Despite its unique high efficiency and good environmental compatibility, the water-soluble binder system still encounters problems achieving a desired sintered part via ceramic injection molding because of the poor co...Despite its unique high efficiency and good environmental compatibility, the water-soluble binder system still encounters problems achieving a desired sintered part via ceramic injection molding because of the poor compatibility and the powder-binder segregation between ceramic powders and binders. The objective of this study was to obtain a sintered part with excellent properties by introducing a small quantity of oleic acid to the surface of zirconia powders before the mixing process. As opposed to many previous investigations that focused only on the rheological behavior and modification mechanism, the sintering behavior and densification process were systematically investigated in this study. With the modified powders, debound parts with a more homogeneous and smaller pore size distribution were fabricated. Also, a higher density and greater flexural strength were achieved in the sintered parts fabricated using the modified powders.展开更多
In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a se...In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a second conductive phase. All ceramic samples were pre-pared by spark plasma sintering （SPS） under a pressure of 30 MPa. AlN composite ceramics sintered with 30wt%-40wt%SiC at 1600℃ for 5 min exhibited the best dielectric loss tangent, which is greater than 0.3. In addition to AlN and β-SiC, the samples also contained 2H-SiC and Fe5Si3, as detected by X-ray difraction （XRD）. The relative densities of the sintered ceramics were higher than 93%. Experimental results indicate that nano-SiC has a strong capability of absorbing electromagnetic waves. The dielectric constant and dielectric loss of AlN-SiC ce-ramics with the same content of SiC decreased as the frequency of electromagnetic waves increased from 1 kHz to 1 MHz.展开更多
Wood-based panels containing urea-formaldehyde resin result in the long-term release of formaldehyde and threaten human health.In this study,inorganic aluminosilicate coatings prepared by combining metakaolin,silica f...Wood-based panels containing urea-formaldehyde resin result in the long-term release of formaldehyde and threaten human health.In this study,inorganic aluminosilicate coatings prepared by combining metakaolin,silica fume,NaOH,and H_(2)O were applied to the surfaces of wood-based panels to obstruct formaldehyde release.The Si/Al,Na/Al,and H_(2)O/Na_(2)O molar ratios of the coatings were regulated to investigate their effects on the structure and formaldehyde-resistant barrier properties of coatings.Results showed that the cracks in the coatings gradually disappeared and the formaldehyde resistance rates of the barrier increased as the Si/Al molar ratio was increased from 1.6 to 2.2.This value also increased as the Na/Al molar ratio was increased from 0.9 to 1.2 because of the improvement of the degree of polymerization.As the H_(2)O/Na_(2)O molar ratio was increased from 12 to 15,the thickness of the dry film decreased gradually and led to the reduction in the formaldehyde resistance rate.When the Si/Al,Na/Al,and H_(2)O/Na_(2)O molar ratios were 2.2,1.2,and 12,respectively,the inorganic aluminosilicate coating showed good performance as a formaldehyde-resistant barrier and its formaldehyde resistance rate could reach up to 83.2%.展开更多
Objective:To detect the expression levels of Forkhead box M1 (FoxM1) and Adisintegrin and metalloproteinase (ADAM17) proteins in colon cancer tissues and to analyze their relationship with clinical pathology of colon ...Objective:To detect the expression levels of Forkhead box M1 (FoxM1) and Adisintegrin and metalloproteinase (ADAM17) proteins in colon cancer tissues and to analyze their relationship with clinical pathology of colon cancer.And to explore its clinical significance. Methods: From June 2016 to December 2017, 68 cases of colon cancer specimens and normal tissues adjacent to the colon cancer were obtained from the Department of General Surgery, North China University of Technology, and the pathologically confirmed colon cancer specimens were examined by immunohistochemistry. The positive expression rates of FoxM1 and ADAM17 proteins in the two groups were detected by immunohistochemistry, and the relationship between them and the clinicopathological features of colon cancer and their correlation were analyzed.Results: Compared with normal colon tissue, the positive rates of FoxM1 and ADAM17 protein expression in colon cancer tissues were significantly increased (P<0.05). The positive expression rate of FoxM1 and ADAM17 protein was correlated with tumor diameter, lymphatic metastasis and clinical stage (P<0.05), and had no correlation with age, gender, tumor differentiation degree and tumor invasion depth (P>0.05). The results of rank correlation analysis showed that there was a positive correlation between the expression of FoxM1 and ADAM17 protein in colon cancer tissues (rs=0.520,P<0.05).Conclusion: The positive expression rate of FoxM1 and ADAM17 protein in colon cancer tissues was higher than that in normal colon tissues. The positive expression of FoxM1 and ADAM17 was related to colon cancer diameter, lymphatic metastasis and clinical stage, suggesting that it may be related to poor prognosis of colon cancer.展开更多
In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investi...In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investigated.All the ceramic samples were prepared by spark plasma sintering(SPS).AlN composite ceramics with additional 10 vol%Mo sintered at 1400℃holding for 5 min exhibit the best dielectric loss tangent,which is greater than 0.23.AlN/Mo ceramics with additional 20 vol%Mo become conductive,with the resistivity of 0.05–0.06Ω·m.High-energy ball milling is better than magnetic stirring powder mixing method.In addition,the additive Mo and lower sintering temperature lead to a better property with the increase in the electromagnetic wave frequency range of 1×10^(3)–1×10^(6)Hz.展开更多
In this paper, V2O5 sol was firstly prepared using vanadyl sulfate as a vanadium source by modified sol-gel method at room temperature. Then flower-like V2O5 powders were prepared by coagulating as-prepared sol with a...In this paper, V2O5 sol was firstly prepared using vanadyl sulfate as a vanadium source by modified sol-gel method at room temperature. Then flower-like V2O5 powders were prepared by coagulating as-prepared sol with anhydrous ethanol and subsequent annealing crystallization. The X-ray diffraction analysis indicated that V2O5 powders exhibited orthorhombic crystal structure after annealing at 450 ℃. The experimental data obtained from both field emission scanning electron microscopy and high-resolution transmission electron microscopy identified that V2O5 powders were approximately flower-like in shape and about 5 μm in size. Besides, the Brunauer-Emmett-Teller specific surface area of flowerlike V2O5 powders was 24.25 m^2/g. According to Uv-Vis spectroscopy, the degradation rate of toluidine blue O（TBO） on as-prepared flower-like V2O5 powders during 10 h of visible light irradiation with an intensity of 15.4 mW/m^2 was 88%,which was faster than those over P25（46%） as a comparison. In addition, the mineralization process of TBO was investigated, which primarily consisted of demethylation and ring-opening oxidation processes, and confirmed by liquid chromatograph-mass spectrometry. The precipitation-oxidation-peptization, coagulation, and crystallization processes were proposed as the formation mechanism for the preparation of flower-like V2O5.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51572035 and 51502041)
文摘Despite its unique high efficiency and good environmental compatibility, the water-soluble binder system still encounters problems achieving a desired sintered part via ceramic injection molding because of the poor compatibility and the powder-binder segregation between ceramic powders and binders. The objective of this study was to obtain a sintered part with excellent properties by introducing a small quantity of oleic acid to the surface of zirconia powders before the mixing process. As opposed to many previous investigations that focused only on the rheological behavior and modification mechanism, the sintering behavior and densification process were systematically investigated in this study. With the modified powders, debound parts with a more homogeneous and smaller pore size distribution were fabricated. Also, a higher density and greater flexural strength were achieved in the sintered parts fabricated using the modified powders.
基金financially supported by the International S&T Cooperation Program of China(No.2010DFR50360)
文摘In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a second conductive phase. All ceramic samples were pre-pared by spark plasma sintering （SPS） under a pressure of 30 MPa. AlN composite ceramics sintered with 30wt%-40wt%SiC at 1600℃ for 5 min exhibited the best dielectric loss tangent, which is greater than 0.3. In addition to AlN and β-SiC, the samples also contained 2H-SiC and Fe5Si3, as detected by X-ray difraction （XRD）. The relative densities of the sintered ceramics were higher than 93%. Experimental results indicate that nano-SiC has a strong capability of absorbing electromagnetic waves. The dielectric constant and dielectric loss of AlN-SiC ce-ramics with the same content of SiC decreased as the frequency of electromagnetic waves increased from 1 kHz to 1 MHz.
基金financially supported by the National Key Research and Development Program of China(Nos.2016 YFC0700607,2017YFB0304305,and 2016YFC0700901)the Fundamental Research Funds for the Central Universities of China(No.FRF-TP-20-006A3).
文摘Wood-based panels containing urea-formaldehyde resin result in the long-term release of formaldehyde and threaten human health.In this study,inorganic aluminosilicate coatings prepared by combining metakaolin,silica fume,NaOH,and H_(2)O were applied to the surfaces of wood-based panels to obstruct formaldehyde release.The Si/Al,Na/Al,and H_(2)O/Na_(2)O molar ratios of the coatings were regulated to investigate their effects on the structure and formaldehyde-resistant barrier properties of coatings.Results showed that the cracks in the coatings gradually disappeared and the formaldehyde resistance rates of the barrier increased as the Si/Al molar ratio was increased from 1.6 to 2.2.This value also increased as the Na/Al molar ratio was increased from 0.9 to 1.2 because of the improvement of the degree of polymerization.As the H_(2)O/Na_(2)O molar ratio was increased from 12 to 15,the thickness of the dry film decreased gradually and led to the reduction in the formaldehyde resistance rate.When the Si/Al,Na/Al,and H_(2)O/Na_(2)O molar ratios were 2.2,1.2,and 12,respectively,the inorganic aluminosilicate coating showed good performance as a formaldehyde-resistant barrier and its formaldehyde resistance rate could reach up to 83.2%.
文摘Objective:To detect the expression levels of Forkhead box M1 (FoxM1) and Adisintegrin and metalloproteinase (ADAM17) proteins in colon cancer tissues and to analyze their relationship with clinical pathology of colon cancer.And to explore its clinical significance. Methods: From June 2016 to December 2017, 68 cases of colon cancer specimens and normal tissues adjacent to the colon cancer were obtained from the Department of General Surgery, North China University of Technology, and the pathologically confirmed colon cancer specimens were examined by immunohistochemistry. The positive expression rates of FoxM1 and ADAM17 proteins in the two groups were detected by immunohistochemistry, and the relationship between them and the clinicopathological features of colon cancer and their correlation were analyzed.Results: Compared with normal colon tissue, the positive rates of FoxM1 and ADAM17 protein expression in colon cancer tissues were significantly increased (P<0.05). The positive expression rate of FoxM1 and ADAM17 protein was correlated with tumor diameter, lymphatic metastasis and clinical stage (P<0.05), and had no correlation with age, gender, tumor differentiation degree and tumor invasion depth (P>0.05). The results of rank correlation analysis showed that there was a positive correlation between the expression of FoxM1 and ADAM17 protein in colon cancer tissues (rs=0.520,P<0.05).Conclusion: The positive expression rate of FoxM1 and ADAM17 protein in colon cancer tissues was higher than that in normal colon tissues. The positive expression of FoxM1 and ADAM17 was related to colon cancer diameter, lymphatic metastasis and clinical stage, suggesting that it may be related to poor prognosis of colon cancer.
基金financially supported by the International Cooperation Project between China and Russia (No. 2010DFR50360)
文摘In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investigated.All the ceramic samples were prepared by spark plasma sintering(SPS).AlN composite ceramics with additional 10 vol%Mo sintered at 1400℃holding for 5 min exhibit the best dielectric loss tangent,which is greater than 0.23.AlN/Mo ceramics with additional 20 vol%Mo become conductive,with the resistivity of 0.05–0.06Ω·m.High-energy ball milling is better than magnetic stirring powder mixing method.In addition,the additive Mo and lower sintering temperature lead to a better property with the increase in the electromagnetic wave frequency range of 1×10^(3)–1×10^(6)Hz.
基金supported by the China National Key Research & Development Plan (Grant Nos.2016YFC0700901,2016YFC0700607) and project (BZZ14J001)
文摘In this paper, V2O5 sol was firstly prepared using vanadyl sulfate as a vanadium source by modified sol-gel method at room temperature. Then flower-like V2O5 powders were prepared by coagulating as-prepared sol with anhydrous ethanol and subsequent annealing crystallization. The X-ray diffraction analysis indicated that V2O5 powders exhibited orthorhombic crystal structure after annealing at 450 ℃. The experimental data obtained from both field emission scanning electron microscopy and high-resolution transmission electron microscopy identified that V2O5 powders were approximately flower-like in shape and about 5 μm in size. Besides, the Brunauer-Emmett-Teller specific surface area of flowerlike V2O5 powders was 24.25 m^2/g. According to Uv-Vis spectroscopy, the degradation rate of toluidine blue O（TBO） on as-prepared flower-like V2O5 powders during 10 h of visible light irradiation with an intensity of 15.4 mW/m^2 was 88%,which was faster than those over P25（46%） as a comparison. In addition, the mineralization process of TBO was investigated, which primarily consisted of demethylation and ring-opening oxidation processes, and confirmed by liquid chromatograph-mass spectrometry. The precipitation-oxidation-peptization, coagulation, and crystallization processes were proposed as the formation mechanism for the preparation of flower-like V2O5.
