This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on th...This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The dif- ferences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and ener- gy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs con- crete samples are lower than those of limestone concrete;the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of Si O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)2.展开更多
Some laterally advanced cholangiocarcinomas behave as ductal spread or local invasion, and hepatopancreatoduodenectomy (HPD) may be performed for R0 resection. To date, there have been no reports of laparoscopic HPD (...Some laterally advanced cholangiocarcinomas behave as ductal spread or local invasion, and hepatopancreatoduodenectomy (HPD) may be performed for R0 resection. To date, there have been no reports of laparoscopic HPD (LHPD) in the English literature. We report the first case of LHPD for the resection of a Bismuth IIIa cholangiocarcinoma invading the duodenum. The patient underwent laparoscopic pancreaticoduodenectomy and right hemihepatectomy. Child’s approach was used for the reconstruction. The patient recovered well with bile leakage from the 2<sup>nd</sup> postoperative day and was discharged on the 16<sup>th</sup> postoperative day with a drainage tube in place which was removed 2 wk after discharge. Postoperative pathology revealed a well-differentiated cholangiocarcinoma and the margin of liver parenchyma, pancreas and stomach was negative for metastases. The results suggest that LHPD is a feasible and safe procedure when performed in highly specialized centers and in suitable patients with cholangiocarcinoma.展开更多
Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to di...Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and blasting.In this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of CTB.The stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and characteristics.For instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically loaded.These findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost.展开更多
Studies on laparoscopic transduodenal local resection have not been readily available.Only three cases have been reported in the English-language literature.We describe herein a case of 25-year-old woman with periampu...Studies on laparoscopic transduodenal local resection have not been readily available.Only three cases have been reported in the English-language literature.We describe herein a case of 25-year-old woman with periampullary neuroendocrine tumor(NET).Endoscopic ultrasonography revealed a duodenal papilla mass originated from the submucosa and close to the ampulla.The periampullary tumor was successfully managed with laparoscopic transduodenal local resection without any procedure-related complications.Pathological examination showed a NET(Grade 2)with negative margin.The patient was followed up for six months without signs of recurrence.This case suggests that laparoscopic transduodenal local resection is a feasible procedure in selected patients with periampullary tumor.展开更多
The Mo alloys reinforced by Al2O3 particles were fabricated by hydrothermal synthesis and powder metallurgy. The microstructures of Mo-Al2O3 alloys were studied by using XRD, SEM and TEM. The results show that Al2O3 p...The Mo alloys reinforced by Al2O3 particles were fabricated by hydrothermal synthesis and powder metallurgy. The microstructures of Mo-Al2O3 alloys were studied by using XRD, SEM and TEM. The results show that Al2O3 particles, existing as a stable hexagonal phase(α-Al2O3), are uniformly dispersed in Mo matrix. The ultrafine α-Al2O3 particles remarkably refine grain size and increase dislocation density of Mo alloys. Moreover, a good interfacial bonding zone between α-Al2O3 and Mo grain is obtained. The crystallographic orientations of the interface of the Al2O3 particles and Mo matrix are [111]a-Al2O3//[111]Mo and(112)a-Al2O3//(0 11)Mo. Due to the effect of secondary phase and dislocation strengthening, the yield strength of Mo-2.0 vol.%Al2O3 alloy annealed at 1200 ℃ is approximately 56.0% higher than that of pure Mo. The results confirm that the addition of Al2O3 particles is a promising method to improve the mechanical properties of Mo alloys.展开更多
BACKGROUND Intraductal papillary neoplasm of the bile duct(IPNB)and intraductal papillary mucinous neoplasm(IPMN)of the pancreas have similar pathological manifestations.However,they often develop separately and it is...BACKGROUND Intraductal papillary neoplasm of the bile duct(IPNB)and intraductal papillary mucinous neoplasm(IPMN)of the pancreas have similar pathological manifestations.However,they often develop separately and it is rare for both to occur together.Patients presenting with heterochronic IPMN after IPNB are prone to be misdiagnosed with tumor recurrence.CASE SUMMARY A 67-year-old male patient was admitted 8.5 years after IPNB carcinoma and 4 years after the discovery of a pancreatic tumor.A left hepatic bile duct tumor with distal bile duct dilatation was found 8.5 years ago by the computed tomography;therefore,a left hepatectomy was performed.The postoperative pathological diagnosis was malignant IPNB with negative cutting edge and pathological stage T1N0M0.Magnetic resonance imaging 4 years ago showed cystic lesions in the pancreatic head with pancreatic duct dilatation,and carcinoembryonic antigen continued to increase.Positron emission tomography showed a maximum standard uptake value of 11.8 in the soft tissue mass in the pancreatic head,and a malignant tumor was considered.Radical pancreatoduodenectomy was performed.Postoperative pathological diagnosis was pancreatic head IPMN with negative cutting edge,pancreaticobiliary type,stage T3N0M0.He was discharged 15 d after the operation.Follow-up for 6 mo showed no tumor recurrence,and quality of life was good.CONCLUSION IPNB and IPMN are precancerous lesions with similar pathological characteristics and require active surgery and long-term follow-up.展开更多
Isolated metastases to the spleen from gastric carcinoma is very rare.Only a few cases have been reported in the literature.We herein present a case of isolated splenic metastases in a 62-year-old man,occurring 12 mo ...Isolated metastases to the spleen from gastric carcinoma is very rare.Only a few cases have been reported in the literature.We herein present a case of isolated splenic metastases in a 62-year-old man,occurring 12 mo after total gastrectomy for gastric carcinoma.The patient underwent a laparoscopic exploration,during which two lesions were found at the upper pole of the spleen,without involvement of other organs.A laparoscopic splenectomy was performed.Histological examination confirmed that the splenic tumor was a poorly differentiated adenocarcinoma similar to the primary gastric lesion.The postoperative course was uneventful and the patient has been well for 9 mo,with no tumor recurrence.The clinical data of 18 cases of isolated splenic metastases from gastric carcinoma treated by splenectomy were summarized after a literature review.To our knowledge,this is the first reported case of isolated splenic metastases undergoing laparoscopic splenectomy.展开更多
The pure molybdenum sheet and the Al2O3-doped molybdenum alloy sheets were prepared by the hydrothermal method and a subsequent powder metallurgy process. The effects of Al2O3particles addition on the recrystallizatio...The pure molybdenum sheet and the Al2O3-doped molybdenum alloy sheets were prepared by the hydrothermal method and a subsequent powder metallurgy process. The effects of Al2O3particles addition on the recrystallization temperature, microstructures and properties of the Mo sheets were investigated as the focus. The Al2O3-doped Mo sheets have greater strength than the pure Mo sheet, and the 0.50 wt% Al2O3-doped Mo sheet has the best performance. For the unannealed specimens, the strength increases with the increase in Al2O3content.Compared with that of pure Mo sheet, the strength of0.50 wt% Al2O3-doped Mo sheet increases by 72%, 54%,73% and 76%, respectively, when annealed at 1000,1100,1200 and 1300 ℃, which is a very obvious reinforcement effect. When lower than 1100 ℃, the elongation of the pure Mo sheet is the best. However, when the annealing temperature is equal to or greater than 1100 ℃,the 0.50 wt% Al2O3-doped Mo sheet obtains the best elongation. Moreover, the Al2O3addition can greatly improve the recrystallization temperature of molybdenum sheets; for example, the recrystallization temperature of the0.50 wt% Al2O3-doped Mo sheet increases by 200 ℃ at least than that of the pure Mo sheet. Lastly, the strengthening mechanism was discussed.展开更多
The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparati...The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparation method of tungsten alloy powder,liquid-phase method avoids the disadvantage of mechanical alloying,and the obtained powder composition is accurate and controllable,with high purity and excellent uniformity.At present,the second phase particles used for dispersion strengthening tungsten alloys are mainly composed of oxides.Oxide particles can be synthesized and precipitated in nitrate solution through in situ chemical reaction,and are uniformly distributed in composite powder by mixing and stirring.Finally,the oxide dispersion strengthened tungsten alloy(ODS-W)was obtained by reduction and sintering.Liquid-phase methods for preparing ODS-W alloys include azeotropic distillation,sol-gel methods,freeze-drying,hydrothermal synthesis,spray-drying,etc.In this paper,several liquid-phase methods for preparing tungsten alloy composite powder precursors are reviewed,and their latest research progresses are discussed.In addition,the morphologies and properties of tungsten alloys prepared by different methods are compared,which provides guidance for preparing high-performance tungsten alloys.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51678049 and 51834001)
文摘This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The dif- ferences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and ener- gy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs con- crete samples are lower than those of limestone concrete;the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of Si O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)2.
基金Supported by Zhejiang Key Subject of Medical Science Foundation,grant No.11-CX-21The Health and Family Planning Commission of Zhejiang Province,No.2012KYB113
文摘Some laterally advanced cholangiocarcinomas behave as ductal spread or local invasion, and hepatopancreatoduodenectomy (HPD) may be performed for R0 resection. To date, there have been no reports of laparoscopic HPD (LHPD) in the English literature. We report the first case of LHPD for the resection of a Bismuth IIIa cholangiocarcinoma invading the duodenum. The patient underwent laparoscopic pancreaticoduodenectomy and right hemihepatectomy. Child’s approach was used for the reconstruction. The patient recovered well with bile leakage from the 2<sup>nd</sup> postoperative day and was discharged on the 16<sup>th</sup> postoperative day with a drainage tube in place which was removed 2 wk after discharge. Postoperative pathology revealed a well-differentiated cholangiocarcinoma and the margin of liver parenchyma, pancreas and stomach was negative for metastases. The results suggest that LHPD is a feasible and safe procedure when performed in highly specialized centers and in suitable patients with cholangiocarcinoma.
基金financially supported by the National Key R&D Program of China (No. 2017YFC0602900)the Fundamental Research Funds for the Central Universities (No. FRF-TP-17-029A2)the Open Fund of Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education of China, No. ustbmslab201803)
文摘Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and blasting.In this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of CTB.The stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and characteristics.For instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically loaded.These findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost.
基金Supported by The key project grant from the Science and Technology Department of Zhejiang Province,China,No.2011C13036-2
文摘Studies on laparoscopic transduodenal local resection have not been readily available.Only three cases have been reported in the English-language literature.We describe herein a case of 25-year-old woman with periampullary neuroendocrine tumor(NET).Endoscopic ultrasonography revealed a duodenal papilla mass originated from the submucosa and close to the ampulla.The periampullary tumor was successfully managed with laparoscopic transduodenal local resection without any procedure-related complications.Pathological examination showed a NET(Grade 2)with negative margin.The patient was followed up for six months without signs of recurrence.This case suggests that laparoscopic transduodenal local resection is a feasible procedure in selected patients with periampullary tumor.
基金Projects(U1704152,U1804124)supported by the National Natural Science Foundation of ChinaProject(174100510012)supported by Plan for Scientific Innovation Talent of Henan Province,China。
文摘The Mo alloys reinforced by Al2O3 particles were fabricated by hydrothermal synthesis and powder metallurgy. The microstructures of Mo-Al2O3 alloys were studied by using XRD, SEM and TEM. The results show that Al2O3 particles, existing as a stable hexagonal phase(α-Al2O3), are uniformly dispersed in Mo matrix. The ultrafine α-Al2O3 particles remarkably refine grain size and increase dislocation density of Mo alloys. Moreover, a good interfacial bonding zone between α-Al2O3 and Mo grain is obtained. The crystallographic orientations of the interface of the Al2O3 particles and Mo matrix are [111]a-Al2O3//[111]Mo and(112)a-Al2O3//(0 11)Mo. Due to the effect of secondary phase and dislocation strengthening, the yield strength of Mo-2.0 vol.%Al2O3 alloy annealed at 1200 ℃ is approximately 56.0% higher than that of pure Mo. The results confirm that the addition of Al2O3 particles is a promising method to improve the mechanical properties of Mo alloys.
文摘BACKGROUND Intraductal papillary neoplasm of the bile duct(IPNB)and intraductal papillary mucinous neoplasm(IPMN)of the pancreas have similar pathological manifestations.However,they often develop separately and it is rare for both to occur together.Patients presenting with heterochronic IPMN after IPNB are prone to be misdiagnosed with tumor recurrence.CASE SUMMARY A 67-year-old male patient was admitted 8.5 years after IPNB carcinoma and 4 years after the discovery of a pancreatic tumor.A left hepatic bile duct tumor with distal bile duct dilatation was found 8.5 years ago by the computed tomography;therefore,a left hepatectomy was performed.The postoperative pathological diagnosis was malignant IPNB with negative cutting edge and pathological stage T1N0M0.Magnetic resonance imaging 4 years ago showed cystic lesions in the pancreatic head with pancreatic duct dilatation,and carcinoembryonic antigen continued to increase.Positron emission tomography showed a maximum standard uptake value of 11.8 in the soft tissue mass in the pancreatic head,and a malignant tumor was considered.Radical pancreatoduodenectomy was performed.Postoperative pathological diagnosis was pancreatic head IPMN with negative cutting edge,pancreaticobiliary type,stage T3N0M0.He was discharged 15 d after the operation.Follow-up for 6 mo showed no tumor recurrence,and quality of life was good.CONCLUSION IPNB and IPMN are precancerous lesions with similar pathological characteristics and require active surgery and long-term follow-up.
基金Supported by The Science Technology Department of Zhejiang Province,No.2011C3036-2the Health Bureau of Zhejiang Province,No.2011ZHB003
文摘Isolated metastases to the spleen from gastric carcinoma is very rare.Only a few cases have been reported in the literature.We herein present a case of isolated splenic metastases in a 62-year-old man,occurring 12 mo after total gastrectomy for gastric carcinoma.The patient underwent a laparoscopic exploration,during which two lesions were found at the upper pole of the spleen,without involvement of other organs.A laparoscopic splenectomy was performed.Histological examination confirmed that the splenic tumor was a poorly differentiated adenocarcinoma similar to the primary gastric lesion.The postoperative course was uneventful and the patient has been well for 9 mo,with no tumor recurrence.The clinical data of 18 cases of isolated splenic metastases from gastric carcinoma treated by splenectomy were summarized after a literature review.To our knowledge,this is the first reported case of isolated splenic metastases undergoing laparoscopic splenectomy.
基金financially supported by the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1234)the National Natural Science Foundation of China (No. 50972039)
文摘The pure molybdenum sheet and the Al2O3-doped molybdenum alloy sheets were prepared by the hydrothermal method and a subsequent powder metallurgy process. The effects of Al2O3particles addition on the recrystallization temperature, microstructures and properties of the Mo sheets were investigated as the focus. The Al2O3-doped Mo sheets have greater strength than the pure Mo sheet, and the 0.50 wt% Al2O3-doped Mo sheet has the best performance. For the unannealed specimens, the strength increases with the increase in Al2O3content.Compared with that of pure Mo sheet, the strength of0.50 wt% Al2O3-doped Mo sheet increases by 72%, 54%,73% and 76%, respectively, when annealed at 1000,1100,1200 and 1300 ℃, which is a very obvious reinforcement effect. When lower than 1100 ℃, the elongation of the pure Mo sheet is the best. However, when the annealing temperature is equal to or greater than 1100 ℃,the 0.50 wt% Al2O3-doped Mo sheet obtains the best elongation. Moreover, the Al2O3addition can greatly improve the recrystallization temperature of molybdenum sheets; for example, the recrystallization temperature of the0.50 wt% Al2O3-doped Mo sheet increases by 200 ℃ at least than that of the pure Mo sheet. Lastly, the strengthening mechanism was discussed.
基金supported by National Natural Science Foundation of China(no.U2004180)。
文摘The addition of the second phase into tungsten can significantly refine the grain size of tungsten alloys,and also play a role in dispersion strengthening,thus improving the properties of tungsten alloy.As a preparation method of tungsten alloy powder,liquid-phase method avoids the disadvantage of mechanical alloying,and the obtained powder composition is accurate and controllable,with high purity and excellent uniformity.At present,the second phase particles used for dispersion strengthening tungsten alloys are mainly composed of oxides.Oxide particles can be synthesized and precipitated in nitrate solution through in situ chemical reaction,and are uniformly distributed in composite powder by mixing and stirring.Finally,the oxide dispersion strengthened tungsten alloy(ODS-W)was obtained by reduction and sintering.Liquid-phase methods for preparing ODS-W alloys include azeotropic distillation,sol-gel methods,freeze-drying,hydrothermal synthesis,spray-drying,etc.In this paper,several liquid-phase methods for preparing tungsten alloy composite powder precursors are reviewed,and their latest research progresses are discussed.In addition,the morphologies and properties of tungsten alloys prepared by different methods are compared,which provides guidance for preparing high-performance tungsten alloys.
