Hydroxyl release of red soil and latosol surfaces was quantitatively measuredusing a self-made constant pH automated titration instrument, to study the changes of hydroxylrelease with different added selenite amounts ...Hydroxyl release of red soil and latosol surfaces was quantitatively measuredusing a self-made constant pH automated titration instrument, to study the changes of hydroxylrelease with different added selenite amounts and pH levels, and to study the effects ofelectrolytes on hydroxyl release. Hydroxyl release increased with the selenite concentration, with arapid increase at a low selenite concentration while slowing down at a high concentration. The pHwhere maximum of hydroxyl release appeared was not constant, shifting to a lower valus withincreasing selenite concentration. Hydroxyl release decreased with increasing electrolyteconcentration, and the decrease was very rapid at a low electrolyte concentration but slow at a highelectrolyte concentration. For NaClO_4, NaCl and Na_2SO_4, hydroxyl release was in the order ofNaClO_4 > NaCl >> Na_2SO_4, and the difference was very significant. But for NaCl, KCl and CaCl_2,the order of hydroxyl release was NaCl > KCl > CaCl_2, and the difference was smaller. The amount ofhydroxyl release from Xuwen latosol was greater than that from Jinxian red soil. Hydroxyl releaseexisted in a wider range of pH with Xuwen latosol than with Jinxian red soil, due to theirdifference in soil properties. However, both soils had similar curves of hydroxyl release,indicating the common characteristics of variable charge soils.展开更多
A self-made constant pH automated titration instrument was used to study thekinetics of hydroxyl release during selenite reacting with variable charge soils. The rate ofhydroxyl release was very rapid at the first sev...A self-made constant pH automated titration instrument was used to study thekinetics of hydroxyl release during selenite reacting with variable charge soils. The rate ofhydroxyl release was very rapid at the first several minutes, then gradually slowed down, and atlast did not change any more. The experimental data was well fitted by the Langmuir kineticequation, arid with increasing selenite concentration or decreasing solution pH, the reaction lastedlonger, the maximum of hydroxyl release (x_m) increased, and the binding constant (k) decreased.The time of hydroxyl release with Xuwen latosol was much longer than that with Jinxian red soil.展开更多
Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER...Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER）. In this paper, LiaSiO4 ceramic pebbles deposited with catalytic metals, including Pt, Pd, Ru and Ir, were prepared by wet impregnation method. The metal particles on Li4SiO4 pebble exhibit a good promotion of hydrogen isotope exchange reactions in H2-D20 gas system, with conversion equilibrium temperature reduction of 200-300 ~C. The out-of-pile tritium release experiments were performed using 1.0 wt% Pt/Li4SiO4 and Li4SiO4 pebbles irradiated in a thermal neutron reactor. The thermal desorption spectroscopy shows that Pt was effective to increase the tritium release rate at lower temperatures, and the ratio of tritium molecule （HT） to tritiated water （HTO） of 1.0 wt% Pt/LiaSiO4 was much more than that of Li4SiO4, which released mainly as HTO. Thus, catalytic metals deposited on LiaSiO4 pebble may help to accelerate the recovery of bred tritium particularly in low temperature region, and increase the tritium molecule form released from the tritium breedin~ materials.展开更多
The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki...The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki, Mazélé in the NE of Ngaoundéré, Tello and Ganguiré in the SE of Ngaoundéré and Likok, locality located in the west of Ngaoundé). The peridotite enclaves of the above localities show restricted mineralogical variation. Most are four-phase spinel-lherzolites, indicating that this is the main lithology that forms the lithospheric mantle below the shallow zone. No traces of garnet or primary plagioclase were detected, which strongly limits the depth range from which the rock fragments were sampled. The textures and the wide equilibrium temperatures (884˚C - 1115˚C) indicate also entrainment of lherzolite xenoliths from shallow depths within the lithosphere and the presence of mantle diapirism. The exchange reactions and equilibrium state established in this work make it possible to characterize the chemical composition of the upper mantle of each region and test the equilibrium state of the phases between them. Variations of major oxides and incompatible elemental concentrations in clinopyroxene indicate a primary control by partial melting. The absence of typical “metasomatic” minerals, low equilibration temperatures and enriched LREE patterns indicate that the upper mantle below septentrional crust of Cameroun underwent an event of cryptic metasomatic enrichment prior to partial melting. The distinctive chemical features, LREE enrichment, strong U, Ce and Pr, depletion relative to Ba, Nb, La, Pb, and T, fractionation of Zr and Hf and therefore ligh high Zr/Hf ratio, low La/Yb, Nb/La and Ti/Eu are all results of interaction of refractory peridotite residues with carbonatite melts.展开更多
Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. Th...Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. The product yields of the reactions with alkanoyl- and alkoxybenzenes were low because of the coordination of aluminum chloride to the oxygens of the benzene substituents. Comparing the reactions using o- and p-dimethoxybenzene, the former was revealed to be less reactive;this is likely due to the deviation of the π-electrons of its benzene ring being larger.展开更多
The directionality of the[N–I–N]^(+)halogen bond makes iodine(I)ions impeccable tools in the design and construction of[N–I–N]^(+)halogen-bonded assemblies.The synthesis of dimeric iodine(I)cages with imidazole-de...The directionality of the[N–I–N]^(+)halogen bond makes iodine(I)ions impeccable tools in the design and construction of[N–I–N]^(+)halogen-bonded assemblies.The synthesis of dimeric iodine(I)cages with imidazole-derived N-donor tripodal ligands is described,as well as their corresponding silver(I)precursors.The addition of elemental iodine to the parent two-coordinate Ag(I)complexes produces iodine(I)complexes with three-center four-electron(3c–4e)[N–I–N]^(+)bonds.展开更多
Highly quality 2D Bi_(2)Te_(3)nanoplates are obtained via solvothermal synthesis and cations with different chemical valences(Ag^(+)/Cu^(2+)/In^(3+))are doped into Bi_(2)Te_(3)by a cation exchange reaction in ethanol ...Highly quality 2D Bi_(2)Te_(3)nanoplates are obtained via solvothermal synthesis and cations with different chemical valences(Ag^(+)/Cu^(2+)/In^(3+))are doped into Bi_(2)Te_(3)by a cation exchange reaction in ethanol solution at room temperature.By combining precise XRD,SEM,HRTEM and XPS characterization,the cations are shown to be doped into the lattice of Bi_(2)Te_(3)bringing lattice defects and distortion,and cation-doping caused a change in chemical state but without obvious changes in the hexagonal morphology.This research provides a possible general strategy for obtaining cation-doped bismuth telluride.展开更多
Silver nanowires(AgNWs),as promising conductor materials,have found their application in various stretchable electronics.However,the mismatch between the work function of AgNWs electrodes and energy level of semicondu...Silver nanowires(AgNWs),as promising conductor materials,have found their application in various stretchable electronics.However,the mismatch between the work function of AgNWs electrodes and energy level of semiconductors limits the obtaining of high-performance devices,especially in stretchable p-type organic thin film transistors(OTFTs)where the resulting severe injection barrier significantly lowers the overall performance of the devices.In this study,we prepared stretchable AgNWs electrodes with high work function that closely matched the highest occupied molecular orbital(HOMO)of the p-type polymer semiconductor poly(indacenodithiophene-co-benzothiadiazole)(IDT-BT)via a ligand exchange reaction with fluorinated molecules and post-treatment-free fabrication.In comparison to the commercial polyvinylpyrrolidone(PVP)stabilized AgNWs,electrodes based on ligand-exchanged AgNWs exhibited higher work function over 5 eV,closer to the HOMO of IDT-BT.As a result,IDT-BT-based p-type OTFTs fabricated using ligand-exchanged AgNWs electrodes achieved a reduced threshold voltage and improved carrier transport property,with a hole mobility of 0.4 cm^(2) V^(-1) s^(-1).Moreover,the ligand exchange on the surface of AgNWs caused no deterioration of the deformability of the resulting devices,largely retaining the original mobility after being stretched by 30%strain.These results demonstrate the effectiveness of the work function tuning via the ligand-exchange strategy in the processing of AgNWs electrodes for enhancing the performance of stretchable electronics.展开更多
We report a detailed investigation of the behavior of chemisorbed hydrogen atoms (Ha) on Pt(111) by a combination of an ex-perimental study of the Ha + Da reaction and first-principles calculations. The coverage-depen...We report a detailed investigation of the behavior of chemisorbed hydrogen atoms (Ha) on Pt(111) by a combination of an ex-perimental study of the Ha + Da reaction and first-principles calculations. The coverage-dependent adsorption and desorption behavior of Ha and Da on Pt(111) have been systematically established and can be well interpreted in terms of repulsive inter-actions between adsorbates. Ha adsorbs exclusively on the face-centered cubic (fcc) sites of Pt(111) at coverages not exceeding 1 monolayer (ML). With increasing Ha coverage,repulsive interactions between Ha increase,leading to a reduction in both the adsorption energy and the desorption activation energy. It is proposed that the lateral interactions within a Ha layer are partly induced by the local repulsive interactions due to high mobility of Ha on Pt(111). For the Ha + Da exchange reaction on Pt(111),it is found that Ha has a higher selectivity for HD formation than Da. Considering that Ha diffuses much faster than Da on Pt(111),we propose that the difference in diffusion rates between Ha and Da may determine the selectivity of Ha and Da in forming HD in the Ha + Da reaction on Pt(111).展开更多
2-Amino-3-ketobutyrate CoA ligase （KBL） of Escherichia coli is a member of the a-oxoamine synthase family; it catalyzes the condensation reaction between glycine and acetyl CoA to yield 2-amino-3-ketobutyrate. We ha...2-Amino-3-ketobutyrate CoA ligase （KBL） of Escherichia coli is a member of the a-oxoamine synthase family; it catalyzes the condensation reaction between glycine and acetyl CoA to yield 2-amino-3-ketobutyrate. We have previously shown that KBL catalyzes the exchange ofpro-R hydrogen of glycine with protons in the medium; however, the kinetics of this reaction has never been determined. In this study, we calculated the kinetic parameters of this exchange reaction by using different concentrations of [2RS- 3H2： 2-14C] glycine. The rate of the exchange reaction was determined by measuring the 3H/14C ratio in recovered ｜2S- 3H： 2J4C]glycine. The Lineweaver-Burk plot showed that Km and kcat of this reaction were 3.8 ×10^-3 M and 0.22 S^-11, respectively. On the other hand, Km and kcat values of the overall KBL-mediated catalysis were correspondingly 1.23 × 10^-2 M and 1.19 S^-1. Thus, the rate of the exchange reaction was almost five times lower than that of overall KBL catalysis.展开更多
The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr...The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr,n-Bu),in chloroform solution have been determined in a temperature range of 20—50°C by means of high-performance liquid chromatography.It was found that both the forward and reverse reactions are of second order.All of the equilibrium constants K determined are 10.3±1.0,much greater than the value(K=4)calculated statistically which indicates that the ternary complexes are more stable than the binary complexes.The experimental results revealed that the reaction rate decreases with the increase in the size of R and R^1 groups and the latter are more remarkable,consistent with the deduction of steric effect.The activation parameters of the reactions have been calculated.In reaction series(11)and(12)(in the text)the isokinetic tempera- tures B=390±8K and β=346±15 K have been observed respectively.A plausiblemechanism in- volving an eight-membered ring intermediate has been proposed on the basis of experimental results.展开更多
(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R...(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R＇=i-Pr and sec-Bu. The crystallographic data of 7 and 8 are herebypresented.展开更多
BACKGROUND As one of the fatal diseases with high incidence,lung cancer has seriously endangered public health and safety.Elderly patients usually have poor self-care and are more likely to show a series of psychologi...BACKGROUND As one of the fatal diseases with high incidence,lung cancer has seriously endangered public health and safety.Elderly patients usually have poor self-care and are more likely to show a series of psychological problems.AIM To investigate the effectiveness of the initial check,information exchange,final accuracy check,reaction(IIFAR)information care model on the mental health status of elderly patients with lung cancer.METHODS This study is a single-centre study.We randomly recruited 60 elderly patients with lung cancer who attended our hospital from January 2021 to January 2022.These elderly patients with lung cancer were randomly divided into two groups,with the control group taking the conventional propaganda and education and the observation group taking the IIFAR information care model based on the conventional care protocol.The differences in psychological distress,anxiety and depression,life quality,fatigue,and the locus of control in psychology were compared between these two groups,and the causes of psychological distress were analyzed.RESULTS After the intervention,Distress Thermometer,Hospital Anxiety and Depression Scale(HADS)for anxiety and the HADS for depression,Revised Piper’s Fatigue Scale,and Chance Health Locus of Control scores were lower in the observation group compared to the pre-intervention period in the same group and were significantly lower in the observation group compared to those of the control group(P<0.05).After the intervention,Quality of Life Questionnaire Core 30(QLQ-C30),Internal Health Locus of Control,and Powerful Others Health Locus of Control scores were significantly higher in the observation and the control groups compared to the pre-intervention period in their same group,and QLQ-C30 scores were significantly higher in the observation group compared to those of the control group(P<0.05).CONCLUSION The IIFAR information care model can help elderly patients with lung cancer by reducing their anxiety and depression,psychological distress,and fatigue,improving their tendencies on the locus of control in psychology,and enhancing their life qualities.展开更多
Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions....Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.展开更多
Coexisting quartz, feldspar and biotite vary widely in their δ18O values and display a remarkable 18O/16O disequilibrium relation; especially, a quartz-feldspar reversal (△ 18OQUartz_feldspar< 0) exsists in the A...Coexisting quartz, feldspar and biotite vary widely in their δ18O values and display a remarkable 18O/16O disequilibrium relation; especially, a quartz-feldspar reversal (△ 18OQUartz_feldspar< 0) exsists in the Aral granite pluton of the Altay Mountains, northern Xinjiang. The 18O / 16O exchange reaction definitely occurred between granite and water. Initial δ18O values of the granite and exotic fluid are evaluated by the mass balance consideration. The conventional method of discrimination between various magma derivations simply with δ18O values of either whole rock or separate minerals is misleading and unreliable. Experiments carried out by the authors show that the 18O / 16O exchange reaction is not accompanied by what geologists describe as petrological and mineralogical alteration effect. This decoupling relation implies that exchange reaction occurs at a relatively high temperature during subsolidus-postmagmatic cooling of magmas. The exchange mechanism is mainly diffusion-controlled. It is demonstrated through quantitative modelling that the hydrothermal system associated with the Aral pluton is long-lived (0.8-6 Ma), with a relatively high fluid flow rate (3 ×10-14 mol. s-1) and high W/ R ratio (0.79-6.14). This means that an intense flow and convection may exist at the midcrustal level of erogenic magmatic arcs.展开更多
The ion conductivity of a solid-state ion conductor generally increases exponentially upon reduction in ionmigration barrier.For prevalent cathode material LiCoO_(2),the room-temperature ion conductivity and migration...The ion conductivity of a solid-state ion conductor generally increases exponentially upon reduction in ionmigration barrier.For prevalent cathode material LiCoO_(2),the room-temperature ion conductivity and migrationbarrier are respectively around 10^(−4)S/cm and 0.3 eV.In this Letter,through first-principles calculations we predictthe existence of 1D superionicity as the Li ions in O_(2)LiCoO_(2)are transformed into Zn_(0.5)CoO_(2)or Li_(0.5)CoO_(2)via cation-exchange reaction or deintercalation.The ion migration barriers(0.01-0.02 eV)even lower than roomtemperature∼𝑘B𝑇are reduced by more than an order of magnitude compared with LiCoO_(2),which are facilitatedby facile transition of mobile ions between two coordination configurations.The room-temperature ion conductivityis estimated to be over 50 S/cm,enhanced by 2-3 orders of magnitude compared with the current highestreported value.Such unprecedented superionicity may also exist in other similar layered ion conductors,whichmay lead to technical advances and exotic effects such as ultrafast ion batteries and quantized ferroelectricity.展开更多
The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth poly...The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth polymerization of diols,carbonyl sulfide(CoS,or carbon disulfide,CS_(2)),and dichlorides.Diols and dichlorides are common chemicals,and CoS(CS_(2))is released as industrial waste.In addition to abun-dant feedstocks,the method is efficient and performed under mild conditions,using common organic bases as catalysts,and affording unprece-dented polymers.When cos,diols,and dihalides were used as monomers,optimized conditions could completely suppress the oxygen-sulfur exchange reaction,enabling the efficient synthesis of well-defined poly(monothiocarbonate)s with melting points ranging from 48°C to 101°C.These polymers,which have a structure similar to polyethylene with low-density in-chain polar groups,exhibit remarkable toughness and ductili-ty that rival those of high-density polyethylene(melting point:90°C,tensile strength:21.6±0.7 MPa,and elongation at break:576%).Moreover,the obtained poly(monothiocarbonate)s can be chemically degraded by alcoholysis to yield small-molecule diols and dithiols.When CS_(2)was used in place of cos,a pronounced oxygen-sulfur exchange reaction occurred.By optimizing reaction condition,it was found that polymers with-S(C=O)S-and-S(C=S)S-as the main repeating units exhibited high thermal stability and crystallinity.Thus,a new approach for regulat-ing the structure of polythiocarbonates via the oxygen-sulfur exchange reaction is developed.Overall,the polymers hold great potential for green materials due to their facile synthesis,readily available feedstocks,excellent performance,and chemical degradability.展开更多
The development of low-cost,highly active and stable electrocatalysts for the oxygen evolution reaction(OER)is desirable and challenging.In this work,we report nickel foam(NF)supported low-crystalline NiCoFe nanosheet...The development of low-cost,highly active and stable electrocatalysts for the oxygen evolution reaction(OER)is desirable and challenging.In this work,we report nickel foam(NF)supported low-crystalline NiCoFe nanosheet array electrocatalysts derived from NiCo layered double hydroxide via spontaneous cation exchange reaction.Driven by the redox properties of NiCo layered double hydroxide and iron salt precursors,the entire cation exchange reaction process is completed without extra energy input.The chemical composition and catalytic properties of the as-prepared NiCoFe/NF catalysts are strongly dependent on the valence state of the Fe cation in the iron salt precursors.The NiCoFe/NF-FeSO_(4)cata lyst with FeSO_(4)as the iron salt precursor exhibits satisfactory OER activity with a much lower overpotential of 293 mV to reach a current density of 100 mA cm^(−2)as compared with NiCoFe/NF-Fe_(2)(SO_(4))_(3)(η_(100)=333 mV),NiCo/NF(η_(100)=425 mV)and commercial RuO_(2)(η_(100)=399 mV)catalysts.Moreover,NiCoFe/NF-FeSO_(4)also exhibits impressive long-term durability for the OER.The current density remains nearly unchanged during the 95 h of continuous OER test,demonstrating a promising application in actual industrial water electrolysis.Thesefindings indicate that the iron ion valence states in the iron salt precur sors have a significant impact on the composition of the catalysts and thus affect their catalytic perform ances.This work is instructive for the rational design and preparation of highly effcient Earth-abundant electrocatalysts for the OER.展开更多
A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed ...A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed by spectral analysis and elemental analysis. Preliminary pharmacological tests showed that several compounds exerted appreciable inhibitory effect on xylene induced ear edema in mice and that alteration of the substituents of anilines had significant influence in anti inflammatory potency.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.49971046 and 49831005).
文摘Hydroxyl release of red soil and latosol surfaces was quantitatively measuredusing a self-made constant pH automated titration instrument, to study the changes of hydroxylrelease with different added selenite amounts and pH levels, and to study the effects ofelectrolytes on hydroxyl release. Hydroxyl release increased with the selenite concentration, with arapid increase at a low selenite concentration while slowing down at a high concentration. The pHwhere maximum of hydroxyl release appeared was not constant, shifting to a lower valus withincreasing selenite concentration. Hydroxyl release decreased with increasing electrolyteconcentration, and the decrease was very rapid at a low electrolyte concentration but slow at a highelectrolyte concentration. For NaClO_4, NaCl and Na_2SO_4, hydroxyl release was in the order ofNaClO_4 > NaCl >> Na_2SO_4, and the difference was very significant. But for NaCl, KCl and CaCl_2,the order of hydroxyl release was NaCl > KCl > CaCl_2, and the difference was smaller. The amount ofhydroxyl release from Xuwen latosol was greater than that from Jinxian red soil. Hydroxyl releaseexisted in a wider range of pH with Xuwen latosol than with Jinxian red soil, due to theirdifference in soil properties. However, both soils had similar curves of hydroxyl release,indicating the common characteristics of variable charge soils.
基金Project supported by the National Natural Science Foundation of China (Nos. 49971046 and 49831005).
文摘A self-made constant pH automated titration instrument was used to study thekinetics of hydroxyl release during selenite reacting with variable charge soils. The rate ofhydroxyl release was very rapid at the first several minutes, then gradually slowed down, and atlast did not change any more. The experimental data was well fitted by the Langmuir kineticequation, arid with increasing selenite concentration or decreasing solution pH, the reaction lastedlonger, the maximum of hydroxyl release (x_m) increased, and the binding constant (k) decreased.The time of hydroxyl release with Xuwen latosol was much longer than that with Jinxian red soil.
基金supported by the Development Fund of China Academy of Engineering Physics (No.2010B0301035)the National Magnetic Confinement Fusion Science Program (No. 2010GB112004)
文摘Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER）. In this paper, LiaSiO4 ceramic pebbles deposited with catalytic metals, including Pt, Pd, Ru and Ir, were prepared by wet impregnation method. The metal particles on Li4SiO4 pebble exhibit a good promotion of hydrogen isotope exchange reactions in H2-D20 gas system, with conversion equilibrium temperature reduction of 200-300 ~C. The out-of-pile tritium release experiments were performed using 1.0 wt% Pt/Li4SiO4 and Li4SiO4 pebbles irradiated in a thermal neutron reactor. The thermal desorption spectroscopy shows that Pt was effective to increase the tritium release rate at lower temperatures, and the ratio of tritium molecule （HT） to tritiated water （HTO） of 1.0 wt% Pt/LiaSiO4 was much more than that of Li4SiO4, which released mainly as HTO. Thus, catalytic metals deposited on LiaSiO4 pebble may help to accelerate the recovery of bred tritium particularly in low temperature region, and increase the tritium molecule form released from the tritium breedin~ materials.
文摘The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki, Mazélé in the NE of Ngaoundéré, Tello and Ganguiré in the SE of Ngaoundéré and Likok, locality located in the west of Ngaoundé). The peridotite enclaves of the above localities show restricted mineralogical variation. Most are four-phase spinel-lherzolites, indicating that this is the main lithology that forms the lithospheric mantle below the shallow zone. No traces of garnet or primary plagioclase were detected, which strongly limits the depth range from which the rock fragments were sampled. The textures and the wide equilibrium temperatures (884˚C - 1115˚C) indicate also entrainment of lherzolite xenoliths from shallow depths within the lithosphere and the presence of mantle diapirism. The exchange reactions and equilibrium state established in this work make it possible to characterize the chemical composition of the upper mantle of each region and test the equilibrium state of the phases between them. Variations of major oxides and incompatible elemental concentrations in clinopyroxene indicate a primary control by partial melting. The absence of typical “metasomatic” minerals, low equilibration temperatures and enriched LREE patterns indicate that the upper mantle below septentrional crust of Cameroun underwent an event of cryptic metasomatic enrichment prior to partial melting. The distinctive chemical features, LREE enrichment, strong U, Ce and Pr, depletion relative to Ba, Nb, La, Pb, and T, fractionation of Zr and Hf and therefore ligh high Zr/Hf ratio, low La/Yb, Nb/La and Ti/Eu are all results of interaction of refractory peridotite residues with carbonatite melts.
文摘Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. The product yields of the reactions with alkanoyl- and alkoxybenzenes were low because of the coordination of aluminum chloride to the oxygens of the benzene substituents. Comparing the reactions using o- and p-dimethoxybenzene, the former was revealed to be less reactive;this is likely due to the deviation of the π-electrons of its benzene ring being larger.
基金Academy of Finland(K.R.grant no.317259)Finnish Cultural Foundation Central Fund(J.S.W.grant number 00201148)+1 种基金the Magnus Ehrnrooth Foundation(J.S.W.),European Union NOAH project(D.L.S,H2020-MSCA-ITN project ref.765297the Core Facility BioSupraMol(supported by the Deutsche Forschungsgemeinschaft,DFG)and the University of Jyväskylä,Finland for financial support.
文摘The directionality of the[N–I–N]^(+)halogen bond makes iodine(I)ions impeccable tools in the design and construction of[N–I–N]^(+)halogen-bonded assemblies.The synthesis of dimeric iodine(I)cages with imidazole-derived N-donor tripodal ligands is described,as well as their corresponding silver(I)precursors.The addition of elemental iodine to the parent two-coordinate Ag(I)complexes produces iodine(I)complexes with three-center four-electron(3c–4e)[N–I–N]^(+)bonds.
基金supported by the Technology Plan of Shenzhen City(Grant no.JCYJ20170412171554022)the National Natural Science Foundation of China(Grant no.51631001,21643003,51702016,51501010,21673058)+2 种基金the Science and Technology Innovation Commission of Shenzhen(Grant no.JCYJ20150529164656097,JSGG20160226201833790,JCYJ20170818093832350)the Guangdong Natural Science Fund for Distinguished Young Scholars(Grant no.2016A030306020)the Guangdong Youth Talent Plan(Grant no.2015TQ01C536).
文摘Highly quality 2D Bi_(2)Te_(3)nanoplates are obtained via solvothermal synthesis and cations with different chemical valences(Ag^(+)/Cu^(2+)/In^(3+))are doped into Bi_(2)Te_(3)by a cation exchange reaction in ethanol solution at room temperature.By combining precise XRD,SEM,HRTEM and XPS characterization,the cations are shown to be doped into the lattice of Bi_(2)Te_(3)bringing lattice defects and distortion,and cation-doping caused a change in chemical state but without obvious changes in the hexagonal morphology.This research provides a possible general strategy for obtaining cation-doped bismuth telluride.
基金supported by the National Natural Science Foundation of China(52173179,52433008 and 52121002)the Fundamental Research Funds for the Central Universities.
文摘Silver nanowires(AgNWs),as promising conductor materials,have found their application in various stretchable electronics.However,the mismatch between the work function of AgNWs electrodes and energy level of semiconductors limits the obtaining of high-performance devices,especially in stretchable p-type organic thin film transistors(OTFTs)where the resulting severe injection barrier significantly lowers the overall performance of the devices.In this study,we prepared stretchable AgNWs electrodes with high work function that closely matched the highest occupied molecular orbital(HOMO)of the p-type polymer semiconductor poly(indacenodithiophene-co-benzothiadiazole)(IDT-BT)via a ligand exchange reaction with fluorinated molecules and post-treatment-free fabrication.In comparison to the commercial polyvinylpyrrolidone(PVP)stabilized AgNWs,electrodes based on ligand-exchanged AgNWs exhibited higher work function over 5 eV,closer to the HOMO of IDT-BT.As a result,IDT-BT-based p-type OTFTs fabricated using ligand-exchanged AgNWs electrodes achieved a reduced threshold voltage and improved carrier transport property,with a hole mobility of 0.4 cm^(2) V^(-1) s^(-1).Moreover,the ligand exchange on the surface of AgNWs caused no deterioration of the deformability of the resulting devices,largely retaining the original mobility after being stretched by 30%strain.These results demonstrate the effectiveness of the work function tuning via the ligand-exchange strategy in the processing of AgNWs electrodes for enhancing the performance of stretchable electronics.
基金supported by the National Natural Science Foundation of China (NSFC20503027, NSFC20773113, NSFC20803072)the Ministry of Sci-ence and Technology of China, MOE Program for PCSIRT (IRT0756)
文摘We report a detailed investigation of the behavior of chemisorbed hydrogen atoms (Ha) on Pt(111) by a combination of an ex-perimental study of the Ha + Da reaction and first-principles calculations. The coverage-dependent adsorption and desorption behavior of Ha and Da on Pt(111) have been systematically established and can be well interpreted in terms of repulsive inter-actions between adsorbates. Ha adsorbs exclusively on the face-centered cubic (fcc) sites of Pt(111) at coverages not exceeding 1 monolayer (ML). With increasing Ha coverage,repulsive interactions between Ha increase,leading to a reduction in both the adsorption energy and the desorption activation energy. It is proposed that the lateral interactions within a Ha layer are partly induced by the local repulsive interactions due to high mobility of Ha on Pt(111). For the Ha + Da exchange reaction on Pt(111),it is found that Ha has a higher selectivity for HD formation than Da. Considering that Ha diffuses much faster than Da on Pt(111),we propose that the difference in diffusion rates between Ha and Da may determine the selectivity of Ha and Da in forming HD in the Ha + Da reaction on Pt(111).
文摘2-Amino-3-ketobutyrate CoA ligase （KBL） of Escherichia coli is a member of the a-oxoamine synthase family; it catalyzes the condensation reaction between glycine and acetyl CoA to yield 2-amino-3-ketobutyrate. We have previously shown that KBL catalyzes the exchange ofpro-R hydrogen of glycine with protons in the medium; however, the kinetics of this reaction has never been determined. In this study, we calculated the kinetic parameters of this exchange reaction by using different concentrations of [2RS- 3H2： 2-14C] glycine. The rate of the exchange reaction was determined by measuring the 3H/14C ratio in recovered ｜2S- 3H： 2J4C]glycine. The Lineweaver-Burk plot showed that Km and kcat of this reaction were 3.8 ×10^-3 M and 0.22 S^-11, respectively. On the other hand, Km and kcat values of the overall KBL-mediated catalysis were correspondingly 1.23 × 10^-2 M and 1.19 S^-1. Thus, the rate of the exchange reaction was almost five times lower than that of overall KBL catalysis.
基金Project supported by the National Natural Science Foundation of China.
文摘The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr,n-Bu),in chloroform solution have been determined in a temperature range of 20—50°C by means of high-performance liquid chromatography.It was found that both the forward and reverse reactions are of second order.All of the equilibrium constants K determined are 10.3±1.0,much greater than the value(K=4)calculated statistically which indicates that the ternary complexes are more stable than the binary complexes.The experimental results revealed that the reaction rate decreases with the increase in the size of R and R^1 groups and the latter are more remarkable,consistent with the deduction of steric effect.The activation parameters of the reactions have been calculated.In reaction series(11)and(12)(in the text)the isokinetic tempera- tures B=390±8K and β=346±15 K have been observed respectively.A plausiblemechanism in- volving an eight-membered ring intermediate has been proposed on the basis of experimental results.
文摘(n-Bu_4N)_3W_2Cl_9, prepared from K_3W_2Cl_9, can be readily converted to a series of [W(IV)]cluster compounds,W_3Cl_4(μ-OR)_2(OR')_2(R'OH)_2, including seven known compounds and two newcompounds with R=Me, R＇=i-Pr and sec-Bu. The crystallographic data of 7 and 8 are herebypresented.
文摘BACKGROUND As one of the fatal diseases with high incidence,lung cancer has seriously endangered public health and safety.Elderly patients usually have poor self-care and are more likely to show a series of psychological problems.AIM To investigate the effectiveness of the initial check,information exchange,final accuracy check,reaction(IIFAR)information care model on the mental health status of elderly patients with lung cancer.METHODS This study is a single-centre study.We randomly recruited 60 elderly patients with lung cancer who attended our hospital from January 2021 to January 2022.These elderly patients with lung cancer were randomly divided into two groups,with the control group taking the conventional propaganda and education and the observation group taking the IIFAR information care model based on the conventional care protocol.The differences in psychological distress,anxiety and depression,life quality,fatigue,and the locus of control in psychology were compared between these two groups,and the causes of psychological distress were analyzed.RESULTS After the intervention,Distress Thermometer,Hospital Anxiety and Depression Scale(HADS)for anxiety and the HADS for depression,Revised Piper’s Fatigue Scale,and Chance Health Locus of Control scores were lower in the observation group compared to the pre-intervention period in the same group and were significantly lower in the observation group compared to those of the control group(P<0.05).After the intervention,Quality of Life Questionnaire Core 30(QLQ-C30),Internal Health Locus of Control,and Powerful Others Health Locus of Control scores were significantly higher in the observation and the control groups compared to the pre-intervention period in their same group,and QLQ-C30 scores were significantly higher in the observation group compared to those of the control group(P<0.05).CONCLUSION The IIFAR information care model can help elderly patients with lung cancer by reducing their anxiety and depression,psychological distress,and fatigue,improving their tendencies on the locus of control in psychology,and enhancing their life qualities.
文摘Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.
基金This research was supported by the National Natural Science Foundation of China (grant No. 49373164)the President's Funds of the Chinese Academy of Sciences
文摘Coexisting quartz, feldspar and biotite vary widely in their δ18O values and display a remarkable 18O/16O disequilibrium relation; especially, a quartz-feldspar reversal (△ 18OQUartz_feldspar< 0) exsists in the Aral granite pluton of the Altay Mountains, northern Xinjiang. The 18O / 16O exchange reaction definitely occurred between granite and water. Initial δ18O values of the granite and exotic fluid are evaluated by the mass balance consideration. The conventional method of discrimination between various magma derivations simply with δ18O values of either whole rock or separate minerals is misleading and unreliable. Experiments carried out by the authors show that the 18O / 16O exchange reaction is not accompanied by what geologists describe as petrological and mineralogical alteration effect. This decoupling relation implies that exchange reaction occurs at a relatively high temperature during subsolidus-postmagmatic cooling of magmas. The exchange mechanism is mainly diffusion-controlled. It is demonstrated through quantitative modelling that the hydrothermal system associated with the Aral pluton is long-lived (0.8-6 Ma), with a relatively high fluid flow rate (3 ×10-14 mol. s-1) and high W/ R ratio (0.79-6.14). This means that an intense flow and convection may exist at the midcrustal level of erogenic magmatic arcs.
基金supported by the National Natural Science Foundation of China(Grant No.22073034)。
文摘The ion conductivity of a solid-state ion conductor generally increases exponentially upon reduction in ionmigration barrier.For prevalent cathode material LiCoO_(2),the room-temperature ion conductivity and migrationbarrier are respectively around 10^(−4)S/cm and 0.3 eV.In this Letter,through first-principles calculations we predictthe existence of 1D superionicity as the Li ions in O_(2)LiCoO_(2)are transformed into Zn_(0.5)CoO_(2)or Li_(0.5)CoO_(2)via cation-exchange reaction or deintercalation.The ion migration barriers(0.01-0.02 eV)even lower than roomtemperature∼𝑘B𝑇are reduced by more than an order of magnitude compared with LiCoO_(2),which are facilitatedby facile transition of mobile ions between two coordination configurations.The room-temperature ion conductivityis estimated to be over 50 S/cm,enhanced by 2-3 orders of magnitude compared with the current highestreported value.Such unprecedented superionicity may also exist in other similar layered ion conductors,whichmay lead to technical advances and exotic effects such as ultrafast ion batteries and quantized ferroelectricity.
基金supported by the National Natural Science Foundation of China(Nos.223B2119,U23A2083,52373014,52203129).
文摘The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth polymerization of diols,carbonyl sulfide(CoS,or carbon disulfide,CS_(2)),and dichlorides.Diols and dichlorides are common chemicals,and CoS(CS_(2))is released as industrial waste.In addition to abun-dant feedstocks,the method is efficient and performed under mild conditions,using common organic bases as catalysts,and affording unprece-dented polymers.When cos,diols,and dihalides were used as monomers,optimized conditions could completely suppress the oxygen-sulfur exchange reaction,enabling the efficient synthesis of well-defined poly(monothiocarbonate)s with melting points ranging from 48°C to 101°C.These polymers,which have a structure similar to polyethylene with low-density in-chain polar groups,exhibit remarkable toughness and ductili-ty that rival those of high-density polyethylene(melting point:90°C,tensile strength:21.6±0.7 MPa,and elongation at break:576%).Moreover,the obtained poly(monothiocarbonate)s can be chemically degraded by alcoholysis to yield small-molecule diols and dithiols.When CS_(2)was used in place of cos,a pronounced oxygen-sulfur exchange reaction occurred.By optimizing reaction condition,it was found that polymers with-S(C=O)S-and-S(C=S)S-as the main repeating units exhibited high thermal stability and crystallinity.Thus,a new approach for regulat-ing the structure of polythiocarbonates via the oxygen-sulfur exchange reaction is developed.Overall,the polymers hold great potential for green materials due to their facile synthesis,readily available feedstocks,excellent performance,and chemical degradability.
基金supported by the National Natural Science Foundation of China(22072070,21403125,and 21908130)the Natural Science Foundation of Shandong Province(ZR2019MB036).
文摘The development of low-cost,highly active and stable electrocatalysts for the oxygen evolution reaction(OER)is desirable and challenging.In this work,we report nickel foam(NF)supported low-crystalline NiCoFe nanosheet array electrocatalysts derived from NiCo layered double hydroxide via spontaneous cation exchange reaction.Driven by the redox properties of NiCo layered double hydroxide and iron salt precursors,the entire cation exchange reaction process is completed without extra energy input.The chemical composition and catalytic properties of the as-prepared NiCoFe/NF catalysts are strongly dependent on the valence state of the Fe cation in the iron salt precursors.The NiCoFe/NF-FeSO_(4)cata lyst with FeSO_(4)as the iron salt precursor exhibits satisfactory OER activity with a much lower overpotential of 293 mV to reach a current density of 100 mA cm^(−2)as compared with NiCoFe/NF-Fe_(2)(SO_(4))_(3)(η_(100)=333 mV),NiCo/NF(η_(100)=425 mV)and commercial RuO_(2)(η_(100)=399 mV)catalysts.Moreover,NiCoFe/NF-FeSO_(4)also exhibits impressive long-term durability for the OER.The current density remains nearly unchanged during the 95 h of continuous OER test,demonstrating a promising application in actual industrial water electrolysis.Thesefindings indicate that the iron ion valence states in the iron salt precur sors have a significant impact on the composition of the catalysts and thus affect their catalytic perform ances.This work is instructive for the rational design and preparation of highly effcient Earth-abundant electrocatalysts for the OER.
文摘A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed by spectral analysis and elemental analysis. Preliminary pharmacological tests showed that several compounds exerted appreciable inhibitory effect on xylene induced ear edema in mice and that alteration of the substituents of anilines had significant influence in anti inflammatory potency.
