A new approach to high-order Boussinesq-type equations with ambient currents is presented. The current velocity is assumed to be uniform over depth and of the same magnitude as the shallow water wave celerity. The wav...A new approach to high-order Boussinesq-type equations with ambient currents is presented. The current velocity is assumed to be uniform over depth and of the same magnitude as the shallow water wave celerity. The wave velocity field is expressed in terms of the horizontal and vertical wave velocity components at an arbitrary water depth level. Linear operators are introduced to improve the accuracy of the kinematic condition at the sea bottom. The dynamic and kinematic conditions at the free surface are expressed in terms of wave velocity variables defined directly on the free surface. The new equations provide high accuracy of linear properties as well as nonlinear properties from shallow to deep water, and extend the applicable range of relative water depth in the case of opposing currents.展开更多
Background Atrial fibrillation （AF） is the most common sustained cardiac arrhythmia without effective treatment. AF is associated with atrial conduction disturbances caused by electrical and / or structural remodeli...Background Atrial fibrillation （AF） is the most common sustained cardiac arrhythmia without effective treatment. AF is associated with atrial conduction disturbances caused by electrical and / or structural remodeling. But the role of connexin （Cx） 43 in the regulation of L type calcium channel （LCC） remains unclear. We hypothesized that Cx 43 might co-localize and regulate the L type calcium channel current （ICa, D. Methods Real-time PCR and whole-cell patch clamp were used to detect the expression of LCC lc subunit and the cur rent density of Ica, L, before and after Cx 43 knocking down respectively. The co-localization of Cx 43 with LCC was investigated by co-immunoprecipitation and confocal microscopy. Results Knocking down of Cx43 significantly inhibited the current density of ICa, L through decreasing the gene expression of LCC alc in cul tured atrium-derived myocytes （HL-1 cells）. Cx43 co-localized with LCC eric subunit in atrial myocytes. Conclusions Cx 43 regulates the ICa, L in atrial myoctyes through LCC, representing a potential pathogenic mechanism in atrial arrhythmias.展开更多
This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission chara...This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.展开更多
Objectives Heart failure （HF） is one of the most common outcome for all kinds of heart diseases, the effects of energetic therapy on HF remains controversial, especially to ischemic HF. The aim of this study was to ...Objectives Heart failure （HF） is one of the most common outcome for all kinds of heart diseases, the effects of energetic therapy on HF remains controversial, especially to ischemic HF. The aim of this study was to explore the effect of exogenous phosphocreatine with different concentration on L-type calcium（I Cc-L） current in ischemic ventricular myocytes of guinea pig and to investigate its underlying electrophysiological mechanism for the treatment of ischemic HF. Methods Single ventricular myocytes were isolated enzymatically from left ventricle of guinea pig. Peak I Ca-L current were recorded using patch clamp techniques in the whole-cell configuration when myocytes had been superfused with normal Tyrode solution, simple ischemic solution, ischemic solution containing phosphocreatine with different concentration for 10 minutes respectively. Results Peak I Ca-L current density of myocytes superfused with simple simulated ischemic solution was remarkably inhibited by 80.6 ± 5.2% compared with myocytes superfused with normal Tyrode solution（P〈0.05）. Ischemic solution containing phosphocreatine of 5, 10, 20, 30mmol/L inhibited Peak I Ca-L current density by （53.8±6.7）%, （41.8 ± 8.2）%, （38.1±7.4）%, （36.6±9.7）% respectively. There was no statistical significance among phosphocreation of 10, 20, 30 mmol / L. Conclusions Extrogenous phosphocreatine could reverse the inhibition of I Ca-L current under ischemic condition, which could be the ionic basis for the treatment of ischemic heart failure. 0-10 mmol/L phosphocreatine exerted significant dose-effect relationship which no longer existed as concentration more than 10 mmol/L. It is supposed that phosphocreatine increased I Ca-L current by many pathways rather than simple substrate for ATP synthesis.展开更多
A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main dischar...A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseu- dospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface ttashover trigger device made of high relative perimittivity dielectric material BaTiO3 （εr = 3460）, the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current waveform of maximum 25 kA was generated with a rise time and time to half peak value of 17.2 μs and 336μs respectively.展开更多
In China, there are 12 types of gold deposits in 57 class-Ill metallogenic zones, formed in 7 main metaUogenic periods. Most gold deposits are small or occur as ore spots; very large deposits are rare with relatively ...In China, there are 12 types of gold deposits in 57 class-Ill metallogenic zones, formed in 7 main metaUogenic periods. Most gold deposits are small or occur as ore spots; very large deposits are rare with relatively poor quality, mainly medium to low grade. Only 35% of the total gold reserves is identified, while a large amount of reserves is yet to be identified. In recent years, China Geological Survey has organized or conducted mineral resources survey and evaluation project, replacement resources prospecting for deposits in crisis, old mines prospecting and commercial prospecting funded or encouraged by the Central Government. These efforts have been fruitful. According to the temporal and spatial allocation of gold resources, and experiences from recent prospecting efforts, western China and the deep layers and peripheries of the-sits in eastern China have relatively high prospecting potential. The government should give even more support to the gold industry and strengthen technological innovation to help address difficulties in gold exploitation and processing. The government should also formulate consistent plans, consolidate mining rights, and promote integrated exploration, so as to achieve new major breakthroughs in gold prospecting. Gold is both a form of material wealth and a way of storing wealth. It is a rare resource with dual functions of commodity and currency. As an important global strategic asset and a cornerstone of financial reserves, gold plays an irreplaceable role in securing national economic development, maintaining financial security, strengthening national comprehensive power and promoting RMB internationalization. Based on latest research and prospecting results, the thesis proposes preliminary conclusions on types, temporal and spatial allocation, and exploration and development of gold deposits in China; predicts China＇s gold resource potential; reviews recent gold prospecting and exploration efforts; and, in the hope of offering some reference for the new round of gold prospecting, exploration and planning, offers some suggestions.展开更多
Objective: The purpose of the paper is to provide the result from investigation on the current situation of coal-burning fluorosis prevalence in Chongqing City and make an assessment on the prevention and curing measu...Objective: The purpose of the paper is to provide the result from investigation on the current situation of coal-burning fluorosis prevalence in Chongqing City and make an assessment on the prevention and curing measures. Method: The Dean’s Method is applied to investigate on the fluorotic teeth of locally-born children aged between 8 to 12;investigate how modified cooking stoves are utilized by households and how food maize and hot pepper are being dried;and test the urinary fluorine content and pepper fluorine content. Result: The investigations show that, in the 661 villages with illness history from the 100 townships of 13 districts in Chongqing City, 11.28% (7464/ 66,162) of the children aged between 8 and 12 suffer from dental fluorosis;the stoves modified rate, qualified rate of modified stoves, and correct utilization rate of qualified modified stoves are respectively 100%, 98.82%, and 99.45%;and food maize and hot pepper’s drying rates are respectively 99.88% and 99.75%. Conclusion: The result shows that the coal-burning type fluorosis prevalence in the endemic area of Chongqing City has decreased dramatically, the preventive measure is effectively implemented, and a long-term preventive mechanism has preliminarily been established.展开更多
AIM: To investigate the effect of gingerol on colonic motility and the action of L-type calcium channel currents in this process.METHODS: The distal colon was cut along the mesenteric border and cleaned with Ca^(2+)-f...AIM: To investigate the effect of gingerol on colonic motility and the action of L-type calcium channel currents in this process.METHODS: The distal colon was cut along the mesenteric border and cleaned with Ca^(2+)-free physiological saline solution. Muscle strips were removed and placed in Ca^(2+)-free physiological saline solution, which was oxygenated continuously. Longitudinal smooth muscle samples were prepared by cutting along the muscle strips and were then placed in a chamber. Mechanical contractile activities of isolated colonic segments in rats were recorded by a 4-channel physiograph. Colon smooth muscle cells were dissociated by enzymatic digestion. L-type calcium currents were recorded using the conventional whole-cell patch-clamp technique.RESULTS: Gingerol inhibited the spontaneous contraction of colonic longitudinal smooth muscle in a dose-dependent manner with inhibition percentages of 13.3% ± 4.1%, 43.4% ± 3.9%, 78.2% ± 3.6% and 80.5% ± 4.5% at 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L, respectively(P < 0.01). Nifedipine, an L-type calcium channel blocker, diminished the inhibition of colonic motility by gingerol. Gingerol inhibited L-type calcium channel currents in colonic longitudinal myocytes of rats. At a 75 μmol/L concentration of gingerol, the percentage of gingerolinduced inhibition was diminished by nifedipine from 77.1% ± 4.2% to 42.6% ± 3.6%(P < 0.01). Gingerol suppressed IBa in a dose-dependent manner, and the inhibition rates were 22.7% ± 2.38%, 35.77% ± 3.14%, 49.78% ± 3.48% and 53.78% ± 4.16% of control at 0 m V, respectively, at concentrations of 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L(P < 0.01). The steady-state activation curve was shifted to the right by treatment with gingerol. The value of half activation was-14.23 ± 1.12 m V in the control group and-10.56 ± 1.04 m V in the 75 μmol/L group(P < 0.05) with slope factors, Ks, of 7.16 ± 0.84 and 7.02 ± 0.93(P < 0.05) in the control and 75 μmol/L groups, respectively. However, the steady-state inactivation curve was not changed, with a half-inactivation voltage, 0.5 V, of-27.43 ± 1.26 m V in the control group and-26.56 ± 1.53 m V in the 75 μmol/L gingerol group(P > 0.05), and a slope factor, K, of 13.24 ± 1.62 in the control group and 13.45 ± 1.68(P > 0.05) in the 75 μmol/L gingerol group.CONCLUSION: Gingerol inhibits colonic motility by preventing Ca^(2+) influx through L-type calcium channels.展开更多
On the basis of the new type Boussinesq equations （Madsen et al., 2002）, a set of equations explicitly including the effects of currents on waves are derived. A numerical implementation of the present equations in o...On the basis of the new type Boussinesq equations （Madsen et al., 2002）, a set of equations explicitly including the effects of currents on waves are derived. A numerical implementation of the present equations in one dimension is described. The numerical model is tested for wave propagation in a wave flume of uniform depth with current present. The present numerical results are compared with those of other researchers. It is validated that the present numerical model can reasonably reflect the nonlinear influences of currents on waves. Moreover, the effects of inputting different incident boundary conditions on the calculated results are studied.展开更多
A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Ex...A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Experimental results of Balmer-line-Emission show that the discharge characteristic,which is mainly determined by gas-flow rate,is not very sensitive to arc current and magnetic field in the operation ranges of the cyclotron.The arc power decreases and ascends while the gas-flow rate goes up from 0.5 SCCM to 20 SCCM.By improving the sealing design and reducing the machine tolerance of the source,the minimum power consumption reduces from 9 SCCM to 4 SCCM,thus having better energy efficiency and benefiting for the pumping system.Preliminary DC extractions show that H–microampere current ranges from several tens to hundreds under different operation conditions.Some problems during the experiments and future plan are discussed in the end.展开更多
基金This work was financially supported by the Science Foundation of National Education Committee of China (Grant No.40106008) and by LED, South China Sea Institute of Oceanology, Chinese Academy of Sciences.
文摘A new approach to high-order Boussinesq-type equations with ambient currents is presented. The current velocity is assumed to be uniform over depth and of the same magnitude as the shallow water wave celerity. The wave velocity field is expressed in terms of the horizontal and vertical wave velocity components at an arbitrary water depth level. Linear operators are introduced to improve the accuracy of the kinematic condition at the sea bottom. The dynamic and kinematic conditions at the free surface are expressed in terms of wave velocity variables defined directly on the free surface. The new equations provide high accuracy of linear properties as well as nonlinear properties from shallow to deep water, and extend the applicable range of relative water depth in the case of opposing currents.
基金supported by National Natural Science Foundation of China(No.81470440)Guangdong Natural Science Foundation(No.S2013010016256)Medical Scientific Research Foundation of Guangdong Province(No.A2013049)
文摘Background Atrial fibrillation （AF） is the most common sustained cardiac arrhythmia without effective treatment. AF is associated with atrial conduction disturbances caused by electrical and / or structural remodeling. But the role of connexin （Cx） 43 in the regulation of L type calcium channel （LCC） remains unclear. We hypothesized that Cx 43 might co-localize and regulate the L type calcium channel current （ICa, D. Methods Real-time PCR and whole-cell patch clamp were used to detect the expression of LCC lc subunit and the cur rent density of Ica, L, before and after Cx 43 knocking down respectively. The co-localization of Cx 43 with LCC was investigated by co-immunoprecipitation and confocal microscopy. Results Knocking down of Cx43 significantly inhibited the current density of ICa, L through decreasing the gene expression of LCC alc in cul tured atrium-derived myocytes （HL-1 cells）. Cx43 co-localized with LCC eric subunit in atrial myocytes. Conclusions Cx 43 regulates the ICa, L in atrial myoctyes through LCC, representing a potential pathogenic mechanism in atrial arrhythmias.
文摘This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.
文摘Objectives Heart failure （HF） is one of the most common outcome for all kinds of heart diseases, the effects of energetic therapy on HF remains controversial, especially to ischemic HF. The aim of this study was to explore the effect of exogenous phosphocreatine with different concentration on L-type calcium（I Cc-L） current in ischemic ventricular myocytes of guinea pig and to investigate its underlying electrophysiological mechanism for the treatment of ischemic HF. Methods Single ventricular myocytes were isolated enzymatically from left ventricle of guinea pig. Peak I Ca-L current were recorded using patch clamp techniques in the whole-cell configuration when myocytes had been superfused with normal Tyrode solution, simple ischemic solution, ischemic solution containing phosphocreatine with different concentration for 10 minutes respectively. Results Peak I Ca-L current density of myocytes superfused with simple simulated ischemic solution was remarkably inhibited by 80.6 ± 5.2% compared with myocytes superfused with normal Tyrode solution（P〈0.05）. Ischemic solution containing phosphocreatine of 5, 10, 20, 30mmol/L inhibited Peak I Ca-L current density by （53.8±6.7）%, （41.8 ± 8.2）%, （38.1±7.4）%, （36.6±9.7）% respectively. There was no statistical significance among phosphocreation of 10, 20, 30 mmol / L. Conclusions Extrogenous phosphocreatine could reverse the inhibition of I Ca-L current under ischemic condition, which could be the ionic basis for the treatment of ischemic heart failure. 0-10 mmol/L phosphocreatine exerted significant dose-effect relationship which no longer existed as concentration more than 10 mmol/L. It is supposed that phosphocreatine increased I Ca-L current by many pathways rather than simple substrate for ATP synthesis.
文摘A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseu- dospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface ttashover trigger device made of high relative perimittivity dielectric material BaTiO3 （εr = 3460）, the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current waveform of maximum 25 kA was generated with a rise time and time to half peak value of 17.2 μs and 336μs respectively.
文摘In China, there are 12 types of gold deposits in 57 class-Ill metallogenic zones, formed in 7 main metaUogenic periods. Most gold deposits are small or occur as ore spots; very large deposits are rare with relatively poor quality, mainly medium to low grade. Only 35% of the total gold reserves is identified, while a large amount of reserves is yet to be identified. In recent years, China Geological Survey has organized or conducted mineral resources survey and evaluation project, replacement resources prospecting for deposits in crisis, old mines prospecting and commercial prospecting funded or encouraged by the Central Government. These efforts have been fruitful. According to the temporal and spatial allocation of gold resources, and experiences from recent prospecting efforts, western China and the deep layers and peripheries of the-sits in eastern China have relatively high prospecting potential. The government should give even more support to the gold industry and strengthen technological innovation to help address difficulties in gold exploitation and processing. The government should also formulate consistent plans, consolidate mining rights, and promote integrated exploration, so as to achieve new major breakthroughs in gold prospecting. Gold is both a form of material wealth and a way of storing wealth. It is a rare resource with dual functions of commodity and currency. As an important global strategic asset and a cornerstone of financial reserves, gold plays an irreplaceable role in securing national economic development, maintaining financial security, strengthening national comprehensive power and promoting RMB internationalization. Based on latest research and prospecting results, the thesis proposes preliminary conclusions on types, temporal and spatial allocation, and exploration and development of gold deposits in China; predicts China＇s gold resource potential; reviews recent gold prospecting and exploration efforts; and, in the hope of offering some reference for the new round of gold prospecting, exploration and planning, offers some suggestions.
文摘Objective: The purpose of the paper is to provide the result from investigation on the current situation of coal-burning fluorosis prevalence in Chongqing City and make an assessment on the prevention and curing measures. Method: The Dean’s Method is applied to investigate on the fluorotic teeth of locally-born children aged between 8 to 12;investigate how modified cooking stoves are utilized by households and how food maize and hot pepper are being dried;and test the urinary fluorine content and pepper fluorine content. Result: The investigations show that, in the 661 villages with illness history from the 100 townships of 13 districts in Chongqing City, 11.28% (7464/ 66,162) of the children aged between 8 and 12 suffer from dental fluorosis;the stoves modified rate, qualified rate of modified stoves, and correct utilization rate of qualified modified stoves are respectively 100%, 98.82%, and 99.45%;and food maize and hot pepper’s drying rates are respectively 99.88% and 99.75%. Conclusion: The result shows that the coal-burning type fluorosis prevalence in the endemic area of Chongqing City has decreased dramatically, the preventive measure is effectively implemented, and a long-term preventive mechanism has preliminarily been established.
基金Supported by National Basic Research Program of China(973 Program)No.2013CB531703+3 种基金National Natural Science Foundation of ChinaNo.81273919Natural Science Foundation of Liaoning ProvinceNo.2012225020 and No.2013023002
文摘AIM: To investigate the effect of gingerol on colonic motility and the action of L-type calcium channel currents in this process.METHODS: The distal colon was cut along the mesenteric border and cleaned with Ca^(2+)-free physiological saline solution. Muscle strips were removed and placed in Ca^(2+)-free physiological saline solution, which was oxygenated continuously. Longitudinal smooth muscle samples were prepared by cutting along the muscle strips and were then placed in a chamber. Mechanical contractile activities of isolated colonic segments in rats were recorded by a 4-channel physiograph. Colon smooth muscle cells were dissociated by enzymatic digestion. L-type calcium currents were recorded using the conventional whole-cell patch-clamp technique.RESULTS: Gingerol inhibited the spontaneous contraction of colonic longitudinal smooth muscle in a dose-dependent manner with inhibition percentages of 13.3% ± 4.1%, 43.4% ± 3.9%, 78.2% ± 3.6% and 80.5% ± 4.5% at 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L, respectively(P < 0.01). Nifedipine, an L-type calcium channel blocker, diminished the inhibition of colonic motility by gingerol. Gingerol inhibited L-type calcium channel currents in colonic longitudinal myocytes of rats. At a 75 μmol/L concentration of gingerol, the percentage of gingerolinduced inhibition was diminished by nifedipine from 77.1% ± 4.2% to 42.6% ± 3.6%(P < 0.01). Gingerol suppressed IBa in a dose-dependent manner, and the inhibition rates were 22.7% ± 2.38%, 35.77% ± 3.14%, 49.78% ± 3.48% and 53.78% ± 4.16% of control at 0 m V, respectively, at concentrations of 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L(P < 0.01). The steady-state activation curve was shifted to the right by treatment with gingerol. The value of half activation was-14.23 ± 1.12 m V in the control group and-10.56 ± 1.04 m V in the 75 μmol/L group(P < 0.05) with slope factors, Ks, of 7.16 ± 0.84 and 7.02 ± 0.93(P < 0.05) in the control and 75 μmol/L groups, respectively. However, the steady-state inactivation curve was not changed, with a half-inactivation voltage, 0.5 V, of-27.43 ± 1.26 m V in the control group and-26.56 ± 1.53 m V in the 75 μmol/L gingerol group(P > 0.05), and a slope factor, K, of 13.24 ± 1.62 in the control group and 13.45 ± 1.68(P > 0.05) in the 75 μmol/L gingerol group.CONCLUSION: Gingerol inhibits colonic motility by preventing Ca^(2+) influx through L-type calcium channels.
基金supported by the National Natural Science Foundation of China (Grant No.40676053)theNational High Technology Research and Development Program of China (863 Program,Grant No.2006AA09A107)the Science and Technology Committee of Shanghai (Grant Nos.08DZ1203005 and 07DZ22027)
文摘On the basis of the new type Boussinesq equations （Madsen et al., 2002）, a set of equations explicitly including the effects of currents on waves are derived. A numerical implementation of the present equations in one dimension is described. The numerical model is tested for wave propagation in a wave flume of uniform depth with current present. The present numerical results are compared with those of other researchers. It is validated that the present numerical model can reasonably reflect the nonlinear influences of currents on waves. Moreover, the effects of inputting different incident boundary conditions on the calculated results are studied.
基金Supported by Army-Civilian Technology Development of CAEP(No.JM200701)National Natural Science Foundation of China(No.11105130)Science Foundation of CAEP(No.2012B0402056)
文摘A cold-cathode Penning Ion Gauge(PIG) type ion source as the internal ion source of an 11 MeV cyclotron is designed and tested at Institute of Fluid Physics.The design considerations and some testings are presented.Experimental results of Balmer-line-Emission show that the discharge characteristic,which is mainly determined by gas-flow rate,is not very sensitive to arc current and magnetic field in the operation ranges of the cyclotron.The arc power decreases and ascends while the gas-flow rate goes up from 0.5 SCCM to 20 SCCM.By improving the sealing design and reducing the machine tolerance of the source,the minimum power consumption reduces from 9 SCCM to 4 SCCM,thus having better energy efficiency and benefiting for the pumping system.Preliminary DC extractions show that H–microampere current ranges from several tens to hundreds under different operation conditions.Some problems during the experiments and future plan are discussed in the end.
