提出更有针对性的控烟对策提供参考。方法利用两次具有全国代表性的中国国家卫生服务调查数据,采用分组分析、logistic回归分析、年龄标准化等方法... 目的揭示戒烟水平、戒烟与复吸原因、成功戒烟的影响因素及与其健康状况的关系,为在中国提出更有针对性的控烟对策提供参考。方法利用两次具有全国代表性的中国国家卫生服务调查数据,采用分组分析、logistic回归分析、年龄标准化等方法分析戒烟相关指标和影响因素。结果2003年只有6.1%的戒烟率,7.9%的正在吸烟者有戒烟意愿,老年吸烟者、城市地区、高收入者、患有慢性病者或自感健康较差者比较容易戒烟成功,而户中有多名吸烟者、经常饮酒者不易戒烟成功;戒烟者本身健康状况已较差;54%的复吸者报告是因为"控制不住烟瘾",约29%的人是因为社交或社会环境影响而复吸。结论中国吸烟者的戒烟水平和意愿均较低、因病而戒烟表明戒烟太晚太被动;除现有控烟政策外,更有针对性的控烟活动如对年轻吸烟者、农村地区吸烟者、多吸烟者住户和促进未病先戒等活动也是迫切需要的。 展开更多
关键词 戒烟 吸烟 健康状况
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不同土壤对钾的选择吸附特性 被引量:6
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作者 胡全才 卢朝东 J.K.Syers 《土壤学报》 CAS CSCD 北大核心 2002年第5期707-713,共7页
用K Ca交换平衡法对砖红壤、红壤、土、黑土和水稻土K的选择吸附特性研究结果表明 :KG 和KV 系数随着K Ca平衡体系中吸附相中钾与钙比率的变化而改变 ,其曲线特征说明土壤胶体存在着对K亲和力不同的吸附点位。在低钾饱和度时 ,土壤对... 用K Ca交换平衡法对砖红壤、红壤、土、黑土和水稻土K的选择吸附特性研究结果表明 :KG 和KV 系数随着K Ca平衡体系中吸附相中钾与钙比率的变化而改变 ,其曲线特征说明土壤胶体存在着对K亲和力不同的吸附点位。在低钾饱和度时 ,土壤对K的高选择吸附主要归于粘粒矿物楔形区域电荷点位吸附 ,五种土壤楔形区域相对吸附点位顺序为 :黑土 >土 >水稻土 >红壤 >砖红壤 ,该相对吸附点位顺序与土壤含有风化云母和蛭石有关。在高钾饱和度时 ,五种土壤对K的吸附主要发生于粘粒矿物的晶层表面电荷点位 ,粘粒矿物的晶层表面电荷起源也许起决定作用 ,此时KG 选择系数的大小顺序为 :砖红壤 >红壤 >黑土 >土 > 展开更多
关键词 土壤 选择吸附特性 K-Ca交换平衡 Gapon系数 Vanselow系数 阳离子交换
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巴克豪森应力检测中激励方式的影响 被引量:4
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作者 丁松 田贵云 +4 位作者 王平 王海涛 闫小明 朱秋君 姬小丽 《无损检测》 2011年第10期19-23,共5页
巴克豪森效应是电磁方式检测材料微观结构和应力的基础。通过试验方法分析不同激励频率、激励电压和激励波形下巴克豪森噪声信号的时域、频域特征,研究激励信号参数对材料应力检测的巴克豪森信号特征值的影响,并探究现象的微观解释。
关键词 巴克豪森噪声 应力检测 激励参数
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Thermodynamic Foundation for High Temperature Electrochemistry
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作者 ZHANG W. E. A. Charles J. Congleton 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第4期494-500,共7页
Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potent... Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ(Ag|O_2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested. 展开更多
关键词 High temperature potential Half cell potential External Ag/AgCl reference electrode Standard chemical potential of an electron High temperature pH sensor.
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SiC WHISKER-TOUGHENED ALUMINIUM NITRIDE CERAMICS
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作者 李凝芳 D.P.Thompson M.C.Witt 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1993年第1期1-12,共12页
Aluminium nitride ceramics containing 15 -30 w/o of SiC whiskers can be sintered to full density (by hot pressing at 1800℃)using 2-3 w/o of Y2O3 additions. The whiskers increase the toughness and strength of the comp... Aluminium nitride ceramics containing 15 -30 w/o of SiC whiskers can be sintered to full density (by hot pressing at 1800℃)using 2-3 w/o of Y2O3 additions. The whiskers increase the toughness and strength of the composite, KIC increasing from 2. & to about 5.0 and flexural strength increasing by 30-50%. However, the whiskers must be well dispersed and if the dispersion is not satisfactory, toughness may increase but the strength decreases. The hot-pressing temperature can be reduced by up to 100℃ if Y(NO3)3 . 5H2O is used as the sintering additive instead of Y2O3, but some oxidation of the AIN occurs during heating. Isopropan-2-01 is a better dispersing agent than cyclohexane, but again some oxidation of the AIN does occur.The best sample prepared during this work contained 20 w/o of SiC whiskers and 2 w/o Y2O3 added as Y(NO3)3. 5H2O and mixed in isopropanol. This exhibited a mean strength of 453MPa (maximum 522MPa, measured by disc flexure) and a fracture toughness of5. 5MPam1/2. 展开更多
关键词 WHISKER aluminium nitride toughen ADDITIVE dispersing agents
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Statistical Approach to Identify Environmental Factors in Controlling Heavy Metal Concentrations in Sediment
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作者 Hassan Alshemmari Eqbal Al-Enezi +1 位作者 Lulwa Ali Ali. AI-Dousari 《Journal of Environmental Science and Engineering(A)》 2012年第8期1025-1035,共11页
Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Co, Cr, Cu, Ni, Pb and Zn concentrations were determined. Grain sizes, TOC (total organic carbon), carbonate, mineralogical and e... Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Co, Cr, Cu, Ni, Pb and Zn concentrations were determined. Grain sizes, TOC (total organic carbon), carbonate, mineralogical and environmental data were also determined. Multiple linear regression is applied to the data from the sediment sequential extractions to assess the relative importance of mineralogical and sedimentological factors in controlling heavy metal concentrations in individual chemical fractions (exchangeable, reducible, oxidizable, residual) under different environmental conditions. The analysis shows that grain size, TOC, calcium carbonate and minerals clearly influence heavy metal concentrations. For the exchangeable fraction, clay, grain size and the mineral pyrite are the main factors, whereas for the reducible fraction, TOC is the main factor influencing concentrations ofZn, Pb, Ni, Cu and Cr. For the oxidizable fraction, modelling shows that TOC is the main factor influencing Zn, Ni, Cu, Cr and Co concentrations. The residual fraction concentrations of Zn, Ni, Cr and Co were best predicted by the abundance of sand, with sand content having a negative effect on heavy metal concentrations in this fraction. The statistical techniques in environmental data interpretation are quite useful in cutting down the volume of the data and identifying identical classes which are statistically distinct. 展开更多
关键词 Metals SEDIMENTS MINERALOGICAL CLAY sequential extraction sedimentological.
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A Wavelet Transform Method to Detect P and S-Phases in Three Component Seismic Data
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作者 Salam Al-Hashmi Adrian Rawlins Frank Vernon 《Open Journal of Earthquake Research》 2013年第1期1-20,共20页
The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavele... The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavelet transform coefficients of the raw seismic data. The algorithm detects phases, determines arrival times and indicates the seismic event direction from three component seismic data that represents the ground displacement in three orthogonal directions. The essential concept is that strong features of the seismic signal are present in the wavelet coefficients across several scales of time and direction. The P-phase is detected by generating a function using polarization information while S-phase is detected by generating a function based on the transverse to radial amplitude ratio. These functions are shown to be very effective metrics in detecting P and S-phases and for determining their arrival times for low signal-to-noise arrivals. Results are compared with arrival times obtained by a human analyst as well as with a standard STA/LTA algorithm from local and regional earthquakes and found to be consistent. 展开更多
关键词 Discrete Time WAVELET Transform P and S-phases Automatic Detection Rectilinearity Function
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