Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into ...Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into W through mechanical alloying. XRD analysis shows that after 50 h of ball milling, the diffraction peak of Al completely disappears and W(Al60) super-saturated solid solution powder is obtained. Further observation by HAADF and HRTEM reveals that the W(Al60) super-saturated solid solution powder is a mixture of solid solution and amorphous phase. Based on the good thermal stability of W(Al60) alloy powder below 1000℃, W(Al60)-Al composite was synthesized by hot pressing process.Impact initiation experiments suggest that the W(Al60)-Al composite has excellent reaction characteristics, and multiple types of tungsten oxides are detected in the reaction products, showing that the modified W is combustible in air. Due to the combustion of tungsten, the energy release rate of the W(Al60)-Al composite at speed of 1362 m/s reaches 2.71 kJ/g.展开更多
Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,c...Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.展开更多
Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage characteristics.In this work the microstructure,mechanical properties and energy release characteristics of multi-elem...Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage characteristics.In this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were studied.The microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of Ti.While the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of Zr.The evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta alloys.The synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation movement.And as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually increase.The higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.展开更多
AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphthe...AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphtheria toxin receptor(DTR) transgenic mice and severe combined immune deficient(SCID)-beige mice,to create Alb-cre/DTR/SCID-beige(ADSB) mice,which coincidentally harbor Alb-cre and DTR transgenes and are immunodeficient. As the Cre expression is driven by the liver-specific promoter Alb(encoding ALB),the DTR stop signal flanked by two lox P sites can be deleted in the ADSB mice,resulting in DTR expression in the liver. ADSB mice aged 8-10 wk were injected intraperitoneally(i.p.) with diphtheria toxin(DT) and liver damage was assessed by serum alanine aminotransferase(ALT) level. Two days later,mouse livers were sampled for histological analysis,and human hepatocytes were transplanted into the livers on the same day. A human ALB enzyme-linked immunosorbent assay was performed 7,14,21 and 28 d after transplantation. Human CD68 immunohistochemistry was performed 30 and 90 d after transplantation.RESULTS We crossed Alb-cre with DTR and SCID-beige mice to obtain ADSB mice. These mice were found to have liver damage 4 d after i.p. injection of 2.5 ng/g bodyweight DT. Bodyweight began to decrease on day 2,increased on day 7,and was lowest on day 4(range,10.5%-13.4%). Serum ALT activity began to increase on day 2 and reached a peak value of 289.7 ± 16.2 IU/m L on day 4,then returned to background values on day 7. After transplantation of human liver cells,peripheral blood human ALB level was 1580 ± 454.8 ng/m L(range,750.2-3064.9 ng/m L) after 28 d and Kupffer cells were present in the liver at 30 d in ADSB mice.CONCLUSION Human hepatocytes were successfully repopulated in the livers of ADSB mice. The inducible mouse model of humanized liver in ADSB mice may have functional applications,such as hepatocyte transplantation,hepatic regeneration and drug metabolism.展开更多
Lithium (Li) metal is considered as one of the most promising anode materials to build next-generation high-energy–density batteries. Nonetheless, dendritic Li deposition has dramatically hindered the practical appli...Lithium (Li) metal is considered as one of the most promising anode materials to build next-generation high-energy–density batteries. Nonetheless, dendritic Li deposition has dramatically hindered the practical applications of Li metal batteries (LMBs). Uniformizing Li deposition is a prerequisite to achieve safe and practical LMBs. Herein, an underpotential deposition (UPD) process is first proposed to alter the kinetic and uniformity of Li deposition morphology. Based on the strong interaction between the Li adatoms and manganese (Mn) based substrate, a competition between the UPD and bulk Li deposition is observed, on which the predominance of the UPD scenario tends to uniformize Li nucleation and deposition by the surface coverage of Li monolayers at potentials that are more positive than the Nernst potential of Li metal. Inspired by this process, an advanced hybrid Mn-graphene oxide structure is developed for Li protection, not only enabling dendrite-free Li anodes for high-capacity and -current density cycling, but also improving the interfacial kinetic of Li metal anodes at subzero temperatures, showing potential applicability in low temperature conditions.展开更多
We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fib...We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fiberized nanosecond amplifier architecture, which consists of Yb-doped fiber preamplifiers and a super-large-mode-area Yb-doped fiber power amplifier. The fiber amplifier with a core of 50 μm is used to raise the threshold of the stimulated Brillouin scattering(SBS) effect and to obtain high output power and single pulse energy. Using lithium triborate(LBO) crystal and betabarium borate(BBO) crystal for realizing the second-harmonic generation(SHG) and fourth-harmonic generation(FHG),we achieve 17 μJ(1.73 W) and 0.66 μJ(66 mW), respectively, at wavelengths of 532 nm and 266 nm and a repetition rate of 100 kHz with pulse width of 4 ns. This source has great potential applications in fluorescence research and solar-blind ultraviolet optical communication.展开更多
We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-ampl...We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.展开更多
A novel shorted anode lateral-insulated gate bipolar transistor(SA LIGBT)with snapback-free characteristic is proposed and investigated.The device features a controlled barrier V_(barrier)and resistance R_(SA)in anode...A novel shorted anode lateral-insulated gate bipolar transistor(SA LIGBT)with snapback-free characteristic is proposed and investigated.The device features a controlled barrier V_(barrier)and resistance R_(SA)in anode,named CBR LIGBT.The electron barrier is formed by the P-float/N-buffer junction,while the anode resistance includes the polysilicon layer and N-float.At forward conduction stage,the V_(barrier)and R_(SA)can be increased by adjusting the doping of the P-float and polysilicon layer,respectively,which can suppress the unipolar mode to eliminate the snapback.At turn-off stage,the low-resistance extraction path(N-buffer/P-float/polysilicon layer/N-float)can quickly extract the electrons in the N-drift,which can effectively accelerate the turn-off speed of the device.The simulation results show that at the same V_(on) of 1.3 V,the E_(off)of the CBR LIGBT is reduced by 85%,73%,and 59.6%compared with the SSA LIGBT,conventional LIGBT,and TSA LIGBT,respectively.Additionally,at the same Eoffof 1.5 m J/cm^(2),the CBR LIGBT achieves the lowest V_(on) of 1.1 V compared with the other LIGBTs.展开更多
Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In thi...Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In this study,we assessed some key factors,including codon usage of the expressed genes,types of promoters,bacterial strains,and culture media,for engineered Escherichia coli to produce astaxanthin.The effect of codon usage was shown to be related to the types of promoters.E.coli DH5a was superior to other strains for astaxanthin production.Different culture media greatly affected the contents and yields of astaxanthin in engineered E.coli.When the expression cassette containing GadE promoter and its driving genes,HpCHY and CrBKT,was inserted into the plasmid pACCAR16DcrtX and expressed in E.coli DH5a,the engineered strain was able to produce 4.30±0.28 mg/g dry cell weight(DCW)or 24.16±2.03 mg/L of astaxanthin,which was a sevenfold or 40-fold increase over the initial production of 0.62±0.03 mg/g DCW or 0.61±0.05 mg/L.展开更多
Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and ...Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and to interpret a large and complex water quality data sets collected from the Songhua River Basin. The data sets, which contained 14 parameters, were generated during the 7-year (1998-2004) monitoring program at 14 different sites along the rivers. Three significant sampling locations (less polluted sites, moderately polluted sites and highly polluted sites) were detected by CA method, and five latent factors (organic, inor-ganic, petrochemical, physiochemical, and heavy metals) were identified by PCA and FA methods. The re-sults of DA showed only five parameters (temperature, pH, dissolved oxygen, ammonia nitrogen, and nitrate nitrogen) and eight parameters (temperature, pH, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, volatile phenols and total arsenic) were necessarily in temporal and spatial varia-tions analysis, respectively. Furthermore, this study revealed the major causes of water quality deterioration were related to inflow of effluent from domestic and industrial wastewater disposal.展开更多
We report an all-fiberized chirped pulse amplification system without any bulk devices.The stretcher and compressor are chirped fiber Bragg gratings inscribed in a 6/125μm single-mode fiber and a 30/250μm largemode-...We report an all-fiberized chirped pulse amplification system without any bulk devices.The stretcher and compressor are chirped fiber Bragg gratings inscribed in a 6/125μm single-mode fiber and a 30/250μm largemode-area fiber.The fabrication system of chirped fiber Bragg gratings was designed and built by ourselves.The width of the linear exposure spot was controlled according to the different fiber sizes to improve the fabrication quality,and the parameters of chirped fiber Bragg gratings were fine-tuned during the fabrication to achieve the overall system’s spectral matching.Two fiber circulators with the same fiber sizes as the chirped fiber Bragg gratings were employed to auxiliarily achieve the pulse stretching and compression.The dispersion accumulations provided by the stretcher and compressor are 129.8 ps and 90.8 ps.The power amplifiers were composed of the two-stage 10/130μm fiber pre-amplifier and the 30/250μm fiber main amplifier.The proposed chirped pulse amplification system with no spatial light is the true sense of an all-fiberized chirped pulse amplification structure and shows the main trend in development of ultrashort pulse fiber lasers.展开更多
DEAR EDITOR,Movement patterns can reflect species-specific characteristics of individuals and animal groups at a given scale. Accurate three-dimensional(3D) assessment can quantify the relationship between movement pa...DEAR EDITOR,Movement patterns can reflect species-specific characteristics of individuals and animal groups at a given scale. Accurate three-dimensional(3D) assessment can quantify the relationship between movement patterns of an animal and its unique habitat. Here, we evaluated the effects of habitat structure on movement patterns of the golden snub-nosed monkey(Rhinopithecus roxellana). We used airborne light detection and ranging(LiDAR) to map the 3D structure of the temperate forest in the Qinling Mountains(Shaanxi, China).展开更多
Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especial...Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon(C), nitrogen(N), and phosphorus(P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling(especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C,N, and P cycling across the soil profile(0–100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N_(2)O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae,Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N_(2)O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.展开更多
A numerical model is presented to simulate the influence function of deformable mirror actuators. The numerical model is formed by Bessel Fourier orthogonal functions, which are constituted of Bessel orthogonal functi...A numerical model is presented to simulate the influence function of deformable mirror actuators. The numerical model is formed by Bessel Fourier orthogonal functions, which are constituted of Bessel orthogonal functions and a Fourier basis. A detailed comparison is presented between the new Bessel Fourier model, the Zernike model, the Gaussian influence function and the modified Gaussian influence function. Numerical experiments indicate that the new numerical model is easy to use and more accurate compared with other numerical models. The new numerical model can be used for describing deformable mirror performances and numerical simulations of adaptive optics systems.展开更多
Investigating deuteron–deuteron(DD)fusion reactions in a plasma environment similar to the early stages of the Big Bang is an important topic in nuclear astrophysics.In this study,we experimentally investigated such ...Investigating deuteron–deuteron(DD)fusion reactions in a plasma environment similar to the early stages of the Big Bang is an important topic in nuclear astrophysics.In this study,we experimentally investigated such reactions,using eight laser beams with the third harmonic impacting on a deuterated polyethylene target at the ShenGuang-II Upgrade laser facility.This work focused on the application of range-filter(RF)spectrometers,assembled from a 70 lm aluminum filter and two CR-39 nuclear track detectors,to measure the yields of primary DD-protons.Based on the track diameter calibration results of 3 MeV protons used to diagnose the tracks on the RF spectrometers,an approximate primary DD-proton yield of(8.5±1.7)×10^6 was obtained,consistent with the yields from similar laser facilities worldwide.This indicates that the RF spectrometer is an effective way to measure primary DD-protons.However,due to the low yields of D^3He-protons and its small track diameter,CR-39 detectors were unable to distinguish it from the background spots.Using other accurate detectors may help to measure these rare events.展开更多
Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a larg...Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and ROSA26 reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.展开更多
Changes in platelet parameters are important in secondary brain injury in acute craniocerebral trauma.We selected 163 patients with craniocerebral trauma who were admitted within 24 hours with nonoperative therapy.Pla...Changes in platelet parameters are important in secondary brain injury in acute craniocerebral trauma.We selected 163 patients with craniocerebral trauma who were admitted within 24 hours with nonoperative therapy.Platelet parameters of 40 healthy subjects served as controls.Platelet number was decreased,while mean platelet volume and platelet distribution width values were increased,at 1 and 3 days after injury.Platelet number was lower and mean platelet volume and platelet distribution width were larger in patients with traumatic cerebral infarction and those in Glasgow Coma Scale score < 8 group.Platelet number was negatively correlated to volume of cerebral edema,but positively correlated to Glasgow Outcome Scale score.These data indicate that changes in platelet parameters may be utilized to indicate the state of central nervous system injury and patient prognosis.展开更多
PbTiO_(3) thin films prepared by metalorganic chemical vapor deposition method were investigated using a transmission electron microscope.The as-deposited thin films were highly c-axis oriented,90°a-c domains wer...PbTiO_(3) thin films prepared by metalorganic chemical vapor deposition method were investigated using a transmission electron microscope.The as-deposited thin films were highly c-axis oriented,90°a-c domains were observed And their crystallographic characteristics were investigated.Tetragonality of the PbTiO_(3) films was also obtained.The disappearance of 90°domains in the very thin film was found and attributed to surface relaxation effect.展开更多
基金supported by the National Natural Science Foundation of China, [Award number: 11972372] and [Award number: U20A20231]。
文摘Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into W through mechanical alloying. XRD analysis shows that after 50 h of ball milling, the diffraction peak of Al completely disappears and W(Al60) super-saturated solid solution powder is obtained. Further observation by HAADF and HRTEM reveals that the W(Al60) super-saturated solid solution powder is a mixture of solid solution and amorphous phase. Based on the good thermal stability of W(Al60) alloy powder below 1000℃, W(Al60)-Al composite was synthesized by hot pressing process.Impact initiation experiments suggest that the W(Al60)-Al composite has excellent reaction characteristics, and multiple types of tungsten oxides are detected in the reaction products, showing that the modified W is combustible in air. Due to the combustion of tungsten, the energy release rate of the W(Al60)-Al composite at speed of 1362 m/s reaches 2.71 kJ/g.
基金support by the National Natural Science Foundation of China(51802269,21773138)Fundamental Research Funds for the Central Universities(XDJK2019AA002)+1 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2018027)the innovation platform for academicians of Hainan province.
文摘Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.
基金supported by the National Natural Science Foundation of China(Grant Nos.52171166,11972372 and U20A20231)supported by Sinoma Institute of Materials Research(Guang Zhou)Co.,Ltd。
文摘Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage characteristics.In this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were studied.The microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of Ti.While the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of Zr.The evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta alloys.The synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation movement.And as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually increase.The higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.
基金Supported by Shanghai Science and Technology Development Foundation Project,No.12140900300Shanghai Municipal Commission of Health and Family Planning Project,No.20144Y0073+1 种基金Shanghai Public Health Clinical Center Project,No.2014M08National Science and Technology Major Project,No.2017ZX10304402-001-012
文摘AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphtheria toxin receptor(DTR) transgenic mice and severe combined immune deficient(SCID)-beige mice,to create Alb-cre/DTR/SCID-beige(ADSB) mice,which coincidentally harbor Alb-cre and DTR transgenes and are immunodeficient. As the Cre expression is driven by the liver-specific promoter Alb(encoding ALB),the DTR stop signal flanked by two lox P sites can be deleted in the ADSB mice,resulting in DTR expression in the liver. ADSB mice aged 8-10 wk were injected intraperitoneally(i.p.) with diphtheria toxin(DT) and liver damage was assessed by serum alanine aminotransferase(ALT) level. Two days later,mouse livers were sampled for histological analysis,and human hepatocytes were transplanted into the livers on the same day. A human ALB enzyme-linked immunosorbent assay was performed 7,14,21 and 28 d after transplantation. Human CD68 immunohistochemistry was performed 30 and 90 d after transplantation.RESULTS We crossed Alb-cre with DTR and SCID-beige mice to obtain ADSB mice. These mice were found to have liver damage 4 d after i.p. injection of 2.5 ng/g bodyweight DT. Bodyweight began to decrease on day 2,increased on day 7,and was lowest on day 4(range,10.5%-13.4%). Serum ALT activity began to increase on day 2 and reached a peak value of 289.7 ± 16.2 IU/m L on day 4,then returned to background values on day 7. After transplantation of human liver cells,peripheral blood human ALB level was 1580 ± 454.8 ng/m L(range,750.2-3064.9 ng/m L) after 28 d and Kupffer cells were present in the liver at 30 d in ADSB mice.CONCLUSION Human hepatocytes were successfully repopulated in the livers of ADSB mice. The inducible mouse model of humanized liver in ADSB mice may have functional applications,such as hepatocyte transplantation,hepatic regeneration and drug metabolism.
基金This work was supported by the 21C Innovation Laboratory,Contemporary Amperex Technology Ltd by project No.21C-OP-202004the Ningbo 2025 Project(Grant No.2018B10061,2018B10087 and 2019B10044)+1 种基金the National Key R&D Program of China(Grant No.2018YFB0905400)the National Natural Science Foundation of China(Grant No.21805297).
文摘Lithium (Li) metal is considered as one of the most promising anode materials to build next-generation high-energy–density batteries. Nonetheless, dendritic Li deposition has dramatically hindered the practical applications of Li metal batteries (LMBs). Uniformizing Li deposition is a prerequisite to achieve safe and practical LMBs. Herein, an underpotential deposition (UPD) process is first proposed to alter the kinetic and uniformity of Li deposition morphology. Based on the strong interaction between the Li adatoms and manganese (Mn) based substrate, a competition between the UPD and bulk Li deposition is observed, on which the predominance of the UPD scenario tends to uniformize Li nucleation and deposition by the surface coverage of Li monolayers at potentials that are more positive than the Nernst potential of Li metal. Inspired by this process, an advanced hybrid Mn-graphene oxide structure is developed for Li protection, not only enabling dendrite-free Li anodes for high-capacity and -current density cycling, but also improving the interfacial kinetic of Li metal anodes at subzero temperatures, showing potential applicability in low temperature conditions.
基金Project supported by the Key Program of Beijing Municipal Natural Science Foundation, China (Grant No. KZ201910005006)the National Nature Science Foundation of China (Grant No. 62005004)+1 种基金the Natural Science Foundation of Beijing Municipality, China (Grant No. 4204091)the National Science Foundation for Postdoctor Scientists of China (Grant No. 212423)。
文摘We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fiberized nanosecond amplifier architecture, which consists of Yb-doped fiber preamplifiers and a super-large-mode-area Yb-doped fiber power amplifier. The fiber amplifier with a core of 50 μm is used to raise the threshold of the stimulated Brillouin scattering(SBS) effect and to obtain high output power and single pulse energy. Using lithium triborate(LBO) crystal and betabarium borate(BBO) crystal for realizing the second-harmonic generation(SHG) and fourth-harmonic generation(FHG),we achieve 17 μJ(1.73 W) and 0.66 μJ(66 mW), respectively, at wavelengths of 532 nm and 266 nm and a repetition rate of 100 kHz with pulse width of 4 ns. This source has great potential applications in fluorescence research and solar-blind ultraviolet optical communication.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61675009 and 61325021)Key Program of Beijing Municipal Natural Science Foundation,China(Grant No.KZ201910005006).
文摘We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61604027 and 61704016)the Fund from Chongqing Technology Innovation and Application Development(Key Industry Research and Development),China(Grant No.cstc2018jszx-cyzd0646)。
文摘A novel shorted anode lateral-insulated gate bipolar transistor(SA LIGBT)with snapback-free characteristic is proposed and investigated.The device features a controlled barrier V_(barrier)and resistance R_(SA)in anode,named CBR LIGBT.The electron barrier is formed by the P-float/N-buffer junction,while the anode resistance includes the polysilicon layer and N-float.At forward conduction stage,the V_(barrier)and R_(SA)can be increased by adjusting the doping of the P-float and polysilicon layer,respectively,which can suppress the unipolar mode to eliminate the snapback.At turn-off stage,the low-resistance extraction path(N-buffer/P-float/polysilicon layer/N-float)can quickly extract the electrons in the N-drift,which can effectively accelerate the turn-off speed of the device.The simulation results show that at the same V_(on) of 1.3 V,the E_(off)of the CBR LIGBT is reduced by 85%,73%,and 59.6%compared with the SSA LIGBT,conventional LIGBT,and TSA LIGBT,respectively.Additionally,at the same Eoffof 1.5 m J/cm^(2),the CBR LIGBT achieves the lowest V_(on) of 1.1 V compared with the other LIGBTs.
基金This study was supported by a research grant from Department of Economic Plants and Biotechnology,Yunnan Key Laboratory for Wild Plant Resources,Kunming Institute of Botany,Chinese Academy of Sciences.
文摘Astaxanthin is a value-added ketocarotenoid with great potential in nutraceutical and pharmaceutical industries.Genetic engineering of heterologous hosts for astaxanthin production has attracted great attention.In this study,we assessed some key factors,including codon usage of the expressed genes,types of promoters,bacterial strains,and culture media,for engineered Escherichia coli to produce astaxanthin.The effect of codon usage was shown to be related to the types of promoters.E.coli DH5a was superior to other strains for astaxanthin production.Different culture media greatly affected the contents and yields of astaxanthin in engineered E.coli.When the expression cassette containing GadE promoter and its driving genes,HpCHY and CrBKT,was inserted into the plasmid pACCAR16DcrtX and expressed in E.coli DH5a,the engineered strain was able to produce 4.30±0.28 mg/g dry cell weight(DCW)or 24.16±2.03 mg/L of astaxanthin,which was a sevenfold or 40-fold increase over the initial production of 0.62±0.03 mg/g DCW or 0.61±0.05 mg/L.
文摘Multivariate statistical techniques, including cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were used to evaluate temporal and spatial variations and to interpret a large and complex water quality data sets collected from the Songhua River Basin. The data sets, which contained 14 parameters, were generated during the 7-year (1998-2004) monitoring program at 14 different sites along the rivers. Three significant sampling locations (less polluted sites, moderately polluted sites and highly polluted sites) were detected by CA method, and five latent factors (organic, inor-ganic, petrochemical, physiochemical, and heavy metals) were identified by PCA and FA methods. The re-sults of DA showed only five parameters (temperature, pH, dissolved oxygen, ammonia nitrogen, and nitrate nitrogen) and eight parameters (temperature, pH, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen, volatile phenols and total arsenic) were necessarily in temporal and spatial varia-tions analysis, respectively. Furthermore, this study revealed the major causes of water quality deterioration were related to inflow of effluent from domestic and industrial wastewater disposal.
基金supported by the Key Program of Beijing Municipal Natural Science Foundation(Grant No.KZ201910005006)the National Natural Science Foundation of China(Grant No.62005004)+1 种基金the Natural Science Foundation of Beijing Municipality(Grant No.4204091)the National Science Foundation for Post-doctor Scientists of China(Grant No.212423)。
文摘We report an all-fiberized chirped pulse amplification system without any bulk devices.The stretcher and compressor are chirped fiber Bragg gratings inscribed in a 6/125μm single-mode fiber and a 30/250μm largemode-area fiber.The fabrication system of chirped fiber Bragg gratings was designed and built by ourselves.The width of the linear exposure spot was controlled according to the different fiber sizes to improve the fabrication quality,and the parameters of chirped fiber Bragg gratings were fine-tuned during the fabrication to achieve the overall system’s spectral matching.Two fiber circulators with the same fiber sizes as the chirped fiber Bragg gratings were employed to auxiliarily achieve the pulse stretching and compression.The dispersion accumulations provided by the stretcher and compressor are 129.8 ps and 90.8 ps.The power amplifiers were composed of the two-stage 10/130μm fiber pre-amplifier and the 30/250μm fiber main amplifier.The proposed chirped pulse amplification system with no spatial light is the true sense of an all-fiberized chirped pulse amplification structure and shows the main trend in development of ultrashort pulse fiber lasers.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31020302)National Natural Science Foundation of China (32170507, 31730104,31870396, and 32070450)。
文摘DEAR EDITOR,Movement patterns can reflect species-specific characteristics of individuals and animal groups at a given scale. Accurate three-dimensional(3D) assessment can quantify the relationship between movement patterns of an animal and its unique habitat. Here, we evaluated the effects of habitat structure on movement patterns of the golden snub-nosed monkey(Rhinopithecus roxellana). We used airborne light detection and ranging(LiDAR) to map the 3D structure of the temperate forest in the Qinling Mountains(Shaanxi, China).
基金supported by the National Key Research and Development Program of China(2021YFD1700200)the earmarked fund for CARS-Green manure(CARS-22)the Agricultural Science and Technology Innovation Program of CAAS。
文摘Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon(C), nitrogen(N), and phosphorus(P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling(especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C,N, and P cycling across the soil profile(0–100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N_(2)O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae,Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N_(2)O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.
基金supported by the Opening Project of the Key Laboratory of Astronomical Optics and Technology, Nanjing Institute of Astronomical Optics and Technology, Chinese Academy of Sciences (No. CAS-KLAOT-KF201206)
文摘A numerical model is presented to simulate the influence function of deformable mirror actuators. The numerical model is formed by Bessel Fourier orthogonal functions, which are constituted of Bessel orthogonal functions and a Fourier basis. A detailed comparison is presented between the new Bessel Fourier model, the Zernike model, the Gaussian influence function and the modified Gaussian influence function. Numerical experiments indicate that the new numerical model is easy to use and more accurate compared with other numerical models. The new numerical model can be used for describing deformable mirror performances and numerical simulations of adaptive optics systems.
基金supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB160203)the National Natural Science Foundation of China(Nos.11875311 and 11421505).
文摘Investigating deuteron–deuteron(DD)fusion reactions in a plasma environment similar to the early stages of the Big Bang is an important topic in nuclear astrophysics.In this study,we experimentally investigated such reactions,using eight laser beams with the third harmonic impacting on a deuterated polyethylene target at the ShenGuang-II Upgrade laser facility.This work focused on the application of range-filter(RF)spectrometers,assembled from a 70 lm aluminum filter and two CR-39 nuclear track detectors,to measure the yields of primary DD-protons.Based on the track diameter calibration results of 3 MeV protons used to diagnose the tracks on the RF spectrometers,an approximate primary DD-proton yield of(8.5±1.7)×10^6 was obtained,consistent with the yields from similar laser facilities worldwide.This indicates that the RF spectrometer is an effective way to measure primary DD-protons.However,due to the low yields of D^3He-protons and its small track diameter,CR-39 detectors were unable to distinguish it from the background spots.Using other accurate detectors may help to measure these rare events.
基金Shanghai Municipal Health and Family Planning Commission Scientific Research Project,Grant/Award Number:20154Y0075Shanghai Municipal Fund for Science and Technology Development,Grant/Award Number:15140904000+1 种基金Shanghai Public Health Clinical Center,Grant/Award Number:KY-GW-2017-04,KY-GW-2018-48National Natural Science Foundation of China,Grant/Award Number:31270217,31601908,81471397
文摘Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and ROSA26 reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.
基金the Key Medical Construction Subject Foundation of Sichuan Province
文摘Changes in platelet parameters are important in secondary brain injury in acute craniocerebral trauma.We selected 163 patients with craniocerebral trauma who were admitted within 24 hours with nonoperative therapy.Platelet parameters of 40 healthy subjects served as controls.Platelet number was decreased,while mean platelet volume and platelet distribution width values were increased,at 1 and 3 days after injury.Platelet number was lower and mean platelet volume and platelet distribution width were larger in patients with traumatic cerebral infarction and those in Glasgow Coma Scale score < 8 group.Platelet number was negatively correlated to volume of cerebral edema,but positively correlated to Glasgow Outcome Scale score.These data indicate that changes in platelet parameters may be utilized to indicate the state of central nervous system injury and patient prognosis.
基金Supported by the National High Technology Program of China.
文摘PbTiO_(3) thin films prepared by metalorganic chemical vapor deposition method were investigated using a transmission electron microscope.The as-deposited thin films were highly c-axis oriented,90°a-c domains were observed And their crystallographic characteristics were investigated.Tetragonality of the PbTiO_(3) films was also obtained.The disappearance of 90°domains in the very thin film was found and attributed to surface relaxation effect.
