The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages a...The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages and outstanding effects in respect of the tobacco moisture content maintaining and cigarette suction comfort promoting.The development necessity,major types,functional mechanism and influence on cigarette quality of new natural tobacco humectants development were compared and elaborated.Additionally,the prospect of new natural tobacco humectants development and application was forecasted.展开更多
Coatings containing Fe-Si particles were electrodeposited on 3.0wt% Si steel sheets under magnetic fields. The effects of magnetic flux density (MFD), electrode arrangement and current density on the surface morphol...Coatings containing Fe-Si particles were electrodeposited on 3.0wt% Si steel sheets under magnetic fields. The effects of magnetic flux density (MFD), electrode arrangement and current density on the surface morphology, the silicon content in the coatings and the cathode current efficiency were investigated. When a magnetic field was applied parallel to the current and when the MFD was less than 0.5 T, numerous needle-like structures appeared on the coating surface. With increasing MFD, the needle-like structures weakened and were transformed into dome-shaped structures. Meanwhile, compared to results obtained in the absence of a magnetic field, the silicon content in the coatings significantly increased as the MFD was increased for all of the samples obtained using a vertical electrode system. However, in the case of an aclinic electrode system, the silicon content decreased. Furthermore, the cathode current efficiency was considerably diminished when a magnetic field was applied. A possible mechanism for these phenomena was discussed.展开更多
Along with the increasing penetration of distributed generation with voltage-source converters(VSCs),there are extensive concerns over the potential virtual rotor angle stability, which is characterized by oscillation...Along with the increasing penetration of distributed generation with voltage-source converters(VSCs),there are extensive concerns over the potential virtual rotor angle stability, which is characterized by oscillations of power and frequency during the dynamic process of synchronization in the grid. Several control strategies have been developed for VSCs to emulate rotating inertia as well as damping of oscillations. This paper classifies these strategies and provides a small-signal modeling framework including all kinds of VSCs in different applications for virtual rotor angle stability. A unified perspective based on the famous Phillips–Heffron model is established for various VSCs. Thus, the concepts of equivalent inertia and the synchronizing and damping coefficients in different VSCs are highlighted, based on the similarities with the synchronous generator(SG) system in both physical mechanisms and mathematical models. It revealed the potentiality of various VSCs to achieve equivalence with the SG. This study helps promote the unity of VSCs and traditional SGs in both theories and methods for analyzing the dynamic behavior and enhancing the stability. Finally,future research needs and new perspectives are addressed.展开更多
The voltage was recorded to investigate the influence of the static magnetic field on droplet evolution during the mag-netically controlled electroslag remelting (MC-ESR) process. MC-ESR experiments were carried out...The voltage was recorded to investigate the influence of the static magnetic field on droplet evolution during the mag-netically controlled electroslag remelting (MC-ESR) process. MC-ESR experiments were carried out under differentremelting current, and transverse static magnetic fields (TSMF) of 85 mT, 130 mT and 160 mT were superimposed.Statistical work was performed to obtain the quantitative data of the droplets. The ASPEX Explorer was utilized toinvestigate the inclusions evolution of GCr15 ingots. The number of the droplets was 31 in 20 s during the traditional ESRprocess and reached 50 and 51 under the MC-ESR process with the TSMF of 85 mT and 130 mT, respectively. Whencompared the traditional ESR process with the MC-ESR process, the inclusions amount reduced 67%.展开更多
Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is ...Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is known about another hotspot p53 mutant, R249S (p53-R249S). p53-R249S is the sole hotspot mutation in hepatocellular carcinoma (HCC) that is highly associated with chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1). Its GOF is suggested by the facts that this mutant is associated with earlier onset of HCC and poorer prognosis of cancer patients and that its overexpression drives HCC proliferation and tumorigenesis. By contrast, simply knocking in this mutant in normal mice did not show apparent GOF activity. Hence, the GOF activity for p53-R249S and its underlying mechanisms have been elusive until recent findings offered some new insights. This review will discuss these findings as well as their clinical significance and implications for the development of a strategy to target multiple molecules as a therapy for p53-R249S-harboring HCC.展开更多
Growing with the increased adoption of renewable energy for the power generation,the reliable and cost-effective operation of grid-connected inverters is of more and more importance.A filter is interfaced between an i...Growing with the increased adoption of renewable energy for the power generation,the reliable and cost-effective operation of grid-connected inverters is of more and more importance.A filter is interfaced between an inverter and the utility grid to reduce the switching harmonics.According to the modulation scheme and the LCL filter impedance,the electrical stresses of the filter capacitor can be thoroughly investigated.With the help of the electro-thermal model,its long-term thermal stress can be obtained based on the mission profile like wind speed,ambient temperature.The reliability of the filter capacitor bank is obtained based on its individual capacitor reliability curves and reliability block diagram method.A case study on a 2MW wind turbine system demonstrates the relationship between the lifetime of the capacitor bank and the single capacitor.Moreover,the severe voltage and current stresses of the filter capacitors are analyzed during abnormal operations(e.g.,fault ride-through)with asymmetrical parasitic parameters.展开更多
Chronic hepatitis B virus (HBV) infection is a major global public health problem. Approximately 887,000 people die of HBV infection-related diseases annually, with cirrhosis and hepatocellular carcinoma (HCC) being t...Chronic hepatitis B virus (HBV) infection is a major global public health problem. Approximately 887,000 people die of HBV infection-related diseases annually, with cirrhosis and hepatocellular carcinoma (HCC) being the principal causes of mortality.[1] Timely antiviral therapy greatly reduces the risks of cirrhosis and HCC. However, unfortunately, of those patients who are eligible for antiviral treatment, only 25% of patients in clinic settings and 12% of those in community settings obtain timely antiviral therapy.[2] Therefore, reliable means of identifying patients with chronic HBV infection that require antiviral therapy are necessary, particularly for use in the community.展开更多
Capacitive DC links are an important part in voltage source power electronic converters,which contribute to cost,size and failure rate on a considerable scale.With more and more stringent constraints brought by indust...Capacitive DC links are an important part in voltage source power electronic converters,which contribute to cost,size and failure rate on a considerable scale.With more and more stringent constraints brought by industrial applications,the capacitive DC links encounter reliability aspect challenges.This paper presents a review on the reliability design and improvement of capacitive DC links from three aspects:1)Quantitative reliability prediction for DC-link capacitors;2)Reliability-oriented design of passive DC-link capacitor banks;and 3)Advanced active DC links to exceed the limits of passive DC-link capacitors.Key solutions for each aspect are highlighted and discussed with case studies.This review serves to provide a picture of state-of-the-art research on the reliability design and improvement of capacitive DC links,highlight the key milestones in this area,and identify the corresponding challenges and future research directions.展开更多
A method for microdissection, isolation and amplification of plant chromosomal fragments using laser microbeam and a glass microneedle was established. Firstly, 7H chromosome of barley (Hordeum vulgare L.) was dissect...A method for microdissection, isolation and amplification of plant chromosomal fragments using laser microbeam and a glass microneedle was established. Firstly, 7H chromosome of barley (Hordeum vulgare L.) was dissected by Nd: YAG laserbeam with suitable parameters and the fragment comprising a satellite was isolated with a glass microneedle which was fixed on a micromanipulator. Then, the chromosomal fragment DNA was amplified by LA_PCR (linker adaptor PCR) for two rounds. The size of the DNA fragments of PCR products varied from 500-3 000 bp and the PCR products originated from the genome of barley were verified by Southern hybridization. Compared with previous reports, there are some advantages in this research. The performance is easier, the dissection is more precise and the cost is low. It also permits efficient amplification with only one single chromosome fragment. Laser microbeam_glass microneedle method may be useful in the microdissection of special chromosome regions, especially in plants with middle or small chromosomes.展开更多
基金Supported by the Fund for the Open Project of Anhui Key Laboratory of Tobacco Chemistry (No.W2015JSKF0493 and W2015JSKF0492)the China Postdoctoral Science Foundation (No.2015T80646 and 2013M531501)the National Natural Science Foundation of China (No.31400049)
文摘The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages and outstanding effects in respect of the tobacco moisture content maintaining and cigarette suction comfort promoting.The development necessity,major types,functional mechanism and influence on cigarette quality of new natural tobacco humectants development were compared and elaborated.Additionally,the prospect of new natural tobacco humectants development and application was forecasted.
基金financially supported by the National Natural Science Foundation of China (No. 51034010)the Science and Technology Commission of Shanghai Municipality (No. 13JC1402500)
文摘Coatings containing Fe-Si particles were electrodeposited on 3.0wt% Si steel sheets under magnetic fields. The effects of magnetic flux density (MFD), electrode arrangement and current density on the surface morphology, the silicon content in the coatings and the cathode current efficiency were investigated. When a magnetic field was applied parallel to the current and when the MFD was less than 0.5 T, numerous needle-like structures appeared on the coating surface. With increasing MFD, the needle-like structures weakened and were transformed into dome-shaped structures. Meanwhile, compared to results obtained in the absence of a magnetic field, the silicon content in the coatings significantly increased as the MFD was increased for all of the samples obtained using a vertical electrode system. However, in the case of an aclinic electrode system, the silicon content decreased. Furthermore, the cathode current efficiency was considerably diminished when a magnetic field was applied. A possible mechanism for these phenomena was discussed.
基金supported by National High Technology Research and Development Program of China(No.2015AA050606)National Key Research and Development Program(No.2016YFB0900302)National Natural Science Foundation of China(No.U1510208,61273045,51361135705)
文摘Along with the increasing penetration of distributed generation with voltage-source converters(VSCs),there are extensive concerns over the potential virtual rotor angle stability, which is characterized by oscillations of power and frequency during the dynamic process of synchronization in the grid. Several control strategies have been developed for VSCs to emulate rotating inertia as well as damping of oscillations. This paper classifies these strategies and provides a small-signal modeling framework including all kinds of VSCs in different applications for virtual rotor angle stability. A unified perspective based on the famous Phillips–Heffron model is established for various VSCs. Thus, the concepts of equivalent inertia and the synchronizing and damping coefficients in different VSCs are highlighted, based on the similarities with the synchronous generator(SG) system in both physical mechanisms and mathematical models. It revealed the potentiality of various VSCs to achieve equivalence with the SG. This study helps promote the unity of VSCs and traditional SGs in both theories and methods for analyzing the dynamic behavior and enhancing the stability. Finally,future research needs and new perspectives are addressed.
基金financial support of the National Key Research and Development Program of China(No.2016YFB0300401)the National Natural Science Foundation of China(Nos.U1732276 and 51704193)+2 种基金the General Financial Grant from the China Postdoctoral Science Foundation(No.2017M621431)the Science and Technology Commission of Shanghai Municipality(No.15520711000)Independent Research and Development Project of State Key of Advanced Special Steel,Shanghai University(SKLASS2015-Z021,SELF-2014-02)
文摘The voltage was recorded to investigate the influence of the static magnetic field on droplet evolution during the mag-netically controlled electroslag remelting (MC-ESR) process. MC-ESR experiments were carried out under differentremelting current, and transverse static magnetic fields (TSMF) of 85 mT, 130 mT and 160 mT were superimposed.Statistical work was performed to obtain the quantitative data of the droplets. The ASPEX Explorer was utilized toinvestigate the inclusions evolution of GCr15 ingots. The number of the droplets was 31 in 20 s during the traditional ESRprocess and reached 50 and 51 under the MC-ESR process with the TSMF of 85 mT and 130 mT, respectively. Whencompared the traditional ESR process with the MC-ESR process, the inclusions amount reduced 67%.
文摘Gain-of-function (GOF), the most malicious oncogenic activity of a cancer-promoting protein, is well illustrated to three hotspot p53 mutations at R248, R175, and R273 with distinct molecular mechanisms. Yet, less is known about another hotspot p53 mutant, R249S (p53-R249S). p53-R249S is the sole hotspot mutation in hepatocellular carcinoma (HCC) that is highly associated with chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1). Its GOF is suggested by the facts that this mutant is associated with earlier onset of HCC and poorer prognosis of cancer patients and that its overexpression drives HCC proliferation and tumorigenesis. By contrast, simply knocking in this mutant in normal mice did not show apparent GOF activity. Hence, the GOF activity for p53-R249S and its underlying mechanisms have been elusive until recent findings offered some new insights. This review will discuss these findings as well as their clinical significance and implications for the development of a strategy to target multiple molecules as a therapy for p53-R249S-harboring HCC.
文摘Growing with the increased adoption of renewable energy for the power generation,the reliable and cost-effective operation of grid-connected inverters is of more and more importance.A filter is interfaced between an inverter and the utility grid to reduce the switching harmonics.According to the modulation scheme and the LCL filter impedance,the electrical stresses of the filter capacitor can be thoroughly investigated.With the help of the electro-thermal model,its long-term thermal stress can be obtained based on the mission profile like wind speed,ambient temperature.The reliability of the filter capacitor bank is obtained based on its individual capacitor reliability curves and reliability block diagram method.A case study on a 2MW wind turbine system demonstrates the relationship between the lifetime of the capacitor bank and the single capacitor.Moreover,the severe voltage and current stresses of the filter capacitors are analyzed during abnormal operations(e.g.,fault ride-through)with asymmetrical parasitic parameters.
基金This work was supported by the National Natural Science Foundation of China(No. 81902115)National Key Research and Development Program of China(No. SQ2020YFF0426358)National S and T Major Project for Infectious Diseases(No. 2017ZX10201201)。
文摘Chronic hepatitis B virus (HBV) infection is a major global public health problem. Approximately 887,000 people die of HBV infection-related diseases annually, with cirrhosis and hepatocellular carcinoma (HCC) being the principal causes of mortality.[1] Timely antiviral therapy greatly reduces the risks of cirrhosis and HCC. However, unfortunately, of those patients who are eligible for antiviral treatment, only 25% of patients in clinic settings and 12% of those in community settings obtain timely antiviral therapy.[2] Therefore, reliable means of identifying patients with chronic HBV infection that require antiviral therapy are necessary, particularly for use in the community.
文摘Capacitive DC links are an important part in voltage source power electronic converters,which contribute to cost,size and failure rate on a considerable scale.With more and more stringent constraints brought by industrial applications,the capacitive DC links encounter reliability aspect challenges.This paper presents a review on the reliability design and improvement of capacitive DC links from three aspects:1)Quantitative reliability prediction for DC-link capacitors;2)Reliability-oriented design of passive DC-link capacitor banks;and 3)Advanced active DC links to exceed the limits of passive DC-link capacitors.Key solutions for each aspect are highlighted and discussed with case studies.This review serves to provide a picture of state-of-the-art research on the reliability design and improvement of capacitive DC links,highlight the key milestones in this area,and identify the corresponding challenges and future research directions.
文摘A method for microdissection, isolation and amplification of plant chromosomal fragments using laser microbeam and a glass microneedle was established. Firstly, 7H chromosome of barley (Hordeum vulgare L.) was dissected by Nd: YAG laserbeam with suitable parameters and the fragment comprising a satellite was isolated with a glass microneedle which was fixed on a micromanipulator. Then, the chromosomal fragment DNA was amplified by LA_PCR (linker adaptor PCR) for two rounds. The size of the DNA fragments of PCR products varied from 500-3 000 bp and the PCR products originated from the genome of barley were verified by Southern hybridization. Compared with previous reports, there are some advantages in this research. The performance is easier, the dissection is more precise and the cost is low. It also permits efficient amplification with only one single chromosome fragment. Laser microbeam_glass microneedle method may be useful in the microdissection of special chromosome regions, especially in plants with middle or small chromosomes.