The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to th...The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values.展开更多
The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that...The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that the intensity of the EME induced from the rock under static stress increases with increasing stress level and loading rate; the relationship between the amplitude of the EME from the rock under different modes of stress wave and elastic parameters and propagation distance was presented. The intensity of the EME relates not only to the strength and elastic moduli of rock masses,but also to the initial damage of the rock. The intensity of EME induced by stress wave reaches the highest at the explosion-center and attenuates with the propagation distance. The intensity of EME increases with increasing the elastic modulus and decreases with increasing initial damage. The results are in good agreement with the experimental results.展开更多
N, N-diethyl dodecyl amine（DEN12） was synthesized from dodecyl amine, formic acid and acetic aldehyde. The collecting property of DENI2 on diaspore, kaolinite and illite was investigated by flotation test and infrar...N, N-diethyl dodecyl amine（DEN12） was synthesized from dodecyl amine, formic acid and acetic aldehyde. The collecting property of DENI2 on diaspore, kaolinite and illite was investigated by flotation test and infrared spectrum. The results show that in the presence of 2.0× 10^-4 mol/L DEN12, the recoveries of kaolinite and illite are all higher than 78% and the recovery of diaspore is 50% in the pH range of 5.5-6.0. The mass ratio of A1203 to SiO2 in concentrate obtained from separation artificial mixture is higher than 10, suggesting that DEN12 can be used as a collector to separate the aluminosilicates from diaspore in bauxite ores at the pulp pH below 8. The measurements of the infrared spectrum approve that the action between aluminosilicates and tertiary amine collector is strong electrostatic adsorption and that of diaspore is weak electrostatic adsorption.展开更多
It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polym...It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polymer chain induced by an external electric held E during forming the biexciton. The time dependence of the charge distribution in the chain reveals that the charge transfer is backward: the positive charge shifts in the opposite direction of the external electric field. Such a backward charge transfer (BCT) produces an opposite dipole, which makes the polarization negative. The effect of electron interaction on the BCT is illustrated.展开更多
The hydrogen peroxide oxidation reaction (HPOOR) on Au(111) electrode in alkaline solutions with pH values ranging from 10 to 13 was examined systematically. HPOOR activity increased and the slope of the i-E curve dec...The hydrogen peroxide oxidation reaction (HPOOR) on Au(111) electrode in alkaline solutions with pH values ranging from 10 to 13 was examined systematically. HPOOR activity increased and the slope of the i-E curve decreased with increasing pH. HO2- is suggested to be the main reactive intermediate for HPOOR in alkaline media. The fast kinetics for HPOOR in alkaline solution is facilitated by the electrostatic interaction between the positively charged electrode and the reactive anions (i.e., HO2- and HO-), which increases the concentration of these reactants and the thermodynamic driving force for HO2- oxidation at the reaction plane.展开更多
A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenerge...A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.展开更多
While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique...While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way展开更多
TongMai Granules is a Chinese medicine patent drug to treat cardiovascular diseases.It is prepared from the water extract of Dan-shen,Chuan-xiong and Ge-gen.The main compounds of TongMai Granules are isoflavone glycos...TongMai Granules is a Chinese medicine patent drug to treat cardiovascular diseases.It is prepared from the water extract of Dan-shen,Chuan-xiong and Ge-gen.The main compounds of TongMai Granules are isoflavone glycosides,isoflavones,and phenolic acids.However,it is difficult to detect low-polar compounds such as tanshinones and phthalides though they may also contribute to the therapeutic effect.In this work,an off-line two-dimensional chromatography method was developed to enrich the minor constituents in TongMai Granules.The extract was subjected to an SEP-PAK silica SPE column and eluted with petroleum ether,ethyl acetate–methanol(6:1,v/v),and methanol,successively.The three fractions were then analyzed using ultra-high performance liquid chromatography coupled with orbitrap mass spectrometry(UHPLC/orbitrap-MS).The isoflavones from Ge-gen,phenolic acids from Dan-shen and phthalides from Chuan-xiong were distributed in different fractions.A total of 131 compounds,including 59 from Ge-gen,26 from Dan-shen,43 from Chuan-xiong,and 3 common ones from Dan-shen and Chuan-xiong were tentatively identified.Among them,26 compounds were identified by comparing with reference standards.This study set a good example for comprehensive analysis of the constituents in traditional Chinese medicine formula.展开更多
In this work, gelatin-poly（acrylic acid） （GEL-PAA） nanospheres with diameter of around 35 nm were prepared using a polymermonomer （gelatin-AA） pair reaction system. These nanospheres can self-assemble into nanor...In this work, gelatin-poly（acrylic acid） （GEL-PAA） nanospheres with diameter of around 35 nm were prepared using a polymermonomer （gelatin-AA） pair reaction system. These nanospheres can self-assemble into nanorods in aqueous solution at 4 ℃. Based on the observation that the intermediate state of the formation of the nanorods and the facts that the self-assembly can only occur at relatively low temperature and the gelatin molecules on the outermost layer of the GEL-PAA nanospheres can be renatured to triple helix conformation, it can be rationally inferred that the hydrogen bonding and electrostatic interactions between the gelatin molecules with the triple helix structure induce the one-dimensional self-assembly of the nanospheres into nanorods.展开更多
文摘The reverse snapback phenomena （RSP） on I-V characteristics of static induction thyristors （SITH） are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values.
基金Project(50490274) supported by National Natural Science Foundation of China
文摘The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that the intensity of the EME induced from the rock under static stress increases with increasing stress level and loading rate; the relationship between the amplitude of the EME from the rock under different modes of stress wave and elastic parameters and propagation distance was presented. The intensity of the EME relates not only to the strength and elastic moduli of rock masses,but also to the initial damage of the rock. The intensity of EME induced by stress wave reaches the highest at the explosion-center and attenuates with the propagation distance. The intensity of EME increases with increasing the elastic modulus and decreases with increasing initial damage. The results are in good agreement with the experimental results.
基金Project(2005CB623701) supported by the Major State Basic Research Development Program of China
文摘N, N-diethyl dodecyl amine（DEN12） was synthesized from dodecyl amine, formic acid and acetic aldehyde. The collecting property of DENI2 on diaspore, kaolinite and illite was investigated by flotation test and infrared spectrum. The results show that in the presence of 2.0× 10^-4 mol/L DEN12, the recoveries of kaolinite and illite are all higher than 78% and the recovery of diaspore is 50% in the pH range of 5.5-6.0. The mass ratio of A1203 to SiO2 in concentrate obtained from separation artificial mixture is higher than 10, suggesting that DEN12 can be used as a collector to separate the aluminosilicates from diaspore in bauxite ores at the pulp pH below 8. The measurements of the infrared spectrum approve that the action between aluminosilicates and tertiary amine collector is strong electrostatic adsorption and that of diaspore is weak electrostatic adsorption.
文摘It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polymer chain induced by an external electric held E during forming the biexciton. The time dependence of the charge distribution in the chain reveals that the charge transfer is backward: the positive charge shifts in the opposite direction of the external electric field. Such a backward charge transfer (BCT) produces an opposite dipole, which makes the polarization negative. The effect of electron interaction on the BCT is illustrated.
基金supported by the National Natural Science Foundation of China(No.21473175 and No.21273215)the National Key Basic Research Program of China from the Ministry of Science andTechnology of China(No.2015CB932301)
文摘The hydrogen peroxide oxidation reaction (HPOOR) on Au(111) electrode in alkaline solutions with pH values ranging from 10 to 13 was examined systematically. HPOOR activity increased and the slope of the i-E curve decreased with increasing pH. HO2- is suggested to be the main reactive intermediate for HPOOR in alkaline media. The fast kinetics for HPOOR in alkaline solution is facilitated by the electrostatic interaction between the positively charged electrode and the reactive anions (i.e., HO2- and HO-), which increases the concentration of these reactants and the thermodynamic driving force for HO2- oxidation at the reaction plane.
文摘A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.
文摘While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way
基金National Key Research and Development Program of China(Grant No.2018YFC1707301,2018YFC1707304)。
文摘TongMai Granules is a Chinese medicine patent drug to treat cardiovascular diseases.It is prepared from the water extract of Dan-shen,Chuan-xiong and Ge-gen.The main compounds of TongMai Granules are isoflavone glycosides,isoflavones,and phenolic acids.However,it is difficult to detect low-polar compounds such as tanshinones and phthalides though they may also contribute to the therapeutic effect.In this work,an off-line two-dimensional chromatography method was developed to enrich the minor constituents in TongMai Granules.The extract was subjected to an SEP-PAK silica SPE column and eluted with petroleum ether,ethyl acetate–methanol(6:1,v/v),and methanol,successively.The three fractions were then analyzed using ultra-high performance liquid chromatography coupled with orbitrap mass spectrometry(UHPLC/orbitrap-MS).The isoflavones from Ge-gen,phenolic acids from Dan-shen and phthalides from Chuan-xiong were distributed in different fractions.A total of 131 compounds,including 59 from Ge-gen,26 from Dan-shen,43 from Chuan-xiong,and 3 common ones from Dan-shen and Chuan-xiong were tentatively identified.Among them,26 compounds were identified by comparing with reference standards.This study set a good example for comprehensive analysis of the constituents in traditional Chinese medicine formula.
基金supported by the National Natural Science Foundation of China (50625311,20874042,50802040 and 51033002)
文摘In this work, gelatin-poly（acrylic acid） （GEL-PAA） nanospheres with diameter of around 35 nm were prepared using a polymermonomer （gelatin-AA） pair reaction system. These nanospheres can self-assemble into nanorods in aqueous solution at 4 ℃. Based on the observation that the intermediate state of the formation of the nanorods and the facts that the self-assembly can only occur at relatively low temperature and the gelatin molecules on the outermost layer of the GEL-PAA nanospheres can be renatured to triple helix conformation, it can be rationally inferred that the hydrogen bonding and electrostatic interactions between the gelatin molecules with the triple helix structure induce the one-dimensional self-assembly of the nanospheres into nanorods.
