The changes and correlations of muscle pH, glycogen, lactic acid and in- tramuscular fat oxidation in Duroc pigs 10 d after their slaughter, and the effects of different storage temperature and time on Duroc muscle pH...The changes and correlations of muscle pH, glycogen, lactic acid and in- tramuscular fat oxidation in Duroc pigs 10 d after their slaughter, and the effects of different storage temperature and time on Duroc muscle pH value, water loss rate, glycogen, lactic acid and 2-thiobarbituric acid （TBA） were studied. The results showed that during the 10 h after the slaughter, the pH value was decreased rapid- ly, the lactic acid content was increased significantly, while the glycogen and TBA contents were remained stable. At the storage temperature of 4 ℃, storage time showed no significant effects on Duroc muscle pH value and glycogen, lactic acid and TBA contents. At the storage temperature of -20 ℃, storage temperature had significant effects on pH value, while no significant effects on other indicators. The correlation analysis demonstrated that during the 10 h after the slaughter, the TBA content was negatively related to glycogen content （P〈0.05）, but positively related to lactic content （P〈0.05）; the pH value was negatively related to lactic acid content （P〈0.05）. At the storage temperature of 4 ℃, the TBA content was negatively relat- ed to water loss rate （P〈0.01） and lactic acid content （P〈0.05）; the water loss rate was positively related to pH value （P〈0.01） and lactic acid content （P〈0.05）. At the storage temperature of -20 ℃, the TBA content was negatively related to pH value （P〈0.01） and positively related to water loss rate （P〈0.05）; the water loss rate was negatively related to pH value （P〈0.01） and lactic acid content （P〈0.05）.展开更多
Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kid...Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kidney capsule or intraperitoneally into Wistar rat w ith STZ-induced diabetes. The blood glucose and insulin secretion of grafts wer e observed. Graft function was tested by oral glucose tolerance test (OGTT). Results: ①Five diabetic rats became normoglycemic for 48 to 72 h after microencapsulated islets transplantation. The survival of transplanted i slets was on an average of 6 W. ②The normalization of the glycemia and insulin in the transplanted rats was associated with normal glucose and insulin profiles in response to OGTT. Conclusion: Microencapsulation with barium -alginate membrane can prolong islet survival and protect islets against allore jection.展开更多
An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraf...An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraft flight simulation based on MATLAB/Simulink ＋ dSPACE. The platform combines the abundant software and hardware resources of dSPACE simulation platform to simulate the flight attitude of an aircraft in six-DOF （ degree of freedom） motion. Based on the platform, the study was then focused on the flight numerical simulation by taking a loitering aerial vehicle as an example. An aircraft mathematical model was created for a modular design and off-line numerical simulation based on MATLAB/Simulink. Finally, the study was focused on the control system design of the loitering aerial vehicle and conduct of an HITL simulation experiment for the vehicle pitch control. The experiment verifies the system design and control effectiveness. Research results show that the dSPACE simulation system provides a real time good experimental platform to improve the efficiency of study and development of a flight control system.展开更多
Hardware-in-the-loop （HWIL） simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can...Hardware-in-the-loop （HWIL） simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting signal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory （DRFM） system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile （HRRP） are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.展开更多
Molecalar dynamics simulation is applied to investigate the microstructure evolution of magnesium single crystals under c-axis extension at different temperatures. At low temperatures, both {1012} and {1011} twins are...Molecalar dynamics simulation is applied to investigate the microstructure evolution of magnesium single crystals under c-axis extension at different temperatures. At low temperatures, both {1012} and {1011} twins are observed. At elevated temperatures, {1011} twining decreases quickly with increasing temperature, while the amount of {1012} twins increases. The （1012} twin is found to be the main deformation mechanism under the c-axis tension in the magnesium single crystal. Meanwhile, shear bands are also observed during deformation. When the temperature is beyond 500 K, the non-basal plane slip due to the thermal .activation is found. The stress-strain curves related with deformation behavior at atomistic scale are presented.展开更多
Structure analyses for hydrate models of ethyleneimine oligomer (5-mer as model of PEI) were investigated by quantum chemical calculations. Conformation energies and structures optimized for hydrate models of (ttt)5 a...Structure analyses for hydrate models of ethyleneimine oligomer (5-mer as model of PEI) were investigated by quantum chemical calculations. Conformation energies and structures optimized for hydrate models of (ttt)5 and (tgt)5 conformers were examined. Hydrate ratio, h [h = H2O/N (mol)], was set from 0.5 to 2. In anhydrates, (tg+t)5 conformer was more stable (?1.8 kcal/m.u.) than (ttt)5. In hydrates, (ttt)5 conformers were more stable (?0.7 - ?4.3) than (tg+t)5. These results corresponded to experimental results that anhydrous linear PEI crystal changes from double helical to single planar chain in hydration process. Structures calculated for (ttt)5 agreed in those observed for hydrates of PEI. In all (tg+t)5 conformers, O???H bonds between waters were found with the decreases of N???H bonds between imino group and water. The O???H bonds in (tg+t)5 conformer resulted in its high chain torsion, and strongly related with instability and structure change (large swelling).展开更多
Objective: To establish a HPLC method using fluorometric detection for quantitatively determinating intracellular accumulation of verapamil (VER). Methods: Chromatography column was packed with spherisorb ODS(250&...Objective: To establish a HPLC method using fluorometric detection for quantitatively determinating intracellular accumulation of verapamil (VER). Methods: Chromatography column was packed with spherisorb ODS(250×4.6 mm,10 μm).The mobile phase consisted of the mixture of methanol:NaAC (0.01 mol/L): diethylamine (65:35:0.25). The detect wavelength was 280/310 nm (Ex/Em). Results: The standard curve showed a good correlation between concentration and peak area within the range of 5-50 ng/ml. RSD was 0.86%, and recovery radio of loading sample, 100%. The detection limit for cell sample was 0.2-148 ng/ml. Intracellular accumulation of VER was observed to decrease from a 13 fold to 5 fold in K562/ADM cells, and from a 3.5 fold to 4.3 fold in K562/VER cells and from a 2.1 fold to 6.5 fold in K562/ADM/VER cells, compared with the relevant control cells. Conclusion: HPLC method was proved to be sensitive and specific for using to quantitatively determine the intracellular accumulation of VER.展开更多
Using oxidation with KMnO4. KMnO4/acetone-H2O. NAS. followed by Polonovskyreaction and imine formation. the N-deethylation of six norditerpenoid alkaloids 6-epi-forsticille.yunnaconitine. 3. 13-diacetylyunnaconitine. ...Using oxidation with KMnO4. KMnO4/acetone-H2O. NAS. followed by Polonovskyreaction and imine formation. the N-deethylation of six norditerpenoid alkaloids 6-epi-forsticille.yunnaconitine. 3. 13-diacetylyunnaconitine. 13-dehydroxy-indaconitine. indaconitine and 3-acetylpseudaconine are reported in 36-60% yields.展开更多
Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and eac...Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and each stage consists of double-layered insulators. To sustain -1 MV in vacuum, reduction of electric field at several triple points existing around the double-layered insulators is a critical issue. To reduce electric field simultaneously at these points, three types of stress ring have been developed. In a voltage holding test of a full-scale mockup equipped with these stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, whose target is the acceleration of a H- ion beam of 1 MeV, 200 A/mS, the gap between the grid support was extended to suppress breakdowns triggered by electric field concentration at the edge and corner of the grid support. This modi- fication improved the voltage holding capability in vacuum, and the MeV accelerator succeeded in sustaining -1 MV stably, b-~rthermore, it appeared that the H- ions beam was deflected and a part of the beam was intercepted at the acceleration grid, This causes high heat load on the grids and breakdowns during beam acceleration. To suppress the direct interception, a new grid was designed with proper aperture displacement based on a three dimensional beam trajectory analysis, As a result, 980 keV, 185 A/ms H- ion beam acceleration has been demonstrated, which is close to the ITER requirement.展开更多
The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relati...The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.展开更多
The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural ...The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural gas pipeline network requires more strictly on the calculation efficiency of transient simulation.To this end,this paper proposes a new method for the transient simulation of natural gas pipeline networks based on fracture-dimension-reduction algorithm.Firstly,a pipeline network model is abstracted into a station model,inter-station pipeline network model and connection node model.Secondlly,the pressure at the connection node connecting the station and the inter-station pipeline network is used as the basic variable to solve the general solution of the flow rate at the connection node,reconstruct the simulation model of the inter-station pipeline network,and reduce the equation set dimension of the inter-station pipeline network model.Thirdly,the transient simulation model of the natural gas pipeline network system is constructed based on the reconstructed simulation model of the inter-station pipeline network.Fnally,the calculation accuracy and efficiency of the proposed algorithm are compared and analyzed for the two working conditions of slow change of compressor speed and rapid shutdown of the compressor.And the following research results are obtained.First,the fracture-dimension-reduction algorithm has a high calculation accuracy,and the relative error of compressor outlet pressure and user pressure is less than 0.1%.Second,the calculation efficiency of the new fracture-dimension-reduction algorithm is high,and compared with the nonlinear equations solv ing method,the speed-up ratios under the two conditions are high up to 17.3 and 12.2 respectively.Third,the speed-up ratio of the fracture-dimension-reduction algorithm is linearly related to the equation set dimension of the transient simulation model of the pipeline network system.The larger the equation set dimension,the higher the speed-up ratio,which means the more complex the pipeline network model,the more remarkable the calculation speed-up effect.In conclusion,this new method improves the calculation speed while keeping the calculation accuracy,which is of great theoretical value and reference significance for improving the calculation efficiency of the transient simulation of complex natural gas pipeline network systems.展开更多
In the present study we have found that proto-oncogene c-fos protein can expressin the noradrenergic neurons of rat hindbrain following peripheral electrical stimulation. Ratswere given peripheral electrical stimulati...In the present study we have found that proto-oncogene c-fos protein can expressin the noradrenergic neurons of rat hindbrain following peripheral electrical stimulation. Ratswere given peripheral electrical stimulation via thin stainless steel pins inserted into the pointsnear knee joint (S36) and ankle joint (Sp6) which mimic the manipulation of electroacupuncture(EA) performed in humans. Animals were perfused for double staining immunohistochemistry 2hafter the termination of EA. In rats subjected to EA stimulation Fos-like protein was found in thetyrosine hydroxylase (TH)-like immunoreactive neurons in rat hindbrain. The Fos and TH coex-isting neurons were distributed in the locus coeruleus, solitary tract nucleus, ventrolateral medul-la, periaqeductal gray, as well as superior colliculus. The percentage of the coexisting neuronscompared with the total number of neurons containing Fos-like protein in these nuclei rangedfrom 6% to 32%. The results suggest that the noradrenergic neurons in these regions may be ac-tivted by acupuncture stimulation.展开更多
On the basis of the calculations and analyses of the intrapair and interpair correlation energy of KX (X = OH, NC) molecules and the results of the transferability of both the innermost intrapair correlation energy an...On the basis of the calculations and analyses of the intrapair and interpair correlation energy of KX (X = OH, NC) molecules and the results of the transferability of both the innermost intrapair correlation energy and the inner core effect of K and X in KX molecules, we defined and calculated the Kδ- and Xδ-correlation contributions to the total correlation energy of KX molecules. With the comparison of the pair correlation energy of K+, X- and KX systems, we present a simple estimation method to estimate the electron correlation energy of strong ionic compound by summarizing the correlation energy of its constituent ion and ionic group. By using this simple method, the reasonable estimation results of the correlation energy of (KOH)2 and (KNC)2 have been obtained at mp2/6-311++G(d) level with Gaussian98 program, and the deviations are very small. Applying the scheme of 'Separate Large System into Smaller Ones' to the calculation of electron correlation energy of large ionic compounds, it can not only save lot of computation work but also reach the chemical accuracy.展开更多
Previous results indicated that in grapevine （Vitis vinifera）, regulation of the flavonoid pathway genes by MYB transcription factors depends on their interaction with basic helix-loop-helix proteins （bHLHs）. The ...Previous results indicated that in grapevine （Vitis vinifera）, regulation of the flavonoid pathway genes by MYB transcription factors depends on their interaction with basic helix-loop-helix proteins （bHLHs）. The present study describes the first functional characterization of a bHLH factor from grapevine named VvMYC1. This transcription factor is phylogenetically related to Arabidopsis bHLH proteins, which participate in the control of flavonoid biosynthesis and epidermal cell fate. Transient promoter and yeast two-hybrid assays demonstrated that VvMYC1 physically interacts with MYB5a, MYB5b, MYBA1/A2, and MYBPA1 to induce promoters of flavonoid pathway genes involved in anthocyanin and/ or proanthocyanidin （PA） synthesis. Additionally, transient promoter assays revealed that VvMYC1 is involved in feedback regulation of its own expression. Transcript levels of VvMYC1 during berry development correlate with the synthesis of anthocyanins and PAs in skins and seeds of berries, suggesting that VvMYC1 is involved in the regulation of anthocyanins and PA synthesis in these organs. Likewise, transient expression of VvMYC1 and VvMYBA1 induces anthocyanin synthesis in grapevine suspension cells. These results suggest that VvMYCl is part of the transcriptional cascade controlling antho- cyanin and PA biosynthesis in grapevine.展开更多
The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant mult...The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology(SCSIO), Chinese Academy of Sciences. Results show that:(1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current;(2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling;(3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed:(i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and(ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road.展开更多
Silicon-based digital cameras can record visible and near-infrared （NIR） information, in which the full color visible image （RGB） must be restored from color filter ar- ray （CFA） interpolation. In this paper, we...Silicon-based digital cameras can record visible and near-infrared （NIR） information, in which the full color visible image （RGB） must be restored from color filter ar- ray （CFA） interpolation. In this paper, we propose a uni- fied framework for CFA interpolation and visible/NIR image combination. To obtain a high quality color image, the tra- ditional color interpolation from raw CFA data is improved at each pixel, which is constrained by the corresponding monochromatic NIR image in gradient difference. The ex- periments indicate the effectiveness of this hybrid scheme to acquire joint color and NIR information in real-time, and show that this hybrid process can generate a better color im- age when compared to treating interpolation and fusion sep- arately.展开更多
Hexanoyl chitosan and polystyrene blends are immiscible by the elucidation of the glass transition temperature （Tg） as well as the viscometric and morphological analyses. Selective localization of the lithium salt i...Hexanoyl chitosan and polystyrene blends are immiscible by the elucidation of the glass transition temperature （Tg） as well as the viscometric and morphological analyses. Selective localization of the lithium salt in hexanoyl chitosan phase as the percolation pathway enhanced the conductivity in the blends as compared to the neat hexanoyl chitosan. The ionic conductivity of a polymer electrolyte is described by σ = enp. Thus, estimation of charge carrier density （n） and mobility （μ） is important in order to assess the performance. In this work, these parameters are calculated using impedance spectroscopy and FTIR.展开更多
基金Supported by Funds for Swine Innovation Team Construction of Shandong Provincial Modern Agriculture Industry Technology System(SDAIT-06-011-03)Fine Breeds Engineering Project of Shandong Province(2011LZ013-01)China Swine Industry Technology System(CARS-36)~~
文摘The changes and correlations of muscle pH, glycogen, lactic acid and in- tramuscular fat oxidation in Duroc pigs 10 d after their slaughter, and the effects of different storage temperature and time on Duroc muscle pH value, water loss rate, glycogen, lactic acid and 2-thiobarbituric acid （TBA） were studied. The results showed that during the 10 h after the slaughter, the pH value was decreased rapid- ly, the lactic acid content was increased significantly, while the glycogen and TBA contents were remained stable. At the storage temperature of 4 ℃, storage time showed no significant effects on Duroc muscle pH value and glycogen, lactic acid and TBA contents. At the storage temperature of -20 ℃, storage temperature had significant effects on pH value, while no significant effects on other indicators. The correlation analysis demonstrated that during the 10 h after the slaughter, the TBA content was negatively related to glycogen content （P〈0.05）, but positively related to lactic content （P〈0.05）; the pH value was negatively related to lactic acid content （P〈0.05）. At the storage temperature of 4 ℃, the TBA content was negatively relat- ed to water loss rate （P〈0.01） and lactic acid content （P〈0.05）; the water loss rate was positively related to pH value （P〈0.01） and lactic acid content （P〈0.05）. At the storage temperature of -20 ℃, the TBA content was negatively related to pH value （P〈0.01） and positively related to water loss rate （P〈0.05）; the water loss rate was negatively related to pH value （P〈0.01） and lactic acid content （P〈0.05）.
基金Subject of Jiangsu Province135 Projects (2001 31)
文摘Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kidney capsule or intraperitoneally into Wistar rat w ith STZ-induced diabetes. The blood glucose and insulin secretion of grafts wer e observed. Graft function was tested by oral glucose tolerance test (OGTT). Results: ①Five diabetic rats became normoglycemic for 48 to 72 h after microencapsulated islets transplantation. The survival of transplanted i slets was on an average of 6 W. ②The normalization of the glycemia and insulin in the transplanted rats was associated with normal glucose and insulin profiles in response to OGTT. Conclusion: Microencapsulation with barium -alginate membrane can prolong islet survival and protect islets against allore jection.
基金Sponsored by the Ministerial Level Advanced Research Foundation(A26020060253)
文摘An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraft flight simulation based on MATLAB/Simulink ＋ dSPACE. The platform combines the abundant software and hardware resources of dSPACE simulation platform to simulate the flight attitude of an aircraft in six-DOF （ degree of freedom） motion. Based on the platform, the study was then focused on the flight numerical simulation by taking a loitering aerial vehicle as an example. An aircraft mathematical model was created for a modular design and off-line numerical simulation based on MATLAB/Simulink. Finally, the study was focused on the control system design of the loitering aerial vehicle and conduct of an HITL simulation experiment for the vehicle pitch control. The experiment verifies the system design and control effectiveness. Research results show that the dSPACE simulation system provides a real time good experimental platform to improve the efficiency of study and development of a flight control system.
基金co-supported by the National Natural Science Foundation of China (Nos. 61071164, 61271327)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Hardware-in-the-loop （HWIL） simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting signal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory （DRFM） system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile （HRRP） are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.
基金supported by the National Natural Science Foundation of China (No.11072026)the Fundamental Research Funds for the Central Universities
文摘Molecalar dynamics simulation is applied to investigate the microstructure evolution of magnesium single crystals under c-axis extension at different temperatures. At low temperatures, both {1012} and {1011} twins are observed. At elevated temperatures, {1011} twining decreases quickly with increasing temperature, while the amount of {1012} twins increases. The （1012} twin is found to be the main deformation mechanism under the c-axis tension in the magnesium single crystal. Meanwhile, shear bands are also observed during deformation. When the temperature is beyond 500 K, the non-basal plane slip due to the thermal .activation is found. The stress-strain curves related with deformation behavior at atomistic scale are presented.
文摘Structure analyses for hydrate models of ethyleneimine oligomer (5-mer as model of PEI) were investigated by quantum chemical calculations. Conformation energies and structures optimized for hydrate models of (ttt)5 and (tgt)5 conformers were examined. Hydrate ratio, h [h = H2O/N (mol)], was set from 0.5 to 2. In anhydrates, (tg+t)5 conformer was more stable (?1.8 kcal/m.u.) than (ttt)5. In hydrates, (ttt)5 conformers were more stable (?0.7 - ?4.3) than (tg+t)5. These results corresponded to experimental results that anhydrous linear PEI crystal changes from double helical to single planar chain in hydration process. Structures calculated for (ttt)5 agreed in those observed for hydrates of PEI. In all (tg+t)5 conformers, O???H bonds between waters were found with the decreases of N???H bonds between imino group and water. The O???H bonds in (tg+t)5 conformer resulted in its high chain torsion, and strongly related with instability and structure change (large swelling).
文摘Objective: To establish a HPLC method using fluorometric detection for quantitatively determinating intracellular accumulation of verapamil (VER). Methods: Chromatography column was packed with spherisorb ODS(250×4.6 mm,10 μm).The mobile phase consisted of the mixture of methanol:NaAC (0.01 mol/L): diethylamine (65:35:0.25). The detect wavelength was 280/310 nm (Ex/Em). Results: The standard curve showed a good correlation between concentration and peak area within the range of 5-50 ng/ml. RSD was 0.86%, and recovery radio of loading sample, 100%. The detection limit for cell sample was 0.2-148 ng/ml. Intracellular accumulation of VER was observed to decrease from a 13 fold to 5 fold in K562/ADM cells, and from a 3.5 fold to 4.3 fold in K562/VER cells and from a 2.1 fold to 6.5 fold in K562/ADM/VER cells, compared with the relevant control cells. Conclusion: HPLC method was proved to be sensitive and specific for using to quantitatively determine the intracellular accumulation of VER.
文摘Using oxidation with KMnO4. KMnO4/acetone-H2O. NAS. followed by Polonovskyreaction and imine formation. the N-deethylation of six norditerpenoid alkaloids 6-epi-forsticille.yunnaconitine. 3. 13-diacetylyunnaconitine. 13-dehydroxy-indaconitine. indaconitine and 3-acetylpseudaconine are reported in 36-60% yields.
文摘Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and each stage consists of double-layered insulators. To sustain -1 MV in vacuum, reduction of electric field at several triple points existing around the double-layered insulators is a critical issue. To reduce electric field simultaneously at these points, three types of stress ring have been developed. In a voltage holding test of a full-scale mockup equipped with these stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, whose target is the acceleration of a H- ion beam of 1 MeV, 200 A/mS, the gap between the grid support was extended to suppress breakdowns triggered by electric field concentration at the edge and corner of the grid support. This modi- fication improved the voltage holding capability in vacuum, and the MeV accelerator succeeded in sustaining -1 MV stably, b-~rthermore, it appeared that the H- ions beam was deflected and a part of the beam was intercepted at the acceleration grid, This causes high heat load on the grids and breakdowns during beam acceleration. To suppress the direct interception, a new grid was designed with proper aperture displacement based on a three dimensional beam trajectory analysis, As a result, 980 keV, 185 A/ms H- ion beam acceleration has been demonstrated, which is close to the ITER requirement.
文摘The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.
文摘The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural gas pipeline network requires more strictly on the calculation efficiency of transient simulation.To this end,this paper proposes a new method for the transient simulation of natural gas pipeline networks based on fracture-dimension-reduction algorithm.Firstly,a pipeline network model is abstracted into a station model,inter-station pipeline network model and connection node model.Secondlly,the pressure at the connection node connecting the station and the inter-station pipeline network is used as the basic variable to solve the general solution of the flow rate at the connection node,reconstruct the simulation model of the inter-station pipeline network,and reduce the equation set dimension of the inter-station pipeline network model.Thirdly,the transient simulation model of the natural gas pipeline network system is constructed based on the reconstructed simulation model of the inter-station pipeline network.Fnally,the calculation accuracy and efficiency of the proposed algorithm are compared and analyzed for the two working conditions of slow change of compressor speed and rapid shutdown of the compressor.And the following research results are obtained.First,the fracture-dimension-reduction algorithm has a high calculation accuracy,and the relative error of compressor outlet pressure and user pressure is less than 0.1%.Second,the calculation efficiency of the new fracture-dimension-reduction algorithm is high,and compared with the nonlinear equations solv ing method,the speed-up ratios under the two conditions are high up to 17.3 and 12.2 respectively.Third,the speed-up ratio of the fracture-dimension-reduction algorithm is linearly related to the equation set dimension of the transient simulation model of the pipeline network system.The larger the equation set dimension,the higher the speed-up ratio,which means the more complex the pipeline network model,the more remarkable the calculation speed-up effect.In conclusion,this new method improves the calculation speed while keeping the calculation accuracy,which is of great theoretical value and reference significance for improving the calculation efficiency of the transient simulation of complex natural gas pipeline network systems.
基金Chinese postdoctoral foundationa grand from the National Institute of Drug Abuse, USA (DA 03983)
文摘In the present study we have found that proto-oncogene c-fos protein can expressin the noradrenergic neurons of rat hindbrain following peripheral electrical stimulation. Ratswere given peripheral electrical stimulation via thin stainless steel pins inserted into the pointsnear knee joint (S36) and ankle joint (Sp6) which mimic the manipulation of electroacupuncture(EA) performed in humans. Animals were perfused for double staining immunohistochemistry 2hafter the termination of EA. In rats subjected to EA stimulation Fos-like protein was found in thetyrosine hydroxylase (TH)-like immunoreactive neurons in rat hindbrain. The Fos and TH coex-isting neurons were distributed in the locus coeruleus, solitary tract nucleus, ventrolateral medul-la, periaqeductal gray, as well as superior colliculus. The percentage of the coexisting neuronscompared with the total number of neurons containing Fos-like protein in these nuclei rangedfrom 6% to 32%. The results suggest that the noradrenergic neurons in these regions may be ac-tivted by acupuncture stimulation.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 29873023 and 20173027).
文摘On the basis of the calculations and analyses of the intrapair and interpair correlation energy of KX (X = OH, NC) molecules and the results of the transferability of both the innermost intrapair correlation energy and the inner core effect of K and X in KX molecules, we defined and calculated the Kδ- and Xδ-correlation contributions to the total correlation energy of KX molecules. With the comparison of the pair correlation energy of K+, X- and KX systems, we present a simple estimation method to estimate the electron correlation energy of strong ionic compound by summarizing the correlation energy of its constituent ion and ionic group. By using this simple method, the reasonable estimation results of the correlation energy of (KOH)2 and (KNC)2 have been obtained at mp2/6-311++G(d) level with Gaussian98 program, and the deviations are very small. Applying the scheme of 'Separate Large System into Smaller Ones' to the calculation of electron correlation energy of large ionic compounds, it can not only save lot of computation work but also reach the chemical accuracy.
文摘Previous results indicated that in grapevine （Vitis vinifera）, regulation of the flavonoid pathway genes by MYB transcription factors depends on their interaction with basic helix-loop-helix proteins （bHLHs）. The present study describes the first functional characterization of a bHLH factor from grapevine named VvMYC1. This transcription factor is phylogenetically related to Arabidopsis bHLH proteins, which participate in the control of flavonoid biosynthesis and epidermal cell fate. Transient promoter and yeast two-hybrid assays demonstrated that VvMYC1 physically interacts with MYB5a, MYB5b, MYBA1/A2, and MYBPA1 to induce promoters of flavonoid pathway genes involved in anthocyanin and/ or proanthocyanidin （PA） synthesis. Additionally, transient promoter assays revealed that VvMYC1 is involved in feedback regulation of its own expression. Transcript levels of VvMYC1 during berry development correlate with the synthesis of anthocyanins and PAs in skins and seeds of berries, suggesting that VvMYC1 is involved in the regulation of anthocyanins and PA synthesis in these organs. Likewise, transient expression of VvMYC1 and VvMYBA1 induces anthocyanin synthesis in grapevine suspension cells. These results suggest that VvMYCl is part of the transcriptional cascade controlling antho- cyanin and PA biosynthesis in grapevine.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFC1405100)the National Natural Science Foundation of China(Grant Nos.41521005,41476011,41706027,41676013)+4 种基金the Natural Science Foundation of Guangdong(Grant No.2016A030310015)the Open Fund of the Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences(Grant No.KLOCW1604)the Open Fund of the State Key Laboratory of Tropical Oceanography(Grant No.LTOZZ1702)the MEL Visiting Fellowship(Grant No.MELRS1640)the Guangzhou Science and Technology Foundation(Grant No.201804010133)
文摘The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology(SCSIO), Chinese Academy of Sciences. Results show that:(1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current;(2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling;(3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed:(i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and(ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road.
文摘Silicon-based digital cameras can record visible and near-infrared （NIR） information, in which the full color visible image （RGB） must be restored from color filter ar- ray （CFA） interpolation. In this paper, we propose a uni- fied framework for CFA interpolation and visible/NIR image combination. To obtain a high quality color image, the tra- ditional color interpolation from raw CFA data is improved at each pixel, which is constrained by the corresponding monochromatic NIR image in gradient difference. The ex- periments indicate the effectiveness of this hybrid scheme to acquire joint color and NIR information in real-time, and show that this hybrid process can generate a better color im- age when compared to treating interpolation and fusion sep- arately.
文摘Hexanoyl chitosan and polystyrene blends are immiscible by the elucidation of the glass transition temperature （Tg） as well as the viscometric and morphological analyses. Selective localization of the lithium salt in hexanoyl chitosan phase as the percolation pathway enhanced the conductivity in the blends as compared to the neat hexanoyl chitosan. The ionic conductivity of a polymer electrolyte is described by σ = enp. Thus, estimation of charge carrier density （n） and mobility （μ） is important in order to assess the performance. In this work, these parameters are calculated using impedance spectroscopy and FTIR.
