Bitmap （BMP） is a widely used format in image processing. With the combination of the digital image processing and computer numerically controlled （NC） techniques, we developed a bitmap-based NC single-step and mu...Bitmap （BMP） is a widely used format in image processing. With the combination of the digital image processing and computer numerically controlled （NC） techniques, we developed a bitmap-based NC single-step and multi-dot method. An example was provided to illustrate the application and principle of this bitmap-based method in our newly innovated sandblasting glass NC sculpture system.展开更多
Objective To identify serum diagnosis or progression biomarkers in patients with lung cancer using protein chip profiling analysis. Method Profiling analysis was performed on 450 sera collected from 213 patients with ...Objective To identify serum diagnosis or progression biomarkers in patients with lung cancer using protein chip profiling analysis. Method Profiling analysis was performed on 450 sera collected from 213 patients with lung cancer, 19 with pneumonia, 16 with pulmonary tuberculosis, 65 with laryngeal carcinoma, 55 with laryngopharyngeal carcinoma patients, and 82 normal individuals. A new strategy was developed to identify the biomarkers on chip by trypsin pre-digestion. Results Profiling analysis demonstrated that an 11.6kDa protein was significandy elevated in lung cancer patients, compared with the control groups （P〈0.001）. The level and percentage of 11.6kDa protein progressively increased with the clinical stages Ⅰ-Ⅳ and were also higher in patients with squamous cell carcinoma than in other subtypes. This biomarker could be decreased after operation or chemotherapy. On the other hand, 11.6kDa protein was also increased in 50% benign diseases of lung and 13% of other cancer controls. After trypsin pre-digestion, a set of new peptide biomarkers was noticed to appear only in the samples containing a 11.6kDa peak. Further identification showed that 2177Da was a fragment of serum amyloid A （SAA, MW 11.6kDa）. Two of the new peaks, 1550Da and 1611Da, were defined from the same protein by database searching. This result was further confirmed by partial purification of 11.6kDa protein and MS analysis. Conclusion SAA is a useful biomarker to monitor the progression of lung cancer and can directly identify some biomarkers on chip.展开更多
Recent studies revealed that in eutectic to slightly hypereutectic grey irons （CE = 4.3%-4.5%） the presence of austenite dendrites provides an opportunity to improve the cast iron properties, as a high number of eut...Recent studies revealed that in eutectic to slightly hypereutectic grey irons （CE = 4.3%-4.5%） the presence of austenite dendrites provides an opportunity to improve the cast iron properties, as a high number of eutectic cells are ＂reinforced＂ by austenite dendrites. An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons, but was accompanied by adverse effect on the characteristics of potential nuclei for graphite. The purpose of the present paper is to investigate the solidification pattern of these irons. Chill wedges with different cooling moduli （CM = 0.11 - 0.43 cm） were poured in resin bonded sand and metal moulds. Relative clear / mottled / total chill measurement criteria were applied. Iron powder additions led to a higher chill tendency, while single inoculation showed the strongest graphiUzing effect. The various double treatments show an intermediate position, but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency, for all cooling moduli and chill evaluation parameters. This performance reflects the improved properties of （Mn,X）S polygonal compounds as nucleation sites for graphite, especially in resin bonded sand mould castings. Both austenite and graphite nucleation benefit from a double addition of iron powder ＋ inoculant, with positive effect on the final structure and chill tendency.展开更多
The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,m...The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,multi-wall carbon nanotube (Zn O-MWCNT) and core-shell rubber (CSR) was prepared,which possesses both high modulus and fracture toughness while maintaining relatively high glass transition temperature (Tg).The improved fracture toughness from 0.82 MPa mfor neat epoxy to 1.46 MPa mfor the ternary epoxy nanocomposites is resulted from a series of synergistic toughening mechanisms,including cavitation of CSR-induced matrix shear banding,along with the fracture of MWCNTs and crack deflection.The implication of the present study for the preparation of high-performance polymer nanocomposites is discussed.展开更多
Objective. To evaluate how the independent predictors of recurrence f or stage IB2 cervical cancers treated with up-front radical hysterectomy apply to establ ished risk models. Methods. Patients with IB2 cervical can...Objective. To evaluate how the independent predictors of recurrence f or stage IB2 cervical cancers treated with up-front radical hysterectomy apply to establ ished risk models. Methods. Patients with IB2 cervical cancers diagnosed from 19 90 to 2000 were identified from tumor registries of two institutions. Patients w ere classified into risk groups: high-risk (HR) (positive nodes, parametria, or margins), intermediate-risk (IR) (positive lymph vascular space involvement (L VSI) with any cervical stromal invasion (CSI), or (-) LVSI and > middle-CSI), or low-risk (LR) (absence of HR or IR characteristics). Disease free survival ( DFS) was estimated by Kaplan-Meier method and comparisons between subgroups wer e studied by log rank. A Cox proportional hazards model was used to determine in dependent predictors of recurrence. Results. We identified 86 patientswith stage IB2 tumors treated by RH.We found 34%of patients to be HR, 60%IR, and 6%LR. Of the 52 IR patients, 28 had (+) LVSI with superficial, middle, and outer 1/3 CSI, and 24 had (-) LVSI with middle or outer 1/3 invasion. Overall, postoperat ive adjuvant radiation (PRT) was used in 52%of the 86 patients, including 0/5 L R, 16/52 IR, and 29/29 HR patients. Univariate predictors of recurrence were pel vic nodal disease, (+) LVSI, (+) parametria, outer 1/3 CSI, and tumor size > 6 cm. Age, grade, histology, and the use of postoperative radiation were not asso ciated with recurrence. Multivariate analysis identified LVSI as the only indepe ndent predictor of recurrence (RR 5.2, P = 0.03). Two-year DFS for LR, IR, and HR patients was 100%, 83%, and 60%, respectively. Only 4/24 (17%) IR patient s with (-) LVSI got PRT compared with 12/28 (43%) of IR patients with (+) LVSI. The 2-year DFS for IR patients with (-) LVSI was 96%. IR (+) pa tients recurred more frequently with a 2-year DFS of 71%. Conclusions. Overall , 66%of patients with IB2 disease were classified as having low or intermediate -risk disease. IR patients with (-) LVSI and all LR patients did well with sur gery alone. This study defines the independent importance of LVSI and questions the utility of published IR models when applied to stage IB2 cervical cancer.展开更多
An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configur...An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configuration enabled one to control ion energy separately from plasma density. Plasma properties were measured with a Langmuir probe. Electron temperature, plasma potential and plasma density were found to be comparable with those reported from Electron Cyclotron Resonance (ECR) and other types of reactors[1].A mixture of HBr and chlorine gases were used for this aluminum etch study. Experimental matrices were designed with Response Surface Methodology (RSM) to analyze the process trends versus etch parameters, such as source power, bias power and gas composition. An etch rate of 8500A to 9000A per minute was obtained at 5 to 15 mTorr pressure ranges. Anisotropic profiles with high photoresist selectivity (5 to 1) and silicon dioxide selectivity greater than 10 were achieved with HBr addition into chlorine plasma.Bromine-containing chemistry for an aluminum etch in a low pressure ICP discharge showed great potential for use in ULSI fabrication. In addition, the hardware used was very simple and the chamber size was much smaller than other high density plasma sources.展开更多
For the first part of this paper, several nitrogen(N2) purge experiments have been performed on a200-mm SMIF Pod full of bare silicon wafers. Vari-ous N2 inlet flow rates are used to understand thechanges in oxygen (O...For the first part of this paper, several nitrogen(N2) purge experiments have been performed on a200-mm SMIF Pod full of bare silicon wafers. Vari-ous N2 inlet flow rates are used to understand thechanges in oxygen (O2) and moisture (H2O) concen-trations with time. As expected, it is found that asthe N2 flow rate increases, the O2 and moisture con-centrations inside the Pod decrease. Initially, thereduction in O2 and moisture concentrations is veryrapid (convection dominated), and slows down atlower concentrations and becomes diffusiondominated. The leak back rate of O2 and moistureinto the Pod was also analyzed by measuring O2 andmoisture concentrations without N2 flow into thepod, and with a trickle charge (very slow flow) ofN2. It was noticed that the leak back rates of O2 andmoisture is fast during the initial stages of retention,and slows down when the O2 and moisture concen-trations reach higher levels. With trickle charge ofN2, it is found that the O2 and moisture concentra-tions inside the Pod can be maintained at very lowlevels for a long time.In the second part of the paper, the effects ofN2 purge on limiting the growth of native oxides areexplored. The particular application of extending theallowable HF Poly deglaze to Tungsten Silicide depo-sition queue time is analyzed. Extension of the al-lowable queue time provides two benefits. First,utilization of upstream wafer HF cleaning equipmentis improved due to reduced dependence on an idledownstream deposition chamber. Second, HF re-cleaning is eliminated. Increased exposure duringHF re-cleaning results in residues at the Polysiliconto Tungsten Silicide interface which later causeblocked etch (reduced yield). It is concluded thatas a result of the N2 purge, the queue time betweenHF deglaze and DCS deposition can be increasedwithout any negative impact resulting from nativeoxide growth.展开更多
为了满足不同的技术和经济目标,从轻度混合动力、插电式混合动力到全电池动力的电动汽车,都将依赖于新型的、先进的(如基于锂的)蓄电池。这些电池在各种应用条件下的性能预测和寿命表征费工、费时,目前尚未得到充分的发展。一些国家已...为了满足不同的技术和经济目标,从轻度混合动力、插电式混合动力到全电池动力的电动汽车,都将依赖于新型的、先进的(如基于锂的)蓄电池。这些电池在各种应用条件下的性能预测和寿命表征费工、费时,目前尚未得到充分的发展。一些国家已投入资金和人力进行相关的研究,其实通过国际合作,这些努力和花费也许能发挥更大的作用,例如目前正在国际能源机构(The International Energy Agency,IEA)框架内开展的准备工作。正在致力于开发一套标准化的、加速的测试程序,将允许各个测试机构合作分析电池的测量数据。该文评述了欧洲、日本和美国在加速寿命测试程序上的最新进展。以国际合作为目标,搜集、对比和分析现有的测试程序。展开更多
In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arre...In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.展开更多
Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the w...Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the water column. Extensive water management commenced in the San Francisco Bay, Beginning around 1850, San Francisco Bay wetlands were converted to salt ponds and mined extensively for more than a century. Long-term (decadal) salt pond restoration efforts began in 2003. A patented device for sampling porewater at varying depths, to calculate the gradient, was employed between 2010 and 2012. Within the former ponds, the benthic flux of soluble reactive phosphorus and that of dissolved ammonia were consistently positive (i.e., moving out of the sediment into the water column). The lack of measurable nitrate or nitrite concentration gradients across the sediment-water interface suggested negligible fluxes for dissolved nitrate and nitrite. The dominance of ammonia in the porewater indicated anoxic sediment conditions, even at only 1 cm depth, which is consistent with the observed, elevated sediment oxygen demand. Nearby open-estuary sediments showed much lower benthic flux values for nutrients than the salt ponds under resortation. Allochthonous solute transport provides a nutrient advective flux for comparison to benthic flux. For ammonia, averaged for all sites and dates, benthic flux was about 80,000 kg/year, well above the advective flux range of -50 to 1500 kg/year, with much of the variability depending on the tidal cycle. By contrast, the average benthic flux of soluble reactive phosphorus was about 12,000 kg/year, of significant magnitude, but less than the advective flux range of 21,500 to 30,000 kg/year. These benthic flux estimates, based on solute diffusion across the sediment-water interface, reveal a significant nutrient source to the water column of the pond which stimulates algal blooms (often autotrophic). This benthic source may be augmented further by bioturbation, bioirrigation and episodic sediment resuspension events.展开更多
基金the Scientific and Technological Research Project of Ningxia Autonomous Region(Grant No.2002-014-05)
文摘Bitmap （BMP） is a widely used format in image processing. With the combination of the digital image processing and computer numerically controlled （NC） techniques, we developed a bitmap-based NC single-step and multi-dot method. An example was provided to illustrate the application and principle of this bitmap-based method in our newly innovated sandblasting glass NC sculpture system.
基金This work was supported by the National Natural Science Foundation of China (Grant No.30370712)Beijing Key Project (Grant No. 7051002)+1 种基金 Beijing Science Technology Committee Project (No.Y0204002040111)a grant of Majon State Basic Research Program of China (No. 2006CB 910100).
文摘Objective To identify serum diagnosis or progression biomarkers in patients with lung cancer using protein chip profiling analysis. Method Profiling analysis was performed on 450 sera collected from 213 patients with lung cancer, 19 with pneumonia, 16 with pulmonary tuberculosis, 65 with laryngeal carcinoma, 55 with laryngopharyngeal carcinoma patients, and 82 normal individuals. A new strategy was developed to identify the biomarkers on chip by trypsin pre-digestion. Results Profiling analysis demonstrated that an 11.6kDa protein was significandy elevated in lung cancer patients, compared with the control groups （P〈0.001）. The level and percentage of 11.6kDa protein progressively increased with the clinical stages Ⅰ-Ⅳ and were also higher in patients with squamous cell carcinoma than in other subtypes. This biomarker could be decreased after operation or chemotherapy. On the other hand, 11.6kDa protein was also increased in 50% benign diseases of lung and 13% of other cancer controls. After trypsin pre-digestion, a set of new peptide biomarkers was noticed to appear only in the samples containing a 11.6kDa peak. Further identification showed that 2177Da was a fragment of serum amyloid A （SAA, MW 11.6kDa）. Two of the new peaks, 1550Da and 1611Da, were defined from the same protein by database searching. This result was further confirmed by partial purification of 11.6kDa protein and MS analysis. Conclusion SAA is a useful biomarker to monitor the progression of lung cancer and can directly identify some biomarkers on chip.
文摘Recent studies revealed that in eutectic to slightly hypereutectic grey irons （CE = 4.3%-4.5%） the presence of austenite dendrites provides an opportunity to improve the cast iron properties, as a high number of eutectic cells are ＂reinforced＂ by austenite dendrites. An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons, but was accompanied by adverse effect on the characteristics of potential nuclei for graphite. The purpose of the present paper is to investigate the solidification pattern of these irons. Chill wedges with different cooling moduli （CM = 0.11 - 0.43 cm） were poured in resin bonded sand and metal moulds. Relative clear / mottled / total chill measurement criteria were applied. Iron powder additions led to a higher chill tendency, while single inoculation showed the strongest graphiUzing effect. The various double treatments show an intermediate position, but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency, for all cooling moduli and chill evaluation parameters. This performance reflects the improved properties of （Mn,X）S polygonal compounds as nucleation sites for graphite, especially in resin bonded sand mould castings. Both austenite and graphite nucleation benefit from a double addition of iron powder ＋ inoculant, with positive effect on the final structure and chill tendency.
基金the KANEKA Corporation for their financial support。
文摘The dispersion of nanoparticles plays a key role in enhancing the mechanical performance of polymer nanocomposites.In this work,one hybrid epoxy nanocomposite reinforced by a well dispersed,zinc oxide functionalized,multi-wall carbon nanotube (Zn O-MWCNT) and core-shell rubber (CSR) was prepared,which possesses both high modulus and fracture toughness while maintaining relatively high glass transition temperature (Tg).The improved fracture toughness from 0.82 MPa mfor neat epoxy to 1.46 MPa mfor the ternary epoxy nanocomposites is resulted from a series of synergistic toughening mechanisms,including cavitation of CSR-induced matrix shear banding,along with the fracture of MWCNTs and crack deflection.The implication of the present study for the preparation of high-performance polymer nanocomposites is discussed.
文摘Objective. To evaluate how the independent predictors of recurrence f or stage IB2 cervical cancers treated with up-front radical hysterectomy apply to establ ished risk models. Methods. Patients with IB2 cervical cancers diagnosed from 19 90 to 2000 were identified from tumor registries of two institutions. Patients w ere classified into risk groups: high-risk (HR) (positive nodes, parametria, or margins), intermediate-risk (IR) (positive lymph vascular space involvement (L VSI) with any cervical stromal invasion (CSI), or (-) LVSI and > middle-CSI), or low-risk (LR) (absence of HR or IR characteristics). Disease free survival ( DFS) was estimated by Kaplan-Meier method and comparisons between subgroups wer e studied by log rank. A Cox proportional hazards model was used to determine in dependent predictors of recurrence. Results. We identified 86 patientswith stage IB2 tumors treated by RH.We found 34%of patients to be HR, 60%IR, and 6%LR. Of the 52 IR patients, 28 had (+) LVSI with superficial, middle, and outer 1/3 CSI, and 24 had (-) LVSI with middle or outer 1/3 invasion. Overall, postoperat ive adjuvant radiation (PRT) was used in 52%of the 86 patients, including 0/5 L R, 16/52 IR, and 29/29 HR patients. Univariate predictors of recurrence were pel vic nodal disease, (+) LVSI, (+) parametria, outer 1/3 CSI, and tumor size > 6 cm. Age, grade, histology, and the use of postoperative radiation were not asso ciated with recurrence. Multivariate analysis identified LVSI as the only indepe ndent predictor of recurrence (RR 5.2, P = 0.03). Two-year DFS for LR, IR, and HR patients was 100%, 83%, and 60%, respectively. Only 4/24 (17%) IR patient s with (-) LVSI got PRT compared with 12/28 (43%) of IR patients with (+) LVSI. The 2-year DFS for IR patients with (-) LVSI was 96%. IR (+) pa tients recurred more frequently with a 2-year DFS of 71%. Conclusions. Overall , 66%of patients with IB2 disease were classified as having low or intermediate -risk disease. IR patients with (-) LVSI and all LR patients did well with sur gery alone. This study defines the independent importance of LVSI and questions the utility of published IR models when applied to stage IB2 cervical cancer.
文摘An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configuration enabled one to control ion energy separately from plasma density. Plasma properties were measured with a Langmuir probe. Electron temperature, plasma potential and plasma density were found to be comparable with those reported from Electron Cyclotron Resonance (ECR) and other types of reactors[1].A mixture of HBr and chlorine gases were used for this aluminum etch study. Experimental matrices were designed with Response Surface Methodology (RSM) to analyze the process trends versus etch parameters, such as source power, bias power and gas composition. An etch rate of 8500A to 9000A per minute was obtained at 5 to 15 mTorr pressure ranges. Anisotropic profiles with high photoresist selectivity (5 to 1) and silicon dioxide selectivity greater than 10 were achieved with HBr addition into chlorine plasma.Bromine-containing chemistry for an aluminum etch in a low pressure ICP discharge showed great potential for use in ULSI fabrication. In addition, the hardware used was very simple and the chamber size was much smaller than other high density plasma sources.
文摘For the first part of this paper, several nitrogen(N2) purge experiments have been performed on a200-mm SMIF Pod full of bare silicon wafers. Vari-ous N2 inlet flow rates are used to understand thechanges in oxygen (O2) and moisture (H2O) concen-trations with time. As expected, it is found that asthe N2 flow rate increases, the O2 and moisture con-centrations inside the Pod decrease. Initially, thereduction in O2 and moisture concentrations is veryrapid (convection dominated), and slows down atlower concentrations and becomes diffusiondominated. The leak back rate of O2 and moistureinto the Pod was also analyzed by measuring O2 andmoisture concentrations without N2 flow into thepod, and with a trickle charge (very slow flow) ofN2. It was noticed that the leak back rates of O2 andmoisture is fast during the initial stages of retention,and slows down when the O2 and moisture concen-trations reach higher levels. With trickle charge ofN2, it is found that the O2 and moisture concentra-tions inside the Pod can be maintained at very lowlevels for a long time.In the second part of the paper, the effects ofN2 purge on limiting the growth of native oxides areexplored. The particular application of extending theallowable HF Poly deglaze to Tungsten Silicide depo-sition queue time is analyzed. Extension of the al-lowable queue time provides two benefits. First,utilization of upstream wafer HF cleaning equipmentis improved due to reduced dependence on an idledownstream deposition chamber. Second, HF re-cleaning is eliminated. Increased exposure duringHF re-cleaning results in residues at the Polysiliconto Tungsten Silicide interface which later causeblocked etch (reduced yield). It is concluded thatas a result of the N2 purge, the queue time betweenHF deglaze and DCS deposition can be increasedwithout any negative impact resulting from nativeoxide growth.
文摘为了满足不同的技术和经济目标,从轻度混合动力、插电式混合动力到全电池动力的电动汽车,都将依赖于新型的、先进的(如基于锂的)蓄电池。这些电池在各种应用条件下的性能预测和寿命表征费工、费时,目前尚未得到充分的发展。一些国家已投入资金和人力进行相关的研究,其实通过国际合作,这些努力和花费也许能发挥更大的作用,例如目前正在国际能源机构(The International Energy Agency,IEA)框架内开展的准备工作。正在致力于开发一套标准化的、加速的测试程序,将允许各个测试机构合作分析电池的测量数据。该文评述了欧洲、日本和美国在加速寿命测试程序上的最新进展。以国际合作为目标,搜集、对比和分析现有的测试程序。
文摘In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.
文摘Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the water column. Extensive water management commenced in the San Francisco Bay, Beginning around 1850, San Francisco Bay wetlands were converted to salt ponds and mined extensively for more than a century. Long-term (decadal) salt pond restoration efforts began in 2003. A patented device for sampling porewater at varying depths, to calculate the gradient, was employed between 2010 and 2012. Within the former ponds, the benthic flux of soluble reactive phosphorus and that of dissolved ammonia were consistently positive (i.e., moving out of the sediment into the water column). The lack of measurable nitrate or nitrite concentration gradients across the sediment-water interface suggested negligible fluxes for dissolved nitrate and nitrite. The dominance of ammonia in the porewater indicated anoxic sediment conditions, even at only 1 cm depth, which is consistent with the observed, elevated sediment oxygen demand. Nearby open-estuary sediments showed much lower benthic flux values for nutrients than the salt ponds under resortation. Allochthonous solute transport provides a nutrient advective flux for comparison to benthic flux. For ammonia, averaged for all sites and dates, benthic flux was about 80,000 kg/year, well above the advective flux range of -50 to 1500 kg/year, with much of the variability depending on the tidal cycle. By contrast, the average benthic flux of soluble reactive phosphorus was about 12,000 kg/year, of significant magnitude, but less than the advective flux range of 21,500 to 30,000 kg/year. These benthic flux estimates, based on solute diffusion across the sediment-water interface, reveal a significant nutrient source to the water column of the pond which stimulates algal blooms (often autotrophic). This benthic source may be augmented further by bioturbation, bioirrigation and episodic sediment resuspension events.
