Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involv...Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.展开更多
Several kinds of slide nozzle plate such as A12O3-C-ZrO2, MgO, Al2O3, Spinel-C and A12O3-C SN plate for high oxygen steel used in BaoSteel have been analysed, the appearance and size of the SN plate after using have b...Several kinds of slide nozzle plate such as A12O3-C-ZrO2, MgO, Al2O3, Spinel-C and A12O3-C SN plate for high oxygen steel used in BaoSteel have been analysed, the appearance and size of the SN plate after using have been measured. The Al2O3-C SN plate has longer service life in casting high oxygen steel, and the wear mechanism of different SN plates is discussed.展开更多
AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were ...AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were studied.With Si element addition,the surface and cross-sectional microstructure of HEA coating are refined,and it was found that both HEA coatings have a body-centered cubic structure,and the X-ray diffraction peaks of AlCoCrFeNiSi HEA coating deviate to the right.The microhardness,bonding strength nanohardness and elastic modulus of AlCoCrFeNi HEA coating increased with addition of Si element due to the fact that Si promotes uniformly distribution of other elements.In terms of wear properties,coefficient of friction and the wear rate were reduced with Si element addition,and the two HEA coatings have similar wear mechanism at the same loads.And at lower loads,the wear mechanism is abrasive wear,adhesive and slight oxidative wear,it is turn to oxidative wear and severe abrasive wear while the load is increased.The AlCoCrFeNiSi HEA coating has a higher corrosion potential and a lower corrosion current density,indicating improved corrosion resistance.This enhancement is attributed to the presence of Si,which reduces interatomic spacing and results in a more compact atomic arrangement.Consequently,element migration and chemical reactions are reduced,leading to the formation of a denser and more uniform passivation film.展开更多
This study investigated the effects of grape seed extract(GSE)on fresh and cooked meat color and premature browning(PMB)in ground meat patties(85% beef and 15% pork back fat)packaged under high-oxygen modified atmosph...This study investigated the effects of grape seed extract(GSE)on fresh and cooked meat color and premature browning(PMB)in ground meat patties(85% beef and 15% pork back fat)packaged under high-oxygen modified atmospheres(HiOx-MAP).The GSE was added to patties at concentrations of 0,0.10,0.25,0.50 and 0.75 g kg^(-1).This study evaluated the surface color,pH,lipid oxidation,and total viable counts(TVC)of raw patties,and the internal color and pH of patties cooked to a temperature of 66 or 71℃ over 10-day storage at 4℃.Compared with the control(0 g kg^(-1) GSE),GSE improved the color stability(P<0.05)and significantly inhibited the lipid and myoglobin oxidation of raw patties from day 5 to 10,but GSE had no effect(P>0.05)on TVC.Patties containing 0.50 and 0.75 g kg^(-1) GSE cooked to 66℃ exhibited greater(P<0.05)interior redness than the control and reduced the PMB of cooked patties in the late storage stage.These results suggested that 0.50 and 0.75 g kg^(-1) GSE can improve fresh meat color and minimize PMB of HiOx-MAP patties.展开更多
The low net efficiency of oxy-fuel circulating fluidized bed(CFB)combustion is mainly due to the addition of air separation unit(ASU)and carbon dioxide compression and purification unit(CPU).High oxygen concentration ...The low net efficiency of oxy-fuel circulating fluidized bed(CFB)combustion is mainly due to the addition of air separation unit(ASU)and carbon dioxide compression and purification unit(CPU).High oxygen concentration is one of the effective methods to improve the net efficiency of oxy-fuel combustion technology in CFB.In this research,a series of calculation and simulation were carried out based on Aspen Plus platform to provide valuable information for further investigation on the CFB oxy-fuel combustion system with high oxygen concentration(40%,50%).A CFB oxy-fuel combustion system model with high oxygen concentration was established including ASU,CPU and CFB oxy-fuel combustion and heat exchange unit.Based on the simulation data,energy and exergy efficiency were analyzed to obtain the following results.The cross-sectional area of furnace and tail flue of 50%CFB oxy-fuel combustion boiler are 43%and 56%of the original size respectively,reducing the construction and investment cost effectively.With the increase of oxygen concentration,the net efficiency of power generation increased significantly,reaching 24.85%and increasing by 6.09%under the condition of 50%oxy-fuel combustion.The total exergy loss increases with the increase of oxygen concentration.In addition,the exergy loss of radiation heat transfer is far higher than convection heat transfer.展开更多
AIM To examine whether high-flow nasal oxygen(HFNO) availability influences the use of general anesthesia(GA) in patients undergoing endoscopic retrograde cholangiopancreatography(ERCP) and endoscopic ultrasound(EUS) ...AIM To examine whether high-flow nasal oxygen(HFNO) availability influences the use of general anesthesia(GA) in patients undergoing endoscopic retrograde cholangiopancreatography(ERCP) and endoscopic ultrasound(EUS) and associated outcomes.METHODS In this retrospective study, patients were stratified into 3 eras between October 1, 2013 and June 30, 2014 based on HFNO availability for deep sedation at the time of their endoscopy. During the first and last 3-mo eras(era 1 and 3), no HFNO was available, whereas it was an option during the second 3-mo era(era 2). The primary outcome was the percent utilization of GA vs deep sedation in each period. Secondary outcomes included oxygen saturation nadir during sedation between periods, as well as procedure duration, and anesthesia-only time between periods and for GA vs sedation cases respectively.RESULTS During the study period 238 ERCP or EUS cases were identified for analysis. Statistical testing was employed and a P < 0.050 was significant unless the Bonferroni correction for multiple comparisons was used. General anesthesia use was significantly lower in era 2 compared to era 1 with the same trend between era 2 and 3(P = 0.012 and 0.045 respectively). The oxygen saturation nadir during sedation was significantly higher in era 2 compared to era 3(P < 0.001) but not between eras 1 and 2(P = 0.028) or 1 and 3(P = 0.069). The procedure time within each era was significantly longer under GA compared to deep sedation(P ≤ 0.007) as was the anesthesia-only time(P ≤ 0.001).CONCLUSION High-flow nasal oxygen availability was associated with decreased GA utilization and improved oxygenation for ERCP and EUS during sedation.展开更多
In this paper,a Ni coating was deposited on the surface of the A356 aluminum alloy by high velocity oxygen fuel spraying to improve the performance of the AZ91D magnesium/A356 aluminum bimetal prepared by a compound c...In this paper,a Ni coating was deposited on the surface of the A356 aluminum alloy by high velocity oxygen fuel spraying to improve the performance of the AZ91D magnesium/A356 aluminum bimetal prepared by a compound casting.The effects of the Ni coating as well as its thickness on microstructure and mechanical properties of the AZ91D/A356 bimetal were systematically researched for the first time.Results demonstrated that the Ni coating and its thickness had a significant effect on the interfacial phase compositions and mechanical properties of the AZ91D/A356 bimetal.The 10μm’s Ni coating cannot prevent the generation of the Al-Mg intermetallic compounds(IMCs)at the interface zone of the AZ91D/A356 bimetal,while the Ni coating with the thickness of 45μm and 190μm can avoid the formation of the Al-Mg IMCs.When the Ni coating was 45μm,the Ni coating disappeared and transformed into Mg-Mg_(2)Ni eutectic structures+Ni_(2)Mg_(3)Al particles at the interface zone.With a thickness of 190μm’s Ni coating,part of the Ni coating remained and the interface layer was composed of the Mg-Mg_(2)Ni eutectic structures+Ni_(2)Mg_(3)Al particles,Mg_(2)Ni layer,Ni solid solution(SS)layer,Al_(3)Ni_(2) layer,Al_(3)Ni layer and sporadic Al_(3)Ni+Al-Al_(3)Ni eutectic structures from AZ91D side to A356 side in sequence.The interface layer consisting of the Mg-Ni and Al-Ni IMCs obtained with the Ni coating had an obvious lower hardness than the Al-Mg IMCs.The shear strength of the AZ91D/A356 bimetal with a Ni coating of 45μm thickness enhanced 41.4%in comparison with that of the bimetal without Ni coating,and the fracture of the bimetal with 45μm’s Ni coating occurred between the Mg matrix and the interface layer with a mixture of brittle fracture and ductile fracture.展开更多
The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen...The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen（DO）was controlled at 3.5–7 mg/L throughout the experiment.The biofilm reactor showed excellent nitritation performance after the inoculation of nitrifying sludge,with the hydraulic retention time being reduced from 24 to 7 hr.Above 90%nitrite accumulation ratio（NAR）was maintained in phase 1.Afterwards,nitratation occurred with the low NH4^＋–N concentration in the reactor.The improvement of NH4^＋–N concentration to 20–35 mg/L had a limited effect on the recovery of nitritation.However,nitritation recovered rapidly when sequencing batch feed mode was adopted in phase 4,with the effluent NH4^＋-N concentration above 7 mg/L.The improvement of ammonia oxidizing bacteria（AOB）activity and the combined inhibition effect of free ammonia（FA）and free nitrous acid（FNA）on the nitrite oxidizing bacteria（NOB）were two key factors for the rapid recovery of nitritation.Sludge activity was obtained in batch tests.The results of batch tests had a good relationship with the long term operation performance of the biofilm reactor.展开更多
BACKGROUND Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications.Therefore,reducing the incidence of postoperative hypoxemia is a clinical concern.AIM...BACKGROUND Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications.Therefore,reducing the incidence of postoperative hypoxemia is a clinical concern.AIM To investigate the clinical efficacy of high-flow nasal cannula oxygen(HFNCO)in the resuscitation period of older orthopedic patients.METHODS In this prospective randomized controlled trial,60 older patients who underwent orthopedic surgery under general anesthesia were randomly divided into two groups:those who used conventional face mask and those who used HFNCO.All patients were treated with 60%oxygen for 1 h after extubation.Patients in the conventional face mask group were treated with a combination of air(2 L)and oxygen(2 L)using a traditional mask,whereas those in the HFNCO group were treated with HFNCO at a constant temperature of 34℃ and flow rate of 40 L/min.We assessed the effectiveness of oxygen therapy by monitoring the patients’arterial blood gas,peripheral oxygen saturation,and postoperative complications.RESULTS The characteristics of the patients were comparable between the groups.One hour after extubation,patients in HFNCO group had a significantly higher arterial partial pressure of oxygen(paO_(2))than that of patients in conventional face mask group(P<0.001).At extubation and 1 h after extubation,patients in both groups showed a significantly higher arterial partial pressure of carbon dioxide(paCO_(2))than the baseline levels(P<0.001).There were no differences in the saturation of peripheral oxygen,paO_(2),and paCO_(2) between the groups before anesthesia and before extubation(P>0.05).There were statistically significant differences in paO_(2) between the two groups before anesthesia and 1 h after extubation and immediately after extubation and 1 h after extubation(P<0.001).However,there were no significant differences in the oxygen tolerance score before leaving the room,airway humidification,and pulmonary complications 3 d after surgery between the two groups(P>0.05).CONCLUSION HFNCO can improve oxygen partial pressure and respiratory function in elderly patients undergoing orthopedic surgery under general endotracheal anesthesia.Thus,HFNCO can be used to prevent postoperative hypoxemia.展开更多
High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve t...High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.展开更多
Using ball milling and single direction pressing, we can produce high performance NdFeB sintered magnets. The oxygen content of sintered magnets can be controlled under 1500xl0^-6 and the magnetic performance can be i...Using ball milling and single direction pressing, we can produce high performance NdFeB sintered magnets. The oxygen content of sintered magnets can be controlled under 1500xl0^-6 and the magnetic performance can be improved by using low oxygen processing. The high preformance NdFeB sintered magnets with Br=(1.4 ± 0.2)T, iHc>796 kA/m and (BH)max=(390± 16) kJ/m^3, have been batch produced.展开更多
Fe-based powder with a composition of Fe_（42.87）Cr_（15.98）Mo_（16.33）C_（15.94）B_（8.88）（at.%）was used to fabricate coatings by high-velocity oxygen fuel spraying.The effects of the spraying parameters on the...Fe-based powder with a composition of Fe_（42.87）Cr_（15.98）Mo_（16.33）C_（15.94）B_（8.88）（at.%）was used to fabricate coatings by high-velocity oxygen fuel spraying.The effects of the spraying parameters on the microstructure and the wear properties of the Fe-based alloy coatings were systematically studied.The results showed that the obtained Fe-based coatings with a thickness of about 400μm consisted of a large-volume amorphous phase and some nanocrystals.With increasing the fuel and oxygen flow rates,the porosity of the obtained coatings decreased.The coating deposited under optimized parameters exhibited the lowest porosity of 2.8%.The excellent wear resistance of this coating was attributed to the properties of the amorphous matrix and the presence of nanocrystals homogeneously distributed within the matrix.The wear mechanism of the coatings was discussed on the basis of observations of the worn surfaces.展开更多
At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to co...At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in-situ measurement of the electrical conductivity of orthopyroxene. The buffering reagents consist of Ni＋NiO, Fe＋Fe3O4, Fe＋FeO and Mo＋MoO2 in order to control the environmental oxygen fugacity. Experimental results made clear that： （1） within the measuring frequency range from 10-1 to 106 Hz, the complex impedance （R） is of intensive dependence on the frequency; （2） The electrical conductivity （a） tends to increase along to the rise of temperature （T）, and Log a vs. 1/ T fit the Arrenhius linear relations; （3） Under the control of oxygen buffer Fe＋Fe3O4, with the rise of pressure, the activation enthalpy tends to increase whereas the electrical conductivity tends to decrease. The activation energy and activation volume of the main current carders of orthopyroxene have been obtained, which are （1.715±0.035） eV and （0.03±0.01） cm^3/mol, respectively; （4） Under given pressure and temperature, the electrical conductivity tends to increase with increasing oxygen fugacity, while under given pressure the activation enthalpy tends to decrease with increasing oxygen fugacity; and （5） The sample＇s small polarons mechanism has provided a reasonable explanations to the conduction behavior at high temperature and high pressure.展开更多
An extended-life and ultra-low oxygen sensor has been fabricated by using polycrystalline Caβ″/β/α-Al2O3 as a solid electrolyte. Five reference electrodes CaO+O2, Caβ″/β/α-Al2O3 (powder)+O2,Cr+Cr2O3, Nb+NbO an...An extended-life and ultra-low oxygen sensor has been fabricated by using polycrystalline Caβ″/β/α-Al2O3 as a solid electrolyte. Five reference electrodes CaO+O2, Caβ″/β/α-Al2O3 (powder)+O2,Cr+Cr2O3, Nb+NbO and Mo+MoO2 were tested in order to select a better reference electrode for this sensor. The limit of determining oxygen activity and the extended-life of the sensor were also tested in this study.展开更多
A new highly oxygenated iridoid,lamiophlomiol C,was isolated from the roots of Lamiophlomis rotata and its structure was elucidated by spectrosoopic techniques and X-ray diffraction.
Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to inve...Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to investigate what types of nursing support are offered to such patients. Methods: We examined one patient each for NPPV and NHF. Polysomnography (PSG), review of the patient charts, and semi-structured interviews were used to collect the data for analysis. Results: Patients treated with NPPV or NHF demonstrated a noticeable reduction in deep sleep, with most of their sleep being shallow. Their sleep patterns varied greatly from those of healthy individuals. These results suggest that, in addition to experiencing extremely fragmented sleep, sleep in these patients was more likely to be interrupted by nursing interventions, such as during auscultation of breath sounds. Furthermore, it was revealed that “anxiety or discomfort that accompanies the mask or air pressure” in patients treated with NPPV and “discomfort that accompanies the nasal cannula or NHF circuit” in patients treated with NHF may be primary causes of disrupted sleep. Our results suggest a need for nursing care aimed at improving sleep quality in patients treated with NPPV or NHF.展开更多
Objective: To study the injury effect and molecular mechanism of high glucose on myocardial cells. Methods: Myocardial cells H9 c2 were cultured and divided into the control group treated with DMEM containing 5.5 mmol...Objective: To study the injury effect and molecular mechanism of high glucose on myocardial cells. Methods: Myocardial cells H9 c2 were cultured and divided into the control group treated with DMEM containing 5.5 mmol/L glucose, the high glucose group treated with DMEM containing 35 mmol/L glucose, and the N-acetylcysteine(NAC) group pre-treated with 1000μmol/L NAC and treated with DMEM containing 1000 μmol/L NAC and 35 mmol/L glucose.The production of ROS and the expression of mitochondria pathway apoptosis molecules in cells as well as the contents of collagen and collagen metabolism molecules were measured.Results: After 8 h, 16 h and 24 h of treatment, ROS RFU as well as Bax, CytC, Caspase-3 and Caspase-9 protein expression in cells and Col-I, Col-Ⅲ, PINP and PⅢNP protein levels in culture medium of high glucose group were higher than those of control group, Bcl-2 protein expression were lower than those of control group, but CTX-Ⅰ protein levels in culture medium were not significantly different from those of control group; after 24 h of treatment, Bax, CytC,Caspase-3 and Caspase-9 protein expression in cells as well as Col-Ⅰ, Col-Ⅲ, PINP and PIIINP protein levels in culture medium of NAC group were lower than those of high glucose group whereas Bcl-2 protein expression was higher than that of high glucose group. Conclusions:High glucose can induce myocardial cell apoptosis, increase collagen synthesis and accelerate interstitial fibrosis by increasing the production of reactive oxygen species.展开更多
We present a novel technique for controlling oxygen fugacity,which is broadly used to in-situ measure the electrical conductivities in minerals and rocks during diamond anvil cell experiments.The electrical conductivi...We present a novel technique for controlling oxygen fugacity,which is broadly used to in-situ measure the electrical conductivities in minerals and rocks during diamond anvil cell experiments.The electrical conductivities of olivine are determined under controlled oxygen fugacity conditions(Mo–MoO2)at pressures up to 4.0 GPa and temperatures up to 873 K.The advantages of this new technique enable the measuring of the activation enthalpy,activation energy,and activation bulk volume in the Arrhenius relationship.This provides an improved understanding of the mechanism of conduction in olivine.Electrical conduction in olivine is best explained by small polaron movement,given the oxygen fugacity-dependent variations in conductivity.展开更多
The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%...The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%, and the coke degradation is accelerated with the temperature. The higher the temperature, the more coke surface is involved in reactions, and the less negative effect on coke strength is. Hydrogen exerts stronger effect on coke degradation than CO at high temperature. The coke degradation is decreased with the reduction of ore to coke ratio and increase of ore prereduction rate.展开更多
With the rapid development of industry, the application field of oxygen is becoming wider and wider. As a good combustion supporting agent, oxygen plays an important role in industrial production. The oxygen can be tr...With the rapid development of industry, the application field of oxygen is becoming wider and wider. As a good combustion supporting agent, oxygen plays an important role in industrial production. The oxygen can be transported through the pipeline, and the valve is an indispensable part. The existence of the valve ensures that the oxygen can be reasonably transported to the major demanders. However, valves and other pipelines are also prone to explosion and other dangerous accidents. It is necessary to fully understand the characteristics of oxygen according to this situation. Many studies should be done on the selection and material selection of high-pressure oxygen valves to reduce the incidence of explosion accidents, make the valve more safe and reliable, improve the service life of materials and reduce the incidence of explosion accidents, which plays a role in improving industrial production efficiency.展开更多
基金supported by the National Natural Science Foundation of China(No.22375021,22235003,22261132516&22205021)the BIT Research and Innovation 265 Promoting Project(Grant No.2023YCXZ017)。
文摘Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.
文摘Several kinds of slide nozzle plate such as A12O3-C-ZrO2, MgO, Al2O3, Spinel-C and A12O3-C SN plate for high oxygen steel used in BaoSteel have been analysed, the appearance and size of the SN plate after using have been measured. The Al2O3-C SN plate has longer service life in casting high oxygen steel, and the wear mechanism of different SN plates is discussed.
基金supported by the National Natural Science Foundation of China(Nos.52175196 and 52275218)the National Key R&D Program of China(No.2022YFB3706600).
文摘AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were studied.With Si element addition,the surface and cross-sectional microstructure of HEA coating are refined,and it was found that both HEA coatings have a body-centered cubic structure,and the X-ray diffraction peaks of AlCoCrFeNiSi HEA coating deviate to the right.The microhardness,bonding strength nanohardness and elastic modulus of AlCoCrFeNi HEA coating increased with addition of Si element due to the fact that Si promotes uniformly distribution of other elements.In terms of wear properties,coefficient of friction and the wear rate were reduced with Si element addition,and the two HEA coatings have similar wear mechanism at the same loads.And at lower loads,the wear mechanism is abrasive wear,adhesive and slight oxidative wear,it is turn to oxidative wear and severe abrasive wear while the load is increased.The AlCoCrFeNiSi HEA coating has a higher corrosion potential and a lower corrosion current density,indicating improved corrosion resistance.This enhancement is attributed to the presence of Si,which reduces interatomic spacing and results in a more compact atomic arrangement.Consequently,element migration and chemical reactions are reduced,leading to the formation of a denser and more uniform passivation film.
基金supported by the National Natural Science Foundation of China(31871731)the Key Technology Research and Development Program of Shandong,China(2019GNC106050)+1 种基金the China Agriculture Research System of MOF and MARA(CARS-37)the Key Technology Research and Development Program of Binzhou City,China(2019ZDYF010)。
文摘This study investigated the effects of grape seed extract(GSE)on fresh and cooked meat color and premature browning(PMB)in ground meat patties(85% beef and 15% pork back fat)packaged under high-oxygen modified atmospheres(HiOx-MAP).The GSE was added to patties at concentrations of 0,0.10,0.25,0.50 and 0.75 g kg^(-1).This study evaluated the surface color,pH,lipid oxidation,and total viable counts(TVC)of raw patties,and the internal color and pH of patties cooked to a temperature of 66 or 71℃ over 10-day storage at 4℃.Compared with the control(0 g kg^(-1) GSE),GSE improved the color stability(P<0.05)and significantly inhibited the lipid and myoglobin oxidation of raw patties from day 5 to 10,but GSE had no effect(P>0.05)on TVC.Patties containing 0.50 and 0.75 g kg^(-1) GSE cooked to 66℃ exhibited greater(P<0.05)interior redness than the control and reduced the PMB of cooked patties in the late storage stage.These results suggested that 0.50 and 0.75 g kg^(-1) GSE can improve fresh meat color and minimize PMB of HiOx-MAP patties.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFB0605303)Youth Innovation Promotion Association CAS(Grant No.2020150)。
文摘The low net efficiency of oxy-fuel circulating fluidized bed(CFB)combustion is mainly due to the addition of air separation unit(ASU)and carbon dioxide compression and purification unit(CPU).High oxygen concentration is one of the effective methods to improve the net efficiency of oxy-fuel combustion technology in CFB.In this research,a series of calculation and simulation were carried out based on Aspen Plus platform to provide valuable information for further investigation on the CFB oxy-fuel combustion system with high oxygen concentration(40%,50%).A CFB oxy-fuel combustion system model with high oxygen concentration was established including ASU,CPU and CFB oxy-fuel combustion and heat exchange unit.Based on the simulation data,energy and exergy efficiency were analyzed to obtain the following results.The cross-sectional area of furnace and tail flue of 50%CFB oxy-fuel combustion boiler are 43%and 56%of the original size respectively,reducing the construction and investment cost effectively.With the increase of oxygen concentration,the net efficiency of power generation increased significantly,reaching 24.85%and increasing by 6.09%under the condition of 50%oxy-fuel combustion.The total exergy loss increases with the increase of oxygen concentration.In addition,the exergy loss of radiation heat transfer is far higher than convection heat transfer.
基金Supported by The Department of Anesthesiology and Perioperative Medicine,Tufts Medical Center,Boston,United States
文摘AIM To examine whether high-flow nasal oxygen(HFNO) availability influences the use of general anesthesia(GA) in patients undergoing endoscopic retrograde cholangiopancreatography(ERCP) and endoscopic ultrasound(EUS) and associated outcomes.METHODS In this retrospective study, patients were stratified into 3 eras between October 1, 2013 and June 30, 2014 based on HFNO availability for deep sedation at the time of their endoscopy. During the first and last 3-mo eras(era 1 and 3), no HFNO was available, whereas it was an option during the second 3-mo era(era 2). The primary outcome was the percent utilization of GA vs deep sedation in each period. Secondary outcomes included oxygen saturation nadir during sedation between periods, as well as procedure duration, and anesthesia-only time between periods and for GA vs sedation cases respectively.RESULTS During the study period 238 ERCP or EUS cases were identified for analysis. Statistical testing was employed and a P < 0.050 was significant unless the Bonferroni correction for multiple comparisons was used. General anesthesia use was significantly lower in era 2 compared to era 1 with the same trend between era 2 and 3(P = 0.012 and 0.045 respectively). The oxygen saturation nadir during sedation was significantly higher in era 2 compared to era 3(P < 0.001) but not between eras 1 and 2(P = 0.028) or 1 and 3(P = 0.069). The procedure time within each era was significantly longer under GA compared to deep sedation(P ≤ 0.007) as was the anesthesia-only time(P ≤ 0.001).CONCLUSION High-flow nasal oxygen availability was associated with decreased GA utilization and improved oxygenation for ERCP and EUS during sedation.
基金supports provided by the National Natural Science Foundation of China (No. 52075198)the National Key Research and Development Program of China (Nos. 2020YFB2008300 and 2020YFB2008304)+1 种基金the State Key Laboratory of High Performance Complex Manufacturing in CSU (No. Kfkt2019-01)the Analytical and Testing Center, HUST.
文摘In this paper,a Ni coating was deposited on the surface of the A356 aluminum alloy by high velocity oxygen fuel spraying to improve the performance of the AZ91D magnesium/A356 aluminum bimetal prepared by a compound casting.The effects of the Ni coating as well as its thickness on microstructure and mechanical properties of the AZ91D/A356 bimetal were systematically researched for the first time.Results demonstrated that the Ni coating and its thickness had a significant effect on the interfacial phase compositions and mechanical properties of the AZ91D/A356 bimetal.The 10μm’s Ni coating cannot prevent the generation of the Al-Mg intermetallic compounds(IMCs)at the interface zone of the AZ91D/A356 bimetal,while the Ni coating with the thickness of 45μm and 190μm can avoid the formation of the Al-Mg IMCs.When the Ni coating was 45μm,the Ni coating disappeared and transformed into Mg-Mg_(2)Ni eutectic structures+Ni_(2)Mg_(3)Al particles at the interface zone.With a thickness of 190μm’s Ni coating,part of the Ni coating remained and the interface layer was composed of the Mg-Mg_(2)Ni eutectic structures+Ni_(2)Mg_(3)Al particles,Mg_(2)Ni layer,Ni solid solution(SS)layer,Al_(3)Ni_(2) layer,Al_(3)Ni layer and sporadic Al_(3)Ni+Al-Al_(3)Ni eutectic structures from AZ91D side to A356 side in sequence.The interface layer consisting of the Mg-Ni and Al-Ni IMCs obtained with the Ni coating had an obvious lower hardness than the Al-Mg IMCs.The shear strength of the AZ91D/A356 bimetal with a Ni coating of 45μm thickness enhanced 41.4%in comparison with that of the bimetal without Ni coating,and the fracture of the bimetal with 45μm’s Ni coating occurred between the Mg matrix and the interface layer with a mixture of brittle fracture and ductile fracture.
基金funded by the National Water Pollution Control and Management Technology Major Projects(No.2014ZX 07201-011)the Beijing Natural Science Foundation(No.8122005)of Chinathe Beijing Municipal EducationCommission General Program(No.KM2012-10005028)
文摘The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen（DO）was controlled at 3.5–7 mg/L throughout the experiment.The biofilm reactor showed excellent nitritation performance after the inoculation of nitrifying sludge,with the hydraulic retention time being reduced from 24 to 7 hr.Above 90%nitrite accumulation ratio（NAR）was maintained in phase 1.Afterwards,nitratation occurred with the low NH4^＋–N concentration in the reactor.The improvement of NH4^＋–N concentration to 20–35 mg/L had a limited effect on the recovery of nitritation.However,nitritation recovered rapidly when sequencing batch feed mode was adopted in phase 4,with the effluent NH4^＋-N concentration above 7 mg/L.The improvement of ammonia oxidizing bacteria（AOB）activity and the combined inhibition effect of free ammonia（FA）and free nitrous acid（FNA）on the nitrite oxidizing bacteria（NOB）were two key factors for the rapid recovery of nitritation.Sludge activity was obtained in batch tests.The results of batch tests had a good relationship with the long term operation performance of the biofilm reactor.
文摘BACKGROUND Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications.Therefore,reducing the incidence of postoperative hypoxemia is a clinical concern.AIM To investigate the clinical efficacy of high-flow nasal cannula oxygen(HFNCO)in the resuscitation period of older orthopedic patients.METHODS In this prospective randomized controlled trial,60 older patients who underwent orthopedic surgery under general anesthesia were randomly divided into two groups:those who used conventional face mask and those who used HFNCO.All patients were treated with 60%oxygen for 1 h after extubation.Patients in the conventional face mask group were treated with a combination of air(2 L)and oxygen(2 L)using a traditional mask,whereas those in the HFNCO group were treated with HFNCO at a constant temperature of 34℃ and flow rate of 40 L/min.We assessed the effectiveness of oxygen therapy by monitoring the patients’arterial blood gas,peripheral oxygen saturation,and postoperative complications.RESULTS The characteristics of the patients were comparable between the groups.One hour after extubation,patients in HFNCO group had a significantly higher arterial partial pressure of oxygen(paO_(2))than that of patients in conventional face mask group(P<0.001).At extubation and 1 h after extubation,patients in both groups showed a significantly higher arterial partial pressure of carbon dioxide(paCO_(2))than the baseline levels(P<0.001).There were no differences in the saturation of peripheral oxygen,paO_(2),and paCO_(2) between the groups before anesthesia and before extubation(P>0.05).There were statistically significant differences in paO_(2) between the two groups before anesthesia and 1 h after extubation and immediately after extubation and 1 h after extubation(P<0.001).However,there were no significant differences in the oxygen tolerance score before leaving the room,airway humidification,and pulmonary complications 3 d after surgery between the two groups(P>0.05).CONCLUSION HFNCO can improve oxygen partial pressure and respiratory function in elderly patients undergoing orthopedic surgery under general endotracheal anesthesia.Thus,HFNCO can be used to prevent postoperative hypoxemia.
基金financially supported by the National Natural Science Foundation of China (Nos. 51422403, 51774078 and U1508217)the Fundamental Research Funds for the Central Universities (No. N162505002)
文摘High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.
文摘Using ball milling and single direction pressing, we can produce high performance NdFeB sintered magnets. The oxygen content of sintered magnets can be controlled under 1500xl0^-6 and the magnetic performance can be improved by using low oxygen processing. The high preformance NdFeB sintered magnets with Br=(1.4 ± 0.2)T, iHc>796 kA/m and (BH)max=(390± 16) kJ/m^3, have been batch produced.
基金Item Sponsored by National Natural Science Foundation of China(51205001)Key Project of Natural Science of Education Department of Anhui Province of China(KJ2014A023)Scientific Research Starting Foundation of Anhui Polytechnic University of China(2012YQQ006)
文摘Fe-based powder with a composition of Fe_（42.87）Cr_（15.98）Mo_（16.33）C_（15.94）B_（8.88）（at.%）was used to fabricate coatings by high-velocity oxygen fuel spraying.The effects of the spraying parameters on the microstructure and the wear properties of the Fe-based alloy coatings were systematically studied.The results showed that the obtained Fe-based coatings with a thickness of about 400μm consisted of a large-volume amorphous phase and some nanocrystals.With increasing the fuel and oxygen flow rates,the porosity of the obtained coatings decreased.The coating deposited under optimized parameters exhibited the lowest porosity of 2.8%.The excellent wear resistance of this coating was attributed to the properties of the amorphous matrix and the presence of nanocrystals homogeneously distributed within the matrix.The wear mechanism of the coatings was discussed on the basis of observations of the worn surfaces.
基金This research project was granted by the Knowledge-Innovation Program sponsored by the Chinese Academy of Sciences(KZCX3-SW-124).
文摘At presure 1.0-4.0 GPa and temperature 1073-1423 K and under oxygen partial pressure conditions, a YJ-3000t multi-anvil solid high-pressure apparatus and Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in-situ measurement of the electrical conductivity of orthopyroxene. The buffering reagents consist of Ni＋NiO, Fe＋Fe3O4, Fe＋FeO and Mo＋MoO2 in order to control the environmental oxygen fugacity. Experimental results made clear that： （1） within the measuring frequency range from 10-1 to 106 Hz, the complex impedance （R） is of intensive dependence on the frequency; （2） The electrical conductivity （a） tends to increase along to the rise of temperature （T）, and Log a vs. 1/ T fit the Arrenhius linear relations; （3） Under the control of oxygen buffer Fe＋Fe3O4, with the rise of pressure, the activation enthalpy tends to increase whereas the electrical conductivity tends to decrease. The activation energy and activation volume of the main current carders of orthopyroxene have been obtained, which are （1.715±0.035） eV and （0.03±0.01） cm^3/mol, respectively; （4） Under given pressure and temperature, the electrical conductivity tends to increase with increasing oxygen fugacity, while under given pressure the activation enthalpy tends to decrease with increasing oxygen fugacity; and （5） The sample＇s small polarons mechanism has provided a reasonable explanations to the conduction behavior at high temperature and high pressure.
文摘An extended-life and ultra-low oxygen sensor has been fabricated by using polycrystalline Caβ″/β/α-Al2O3 as a solid electrolyte. Five reference electrodes CaO+O2, Caβ″/β/α-Al2O3 (powder)+O2,Cr+Cr2O3, Nb+NbO and Mo+MoO2 were tested in order to select a better reference electrode for this sensor. The limit of determining oxygen activity and the extended-life of the sensor were also tested in this study.
文摘A new highly oxygenated iridoid,lamiophlomiol C,was isolated from the roots of Lamiophlomis rotata and its structure was elucidated by spectrosoopic techniques and X-ray diffraction.
文摘Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to investigate what types of nursing support are offered to such patients. Methods: We examined one patient each for NPPV and NHF. Polysomnography (PSG), review of the patient charts, and semi-structured interviews were used to collect the data for analysis. Results: Patients treated with NPPV or NHF demonstrated a noticeable reduction in deep sleep, with most of their sleep being shallow. Their sleep patterns varied greatly from those of healthy individuals. These results suggest that, in addition to experiencing extremely fragmented sleep, sleep in these patients was more likely to be interrupted by nursing interventions, such as during auscultation of breath sounds. Furthermore, it was revealed that “anxiety or discomfort that accompanies the mask or air pressure” in patients treated with NPPV and “discomfort that accompanies the nasal cannula or NHF circuit” in patients treated with NHF may be primary causes of disrupted sleep. Our results suggest a need for nursing care aimed at improving sleep quality in patients treated with NPPV or NHF.
基金supported by Research Projects of Wuhan Health Bureau(No.wx12c35)
文摘Objective: To study the injury effect and molecular mechanism of high glucose on myocardial cells. Methods: Myocardial cells H9 c2 were cultured and divided into the control group treated with DMEM containing 5.5 mmol/L glucose, the high glucose group treated with DMEM containing 35 mmol/L glucose, and the N-acetylcysteine(NAC) group pre-treated with 1000μmol/L NAC and treated with DMEM containing 1000 μmol/L NAC and 35 mmol/L glucose.The production of ROS and the expression of mitochondria pathway apoptosis molecules in cells as well as the contents of collagen and collagen metabolism molecules were measured.Results: After 8 h, 16 h and 24 h of treatment, ROS RFU as well as Bax, CytC, Caspase-3 and Caspase-9 protein expression in cells and Col-I, Col-Ⅲ, PINP and PⅢNP protein levels in culture medium of high glucose group were higher than those of control group, Bcl-2 protein expression were lower than those of control group, but CTX-Ⅰ protein levels in culture medium were not significantly different from those of control group; after 24 h of treatment, Bax, CytC,Caspase-3 and Caspase-9 protein expression in cells as well as Col-Ⅰ, Col-Ⅲ, PINP and PIIINP protein levels in culture medium of NAC group were lower than those of high glucose group whereas Bcl-2 protein expression was higher than that of high glucose group. Conclusions:High glucose can induce myocardial cell apoptosis, increase collagen synthesis and accelerate interstitial fibrosis by increasing the production of reactive oxygen species.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674404,41330206,and 11374121)
文摘We present a novel technique for controlling oxygen fugacity,which is broadly used to in-situ measure the electrical conductivities in minerals and rocks during diamond anvil cell experiments.The electrical conductivities of olivine are determined under controlled oxygen fugacity conditions(Mo–MoO2)at pressures up to 4.0 GPa and temperatures up to 873 K.The advantages of this new technique enable the measuring of the activation enthalpy,activation energy,and activation bulk volume in the Arrhenius relationship.This provides an improved understanding of the mechanism of conduction in olivine.Electrical conduction in olivine is best explained by small polaron movement,given the oxygen fugacity-dependent variations in conductivity.
文摘The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%, and the coke degradation is accelerated with the temperature. The higher the temperature, the more coke surface is involved in reactions, and the less negative effect on coke strength is. Hydrogen exerts stronger effect on coke degradation than CO at high temperature. The coke degradation is decreased with the reduction of ore to coke ratio and increase of ore prereduction rate.
文摘With the rapid development of industry, the application field of oxygen is becoming wider and wider. As a good combustion supporting agent, oxygen plays an important role in industrial production. The oxygen can be transported through the pipeline, and the valve is an indispensable part. The existence of the valve ensures that the oxygen can be reasonably transported to the major demanders. However, valves and other pipelines are also prone to explosion and other dangerous accidents. It is necessary to fully understand the characteristics of oxygen according to this situation. Many studies should be done on the selection and material selection of high-pressure oxygen valves to reduce the incidence of explosion accidents, make the valve more safe and reliable, improve the service life of materials and reduce the incidence of explosion accidents, which plays a role in improving industrial production efficiency.
