Secondary brain damage caused by hyperactivation of autophagy and inflammatory responses in neurons plays an important role in hypoxic-ischemic brain damage(HIBD).Although previous studies have implicated Toll-like re...Secondary brain damage caused by hyperactivation of autophagy and inflammatory responses in neurons plays an important role in hypoxic-ischemic brain damage(HIBD).Although previous studies have implicated Toll-like receptor 4(TLR4)and nuclear factor kappa-B(NF-κB)in the neuroinflammatory response elicited by brain injury,the role and mechanisms of the TLR4-mediated autophagy signaling pathway in neonatal HIBD are still unclear.We hypothesized that this pathway can regulate brain damage by modulating neuron autophagy and neuroinflammation in neonatal rats with HIBD.Hence,we established a neonatal HIBD rat model using the Rice-Vannucci method,and injected 0.75,1.5,or 3 mg/kg of the TLR4 inhibitor resatorvid(TAK-242)30 minutes after hypoxic ischemia.Our results indicate that administering TAK-242 to neonatal rats after HIBD could significantly reduce the infarct volume and the extent of cerebral edema,alleviate neuronal damage and neurobehavioral impairment,and decrease the expression levels of TLR4,phospho-NF-κB p65,Beclin-1,microtubule-associated protein l light chain 3,tumor necrosis factor-α,and interleukin-1βin the hippocampus.Thus,TAK-242 appears to exert a neuroprotective effect after HIBD by inhibiting activation of autophagy and the release of inflammatory cytokines via inhibition of the TLR4/NF-κB signaling pathway.This study was approved by the Laboratory Animal Ethics Committee of Affiliated Hospital of Yangzhou University,China(approval No.20180114-15)on January 14,2018.展开更多
AIM: To explore the changes of X-box binding protein 1splicing(XBP1s) and inflammatory cytokine expression in patients with ulcerative colitis(UC) in response to endoplasmic reticulum stress(ERS).METHODS: Reverse tran...AIM: To explore the changes of X-box binding protein 1splicing(XBP1s) and inflammatory cytokine expression in patients with ulcerative colitis(UC) in response to endoplasmic reticulum stress(ERS).METHODS: Reverse transcription polymerase chain reaction and quantitative polymerase chain reaction were performed to detect the forms of XBP1 s and the expression of interleukin(IL)-2, interferon(IFN)-γ, and IL-17α. Differences between patients with UC and normal subjects were then determined.RESULTS: Mononuclear cells of the peripheral blood of normal subjects and UC patients with were stimulated with no drugs(control), phytohemagglutinin(PHA), thapsigargin(TG), or both PHA and TG. XBP1 s in patients with UC exhibited splicing, which was greater with co-stimulation than single stimulation. Costimulation increased the expression level of IL-2, IFN-γ, and IL-17α.CONCLUSION: The T lymphocytes of both normal subjects and patients with UC responded to ERS by activating the XBP1s-mediated signalling pathway, upregulating the expression of inflammatory cytokines, and increasing the occurrence of inflammation. The mononuclear cells in the peripheral blood of patients with UC were more sensitive to ERS than those in the peripheral blood of normal subjects.展开更多
A loop antenna for near field readers is proposed. Through periodic interdigital capacitors, the phase of the current on the loop is compensated and kept in phase. Hence, a loop with a perimeter of one wavelength at 9...A loop antenna for near field readers is proposed. Through periodic interdigital capacitors, the phase of the current on the loop is compensated and kept in phase. Hence, a loop with a perimeter of one wavelength at 900 MHz achieves a uniform near magnetic field distribution inside the loop. A novel method is proposed to evaluate the performance of the coplanar waveguide （CPW） to coplanar stripline （CPS） transition, which is used as a balun for the feeding network in this paper. This loop antenna has a 70 MHz operating bandwidth and 12 cm maximum reading range when the output power is 24 dBm, which is suitable for most near field radio frequency identification （RFID） applications.展开更多
Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation...Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation. The core-shell structure is considered as an effective strategy to solve the expansion problem of silicon-based anodes. In this paper, the double-shell structured Si@SnO_(2) @C nanocomposite with nano-silicon as the core and SnO_(2) , C as the shells is synthesized by a facile hydrothermal method.Structural characterization shows that Si@SnO_(2) @C nanocomposite is composed of crystalline Si, crystalline SnO_(2) and amorphous C, and the contents of them are 42.1wt%, 37.8 wt% and 20.1 wt%, respectively. Transmission electron microscope(TEM) observations confirm the double-shell structure of Si@SnO_(2) @C nanocomposite, and the thicknesses of the SnO_(2) and C layers are 20 and 7 nm. The Si@SnO_(2) @C electrode exhibits a high initial discharge capacity of 2777 mAh·g^(-1)at 100 mA·g^(-1)and an excellent rate capability of 340 mAh·g^(-1)at 1500 mA·g^(-1). The outstanding capacity retention is 50.2% after 300 cycles over a potential of 0.01 to 2.00 V(vs. Li/Li+) at 500 mA·g^(-1). The resistance of solid electrolyte interphase(SEI) film(Rf) and charge transfer resistance(Rct) of Si@SnO_(2) @C are 7.68and 0.82 Ω, which are relatively smaller than those of Si@C(21.64 and 2.62 Ω). It is obviously seen that the SnO_(2) shell can reduce the charge transfer resistance, leading to high ion and electron transport efficiency in the Si@SnO_(2) @C electrode. The incorporation of SnO_(2) shell is attributed to the enhanced rate capability and cycling performance of Si@SnO_(2) @C nanocomposite.展开更多
The effect of heat treatment on phase occurrence,crystal structures and hydrogen sorption properties of Y_(0.5)La_(0.2)Mg_(0.3-x)Ni_(2) compounds has been investigated.The targeted compounds were synthesized through i...The effect of heat treatment on phase occurrence,crystal structures and hydrogen sorption properties of Y_(0.5)La_(0.2)Mg_(0.3-x)Ni_(2) compounds has been investigated.The targeted compounds were synthesized through induction melting and processed heat treatment at 700 and 900℃,respectively.Phase occurrence and structural properties were studied by X-ray powder diffraction(XRD).The global compositions and phase compositions have been determined by inductively coupled plasma-optical emission spectrometer(ICP-AES) and electron probe microanalysis(EPMA) respectively.展开更多
Li-Mg-N-B-H/ZrCoH_(3) composites were successfully synthesized by ball milling of the reactants under argon and hydrogen atmosphere,respectively.The composite synthesized by reactive ball milling(RBM)under hydrogen ha...Li-Mg-N-B-H/ZrCoH_(3) composites were successfully synthesized by ball milling of the reactants under argon and hydrogen atmosphere,respectively.The composite synthesized by reactive ball milling(RBM)under hydrogen has the best hydrogen storage properties.It can desorb 3.71 wt%hydrogen in 60 min at 150℃under pressure of 0.1 MPa,and the dehydrogenation capacity reaches 4.59 wt%in 8 h.For the re-hydrogenation,5.27 wt%hydrogen was absorbed in only 10 min at 150℃under H_(2) pressure of 8 MPa.The phases of the as-milled and subsequently dehydrogenated and re-hydrogenated samples were determined by X-ray diffraction(XRD).The microstructures and elemental distributions were characterized by scanning electron microscope(SEM)and energy-dispersive spectrometer(EDS)measurements.It is shown that Mg is in situ hydrogenated and introduced homogeneous distribution of ZrCoH_(3) particles during the RBM process under hydrogen atmosphere.The activation energies for the composites were calculated by Kissinger method through differential scanning calorimetric(DSC)measurements for the dehydrogenation process with different heating rates.It is determined that the activation energy for the Li-Mg-N-B-H/ZrCoH_(3) composite synthesized by RBM under hydrogen is 79.9 kJ·mol^(-1),which is14 kJ·mol^(-1) lower than that for the sample without ZrCoH_(3) addition.The N-H bond energies were analyzed by infrared(IR)absorption spectrum,and the reasons for weakening of the N-H bond were further discussed.展开更多
The structure and hydrogenation properties of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce(x=0,1,3,5;at%) alloys with M=Cr,Mo,Al were investigated.All the alloys show the same phase composition consisting of BCC matric and CeO...The structure and hydrogenation properties of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce(x=0,1,3,5;at%) alloys with M=Cr,Mo,Al were investigated.All the alloys show the same phase composition consisting of BCC matric and CeO_(2)phases which distribute along the grain boundary.The hydrogen capacities of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce change little with M,and none of them exceeds 2.0 wt%.But the plateau pressure shows remarkable linearly variation with the amount of M and the lattice parameter of BCC matric.The additions of Cr,Mo and A1 raise the plateau,but the linear relation of plateau versus BCC lattice parameter of Mo/Al-added alloys is opposite to that of Cr-added alloys and many other conventional hydrogen storage alloys.The radius of hydrogen site is introduced to explain the inconsistent.The plateau pressure of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce with any kind of M added increases with the contraction of the hydrogen site.The plateau pressure of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce can also be reflected by the stability of hydride which is judged by the enthalpy change during the dehydrogenation.展开更多
The effect of LaNi and Ti on thermal storage properties of MgH_(2)was investigated.The thermal storage performances of Mg are significantly improved by adding LaNi and Ti.The pressure-composition-temperature(PCT)curve...The effect of LaNi and Ti on thermal storage properties of MgH_(2)was investigated.The thermal storage performances of Mg are significantly improved by adding LaNi and Ti.The pressure-composition-temperature(PCT)curves indicate that the formation enthalpy for Mg-15 wt%Ti-5 wt%LaNi sample is 73.00 kJ·mol^(-1),which approaches to the theoretical values of pure MgH_(2).The isothermal measurement indicates that,for the Mg-15wt%Ti-5 wt%LaNi,the first absorption reaction fraction within 2 min is 93.77%,increasing by 0.32%,0.24%and0.08%compared with those for Mg,Mg-5 wt%LaNi and Mg-15 wt%Ti,respectively.The first desorption reaction fraction within 2 min is 73.18%,increasing by 55.91%,9.79%and 8.12%compared with those for Mg,Mg-5wt%LaNi and Mg-15 wt%Ti,respectively.Moreover,Mg-15 wt%Ti-5 wt%LaNi has the best cyclic stability in all the samples.The thermal storage performances of Mg by adding both LaNi and Ti are improved mainly ascribed to synergistic effect of in situ formed La_(4)H_(12.19),Mg_(2)NiH_(4),H_(0.3)Mg_(2)Ni and TiH_(2)particles during cyclic process.The above analysis demonstrates that Mg-15 wt%Ti-5wt%LaNi is suitable for using as a heat storage material.展开更多
The effect of LaNi on thermal storage properties of MgH2 prepared by ball milling under hydrogen atmosphere was investigated.The thermal storage properties,cyclic property and thermal storage mechanism were studied by...The effect of LaNi on thermal storage properties of MgH2 prepared by ball milling under hydrogen atmosphere was investigated.The thermal storage properties,cyclic property and thermal storage mechanism were studied by pres sure-composition-temperature(PC T),X-ray diffraction(XRD)and transmission electron microscopy(TEM).The Van't Hoff curve indicates that the formation enthalpy of Mg-16 wt%LaNi is 74.62 kJ·mol^(-1),which approaches to the theoretical values of MgH2.The isothermal measurement indicates that Mg-16 wt%LaNi can absorb 6.263 wt%H_(2)within 30 min at 390℃for the first absorption,the absorption reaction fraction within2 min is over 90.00%,and the desorption reaction fraction within 2 min is 72.63%,increasing by 55.36%compared with that of Mg.Mg-16 wt%LaNi has better cyclic stability than that of Mg,only decreasing by 0.609 wt%after 80cycles.The enhancement in thermal storage performances of Mg by adding LaNi is mainly ascribed to the formed Mg_(2)NiH_(4),H_(0.3)Mg_(2)Ni and La_(4)H_(12.19)during the cyclic process which act as catalysts and inhibit the growth of Mg.The above results prove that Mg-16 wt%LaNi is suitable for use as a heat storage material.展开更多
Metal hydride with proper hydrogen storage properties is the key component of hydride thermal hydrogen compressor.In this work,Ti_(0.85)Zr_(0.17)(Cr-Mn-V)_(1.3)Fe_(0.7)-based alloys were developed to achieve thermal h...Metal hydride with proper hydrogen storage properties is the key component of hydride thermal hydrogen compressor.In this work,Ti_(0.85)Zr_(0.17)(Cr-Mn-V)_(1.3)Fe_(0.7)-based alloys were developed to achieve thermal hydrogen compression at mild operating temperatures of water bath.The results indicate the single C 14-type Laves phase as well as homogeneously distributed elements of all alloys.With increased Mn content in Ti_(0.85)Zr_(0.17)Cr_(1.2-x)Mn_xFe_(0.7)V_(0.1)(x=0,0.1,0.2,0.3)alloys.展开更多
Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental speed and size limits by electronics and photonics, respectively. Graphene offers multiple functions of ...Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental speed and size limits by electronics and photonics, respectively. Graphene offers multiple functions of signal transmission, emission, modulation, and detection in a broad band, high speed, compact size, and low loss. Here, we have a brief view of graphene based functional devices at microwave, terahertz, and optical frequencies. Their fundamental physics and computational models were discussed as well.展开更多
The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directl...The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.展开更多
Cu2ZnSnS4 thin films were prepared by cosputtering with Cu(or Cu2S),ZnS and SnS2 targets in this study.S amount in the precursor of Cu2ZnSnS4 thin film was verified by using Cu or Cu2S target.The effect of S amount in...Cu2ZnSnS4 thin films were prepared by cosputtering with Cu(or Cu2S),ZnS and SnS2 targets in this study.S amount in the precursor of Cu2ZnSnS4 thin film was verified by using Cu or Cu2S target.The effect of S amount in the precursor on the microstructure and element distribution of Cu2ZnSnS4 thin film was discussed.It was found that S content is sufficient in the precursor thin film using Cu2 S instead of Cu target.The microstructure,composition homogeneity,and secondary phase formation of the Cu2ZnSnS4 thin film are seriously affected by S amount in the precursor thin film.Namely,sufficient S can improve the crystallization and orientation of the precursor thin film and enhance the compactness as well as composition homogeneity of the Cu2ZnSnS4 thin film after sulfurization.Moreover,the secondary phase formation in Cu2ZnSnS4 thin film can be greatly inhibited by increasing S content in the precursor thin film.展开更多
Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides （PC-CROWs）. According to the eye-shaped scatterers and various microcavities, saddle- like curves be...Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides （PC-CROWs）. According to the eye-shaped scatterers and various microcavities, saddle- like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is 〉 104, and the normalized delay bandwidth product within a new varying range of ng 〉 102 or ng 〉 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.展开更多
基金financially supported by the National Natural Science Foundation of China,No.81771625(to XF)the Jiangsu Provincial Key Medical Discipline of China,No.ZDXKA2016013(to XF)the Pediatric Clinical Center of Suzhou City of China,No.Szzx201504(to XF)
文摘Secondary brain damage caused by hyperactivation of autophagy and inflammatory responses in neurons plays an important role in hypoxic-ischemic brain damage(HIBD).Although previous studies have implicated Toll-like receptor 4(TLR4)and nuclear factor kappa-B(NF-κB)in the neuroinflammatory response elicited by brain injury,the role and mechanisms of the TLR4-mediated autophagy signaling pathway in neonatal HIBD are still unclear.We hypothesized that this pathway can regulate brain damage by modulating neuron autophagy and neuroinflammation in neonatal rats with HIBD.Hence,we established a neonatal HIBD rat model using the Rice-Vannucci method,and injected 0.75,1.5,or 3 mg/kg of the TLR4 inhibitor resatorvid(TAK-242)30 minutes after hypoxic ischemia.Our results indicate that administering TAK-242 to neonatal rats after HIBD could significantly reduce the infarct volume and the extent of cerebral edema,alleviate neuronal damage and neurobehavioral impairment,and decrease the expression levels of TLR4,phospho-NF-κB p65,Beclin-1,microtubule-associated protein l light chain 3,tumor necrosis factor-α,and interleukin-1βin the hippocampus.Thus,TAK-242 appears to exert a neuroprotective effect after HIBD by inhibiting activation of autophagy and the release of inflammatory cytokines via inhibition of the TLR4/NF-κB signaling pathway.This study was approved by the Laboratory Animal Ethics Committee of Affiliated Hospital of Yangzhou University,China(approval No.20180114-15)on January 14,2018.
基金Beijing Municipal Natural Scientific Research Foundation,No.7132175
文摘AIM: To explore the changes of X-box binding protein 1splicing(XBP1s) and inflammatory cytokine expression in patients with ulcerative colitis(UC) in response to endoplasmic reticulum stress(ERS).METHODS: Reverse transcription polymerase chain reaction and quantitative polymerase chain reaction were performed to detect the forms of XBP1 s and the expression of interleukin(IL)-2, interferon(IFN)-γ, and IL-17α. Differences between patients with UC and normal subjects were then determined.RESULTS: Mononuclear cells of the peripheral blood of normal subjects and UC patients with were stimulated with no drugs(control), phytohemagglutinin(PHA), thapsigargin(TG), or both PHA and TG. XBP1 s in patients with UC exhibited splicing, which was greater with co-stimulation than single stimulation. Costimulation increased the expression level of IL-2, IFN-γ, and IL-17α.CONCLUSION: The T lymphocytes of both normal subjects and patients with UC responded to ERS by activating the XBP1s-mediated signalling pathway, upregulating the expression of inflammatory cytokines, and increasing the occurrence of inflammation. The mononuclear cells in the peripheral blood of patients with UC were more sensitive to ERS than those in the peripheral blood of normal subjects.
文摘A loop antenna for near field readers is proposed. Through periodic interdigital capacitors, the phase of the current on the loop is compensated and kept in phase. Hence, a loop with a perimeter of one wavelength at 900 MHz achieves a uniform near magnetic field distribution inside the loop. A novel method is proposed to evaluate the performance of the coplanar waveguide （CPW） to coplanar stripline （CPS） transition, which is used as a balun for the feeding network in this paper. This loop antenna has a 70 MHz operating bandwidth and 12 cm maximum reading range when the output power is 24 dBm, which is suitable for most near field radio frequency identification （RFID） applications.
基金financially supported by GRINM Science and Technology Innovation Fund (Nos. 2020DY0109 and 57222001)the Opening Project Fund of Materials Service Safety Assessment Facilities (No. MSAF-2021-001)Guangdong High Level Innovation Research Institute (No. 2021B0909050001)。
文摘Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation. The core-shell structure is considered as an effective strategy to solve the expansion problem of silicon-based anodes. In this paper, the double-shell structured Si@SnO_(2) @C nanocomposite with nano-silicon as the core and SnO_(2) , C as the shells is synthesized by a facile hydrothermal method.Structural characterization shows that Si@SnO_(2) @C nanocomposite is composed of crystalline Si, crystalline SnO_(2) and amorphous C, and the contents of them are 42.1wt%, 37.8 wt% and 20.1 wt%, respectively. Transmission electron microscope(TEM) observations confirm the double-shell structure of Si@SnO_(2) @C nanocomposite, and the thicknesses of the SnO_(2) and C layers are 20 and 7 nm. The Si@SnO_(2) @C electrode exhibits a high initial discharge capacity of 2777 mAh·g^(-1)at 100 mA·g^(-1)and an excellent rate capability of 340 mAh·g^(-1)at 1500 mA·g^(-1). The outstanding capacity retention is 50.2% after 300 cycles over a potential of 0.01 to 2.00 V(vs. Li/Li+) at 500 mA·g^(-1). The resistance of solid electrolyte interphase(SEI) film(Rf) and charge transfer resistance(Rct) of Si@SnO_(2) @C are 7.68and 0.82 Ω, which are relatively smaller than those of Si@C(21.64 and 2.62 Ω). It is obviously seen that the SnO_(2) shell can reduce the charge transfer resistance, leading to high ion and electron transport efficiency in the Si@SnO_(2) @C electrode. The incorporation of SnO_(2) shell is attributed to the enhanced rate capability and cycling performance of Si@SnO_(2) @C nanocomposite.
基金financially supported by the National Key R&D Program of China (No.2019YFE0103600)。
文摘The effect of heat treatment on phase occurrence,crystal structures and hydrogen sorption properties of Y_(0.5)La_(0.2)Mg_(0.3-x)Ni_(2) compounds has been investigated.The targeted compounds were synthesized through induction melting and processed heat treatment at 700 and 900℃,respectively.Phase occurrence and structural properties were studied by X-ray powder diffraction(XRD).The global compositions and phase compositions have been determined by inductively coupled plasma-optical emission spectrometer(ICP-AES) and electron probe microanalysis(EPMA) respectively.
基金financially supported by Beijing Science and Technology Program(No.D141100002014002)。
文摘Li-Mg-N-B-H/ZrCoH_(3) composites were successfully synthesized by ball milling of the reactants under argon and hydrogen atmosphere,respectively.The composite synthesized by reactive ball milling(RBM)under hydrogen has the best hydrogen storage properties.It can desorb 3.71 wt%hydrogen in 60 min at 150℃under pressure of 0.1 MPa,and the dehydrogenation capacity reaches 4.59 wt%in 8 h.For the re-hydrogenation,5.27 wt%hydrogen was absorbed in only 10 min at 150℃under H_(2) pressure of 8 MPa.The phases of the as-milled and subsequently dehydrogenated and re-hydrogenated samples were determined by X-ray diffraction(XRD).The microstructures and elemental distributions were characterized by scanning electron microscope(SEM)and energy-dispersive spectrometer(EDS)measurements.It is shown that Mg is in situ hydrogenated and introduced homogeneous distribution of ZrCoH_(3) particles during the RBM process under hydrogen atmosphere.The activation energies for the composites were calculated by Kissinger method through differential scanning calorimetric(DSC)measurements for the dehydrogenation process with different heating rates.It is determined that the activation energy for the Li-Mg-N-B-H/ZrCoH_(3) composite synthesized by RBM under hydrogen is 79.9 kJ·mol^(-1),which is14 kJ·mol^(-1) lower than that for the sample without ZrCoH_(3) addition.The N-H bond energies were analyzed by infrared(IR)absorption spectrum,and the reasons for weakening of the N-H bond were further discussed.
基金financially supported by the National High Technology Research and Development Program of China (No.2012AA051503)。
文摘The structure and hydrogenation properties of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce(x=0,1,3,5;at%) alloys with M=Cr,Mo,Al were investigated.All the alloys show the same phase composition consisting of BCC matric and CeO_(2)phases which distribute along the grain boundary.The hydrogen capacities of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce change little with M,and none of them exceeds 2.0 wt%.But the plateau pressure shows remarkable linearly variation with the amount of M and the lattice parameter of BCC matric.The additions of Cr,Mo and A1 raise the plateau,but the linear relation of plateau versus BCC lattice parameter of Mo/Al-added alloys is opposite to that of Cr-added alloys and many other conventional hydrogen storage alloys.The radius of hydrogen site is introduced to explain the inconsistent.The plateau pressure of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce with any kind of M added increases with the contraction of the hydrogen site.The plateau pressure of (V_(0.85)Fe_(0.15))_(100-x)M_(x)-Ce can also be reflected by the stability of hydride which is judged by the enthalpy change during the dehydrogenation.
基金financially supported by the Beijing Municipal Commission of Science and Technology of China(D141100002014001)。
文摘The effect of LaNi and Ti on thermal storage properties of MgH_(2)was investigated.The thermal storage performances of Mg are significantly improved by adding LaNi and Ti.The pressure-composition-temperature(PCT)curves indicate that the formation enthalpy for Mg-15 wt%Ti-5 wt%LaNi sample is 73.00 kJ·mol^(-1),which approaches to the theoretical values of pure MgH_(2).The isothermal measurement indicates that,for the Mg-15wt%Ti-5 wt%LaNi,the first absorption reaction fraction within 2 min is 93.77%,increasing by 0.32%,0.24%and0.08%compared with those for Mg,Mg-5 wt%LaNi and Mg-15 wt%Ti,respectively.The first desorption reaction fraction within 2 min is 73.18%,increasing by 55.91%,9.79%and 8.12%compared with those for Mg,Mg-5wt%LaNi and Mg-15 wt%Ti,respectively.Moreover,Mg-15 wt%Ti-5 wt%LaNi has the best cyclic stability in all the samples.The thermal storage performances of Mg by adding both LaNi and Ti are improved mainly ascribed to synergistic effect of in situ formed La_(4)H_(12.19),Mg_(2)NiH_(4),H_(0.3)Mg_(2)Ni and TiH_(2)particles during cyclic process.The above analysis demonstrates that Mg-15 wt%Ti-5wt%LaNi is suitable for using as a heat storage material.
基金financially supported by the Beijing Municipal Commission of Science and Technology of China(No.D141100002014001)。
文摘The effect of LaNi on thermal storage properties of MgH2 prepared by ball milling under hydrogen atmosphere was investigated.The thermal storage properties,cyclic property and thermal storage mechanism were studied by pres sure-composition-temperature(PC T),X-ray diffraction(XRD)and transmission electron microscopy(TEM).The Van't Hoff curve indicates that the formation enthalpy of Mg-16 wt%LaNi is 74.62 kJ·mol^(-1),which approaches to the theoretical values of MgH2.The isothermal measurement indicates that Mg-16 wt%LaNi can absorb 6.263 wt%H_(2)within 30 min at 390℃for the first absorption,the absorption reaction fraction within2 min is over 90.00%,and the desorption reaction fraction within 2 min is 72.63%,increasing by 55.36%compared with that of Mg.Mg-16 wt%LaNi has better cyclic stability than that of Mg,only decreasing by 0.609 wt%after 80cycles.The enhancement in thermal storage performances of Mg by adding LaNi is mainly ascribed to the formed Mg_(2)NiH_(4),H_(0.3)Mg_(2)Ni and La_(4)H_(12.19)during the cyclic process which act as catalysts and inhibit the growth of Mg.The above results prove that Mg-16 wt%LaNi is suitable for use as a heat storage material.
基金financially supported by the National Key Research and Development Program of China (No. 2019YFB1505100)the National Natural Science Foundation of China (No.U20A20237)Zhejiang Provincial Natural Science Foundation of China (No.LZ21E010002)
文摘Metal hydride with proper hydrogen storage properties is the key component of hydride thermal hydrogen compressor.In this work,Ti_(0.85)Zr_(0.17)(Cr-Mn-V)_(1.3)Fe_(0.7)-based alloys were developed to achieve thermal hydrogen compression at mild operating temperatures of water bath.The results indicate the single C 14-type Laves phase as well as homogeneously distributed elements of all alloys.With increased Mn content in Ti_(0.85)Zr_(0.17)Cr_(1.2-x)Mn_xFe_(0.7)V_(0.1)(x=0,0.1,0.2,0.3)alloys.
文摘Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental speed and size limits by electronics and photonics, respectively. Graphene offers multiple functions of signal transmission, emission, modulation, and detection in a broad band, high speed, compact size, and low loss. Here, we have a brief view of graphene based functional devices at microwave, terahertz, and optical frequencies. Their fundamental physics and computational models were discussed as well.
基金financially supported by the Beijing Science and Technology Program(No.D141100002014002)the European COST Action(No.MP1103)
文摘The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.
基金financially supported by the Foundation of Special Scientific Research Institutes(No.2013EG115002)the Innovation Foundation of General Research Institute for Nonferrous Metals(No.52215).
文摘Cu2ZnSnS4 thin films were prepared by cosputtering with Cu(or Cu2S),ZnS and SnS2 targets in this study.S amount in the precursor of Cu2ZnSnS4 thin film was verified by using Cu or Cu2S target.The effect of S amount in the precursor on the microstructure and element distribution of Cu2ZnSnS4 thin film was discussed.It was found that S content is sufficient in the precursor thin film using Cu2 S instead of Cu target.The microstructure,composition homogeneity,and secondary phase formation of the Cu2ZnSnS4 thin film are seriously affected by S amount in the precursor thin film.Namely,sufficient S can improve the crystallization and orientation of the precursor thin film and enhance the compactness as well as composition homogeneity of the Cu2ZnSnS4 thin film after sulfurization.Moreover,the secondary phase formation in Cu2ZnSnS4 thin film can be greatly inhibited by increasing S content in the precursor thin film.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 11144007） and the Natural Science Foundation of Shandong Province （Grant No. ZR2016AM27）.
文摘Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides （PC-CROWs）. According to the eye-shaped scatterers and various microcavities, saddle- like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is 〉 104, and the normalized delay bandwidth product within a new varying range of ng 〉 102 or ng 〉 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.
