Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2...Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distin…展开更多
Experiments were conducted to examine the effects of salinity fluctuation on the intermolt period and growth of Fenneropenaeus chi- nensis with an initial body weight of (0.553 2±0.000 1)g (mean plus or minus SE)...Experiments were conducted to examine the effects of salinity fluctuation on the intermolt period and growth of Fenneropenaeus chi- nensis with an initial body weight of (0.553 2±0.000 1)g (mean plus or minus SE). The salinity (S0) of the control treatment is 30 throughout the experiment, while the treatments S2, S4, S7 and S10 are subjected to different salinity fluctuations, and the ranges are 2, 4, 7 and 10, respectively. After a 30-day feeding trial, the longest and the shortest intermolt periods of the shrimp occur under Treatments S10 and S2, respectively (difference 37.14%). The special growth rates (SGR) of the shrimp under the five treatments are ranked as S7> S4> S2> S10> S0, and the SGR of the shrimp under Treatment S0 is lower than that under Treatments S4 and S7 by 22.36% and 28.11%, respectively (P< 0.05). The minimal feed intake (FI) of the experimental animals occurs in Treatment S0 (84.04% and 88.54% of that under Treatments S4 and S7, respectively) (P< 0.05). There are no significant differences in the food conversion efficiency (FCE) of the shrimp under the five treatments (P> 0.05).展开更多
Considering the aim of carbon neutrality and reducing plastic pollution,lightweight porous materials with good thermal insulation and mechanical robustness derived from renewable resources are in high demand.Cellulose...Considering the aim of carbon neutrality and reducing plastic pollution,lightweight porous materials with good thermal insulation and mechanical robustness derived from renewable resources are in high demand.Cellulose-based pulp foams(PFs)offer considerable potential applications in many fields;however,the cost-effective manufacturing of PFs with satisfactory properties remains challenging.Herein,we demonstrate a simple and low-cost strategy to prepare a novel pulp/natural rubber(PNR)foam by combining wood pulp fiber and natural rubber latex through wet foaming and oven drying,eliminating traditional freeze-drying and solvent exchange processes.The obtained PNR foam exhibited high porosity(98.4%-99.1%),low density(14.1–24.0 mg/cm^(3)),and excellent water stability(without disintegration under magnetic stirring for 14 days).Moreover,montmorillonite(MMT)was easily incorporated into the PNR during the preparation process,improving the mechanical strength and heat insulation of the obtained PNRMMT foam.The optimized PNR-MMT foam could be compressed more than ten times without losing its resilience,exhibiting a compressive strength of 2.7 MPa at 80%strain,five times higher than that of pristine PF.Moreover,the PNR-MMT foam exhibited excellent flame retardant,good“spill”oil absorption,and good antibacterial properties towards Escherichia coli and Bacillus subtilis.Overall,this study provides a facile,sustainable,and low-cost route for manufacturing PNR-MMT foams with high resilience,good thermal insulation,excellent flame retardancy,and strong antibacterial properties,thus highlighting their usage potential in a broad range of applications.展开更多
On the basis of analyzing the history and characteristics of the undergroundspace exploitation and the urban space development in Guangzhou, and making a thorough study on theunderground space exploitation based on th...On the basis of analyzing the history and characteristics of the undergroundspace exploitation and the urban space development in Guangzhou, and making a thorough study on theunderground space exploitation based on the subway building, this paper points out some mam problemsin the exploitation of underground space in Guangzhou, and emphasizes that Guangzhou must developthe underground space on a large scale with the aid of the subway building, and puts forward aproposal on the urban space coordinate development between on-ground and underground in GuangzhouCity.展开更多
Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inocula...Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inoculated sludge in the systems. Morphological variations of sludge in the reactors were observed. It was found that the cultivation of aerobic granules was closely associated with the kind of inoculated sludge. Round and regular aerobic granules were prevailed in both reactors, and the physical characteristics of the aerobic granules in terms of settling ability, specific gravity, and ratio of water containing were distinct when the inoculate sludge was different. Aerobic granules formed by seeding activated floc are more excellent in simultaneous nitrification and denitrification than that by aerobic granules formed from anaerobic granules. It was concluded that inoculated sludge plays a crucial role in the cultivation of aerobic granules for simultaneous nitrification and denitrification.展开更多
According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies...According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K 490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m 2 /d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m 2 /a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean 展开更多
There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigeri...There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigerite (pengzhizhongite), etc.. According to the principle of closest packing, the crystal chemical properties of nigerite (brown), pengzhizhongite (buff), Zn-nigerite (fawn), Fe-nigerite, Mn-nigerite (greenish-black) etc. have been analyzed. Their crystal structures may be characterized by O (the layers of cation octahedral coordinations), T_1 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in same directions), T_2 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordination in different directions). The position of layer-O and layer-T is alternate permutation. The crystal structure of pengzhizhongite (6 H ) may be expressed by …OT_2OT_1OT_1…, taaffeite (8 H ), …OT_2OT_1OT_2OT_1…, and nigerite (24 R ), … OT_1OT_2 OT_2OT_1 …×3 etc.. In their structure, there are not only the crystal structure units of spinel … OT_2 OT_2 … but also the units of nolanite … OT_1 OT_1 …. The research of these minerals has important theoretic and practical significance in the fields of minerals, gemology, material science etc..展开更多
To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prep...To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prepared. The preparation of high density filters were made with the Biomek 2000 HDRTsystem, and then hybridized separately with three probes prepared by reverse transcription of RNA ofunpollinated ovary, embryo and endosperm. Based on the hybridization results, 800 clones expressed inembryo and/or endosperm were chosen for further analysis of expressed sequence tags (ESTs). Finally,216 different genes were identified preliminarily. Of them, 24 (11.5%) were considered identical to knownwheat genes, 122 (56%) were identified as putative new plant genes which may be involved in seed storageproteins, biochemical metabolisms, development, and other biological processes of seeds, while 70 (32.5%)sequence identities could not be determined.展开更多
Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experi...Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.展开更多
A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, w...A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10 ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.展开更多
Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is...Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.展开更多
Objective To investigate the alterations of L-type calcium current (IcaL) in abdominal aorticligation-induced hypertrophied rat hearts and the effect of losartan on these alterations. METHODS Cardiachypertrophy was in...Objective To investigate the alterations of L-type calcium current (IcaL) in abdominal aorticligation-induced hypertrophied rat hearts and the effect of losartan on these alterations. METHODS Cardiachypertrophy was induced by abdominal aortic ligation in rats. To record IcaL, whole-cell patch-clamp technique wasused. RESULTS Membrane capacitance was larger in hypertrophied cells (148±29 pF) than in sham-operated cells(102±14 pF, P<0.01) and losartan-treated cells (118±27, P<0.01). The maximal peak IcaL Was increased from-835±124 pA in sham-operated cells to -1404+_417 pA in hypertrophied cells (P<0.01), the corresponding IcaL density was increased from -7.5±1.8 pA.pF^1 to -10.5±2.2 pA.pF^1 (P<0.01), while they were reduced to -956-2:170pF (P<0.01) and -8.2±1.6 pA.pF^1 (P<0.05) respectively in losartan-treated cells. The membrane potential of halfmaximal activation of the hypertrophied cells (-20.6±1.0 mV) shifted to more negative potentials than sham-operatedcells (-15.6±1.6 mV, P<0.01) and lorsartan-treated cells (-17.4±1.0 mV, P<0.01). The slope of the activation curveof hypertrophied cells (5.7±0.4) was decreased slightly than sham-operated cells (6.4±0.5, P<0.05). The membranepotential of half maximal inactivation of hypertrophied cells (-27.6±1.9 mV) shifted to more positive potentials thansham-operated cells (-31.4±2.2 mV, P<0.05). The slope of inactivation curves were not different in the three groups.展开更多
FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properti...FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properties of [FePt/Ag]10multilayer films are influenced by the Ag content. The highest coercivity is obtained for those multilayer films that the Ag content is about 25%. The analysis for the re- manence curves shows that the lower FePt layer thickness is favorable for decreasing the intergranular interaction. Re- sult of XRD shows that a thick Ag layer can enhance the intensity of FePt(001) peak. A magnetic activation volume of the order of 10?24 m3 is obtained by the measurement of magnetic viscosity, showing that it is promising to be ultra- high density recording media.展开更多
基金1Project supported by the National Key Basic Research Support Foundation (NKBRSF) of China (No. 2002CB410805)and the Outstanding Youth Fund of National Natural Science Foundation of China (No. 40325001).
文摘Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distin…
文摘Experiments were conducted to examine the effects of salinity fluctuation on the intermolt period and growth of Fenneropenaeus chi- nensis with an initial body weight of (0.553 2±0.000 1)g (mean plus or minus SE). The salinity (S0) of the control treatment is 30 throughout the experiment, while the treatments S2, S4, S7 and S10 are subjected to different salinity fluctuations, and the ranges are 2, 4, 7 and 10, respectively. After a 30-day feeding trial, the longest and the shortest intermolt periods of the shrimp occur under Treatments S10 and S2, respectively (difference 37.14%). The special growth rates (SGR) of the shrimp under the five treatments are ranked as S7> S4> S2> S10> S0, and the SGR of the shrimp under Treatment S0 is lower than that under Treatments S4 and S7 by 22.36% and 28.11%, respectively (P< 0.05). The minimal feed intake (FI) of the experimental animals occurs in Treatment S0 (84.04% and 88.54% of that under Treatments S4 and S7, respectively) (P< 0.05). There are no significant differences in the food conversion efficiency (FCE) of the shrimp under the five treatments (P> 0.05).
基金supported by the National Natural Science Foundation of China(Nos.U22A20423,22208358)the International Partnership Program of the Chinese Academy of Sciences(No.323GJHZ2023019MI)+1 种基金as well as Qingdao Science and Technology Demonstration Projects(Nos.24–1–8-smjk-18-nsh,24–1–8-cspz-6-nsh)support from the China Scholarship Council(Nos.202207960008,202307960001).
文摘Considering the aim of carbon neutrality and reducing plastic pollution,lightweight porous materials with good thermal insulation and mechanical robustness derived from renewable resources are in high demand.Cellulose-based pulp foams(PFs)offer considerable potential applications in many fields;however,the cost-effective manufacturing of PFs with satisfactory properties remains challenging.Herein,we demonstrate a simple and low-cost strategy to prepare a novel pulp/natural rubber(PNR)foam by combining wood pulp fiber and natural rubber latex through wet foaming and oven drying,eliminating traditional freeze-drying and solvent exchange processes.The obtained PNR foam exhibited high porosity(98.4%-99.1%),low density(14.1–24.0 mg/cm^(3)),and excellent water stability(without disintegration under magnetic stirring for 14 days).Moreover,montmorillonite(MMT)was easily incorporated into the PNR during the preparation process,improving the mechanical strength and heat insulation of the obtained PNRMMT foam.The optimized PNR-MMT foam could be compressed more than ten times without losing its resilience,exhibiting a compressive strength of 2.7 MPa at 80%strain,five times higher than that of pristine PF.Moreover,the PNR-MMT foam exhibited excellent flame retardant,good“spill”oil absorption,and good antibacterial properties towards Escherichia coli and Bacillus subtilis.Overall,this study provides a facile,sustainable,and low-cost route for manufacturing PNR-MMT foams with high resilience,good thermal insulation,excellent flame retardancy,and strong antibacterial properties,thus highlighting their usage potential in a broad range of applications.
文摘On the basis of analyzing the history and characteristics of the undergroundspace exploitation and the urban space development in Guangzhou, and making a thorough study on theunderground space exploitation based on the subway building, this paper points out some mam problemsin the exploitation of underground space in Guangzhou, and emphasizes that Guangzhou must developthe underground space on a large scale with the aid of the subway building, and puts forward aproposal on the urban space coordinate development between on-ground and underground in GuangzhouCity.
文摘Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inoculated sludge in the systems. Morphological variations of sludge in the reactors were observed. It was found that the cultivation of aerobic granules was closely associated with the kind of inoculated sludge. Round and regular aerobic granules were prevailed in both reactors, and the physical characteristics of the aerobic granules in terms of settling ability, specific gravity, and ratio of water containing were distinct when the inoculate sludge was different. Aerobic granules formed by seeding activated floc are more excellent in simultaneous nitrification and denitrification than that by aerobic granules formed from anaerobic granules. It was concluded that inoculated sludge plays a crucial role in the cultivation of aerobic granules for simultaneous nitrification and denitrification.
基金The Key National Project for the Ninth Five-Year PlanNo.HY126-06-04-04
文摘According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K 490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m 2 /d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m 2 /a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean
基金ThispaperissupportedbytheNationalNaturalScienceFoundationofChina (No .492 72 0 91 )
文摘There is a type of complex oxide mineral, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu and Shizhuyuan of Hunan Province. These minerals belong to nigerite, Mg-nigerite (pengzhizhongite), etc.. According to the principle of closest packing, the crystal chemical properties of nigerite (brown), pengzhizhongite (buff), Zn-nigerite (fawn), Fe-nigerite, Mn-nigerite (greenish-black) etc. have been analyzed. Their crystal structures may be characterized by O (the layers of cation octahedral coordinations), T_1 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in same directions), T_2 (the mixed layers of cation octahedral coordinations and cation tetrahedral coordination in different directions). The position of layer-O and layer-T is alternate permutation. The crystal structure of pengzhizhongite (6 H ) may be expressed by …OT_2OT_1OT_1…, taaffeite (8 H ), …OT_2OT_1OT_2OT_1…, and nigerite (24 R ), … OT_1OT_2 OT_2OT_1 …×3 etc.. In their structure, there are not only the crystal structure units of spinel … OT_2 OT_2 … but also the units of nolanite … OT_1 OT_1 …. The research of these minerals has important theoretic and practical significance in the fields of minerals, gemology, material science etc..
文摘To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prepared. The preparation of high density filters were made with the Biomek 2000 HDRTsystem, and then hybridized separately with three probes prepared by reverse transcription of RNA ofunpollinated ovary, embryo and endosperm. Based on the hybridization results, 800 clones expressed inembryo and/or endosperm were chosen for further analysis of expressed sequence tags (ESTs). Finally,216 different genes were identified preliminarily. Of them, 24 (11.5%) were considered identical to knownwheat genes, 122 (56%) were identified as putative new plant genes which may be involved in seed storageproteins, biochemical metabolisms, development, and other biological processes of seeds, while 70 (32.5%)sequence identities could not be determined.
基金supported by the Advanced Research Foundation of Chinese General Equipment Department(9140C880101140C88367)Major Program of the National Natural Science Foundation of China(U1435218)
基金supported by the Advance Research Foundation of Chinese General Equipment Department(9140C880101140C88367)Major Program of the National Natural Science Foundation of China(U1435218)
基金the Major State Basic Research of China(Grant No.G1999012011)the State Agriculture Program(Grant No.K2002-16) the Initializing Fund for Teachers of Ocean University of China.
文摘Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.
文摘A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons(CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10 ml 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption.
文摘Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.
文摘Objective To investigate the alterations of L-type calcium current (IcaL) in abdominal aorticligation-induced hypertrophied rat hearts and the effect of losartan on these alterations. METHODS Cardiachypertrophy was induced by abdominal aortic ligation in rats. To record IcaL, whole-cell patch-clamp technique wasused. RESULTS Membrane capacitance was larger in hypertrophied cells (148±29 pF) than in sham-operated cells(102±14 pF, P<0.01) and losartan-treated cells (118±27, P<0.01). The maximal peak IcaL Was increased from-835±124 pA in sham-operated cells to -1404+_417 pA in hypertrophied cells (P<0.01), the corresponding IcaL density was increased from -7.5±1.8 pA.pF^1 to -10.5±2.2 pA.pF^1 (P<0.01), while they were reduced to -956-2:170pF (P<0.01) and -8.2±1.6 pA.pF^1 (P<0.05) respectively in losartan-treated cells. The membrane potential of halfmaximal activation of the hypertrophied cells (-20.6±1.0 mV) shifted to more negative potentials than sham-operatedcells (-15.6±1.6 mV, P<0.01) and lorsartan-treated cells (-17.4±1.0 mV, P<0.01). The slope of the activation curveof hypertrophied cells (5.7±0.4) was decreased slightly than sham-operated cells (6.4±0.5, P<0.05). The membranepotential of half maximal inactivation of hypertrophied cells (-27.6±1.9 mV) shifted to more positive potentials thansham-operated cells (-31.4±2.2 mV, P<0.05). The slope of inactivation curves were not different in the three groups.
文摘FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properties of [FePt/Ag]10multilayer films are influenced by the Ag content. The highest coercivity is obtained for those multilayer films that the Ag content is about 25%. The analysis for the re- manence curves shows that the lower FePt layer thickness is favorable for decreasing the intergranular interaction. Re- sult of XRD shows that a thick Ag layer can enhance the intensity of FePt(001) peak. A magnetic activation volume of the order of 10?24 m3 is obtained by the measurement of magnetic viscosity, showing that it is promising to be ultra- high density recording media.
