With the rapid development of science and technology,the minimally invasive surgery(MIS)has become a reality.MIS is associated with less pain,a shorter hospital stay and fewer complications.The higher-quality minimall...With the rapid development of science and technology,the minimally invasive surgery(MIS)has become a reality.MIS is associated with less pain,a shorter hospital stay and fewer complications.The higher-quality minimally invasive instruments allow the surgeons to perform the surgical interventions efficiently without sacrificing patient safety.Therefore,the academic research,technology development,achievement transformation as well as clinical application of minimally invasive devices is extremely important。展开更多
The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal de...The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal deposition behaviors through in situ forming stable artificial solid electrolyte interface(SEI)passivating layers.The concentration of MnO in the cells can be maintained at a constant based on quite low solubility of MnO in the liquid electrolyte,and the dissolved MnO can be reduced to produce Li_(2)O and Mn metal nanoparticles,which can not only function as nucleating seeds of lithium metal deposits but also repair the broken SEI layer.Dendritic-free Li deposits can be obtained by simple separator coating.It can also improve the electrochemical performance of lithium metal batteries.And it is benefit for applications of Li metal anodes.展开更多
Limitations regarding phosphorus(P)are widespread in ecosystems.Understanding the impacts of the wetland types on microbially mediated soil P availability and cycling is essential for the effective management of wetla...Limitations regarding phosphorus(P)are widespread in ecosystems.Understanding the impacts of the wetland types on microbially mediated soil P availability and cycling is essential for the effective management of wetlands.In this study,the Beidagang wetland,Baodi paddy field,and Dahuangpu wetland in Tianjin,China were chosen as representatives of the coastal wetland(B),constructed wetland(R),and swampy wetland(W),respectively.Sequential P extraction and metagenomics approaches were adopted to explore the soil P fraction and microbially regulated P cycle.Proteobacteria were the predominant microbes-related soil P cycle.IMPA,gph,rsbU_P,ugpQ,and glpK genes were dominant in organic P(Po)mineralization,while gcd,ppa,and ppx genes were dominant in inorganic P(Pi)solubilization.The salinity,NO_(3)^(-)-N concentration,the ratio of total carbon to total nitrogen(TC/TN),total carbon(TC),and the ratio of soil organic carbon to total P(SOC/TP)were the co-drivers of microbially mediated P cycle processes.Microbial network complexity-relate P cycle was the lowest in the coastal wetland.Salinity and NO_(3)^(-)-N exhibited a significant negative relation to the abundance of most genes-relate Pi solubilization and a remarkable positive correlation with the abundance of many genes-relate Po mineralization.These findings demonstrated that Po mineralization tended to occur in habitats with high salinity and nutrient imbalances,whereas the dissolution of Pi was prone to occur in low-salinity environments with relatively balanced soil nutrients.This study improves understanding of how salinity and soil nutrients jointly shape microbial-regulated soil P cycle in different types of wetlands.展开更多
A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water, acetone, and HCl （volume ratio, 45：45：10） was int...A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water, acetone, and HCl （volume ratio, 45：45：10） was introduced. Four different kinds of inclusions in ultra low carbon steel were compared by metallographic observation and erosion observation. The results show that the three-dimensional morphologies of different kinds of inclusions could be observed clearly and simply after erosion. The method is useful for the observation and analysis of inclusions made by deep erosion. It also provides a new way to control and remove inclusions based on the true morphologies of inclusions.展开更多
The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, te...The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency(IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl_3 solution.展开更多
Carbon nanotubes （CNTs） were coated by tungsten layer using metal organic chemical vapor deposition process with tungsten hexacarbonyl as a precursor. The W-coated CNTs （W-CNTs） were dispersed into Cu powders by m...Carbon nanotubes （CNTs） were coated by tungsten layer using metal organic chemical vapor deposition process with tungsten hexacarbonyl as a precursor. The W-coated CNTs （W-CNTs） were dispersed into Cu powders by magnetic stirring process and then the mixed powders were consolidated by spark plasma sintering to fabricate W-CNTs/Cu composites. The CNTs/Cu composites were fabricated using the similafprocesses. The friction coefficient and mass wear loss of W-CNTs/Cu and CNTs/Cu composites were studied. The results showed that the W-CNT content, interfacial bonding situation, and applied load could influence the friction coefficient and wear loss of W-CNTs/Cu com- posites. When the W-CNT content was 1.0 wt.%, the W-CNTs/Cu composites got the minimum friction coefficient and wear loss, which were decreased by 72.1% and 47.6%, respectively, compared with pure Cu specimen. The friction coefficient and wear loss of W-CNTs/Cu composites were lower than those of CNTs/Cu composites, which was due to that the interracial bonding at （W-CNTs）-Cu interface was better than that at CNTs-Cu interface. The friction coefficient of composites did not vary obviously with increasing applied load, while the wear loss of composites increased significantly with the increase of applied load.展开更多
AIM To perform a systematic review and meta-analysis on minimally vs conventional invasive techniques for harvesting grafts for living donor liver transplantation. METHODS PubMed, Web of Science, EMBASE, and the Cochr...AIM To perform a systematic review and meta-analysis on minimally vs conventional invasive techniques for harvesting grafts for living donor liver transplantation. METHODS PubMed, Web of Science, EMBASE, and the Cochrane Library were searched comprehensively for studies comparing MILDH with conventional living donor hepatectomy (CLDH). Intraoperative and postoperative outcomes (operative time, estimated blood loss, postoperative liver function, length of hospital stay, analgesia use, complications, and survival rate) were analyzed in donors and recipients. Articles were included if they: (1) compared the outcomes of MILDH and CLDH; and (2) reported at least some of the above outcomes. RESULTS Of 937 articles identified, 13, containing 1592 patients, met our inclusion criteria and were included in the meta-analysis. For donors, operative time [weighted mean difference (WMD) = 20.68, 95% CI: -6.25-47.60, p = 0.13] and blood loss (WMD = -32.61, 95% CI: -80.44-5.21, p = 0.18) were comparable in the two groups. In contrast, analgesia use (WMD = -7.79, 95% CI: -14.06-1.87, p = 0.01), postoperative complications [odds ratio (OR) = 0.62, 95% CI: 0.44-0.89, p = 0.009], and length of hospital stay (WMD): -1.25, 95% CI: -2.35-0.14, p = 0.03) significantly favored MILDH. No differences were observed in recipient outcomes, including postoperative complications (OR = 0.93, 95% CI: 0.66-1.31, p = 0.68) and survival rate (hr = 0.96, 95% CI: 0.27-3.47, p = 0.95). Funnel plot and statistical methods showed a low probability of publication bias. CONCLUSION MILDH is safe, effective, and feasible for living donor liver resection with fewer donor postoperative complications, reduced length of hospital stay and analgesia requirement than CLDH.展开更多
In order to develop AlN composites suitable for high average power electronic tube, AlN-W materials were prepared by spark plasma sintering. The effects of manufacture parameters on dielectric loss tangent and permitt...In order to develop AlN composites suitable for high average power electronic tube, AlN-W materials were prepared by spark plasma sintering. The effects of manufacture parameters on dielectric loss tangent and permittivity constant were investigated, which include powder-mixed method, milling time of high-energy ball milling, starting powder particle size, sintering temperature and holding time and adding amount of the conductive second phase. The results showed that A1N-W materials sintered at the temperature of 1700℃ holding for 5 min with 10 vol.% W showed the best dielectric loss tangent larger than 0.81 at the frequency 1 kHz-1 MHz. In addition, magnetic stirring mixed powder and lower sintering temperature led to the better propelties because of the higher porosity. The samples sintered from the starting AlN powder with smaller particle size also had the better properties.展开更多
The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss ...The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss steps maximized at about 78, 272, 583, and 826℃ are observed for the laterite ore, representing the vaporization of free water, the dehydroxylation of goethite, the decomposition of serpentines, and the second dehydroxylation of serpentines, respectively. The reduction reactions of the graphite-laterite mixtures start at around 700℃ and can be divided into three major temperature regions. Coal-laterite composites with an addition of 10 wt.% CaO were roasted at 1100-1350℃ for 30 min, and the reduced samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indi- cate that the reduction reactions proceed more completely at higher temperatures. The growth of the reduced ferronickel particles is greatly influenced by the roasting temperature, Obvious growth of the reduced ferronickel particles appears with the formation of worm-like crystals for the sample reduced at 1250℃ and spheric particles are observed for the sample reduced at 1300℃. When the reduction temperature increases to 1350℃, the reduced ferronickel particles agglomerate to ferronickel granules of 3-8 mm in diameter. The main elements in the granules include iron, nickel, chromium, carbon, and sulfur, with the content of nickel and that of iron of 9.08 wt.% and 85.21 wt.%, respectively.展开更多
Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low tem...Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low temperatures,increase fuel conversion and the heat sink capacity,and suppress coke deposition,thereby reducing waste heat.Catalysts mainly include metal oxide catalysts,noble metal catalysts and metal nanoparticles,zeolite catalysts,nanozeolite catalysts,and coating catalysts.Moreover,initiators roughly include nitrogenous compounds,oxygenated compounds,and hyperbranched polymer initiators.In this review,we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking.This review will facilitate the development of the synthesis and exploration of catalysts and initiators.展开更多
In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field inten- sities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2,...In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field inten- sities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2, A1203 and TiO2 melting modification of converter slag was made respectively and phosphorus-rich phase was extracted by magnetic separation. The results show that MgO, MnO, Na2 0 and CaF2 have little effect on the phosphorus recovery, whereas the addition of SiO2, Al2 03, and TiO2 has great effect on phosphorus enrichment in slag and magnetic separation. With adding the reagent of SiO2 Al2 03 and TiO2, recycled non-magnetic substances are increased obviously and P2 05 content in nowmagnetic substances and phosphorus recovery rate are also increased. The phosphorus recovery rates of modified slag No. 8 （SiO2 modification）, slag No. 10 （AI2 03 modification） and slag No. 11 （TiO2 modification） are 84.75 %, 82.16 % and 74.46 %, respectively. Then, most of phosphorus was recycled.展开更多
The circulation period of RH vacuum refining was studied to promote the refining efficiency. The influences of the lift gas flow rate and submersion depth of snorkels on the circulation period, and the relationship be...The circulation period of RH vacuum refining was studied to promote the refining efficiency. The influences of the lift gas flow rate and submersion depth of snorkels on the circulation period, and the relationship between mixing time and circulation flow were dis- cussed. The effects of the lift gas flow rate and submersion depth on the degassing rate in one circulation period were studied by water modeling. The results show that the circulation period is shortened by increasing the lift gas flow rate. The circulation period is the shortest when the submersion depth of snorkels is 560 mm. The whole ladle can be mixed thoroughly after three times of circulation. Increasing the lift gas flow rate can enhance the degassing rate of RH circulation.展开更多
Peer review is the backbone of a scientific journal.Although reviewing is a volunteer task,following international reviewers dedicated their considerable time and expertise to review manuscripts for Laparoscopic,Endos...Peer review is the backbone of a scientific journal.Although reviewing is a volunteer task,following international reviewers dedicated their considerable time and expertise to review manuscripts for Laparoscopic,Endoscopic and Robotic Surgery in 2021.展开更多
3Y-TZP/3wt%Al_(2)O_(3) powder was coated with varying amounts of BN using the urea and borate reaction sintering method,and then multiphase ceramics were prepared by hot pressing sintering.The micro-topography and the...3Y-TZP/3wt%Al_(2)O_(3) powder was coated with varying amounts of BN using the urea and borate reaction sintering method,and then multiphase ceramics were prepared by hot pressing sintering.The micro-topography and the compositional analysis of synthesized ceramics were conducted through scanning electron microscopy,transmission electron microscopy and X-ray diffraction.A mechanical tester was used to analyze the Vickers hardness,fracture toughness,and bending strength of the synthesized ceramics.The results showed that the ceramic with a BN content of 12wt%showed the best processability,but had diminished mechanical properties(such as fracture toughness and bending strength).The ceramic with a BN content of 9wt%showed better processability than those with 3wt%and 6wt%BN.However,the fracture toughness was affected by the addition of 9wt%BN,making this ceramic only usable as a base material for a three-unit fixed bridge.In contrast,the ceramics with a BN content of 3wt%or 6wt%fulfilled the criteria for use in multi-unit restoration,but their low processability made them unsuitable for milling after sintering.展开更多
Objective:To determine the effect of gut microbiota on a rat model of post-traumatic stress disorder(PTSD)and explore the correlation of gut microbiota with behavior and neurotransmitters.Methods:We established a sing...Objective:To determine the effect of gut microbiota on a rat model of post-traumatic stress disorder(PTSD)and explore the correlation of gut microbiota with behavior and neurotransmitters.Methods:We established a single prolonged stress(SPS)model to examine the pathogenesis of PTSD on rat behavior,gut microbiota,and neurotransmitter levels.Rats were separated into control and model groups,and neurotransmitter levels were measured using enzyme linked immunosorbent assay.Then,16 S rRNA sequencing was used to compare the gut microbiota between the control and model groups.Results:Compared with those in the control group,freezing time significantly increased,while number of standing upright,crossing frequency,time spent in the central arena,and total distance traveled were significantly reduced in the model group after exposure to SPS(all P<.05).Meanwhile,serotonin,or 5-hydroxytryptamine,levels in the brain in the model group were significantly lower than those the control group(P紏.0332).In addition,changes were observed in the gut microbiota diversity and relative abundances of bacterial phyla,orders,families,and genera in the model group.Especially,changes in Firmicutes,Bacteroidetes,Cyanobacteria,and Proteobacteria levels were most pronounced after SPS exposure.Correlation analysis showed that the strongest positive correlation was found between Bacteroidaceae and 5-HT(P?.0009).Moreover,RF32 abundance was the most negatively related to 5-HT(P?.0009),crossing frequency(P?.0007),and total distance(P?.0003).Conclusion:Our results suggest that SPS model rats showed differences in behavior,neurotransmitter levels,and gut microbiota with control rats.Moreover,Firmicutes,Bacteroidetes,Cyanobacteria,and Proteobacteria were most relevant to the exhibited fear-like and anxiety-like behaviors and significant serotonin content reduction in SPS model rats.展开更多
We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inv...We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inversion and the entanglement dynamics in terms of the linear entropy. It is shown that the long-lived entanglement is an intriguing result corresponding to the collapse region of the atomic inversion. As illustration, we examine the long-time interaction of the entanglement under the resonance and off-resonance regimes.展开更多
The diameters of the ordinary hard bubbles （OHBs） and soft bubbles in epitaxial garnet films are measured under the microscope at various temperatures. It is found that the bubble diameters of OHBs increase with tem...The diameters of the ordinary hard bubbles （OHBs） and soft bubbles in epitaxial garnet films are measured under the microscope at various temperatures. It is found that the bubble diameters of OHBs increase with temperature, and it is concluded that the equilibrium separation between two neighbouring vertical Bloch lines （VBLs） Seq is widened with increasing temperature. At the same time, the results can be understood simply as that there are more VBLs in the domain walls of the first dumbbell domains （IDs） than those in walls of OHBs at the same temperature.展开更多
For helping millions of patients to live longer and possess higher quality life,the innovation of novel surgical procedures is very necessary and urgent.This paper introduces a series of innovations of Dr.Xiujun Cai,s...For helping millions of patients to live longer and possess higher quality life,the innovation of novel surgical procedures is very necessary and urgent.This paper introduces a series of innovations of Dr.Xiujun Cai,such as Laparoscopic Peng's multifunctional operative dissector,curettage and aspiration procedure,Cai's associating liver partition with portal vein ligation for staged hepatectomy,sutureless anastomosisetc in minimally invasive field.The paper advocates the pace of medical invention should be accelerated,inspiring hope for better clinical outcomes with less invasive procedures and shorter recovery time.展开更多
The electronic structural, effective masses of carriers, and optical properties of pure and La-doped Cd2SnO4 are calculated by using the first-principles method based on the density functional theory. Using the GGA＋U...The electronic structural, effective masses of carriers, and optical properties of pure and La-doped Cd2SnO4 are calculated by using the first-principles method based on the density functional theory. Using the GGA＋U method, we show that Cd2SnO4 is a direct band-gap semiconductor with a band gap of 2.216 eV, the band gap decreases to 2.02 eV and the Fermi energy level moves to the conduction band after La doping. The density of states of Cd2SnO4 shows that the bottom of the conduction band is composed of Cd 5s, Sn 5s, and Sn 5p orbits, the top of the valence band is composed of Cd 4d and O 2p, and the La 5d orbital is hybridized with the O 2p orbital, which plays a key role at the conduction band bottom after La doping. The effective masses at the conduction band bottom of pure and La-doped Cd2SnO4 are 0.18m0 and 0.092m0, respectively, which indicates that the electrical conductivity of Cd2SnO4 after La doping is improved. The calculated optical properties show that the optical transmittance of La-doped Cd2SnO4 is 92%, the optical absorption edge is slightly blue shifted, and the optical band gap is increased to 3.263 eV. All the results indicate that the conductivity and optical transmittance of Cd2SnO4 can be improved by doping La.展开更多
Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon a...Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon agricultural development approaches are lacking of deep and systematical researches. Therefore, the paper briefly analyzed the situation and the existing problems of China＇s low carbon agricultural development, and then put forward the approaches to promote the low carbon agricultural development.展开更多
文摘With the rapid development of science and technology,the minimally invasive surgery(MIS)has become a reality.MIS is associated with less pain,a shorter hospital stay and fewer complications.The higher-quality minimally invasive instruments allow the surgeons to perform the surgical interventions efficiently without sacrificing patient safety.Therefore,the academic research,technology development,achievement transformation as well as clinical application of minimally invasive devices is extremely important。
文摘The application of lithium metal anodes is hindered by low Coulombic efficiency(CE),serious lithium dendrites and volume expansion.An MnO/Polypropylene(PP)composite separator was developed to regulate lithium metal deposition behaviors through in situ forming stable artificial solid electrolyte interface(SEI)passivating layers.The concentration of MnO in the cells can be maintained at a constant based on quite low solubility of MnO in the liquid electrolyte,and the dissolved MnO can be reduced to produce Li_(2)O and Mn metal nanoparticles,which can not only function as nucleating seeds of lithium metal deposits but also repair the broken SEI layer.Dendritic-free Li deposits can be obtained by simple separator coating.It can also improve the electrochemical performance of lithium metal batteries.And it is benefit for applications of Li metal anodes.
基金supported by the National Natural Science Foundation of China(Nos.32271777,31500365,31770499,and 42303014)Tianjin Natural Science Foundation(Nos.12JCYBJC19700 and 18JCYBJC96500)+1 种基金Tianjin Science and Technology Support Program(Nos.23YFZCSN00100,15ZCZDSF00410,and 23YFZCSN00210)the Special Investigation of Technological Basic Resources(No.2021FY101002)。
文摘Limitations regarding phosphorus(P)are widespread in ecosystems.Understanding the impacts of the wetland types on microbially mediated soil P availability and cycling is essential for the effective management of wetlands.In this study,the Beidagang wetland,Baodi paddy field,and Dahuangpu wetland in Tianjin,China were chosen as representatives of the coastal wetland(B),constructed wetland(R),and swampy wetland(W),respectively.Sequential P extraction and metagenomics approaches were adopted to explore the soil P fraction and microbially regulated P cycle.Proteobacteria were the predominant microbes-related soil P cycle.IMPA,gph,rsbU_P,ugpQ,and glpK genes were dominant in organic P(Po)mineralization,while gcd,ppa,and ppx genes were dominant in inorganic P(Pi)solubilization.The salinity,NO_(3)^(-)-N concentration,the ratio of total carbon to total nitrogen(TC/TN),total carbon(TC),and the ratio of soil organic carbon to total P(SOC/TP)were the co-drivers of microbially mediated P cycle processes.Microbial network complexity-relate P cycle was the lowest in the coastal wetland.Salinity and NO_(3)^(-)-N exhibited a significant negative relation to the abundance of most genes-relate Pi solubilization and a remarkable positive correlation with the abundance of many genes-relate Po mineralization.These findings demonstrated that Po mineralization tended to occur in habitats with high salinity and nutrient imbalances,whereas the dissolution of Pi was prone to occur in low-salinity environments with relatively balanced soil nutrients.This study improves understanding of how salinity and soil nutrients jointly shape microbial-regulated soil P cycle in different types of wetlands.
基金supported by the National Natural Science Foundation of China (No.51074019)
文摘A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water, acetone, and HCl （volume ratio, 45：45：10） was introduced. Four different kinds of inclusions in ultra low carbon steel were compared by metallographic observation and erosion observation. The results show that the three-dimensional morphologies of different kinds of inclusions could be observed clearly and simply after erosion. The method is useful for the observation and analysis of inclusions made by deep erosion. It also provides a new way to control and remove inclusions based on the true morphologies of inclusions.
基金financially supported by the National Natural Science Foundation of China (No. 81371183)
文摘The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency(IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl_3 solution.
基金financially supported by the National Natural Science Foundation of China (No.50971020)National HighTech Research and Development Program of China (No.2009AA03Z116)
文摘Carbon nanotubes （CNTs） were coated by tungsten layer using metal organic chemical vapor deposition process with tungsten hexacarbonyl as a precursor. The W-coated CNTs （W-CNTs） were dispersed into Cu powders by magnetic stirring process and then the mixed powders were consolidated by spark plasma sintering to fabricate W-CNTs/Cu composites. The CNTs/Cu composites were fabricated using the similafprocesses. The friction coefficient and mass wear loss of W-CNTs/Cu and CNTs/Cu composites were studied. The results showed that the W-CNT content, interfacial bonding situation, and applied load could influence the friction coefficient and wear loss of W-CNTs/Cu com- posites. When the W-CNT content was 1.0 wt.%, the W-CNTs/Cu composites got the minimum friction coefficient and wear loss, which were decreased by 72.1% and 47.6%, respectively, compared with pure Cu specimen. The friction coefficient and wear loss of W-CNTs/Cu composites were lower than those of CNTs/Cu composites, which was due to that the interracial bonding at （W-CNTs）-Cu interface was better than that at CNTs-Cu interface. The friction coefficient of composites did not vary obviously with increasing applied load, while the wear loss of composites increased significantly with the increase of applied load.
基金Science and Technology Planning Project of Guangzhou,No.201604020001
文摘AIM To perform a systematic review and meta-analysis on minimally vs conventional invasive techniques for harvesting grafts for living donor liver transplantation. METHODS PubMed, Web of Science, EMBASE, and the Cochrane Library were searched comprehensively for studies comparing MILDH with conventional living donor hepatectomy (CLDH). Intraoperative and postoperative outcomes (operative time, estimated blood loss, postoperative liver function, length of hospital stay, analgesia use, complications, and survival rate) were analyzed in donors and recipients. Articles were included if they: (1) compared the outcomes of MILDH and CLDH; and (2) reported at least some of the above outcomes. RESULTS Of 937 articles identified, 13, containing 1592 patients, met our inclusion criteria and were included in the meta-analysis. For donors, operative time [weighted mean difference (WMD) = 20.68, 95% CI: -6.25-47.60, p = 0.13] and blood loss (WMD = -32.61, 95% CI: -80.44-5.21, p = 0.18) were comparable in the two groups. In contrast, analgesia use (WMD = -7.79, 95% CI: -14.06-1.87, p = 0.01), postoperative complications [odds ratio (OR) = 0.62, 95% CI: 0.44-0.89, p = 0.009], and length of hospital stay (WMD): -1.25, 95% CI: -2.35-0.14, p = 0.03) significantly favored MILDH. No differences were observed in recipient outcomes, including postoperative complications (OR = 0.93, 95% CI: 0.66-1.31, p = 0.68) and survival rate (hr = 0.96, 95% CI: 0.27-3.47, p = 0.95). Funnel plot and statistical methods showed a low probability of publication bias. CONCLUSION MILDH is safe, effective, and feasible for living donor liver resection with fewer donor postoperative complications, reduced length of hospital stay and analgesia requirement than CLDH.
文摘In order to develop AlN composites suitable for high average power electronic tube, AlN-W materials were prepared by spark plasma sintering. The effects of manufacture parameters on dielectric loss tangent and permittivity constant were investigated, which include powder-mixed method, milling time of high-energy ball milling, starting powder particle size, sintering temperature and holding time and adding amount of the conductive second phase. The results showed that A1N-W materials sintered at the temperature of 1700℃ holding for 5 min with 10 vol.% W showed the best dielectric loss tangent larger than 0.81 at the frequency 1 kHz-1 MHz. In addition, magnetic stirring mixed powder and lower sintering temperature led to the better propelties because of the higher porosity. The samples sintered from the starting AlN powder with smaller particle size also had the better properties.
文摘The thermal behaviors of single laterite ore and graphite-laterite mixtures were investigated by thermogravimetry （TG）, derivative thermogravimetry （DTG）, and differential thermal analysis （DTA）. Four mass loss steps maximized at about 78, 272, 583, and 826℃ are observed for the laterite ore, representing the vaporization of free water, the dehydroxylation of goethite, the decomposition of serpentines, and the second dehydroxylation of serpentines, respectively. The reduction reactions of the graphite-laterite mixtures start at around 700℃ and can be divided into three major temperature regions. Coal-laterite composites with an addition of 10 wt.% CaO were roasted at 1100-1350℃ for 30 min, and the reduced samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indi- cate that the reduction reactions proceed more completely at higher temperatures. The growth of the reduced ferronickel particles is greatly influenced by the roasting temperature, Obvious growth of the reduced ferronickel particles appears with the formation of worm-like crystals for the sample reduced at 1250℃ and spheric particles are observed for the sample reduced at 1300℃. When the reduction temperature increases to 1350℃, the reduced ferronickel particles agglomerate to ferronickel granules of 3-8 mm in diameter. The main elements in the granules include iron, nickel, chromium, carbon, and sulfur, with the content of nickel and that of iron of 9.08 wt.% and 85.21 wt.%, respectively.
基金supported by the National Natural Science Foundation of China(No.21978200).
文摘Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low temperatures,increase fuel conversion and the heat sink capacity,and suppress coke deposition,thereby reducing waste heat.Catalysts mainly include metal oxide catalysts,noble metal catalysts and metal nanoparticles,zeolite catalysts,nanozeolite catalysts,and coating catalysts.Moreover,initiators roughly include nitrogenous compounds,oxygenated compounds,and hyperbranched polymer initiators.In this review,we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking.This review will facilitate the development of the synthesis and exploration of catalysts and initiators.
文摘In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field inten- sities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2, A1203 and TiO2 melting modification of converter slag was made respectively and phosphorus-rich phase was extracted by magnetic separation. The results show that MgO, MnO, Na2 0 and CaF2 have little effect on the phosphorus recovery, whereas the addition of SiO2, Al2 03, and TiO2 has great effect on phosphorus enrichment in slag and magnetic separation. With adding the reagent of SiO2 Al2 03 and TiO2, recycled non-magnetic substances are increased obviously and P2 05 content in nowmagnetic substances and phosphorus recovery rate are also increased. The phosphorus recovery rates of modified slag No. 8 （SiO2 modification）, slag No. 10 （AI2 03 modification） and slag No. 11 （TiO2 modification） are 84.75 %, 82.16 % and 74.46 %, respectively. Then, most of phosphorus was recycled.
基金supported by the National Key Technology R & D Program of China (No.2006BAE03A06)
文摘The circulation period of RH vacuum refining was studied to promote the refining efficiency. The influences of the lift gas flow rate and submersion depth of snorkels on the circulation period, and the relationship between mixing time and circulation flow were dis- cussed. The effects of the lift gas flow rate and submersion depth on the degassing rate in one circulation period were studied by water modeling. The results show that the circulation period is shortened by increasing the lift gas flow rate. The circulation period is the shortest when the submersion depth of snorkels is 560 mm. The whole ladle can be mixed thoroughly after three times of circulation. Increasing the lift gas flow rate can enhance the degassing rate of RH circulation.
文摘Peer review is the backbone of a scientific journal.Although reviewing is a volunteer task,following international reviewers dedicated their considerable time and expertise to review manuscripts for Laparoscopic,Endoscopic and Robotic Surgery in 2021.
基金financially supported by the National Natural Science Foundation of China(No.81371183).
文摘3Y-TZP/3wt%Al_(2)O_(3) powder was coated with varying amounts of BN using the urea and borate reaction sintering method,and then multiphase ceramics were prepared by hot pressing sintering.The micro-topography and the compositional analysis of synthesized ceramics were conducted through scanning electron microscopy,transmission electron microscopy and X-ray diffraction.A mechanical tester was used to analyze the Vickers hardness,fracture toughness,and bending strength of the synthesized ceramics.The results showed that the ceramic with a BN content of 12wt%showed the best processability,but had diminished mechanical properties(such as fracture toughness and bending strength).The ceramic with a BN content of 9wt%showed better processability than those with 3wt%and 6wt%BN.However,the fracture toughness was affected by the addition of 9wt%BN,making this ceramic only usable as a base material for a three-unit fixed bridge.In contrast,the ceramics with a BN content of 3wt%or 6wt%fulfilled the criteria for use in multi-unit restoration,but their low processability made them unsuitable for milling after sintering.
基金This work was partially supported by the National Natural Science Foundation of China(81874427).
文摘Objective:To determine the effect of gut microbiota on a rat model of post-traumatic stress disorder(PTSD)and explore the correlation of gut microbiota with behavior and neurotransmitters.Methods:We established a single prolonged stress(SPS)model to examine the pathogenesis of PTSD on rat behavior,gut microbiota,and neurotransmitter levels.Rats were separated into control and model groups,and neurotransmitter levels were measured using enzyme linked immunosorbent assay.Then,16 S rRNA sequencing was used to compare the gut microbiota between the control and model groups.Results:Compared with those in the control group,freezing time significantly increased,while number of standing upright,crossing frequency,time spent in the central arena,and total distance traveled were significantly reduced in the model group after exposure to SPS(all P<.05).Meanwhile,serotonin,or 5-hydroxytryptamine,levels in the brain in the model group were significantly lower than those the control group(P紏.0332).In addition,changes were observed in the gut microbiota diversity and relative abundances of bacterial phyla,orders,families,and genera in the model group.Especially,changes in Firmicutes,Bacteroidetes,Cyanobacteria,and Proteobacteria levels were most pronounced after SPS exposure.Correlation analysis showed that the strongest positive correlation was found between Bacteroidaceae and 5-HT(P?.0009).Moreover,RF32 abundance was the most negatively related to 5-HT(P?.0009),crossing frequency(P?.0007),and total distance(P?.0003).Conclusion:Our results suggest that SPS model rats showed differences in behavior,neurotransmitter levels,and gut microbiota with control rats.Moreover,Firmicutes,Bacteroidetes,Cyanobacteria,and Proteobacteria were most relevant to the exhibited fear-like and anxiety-like behaviors and significant serotonin content reduction in SPS model rats.
文摘We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inversion and the entanglement dynamics in terms of the linear entropy. It is shown that the long-lived entanglement is an intriguing result corresponding to the collapse region of the atomic inversion. As illustration, we examine the long-time interaction of the entanglement under the resonance and off-resonance regimes.
基金Supported by the National Natural Science Foundation of China under Grant No 10274018, and the Key Foundation of Hebei Normal University under Grant No L2006B10.
文摘The diameters of the ordinary hard bubbles （OHBs） and soft bubbles in epitaxial garnet films are measured under the microscope at various temperatures. It is found that the bubble diameters of OHBs increase with temperature, and it is concluded that the equilibrium separation between two neighbouring vertical Bloch lines （VBLs） Seq is widened with increasing temperature. At the same time, the results can be understood simply as that there are more VBLs in the domain walls of the first dumbbell domains （IDs） than those in walls of OHBs at the same temperature.
文摘For helping millions of patients to live longer and possess higher quality life,the innovation of novel surgical procedures is very necessary and urgent.This paper introduces a series of innovations of Dr.Xiujun Cai,such as Laparoscopic Peng's multifunctional operative dissector,curettage and aspiration procedure,Cai's associating liver partition with portal vein ligation for staged hepatectomy,sutureless anastomosisetc in minimally invasive field.The paper advocates the pace of medical invention should be accelerated,inspiring hope for better clinical outcomes with less invasive procedures and shorter recovery time.
文摘The electronic structural, effective masses of carriers, and optical properties of pure and La-doped Cd2SnO4 are calculated by using the first-principles method based on the density functional theory. Using the GGA＋U method, we show that Cd2SnO4 is a direct band-gap semiconductor with a band gap of 2.216 eV, the band gap decreases to 2.02 eV and the Fermi energy level moves to the conduction band after La doping. The density of states of Cd2SnO4 shows that the bottom of the conduction band is composed of Cd 5s, Sn 5s, and Sn 5p orbits, the top of the valence band is composed of Cd 4d and O 2p, and the La 5d orbital is hybridized with the O 2p orbital, which plays a key role at the conduction band bottom after La doping. The effective masses at the conduction band bottom of pure and La-doped Cd2SnO4 are 0.18m0 and 0.092m0, respectively, which indicates that the electrical conductivity of Cd2SnO4 after La doping is improved. The calculated optical properties show that the optical transmittance of La-doped Cd2SnO4 is 92%, the optical absorption edge is slightly blue shifted, and the optical band gap is increased to 3.263 eV. All the results indicate that the conductivity and optical transmittance of Cd2SnO4 can be improved by doping La.
文摘Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon agricultural development approaches are lacking of deep and systematical researches. Therefore, the paper briefly analyzed the situation and the existing problems of China＇s low carbon agricultural development, and then put forward the approaches to promote the low carbon agricultural development.
