Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remai...Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.展开更多
This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si：H or μc...This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si：H or μc-Si：H covering layer between solar cells. Their effectiveness for the pretreatment is evaluated by means of phosphorus concentration in films, the dark conductivity of p-layer properties and cell performance.展开更多
We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction st...We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum （Al） back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.展开更多
Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia,increasing in prevalence with age.Catheter ablation is recommended to symptomatic paroxysmal AF refractory or intolerant to at least one Class I o...Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia,increasing in prevalence with age.Catheter ablation is recommended to symptomatic paroxysmal AF refractory or intolerant to at least one Class I or III antiarrhythmic medication.[1]Main current catheter ablation of AF with radiofrequency can give priority to,other include freezing,ultrasonic and laser ablation etc.Recent studies provides substantial information regarding the efficacy and safety of novel cryoballoon technology in creating pulmonary vein(PV)isolation.[2,3]Processed in cyroballoon ablation,some AF patients implanted with double chamber pacemaker are difficult to puncture atrial septal,because of the atrial electrode.My case report was as follows.展开更多
This paper studies boron contamination at the interface between the p and i layers of μc-Si：H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary ...This paper studies boron contamination at the interface between the p and i layers of μc-Si：H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary Ion Mass Spectroscopy. It is found that the mixed-phase μc-Si：H materials with 40% crystalline volume fraction is easy to be affected by the residual boron in the reactor. The experimental results showed that a 500-nm thick μc-Si：H covering layer or a 30-seconds of hydrogen plasma treatment can effectively reduce the boron contamination at the p/i interface. However, from viewpoint of cost reduction, the hydrogen plasma treatment is desirable for solar cell manufacture because the substrate is not moved during the hydrogen plasma treatment.展开更多
A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonance...A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.展开更多
Observing nuclear neutrinoless double beta (0vββ) decay would be a revolutionary result in particle physics.Observing such a decay would prove that the neutrinos are their own antiparticles,help to study the absolut...Observing nuclear neutrinoless double beta (0vββ) decay would be a revolutionary result in particle physics.Observing such a decay would prove that the neutrinos are their own antiparticles,help to study the absolute mass of neutrinos,explore the origin of their mass,and may explain the matter-antimatter asymmetry in our universe by lepton number violation.We propose developing a time projection chamber (TPC) using high-pressure ^(82)SeF_(6) gas and Topmetal silicon sensors for readout in the China Jinping Underground Laboratory (CJPL) to search for neutrinoless double beta decay of82Se,called the NvDEx experiment.Besides being located at CJPL with the world’s thickest rock shielding,NvDEx combines the advantages of the high Qββ(2.996 MeV) of82Se and the TPC’s ability to distinguish signal and background events using their different topological characteristics.This makes NvDEx unique,with great potential for low-background and high-sensitivity 0 vββsearches.NvDEx-100,a NvDEx experiment phase with 100 kg of SeF_(6)gas,is being built,with plans to complete installation at CJPL by 2025.This report introduces 0 vββ physics,the NvDEx concept and its advantages,and the schematic design of NvDEx-100,its subsystems,and background and sensitivity estimation.展开更多
A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the p...A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the plasma optical emission.The cathode chamber cooling scheme is also modified to be naturally cooled only by light emission without cooling water to improve the optical thin performance in the optical path.A single-parameter physical model has been developed to describe the power dissipated in the cascaded bias voltage arc discharge argon plasmas,which have been investigated by utilizing optical emission spectroscopy（OES） and Langmuir probe.In the experiments,discharge currents from 50 A to 100 A,argon flow rates from 800 sccm to 2000 sccm and magnetic fields of 0.1 T and 0.2 T were chosen.The results show：（a） the relationship between the averaged resistivity and the averaged current density exhibits an empirical scaling law as η∝ j^（-0.63369） and the power dissipated in the arc has a strong relation with the filling factor;（b） through the quartz,the argon ions optical emission lines have been easily observed and are dominating with wavelengths between 340 nm and 520 nm,which are the emissions of Ar^＋-434.81 nm and Ar^＋-442.60 nm line,and theintensities are increasing with the arc current and decreasing with the inlet argon flow rate;and（c） the electron density and temperature can reach 2.0 × 10^19 m^-3 and 0.48 eV,respectively,under the conditions of an arc current of 90 A and a magnetic field of 0.2 T.The half-width of the ne radial profile is approximatively equal to a few Larmor radii of electrons and can be regarded as the diameter of the plasma jet in the experiments.展开更多
基金supported by the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project (TSBICIP-KJGG003)Qinglan Plan of the Jiangsu Education Department。
文摘Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.
基金supported by Hi-Tech Research and Development Program of China (Grant Nos.2007AA05Z436 and 2009AA050602)Science and Technology Support Project of Tianjin of China (Grant No.08ZCKFGX03500)+3 种基金National Basic Research Program of China (Grant Nos.2006CB202602 and 2006CB202603)National Natural Science Foundation of China (Grant No.60976051)International Cooperation Project between China-Greece Government (Grant Nos.2006DFA62390 and 2009DFA62580)Program for New Century Excellent Talents in University of China (Grant No.NCET-08-0295)
文摘This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si：H or μc-Si：H covering layer between solar cells. Their effectiveness for the pretreatment is evaluated by means of phosphorus concentration in films, the dark conductivity of p-layer properties and cell performance.
基金supported by the Hi-Tech Research and Development Program of China (Grant Nos. 2007AA05Z436 and 2009AA050602)the Science and Technology Support Project of Tianjin (Grant No. 08ZCKFGX03500)+2 种基金the National Natural Science Foundation of China (Grant No. 60976051)the International Cooperation Project between China–Greece Government (GrantNo. 2009DFA62580)the Program for New Century Excellent Talents in University of China (NCET-08-0295)
文摘We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum （Al） back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.
文摘Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia,increasing in prevalence with age.Catheter ablation is recommended to symptomatic paroxysmal AF refractory or intolerant to at least one Class I or III antiarrhythmic medication.[1]Main current catheter ablation of AF with radiofrequency can give priority to,other include freezing,ultrasonic and laser ablation etc.Recent studies provides substantial information regarding the efficacy and safety of novel cryoballoon technology in creating pulmonary vein(PV)isolation.[2,3]Processed in cyroballoon ablation,some AF patients implanted with double chamber pacemaker are difficult to puncture atrial septal,because of the atrial electrode.My case report was as follows.
基金Project supported by Hi-Tech Research and Development Program of China (Grant No 2007AA05Z436)Science and Technology Support Project of Tianjin (Grant No 08ZCKFGX03500)+4 种基金National Basic Research Program of China (Grant Nos 2006CB202602 and 2006CB202603)National Natural Science Foundation of China (Grant No 60506003)Starting Project of Nankai University (Grant No J02031)International Cooperation Project Between China-Greece Government (Grant No 2006DFA62390)Program for New Century Excellent Talents in University of China (NCET)
文摘This paper studies boron contamination at the interface between the p and i layers of μc-Si：H solar cells deposited in a single-chamber PECVD system. The boron depth profile in the i layer was measured by Secondary Ion Mass Spectroscopy. It is found that the mixed-phase μc-Si：H materials with 40% crystalline volume fraction is easy to be affected by the residual boron in the reactor. The experimental results showed that a 500-nm thick μc-Si：H covering layer or a 30-seconds of hydrogen plasma treatment can effectively reduce the boron contamination at the p/i interface. However, from viewpoint of cost reduction, the hydrogen plasma treatment is desirable for solar cell manufacture because the substrate is not moved during the hydrogen plasma treatment.
基金This project is supported by Commission of Science Technology and Industry for National Defense, China.
文摘A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.
基金This work was supported by the National Key Research and Development Program of China(Nos.2021YFA1601300 and 2022YFA1604703)From-0-to-1 Original Innovation Program of Chinese Academy of Sciences(No.ZDBS-LY-SLH014)+1 种基金International Partner Program of Chinese Academy of Sciences(No.GJHZ2067)National Natural Science Foundation of China Youth Science Fund Project(No.12105110).
文摘Observing nuclear neutrinoless double beta (0vββ) decay would be a revolutionary result in particle physics.Observing such a decay would prove that the neutrinos are their own antiparticles,help to study the absolute mass of neutrinos,explore the origin of their mass,and may explain the matter-antimatter asymmetry in our universe by lepton number violation.We propose developing a time projection chamber (TPC) using high-pressure ^(82)SeF_(6) gas and Topmetal silicon sensors for readout in the China Jinping Underground Laboratory (CJPL) to search for neutrinoless double beta decay of82Se,called the NvDEx experiment.Besides being located at CJPL with the world’s thickest rock shielding,NvDEx combines the advantages of the high Qββ(2.996 MeV) of82Se and the TPC’s ability to distinguish signal and background events using their different topological characteristics.This makes NvDEx unique,with great potential for low-background and high-sensitivity 0 vββsearches.NvDEx-100,a NvDEx experiment phase with 100 kg of SeF_(6)gas,is being built,with plans to complete installation at CJPL by 2025.This report introduces 0 vββ physics,the NvDEx concept and its advantages,and the schematic design of NvDEx-100,its subsystems,and background and sensitivity estimation.
基金supported by the International Thermonuclear Experimental Reactor(ITER)Program Special of Ministry of Science and Technology(No.2013GB114003)National Natural Science Foundation of China(Nos.11275135,11475122)
文摘A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the plasma optical emission.The cathode chamber cooling scheme is also modified to be naturally cooled only by light emission without cooling water to improve the optical thin performance in the optical path.A single-parameter physical model has been developed to describe the power dissipated in the cascaded bias voltage arc discharge argon plasmas,which have been investigated by utilizing optical emission spectroscopy（OES） and Langmuir probe.In the experiments,discharge currents from 50 A to 100 A,argon flow rates from 800 sccm to 2000 sccm and magnetic fields of 0.1 T and 0.2 T were chosen.The results show：（a） the relationship between the averaged resistivity and the averaged current density exhibits an empirical scaling law as η∝ j^（-0.63369） and the power dissipated in the arc has a strong relation with the filling factor;（b） through the quartz,the argon ions optical emission lines have been easily observed and are dominating with wavelengths between 340 nm and 520 nm,which are the emissions of Ar^＋-434.81 nm and Ar^＋-442.60 nm line,and theintensities are increasing with the arc current and decreasing with the inlet argon flow rate;and（c） the electron density and temperature can reach 2.0 × 10^19 m^-3 and 0.48 eV,respectively,under the conditions of an arc current of 90 A and a magnetic field of 0.2 T.The half-width of the ne radial profile is approximatively equal to a few Larmor radii of electrons and can be regarded as the diameter of the plasma jet in the experiments.
