Sixteen controlled low-strength material( CLSM)mixtures with various cement-to-sand( C/Sa) ratios and water-to-solid( W/So) ratios were prepared using recycled fine aggregate from urban red brick based construction wa...Sixteen controlled low-strength material( CLSM)mixtures with various cement-to-sand( C/Sa) ratios and water-to-solid( W/So) ratios were prepared using recycled fine aggregate from urban red brick based construction waste.The fluidity and bleeding of the fresh CLSM mixtures were measured via the modified test methods, and the hardened CLSM mixtures were then molded to evaluate their compressive strength and durability. The results showthat the fluidity of the fresh CLSM mixtures is 105 to 227 mm with the corresponding bleeding rate of 3. 7% to 15. 5%, which increases with the increase in fluidity. After aging for 28 d,the compressive strength of the hardened CLSM mixtures reaches 1. 15 to 13. 96 M Pa, and their strength can be further enhanced with longer curing ages. Additionally, the strength increases with the increase of the C/Sa ratio, and decreases with the increase of the W/So ratio under the same curing age. Based on the obtained compressive strength, a fitting model for accurately predicting the compressive strength of the CLSM mixtures was established, which takes into account the above two independent variables( C/Sa and W/So ratios).M oreover, the durability of the hardened CLSM mixtures is enhanced for samples with higher C/Sa ratios.展开更多
The effect of trace Ti and Y on Au-based alloys with 990 fineness has beeninvestigated systematically by means of tensile test, hardness test, scanning and transmissionelectron microscopic analyses. These experimental...The effect of trace Ti and Y on Au-based alloys with 990 fineness has beeninvestigated systematically by means of tensile test, hardness test, scanning and transmissionelectron microscopic analyses. These experimental results show that trace Ti and Y can significantlyimprove the mechanical properties of Au-based alloys with 990 fineness because Ti and Y cansignificantly refine matrix grains, and solid solution strengthening, work strengthening andprecipitation strengthening occur during mechanical heat treatment.展开更多
This study examined cells contained in needles used for the collection of breast fine needle aspirates for the detection of malignant cells trapped in the needles. Remnants of cells contained in 50 needles used for th...This study examined cells contained in needles used for the collection of breast fine needle aspirates for the detection of malignant cells trapped in the needles. Remnants of cells contained in 50 needles used for the collection of scanty breast fine needle aspirates were examined by the liquid based cytology technique and compared with the conventional cytological technique of specimens in the corresponding syringes. The breast specimens were collected with clean sterile needles attached to the syringes. Smears were made and stained by the conventional method. The needles were removed from the syringes and a fixative was withdrawn into the syringes and the syringes were recapped with the needles. The fixative containing the specimen was then completely discharged into a centrifuge tube through the needles and treated by the liquid based cytology technique. The study revealed that cells were found trapped in all the needles used for the collection of breast FNA. 6% of them were positive for malignancy, similar to results obtained in the conventional method. Needles used for the collection of breast FNA should be examined before malignancy is completely ruled out particularly in extremely scanty specimens with a clinical suspicion of malignancy.展开更多
Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and ...Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and heat treatment were investigated and discussed. Ensuring the powder T c at 83～85 K, the crucial impurity carbon was reduced to 0.03% and less. Adopting uncommon technique made the powder size to micrometer level, meanwhile the superconducting performance of the powder was unchanged. The fine superconducting powder was characterized. This process of Bi based 2212 superconducting powder was successful.展开更多
基金The National Science and Technology Support Program of China(No.2014BAC07B03)the Science and Technology Project of Transportation Committee of Beijing Government(No.2016-LZJKJ-01-006)the National Natural Science Foundation of China(No.51278016)
文摘Sixteen controlled low-strength material( CLSM)mixtures with various cement-to-sand( C/Sa) ratios and water-to-solid( W/So) ratios were prepared using recycled fine aggregate from urban red brick based construction waste.The fluidity and bleeding of the fresh CLSM mixtures were measured via the modified test methods, and the hardened CLSM mixtures were then molded to evaluate their compressive strength and durability. The results showthat the fluidity of the fresh CLSM mixtures is 105 to 227 mm with the corresponding bleeding rate of 3. 7% to 15. 5%, which increases with the increase in fluidity. After aging for 28 d,the compressive strength of the hardened CLSM mixtures reaches 1. 15 to 13. 96 M Pa, and their strength can be further enhanced with longer curing ages. Additionally, the strength increases with the increase of the C/Sa ratio, and decreases with the increase of the W/So ratio under the same curing age. Based on the obtained compressive strength, a fitting model for accurately predicting the compressive strength of the CLSM mixtures was established, which takes into account the above two independent variables( C/Sa and W/So ratios).M oreover, the durability of the hardened CLSM mixtures is enhanced for samples with higher C/Sa ratios.
基金This work is financially supported by the Key Scientific and Technological Project of Hubei Province (No. 971P0216).
文摘The effect of trace Ti and Y on Au-based alloys with 990 fineness has beeninvestigated systematically by means of tensile test, hardness test, scanning and transmissionelectron microscopic analyses. These experimental results show that trace Ti and Y can significantlyimprove the mechanical properties of Au-based alloys with 990 fineness because Ti and Y cansignificantly refine matrix grains, and solid solution strengthening, work strengthening andprecipitation strengthening occur during mechanical heat treatment.
文摘This study examined cells contained in needles used for the collection of breast fine needle aspirates for the detection of malignant cells trapped in the needles. Remnants of cells contained in 50 needles used for the collection of scanty breast fine needle aspirates were examined by the liquid based cytology technique and compared with the conventional cytological technique of specimens in the corresponding syringes. The breast specimens were collected with clean sterile needles attached to the syringes. Smears were made and stained by the conventional method. The needles were removed from the syringes and a fixative was withdrawn into the syringes and the syringes were recapped with the needles. The fixative containing the specimen was then completely discharged into a centrifuge tube through the needles and treated by the liquid based cytology technique. The study revealed that cells were found trapped in all the needles used for the collection of breast FNA. 6% of them were positive for malignancy, similar to results obtained in the conventional method. Needles used for the collection of breast FNA should be examined before malignancy is completely ruled out particularly in extremely scanty specimens with a clinical suspicion of malignancy.
文摘Laying emphasis on the preparation of Bi based 2212 single phase superconducting powder, some technological parameters, which effect the single phase degree and uniformity of powder, such as prebaking, sintering and heat treatment were investigated and discussed. Ensuring the powder T c at 83～85 K, the crucial impurity carbon was reduced to 0.03% and less. Adopting uncommon technique made the powder size to micrometer level, meanwhile the superconducting performance of the powder was unchanged. The fine superconducting powder was characterized. This process of Bi based 2212 superconducting powder was successful.
