To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around t...To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around the wellbore will form a near-well high-permeability reservoir area with the penetration depth as the radius,that is,the formation has different permeability characteristics with the perforation depth as the dividing line.Generally,the permeability is measured by the permeability tester,but this approach has a high workload and limited application.In this paper,according to the reservoir characteristics of perforated horizontal wells,the reservoir is divided into two areas:the original reservoir area and the near-well high permeability reservoir area.Based on the theory of seepage mechanics and the formula of open hole productivity,the permeability calculation formula of near-well high permeability reservoir area with perforation parameters is deduced.According to the principle of seepage continuity,the seepage is regarded as the synthesis of two directions:the horizontal plane elliptic seepage field and the vertical plane radial seepage field,and the oil well productivity prediction model of the perforated horizontal well is established by partition.The model comparison demonstrates that the model is reasonable and feasible.To calculate and analyze the effect of oil well production and the law of influencing factors,actual production data of the oilfield are substituted into the oil well productivity formula.It can effectively guide the technical process design and effect prediction of perforated horizontal wells.展开更多
Diffusion bonding of as-cast Mg−6Gd−3Y magnesium alloy was carried out at temperatures of 400−480℃ with bonding pressure of 6 MPa for 90 min.Diffusion bonded joints were solution treated at 495℃ for 14 h and then ag...Diffusion bonding of as-cast Mg−6Gd−3Y magnesium alloy was carried out at temperatures of 400−480℃ with bonding pressure of 6 MPa for 90 min.Diffusion bonded joints were solution treated at 495℃ for 14 h and then aged at 200℃ for 30 h.Microstructures and mechanical properties of joints were analyzed.The results showed that rare earth elements and their compounds gathering at bonding interface hindered the grain boundary migration crossing bonding interface.Tensile strength of as-bonded and as-solution treated joints increased firstly and then decreased with the bonding temperature increasing due to the combined effects of grain coarsening and solid-solution strengthening.As-bonded and solution-treated joints fractured at matrix except the joint bonded at 400℃,while aged joints fractured at bonding interface.The highest ultimate tensile strength of 279 MPa with elongation of 2.8%was found in joint bonded at 440℃ with solution treatment followed by aging treatment.展开更多
We demonstrate a direct, fluorescence-free measurement of the oscillation frequency of cold atoms in an optical dipole trap based on a high-finesse optical cavity strongly coupled to atoms. The parametric heating spec...We demonstrate a direct, fluorescence-free measurement of the oscillation frequency of cold atoms in an optical dipole trap based on a high-finesse optical cavity strongly coupled to atoms. The parametric heating spectra of the trapped atoms are obtained by recording the transmitted photons from the cavity with the trap depth is modulated by different frequency.Moreover, in our method the oscillation can be observed directly in the time scale. Being compared to the conventional fluorescence-dependent method, our approach avoids uncertainties associated with the illuminating light and auxiliary imaging optics. This method has the potential application of determining the motion of atoms with stored quantum bits or degenerate gases without destroying them.展开更多
Gully erosion is one of the most severe types of land degradation,hindering food production and sustainable agricultural development.However,the historical evolution process and the impact of land use change on gully ...Gully erosion is one of the most severe types of land degradation,hindering food production and sustainable agricultural development.However,the historical evolution process and the impact of land use change on gully erosion remain unclear.To address this issue,we conducted a field investigation on gully erosion in 2018 and interpreted land use and gullies using historical remote sensing images in 1968 and 1978 over an area of 84.48 km^(2).The study found that from 1968 to 1978 to 2018,all gully morphological parameters including gully length density and gully areal density increased significantly.The main origin of gully erosion found was from dry farmland.The annual soil loss rate induced by gully erosion was 1.46 mm during 1968–2018.Gully erosion rates were higher during 1968–1978 than during 1978–2018.Furthermore,the length,areal and volumetric erosion rates in gullies formed by multiple gullies merging was greater than that of newly formed gullies(NFG)and gullies developing continuously from a single pre-existing gully,while the widening rate of NFG was highest.The susceptibility of land use types to gully erosion was in the order of woodland<dry farmland<degraded land.The annual average increase in gully area was 871.09 m^(2) km^(-2) year^(-1) for parcels that were converted from woodland to dry farmland,which was 5.56 times and 1.78 times greater than that of woodland and dry farmland maintenance,respectively.Therefore,urgent implementation of ecological land use plans and gully erosion control practices is suggested for this region.展开更多
为研究干旱胁迫下喷施三唑酮对大豆花期根系耐旱性的影响,以大豆品种南农99-6为材料,通过盆栽试验,在初花期喷施三唑酮后,开始干旱胁迫处理,土壤相对含水量逐渐降至45%,干旱持续21 d后复水,研究干旱胁迫下喷施三唑酮对大豆根系膜脂过氧...为研究干旱胁迫下喷施三唑酮对大豆花期根系耐旱性的影响,以大豆品种南农99-6为材料,通过盆栽试验,在初花期喷施三唑酮后,开始干旱胁迫处理,土壤相对含水量逐渐降至45%,干旱持续21 d后复水,研究干旱胁迫下喷施三唑酮对大豆根系膜脂过氧化程度、活性氧和抗坏血酸-谷胱甘肽(AsA-GSH)循环系统的影响。结果表明:相较于第21天的干旱(D)处理,干旱喷施三唑酮(TD)处理使整个花期干旱胁迫下根系中MDA含量降低了18.75%;O-2·产生速率和H2O2含量分别减少了10.05%和8.55%。TD处理增加了整个花期干旱胁迫下APX和GR活性;干旱胁迫后期增加了MDHAR活性并延缓了GPX和DHAR活性的降低。TD处理的第21天的AsA和GSH含量分别高于D处理17.67%和18.12%。在干旱复水后7 d TD比D处理维持了较高的抗氧化酶活性和抗氧化剂含量。以上结果表明:喷施三唑酮提高了干旱胁迫下大豆根系中抗氧化酶的活性,增强了AsA和GSH的再生能力,增加了抗氧化物质的含量,促进了大豆根系中活性氧的清除,减轻了膜脂过氧化程度。而复水后较高的抗氧化酶活性和抗氧化剂,促进了根系向正常生理状态的恢复。因此TD处理增强了大豆的抗旱性。展开更多
Phytophthora sojae Kanfman and Gerdemann （P. sojae） is one of the most prevalent pathogens and causes Phytophthora root rot, which limits soybean production worldwide. Development of resistant cultivars is a cost-ef...Phytophthora sojae Kanfman and Gerdemann （P. sojae） is one of the most prevalent pathogens and causes Phytophthora root rot, which limits soybean production worldwide. Development of resistant cultivars is a cost-effective approach to controlling this disease. In this study, 127 soybean germplasm were evaluated for their responses to Phytophthora sojae strain Pm28 using the hypocotyl inoculation technique, and 49 were found resistant to the strain. The hypocotyl of P1, P2, F1, and F2：3 of two crosses of Ludou 4 （resistant）×Youchu 4 （susceptible） and Cangdou 5 （resistant）×Williams （susceptible） were inoculated with Pm28, and were used to analyze the inheritance of resistance. The population derived from the cross of Ludou 4×Youchu 4 was used to map the resistance gene （designated as Rps9） to a linkage group. 932 pairs of SSR primers were used to detect polymorphism, and seven SSR markers were mapped near the resistance gene. The results showed that the resistance to Pm28 in Ludou 4 and Cangdou 5 was controlled by a single dominant gene Rps9, which was located on the molecular linkage group N between the SSR markers Satt631 （7.5 cM） and Sat_186 （4.3 cM）.展开更多
Hair follicles are easily accessible skin appendages that protect against cold and potential injuries.Hair follicles contain various pools of stem cells,such as epithelial,melanocyte,and mesenchymal stem cells(MSCs)th...Hair follicles are easily accessible skin appendages that protect against cold and potential injuries.Hair follicles contain various pools of stem cells,such as epithelial,melanocyte,and mesenchymal stem cells(MSCs)that continuously self-renew,differentiate,regulate hair growth,and maintain skin homeostasis.Recently,MSCs derived from the dermal papilla or dermal sheath of the human hair follicle have received attention because of their accessibility and broad differentiation potential.In this review,we describe the applications of human hair follicle-derived MSCs(hHF-MSCs)in tissue engineering and regenerative medicine.We have described protocols for isolating hHF-MSCs from human hair follicles and their culture condition in detail.We also summarize strategies for maintaining hHF-MSCs in a highly proliferative but undifferentiated state after repeated in vitro passages,including supplementation of growth factors,3D suspension culture technology,and 3D aggregates of MSCs.In addition,we report the potential of hHF-MSCs in obtaining induced smooth muscle cells and tissue-engineered blood vessels,regenerated hair follicles,induced red blood cells,and induced pluripotent stem cells.In summary,the abundance,convenient accessibility,and broad differentiation potential make hHF-MSCs an ideal seed cell source of regenerative medical and cell therapy.展开更多
The insensitive response to photoperiod and temperature is an important quantitative trait for soybean in wide adaptation breeding. The natural variation in response to photoperiod and temperature was detected using 2...The insensitive response to photoperiod and temperature is an important quantitative trait for soybean in wide adaptation breeding. The natural variation in response to photoperiod and temperature was detected using 275 accessions of soybean [Glycine max （L.） Merrill] from China. Genome-wide association mapping, based on population structure analysis, was carried out using 118 SSR markers by the TASSEL GLM （general linear model） program. Nine SSR markers （P〈0.01） were associated with the value of the response to photoperiod and temperature （VRPT） caused by days to flowering （DF）, among which, Satt308 （LG M）, Sattl50 （LG M） and Satt440 （LG l）, were identified in both 2006 and 2007. Twelve SSR markers （P〈0.01） were associated with VRPT caused by days to maturity （DM）, among which three markers, Satt387 （LG N）, Satt307 （LG C2） and AW310961 （LG J）, were detected in both 2006 and 2007. In addition, a total of 20 elite alleles were screened out over 2006 and 2007 for being associated with an insensitive response to photoperiod and temperature （IRPT） caused by DF and a total of seven different elite alleles were screened out for being associated with IRPT caused by DM. Among these elite alleles, five alleles, Satt150-244, Satt308-164, Satt308-206, Satt440-176, and Satt440-206, were associated with IRPT caused by DF and were identified in both years, but only one allele, Satt307-170, was identified as being associated with an IRPT caused by DM. Based on these elite alleles, a set of typical accessions were screened out. The result about the genetic basis of IRPT is meaningful for soybean wide adaption breeding.展开更多
文摘To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around the wellbore will form a near-well high-permeability reservoir area with the penetration depth as the radius,that is,the formation has different permeability characteristics with the perforation depth as the dividing line.Generally,the permeability is measured by the permeability tester,but this approach has a high workload and limited application.In this paper,according to the reservoir characteristics of perforated horizontal wells,the reservoir is divided into two areas:the original reservoir area and the near-well high permeability reservoir area.Based on the theory of seepage mechanics and the formula of open hole productivity,the permeability calculation formula of near-well high permeability reservoir area with perforation parameters is deduced.According to the principle of seepage continuity,the seepage is regarded as the synthesis of two directions:the horizontal plane elliptic seepage field and the vertical plane radial seepage field,and the oil well productivity prediction model of the perforated horizontal well is established by partition.The model comparison demonstrates that the model is reasonable and feasible.To calculate and analyze the effect of oil well production and the law of influencing factors,actual production data of the oilfield are substituted into the oil well productivity formula.It can effectively guide the technical process design and effect prediction of perforated horizontal wells.
基金financially supported by the Science Innovation Foundation of Shanghai Academy of Spaceflight Technology,China (No.SAST2020-117)。
文摘Diffusion bonding of as-cast Mg−6Gd−3Y magnesium alloy was carried out at temperatures of 400−480℃ with bonding pressure of 6 MPa for 90 min.Diffusion bonded joints were solution treated at 495℃ for 14 h and then aged at 200℃ for 30 h.Microstructures and mechanical properties of joints were analyzed.The results showed that rare earth elements and their compounds gathering at bonding interface hindered the grain boundary migration crossing bonding interface.Tensile strength of as-bonded and as-solution treated joints increased firstly and then decreased with the bonding temperature increasing due to the combined effects of grain coarsening and solid-solution strengthening.As-bonded and solution-treated joints fractured at matrix except the joint bonded at 400℃,while aged joints fractured at bonding interface.The highest ultimate tensile strength of 279 MPa with elongation of 2.8%was found in joint bonded at 440℃ with solution treatment followed by aging treatment.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304502)the National Natural Science Foundation of China(Grant Nos.11634008,11674203,11574187,and 61227902)the Fund for Shanxi "1331 Project" Key Subjects Construction
文摘We demonstrate a direct, fluorescence-free measurement of the oscillation frequency of cold atoms in an optical dipole trap based on a high-finesse optical cavity strongly coupled to atoms. The parametric heating spectra of the trapped atoms are obtained by recording the transmitted photons from the cavity with the trap depth is modulated by different frequency.Moreover, in our method the oscillation can be observed directly in the time scale. Being compared to the conventional fluorescence-dependent method, our approach avoids uncertainties associated with the illuminating light and auxiliary imaging optics. This method has the potential application of determining the motion of atoms with stored quantum bits or degenerate gases without destroying them.
基金founded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA28010200)the National Natural Science Foundation of China(42107356)+1 种基金National Key Research and Development Program of China(2021YFD1500800)the Heilongjiang Provincial Natural Science Foundation of China(YQ2021C036).
文摘Gully erosion is one of the most severe types of land degradation,hindering food production and sustainable agricultural development.However,the historical evolution process and the impact of land use change on gully erosion remain unclear.To address this issue,we conducted a field investigation on gully erosion in 2018 and interpreted land use and gullies using historical remote sensing images in 1968 and 1978 over an area of 84.48 km^(2).The study found that from 1968 to 1978 to 2018,all gully morphological parameters including gully length density and gully areal density increased significantly.The main origin of gully erosion found was from dry farmland.The annual soil loss rate induced by gully erosion was 1.46 mm during 1968–2018.Gully erosion rates were higher during 1968–1978 than during 1978–2018.Furthermore,the length,areal and volumetric erosion rates in gullies formed by multiple gullies merging was greater than that of newly formed gullies(NFG)and gullies developing continuously from a single pre-existing gully,while the widening rate of NFG was highest.The susceptibility of land use types to gully erosion was in the order of woodland<dry farmland<degraded land.The annual average increase in gully area was 871.09 m^(2) km^(-2) year^(-1) for parcels that were converted from woodland to dry farmland,which was 5.56 times and 1.78 times greater than that of woodland and dry farmland maintenance,respectively.Therefore,urgent implementation of ecological land use plans and gully erosion control practices is suggested for this region.
文摘为研究干旱胁迫下喷施三唑酮对大豆花期根系耐旱性的影响,以大豆品种南农99-6为材料,通过盆栽试验,在初花期喷施三唑酮后,开始干旱胁迫处理,土壤相对含水量逐渐降至45%,干旱持续21 d后复水,研究干旱胁迫下喷施三唑酮对大豆根系膜脂过氧化程度、活性氧和抗坏血酸-谷胱甘肽(AsA-GSH)循环系统的影响。结果表明:相较于第21天的干旱(D)处理,干旱喷施三唑酮(TD)处理使整个花期干旱胁迫下根系中MDA含量降低了18.75%;O-2·产生速率和H2O2含量分别减少了10.05%和8.55%。TD处理增加了整个花期干旱胁迫下APX和GR活性;干旱胁迫后期增加了MDHAR活性并延缓了GPX和DHAR活性的降低。TD处理的第21天的AsA和GSH含量分别高于D处理17.67%和18.12%。在干旱复水后7 d TD比D处理维持了较高的抗氧化酶活性和抗氧化剂含量。以上结果表明:喷施三唑酮提高了干旱胁迫下大豆根系中抗氧化酶的活性,增强了AsA和GSH的再生能力,增加了抗氧化物质的含量,促进了大豆根系中活性氧的清除,减轻了膜脂过氧化程度。而复水后较高的抗氧化酶活性和抗氧化剂,促进了根系向正常生理状态的恢复。因此TD处理增强了大豆的抗旱性。
基金supported by the Earmarked Fund for Modern Agro-Industry Technology Research System, China (nyhyzx07-053)the Program for Changjiang Scholars and Innovative Research Team in University, China (PCSIRT)the Research Fund for the Doctoral Program of Higher Education of China (20090097120023)
文摘Phytophthora sojae Kanfman and Gerdemann （P. sojae） is one of the most prevalent pathogens and causes Phytophthora root rot, which limits soybean production worldwide. Development of resistant cultivars is a cost-effective approach to controlling this disease. In this study, 127 soybean germplasm were evaluated for their responses to Phytophthora sojae strain Pm28 using the hypocotyl inoculation technique, and 49 were found resistant to the strain. The hypocotyl of P1, P2, F1, and F2：3 of two crosses of Ludou 4 （resistant）×Youchu 4 （susceptible） and Cangdou 5 （resistant）×Williams （susceptible） were inoculated with Pm28, and were used to analyze the inheritance of resistance. The population derived from the cross of Ludou 4×Youchu 4 was used to map the resistance gene （designated as Rps9） to a linkage group. 932 pairs of SSR primers were used to detect polymorphism, and seven SSR markers were mapped near the resistance gene. The results showed that the resistance to Pm28 in Ludou 4 and Cangdou 5 was controlled by a single dominant gene Rps9, which was located on the molecular linkage group N between the SSR markers Satt631 （7.5 cM） and Sat_186 （4.3 cM）.
基金National Natural Science Foundation of China,No.81573067the Joint Construction Project between Jilin Province and Provincial Colleges,No.SXGJQY2017-12+2 种基金the Jilin Province Science and Technology Development Plan,No.20190304044YYthe Innovative Special Industry Fund Project in Jilin Province,No.2018C049-2the Open Research Project of the State Key Laboratory of Industrial Control Technology,Zhejiang University,China,No.ICT1800381.
文摘Hair follicles are easily accessible skin appendages that protect against cold and potential injuries.Hair follicles contain various pools of stem cells,such as epithelial,melanocyte,and mesenchymal stem cells(MSCs)that continuously self-renew,differentiate,regulate hair growth,and maintain skin homeostasis.Recently,MSCs derived from the dermal papilla or dermal sheath of the human hair follicle have received attention because of their accessibility and broad differentiation potential.In this review,we describe the applications of human hair follicle-derived MSCs(hHF-MSCs)in tissue engineering and regenerative medicine.We have described protocols for isolating hHF-MSCs from human hair follicles and their culture condition in detail.We also summarize strategies for maintaining hHF-MSCs in a highly proliferative but undifferentiated state after repeated in vitro passages,including supplementation of growth factors,3D suspension culture technology,and 3D aggregates of MSCs.In addition,we report the potential of hHF-MSCs in obtaining induced smooth muscle cells and tissue-engineered blood vessels,regenerated hair follicles,induced red blood cells,and induced pluripotent stem cells.In summary,the abundance,convenient accessibility,and broad differentiation potential make hHF-MSCs an ideal seed cell source of regenerative medical and cell therapy.
基金supported by the National Basic Research Program of China(2009CB118400)the Earmarked Fund for Modern Agro-Industry Technology Research System,China(nycytx-004)
文摘The insensitive response to photoperiod and temperature is an important quantitative trait for soybean in wide adaptation breeding. The natural variation in response to photoperiod and temperature was detected using 275 accessions of soybean [Glycine max （L.） Merrill] from China. Genome-wide association mapping, based on population structure analysis, was carried out using 118 SSR markers by the TASSEL GLM （general linear model） program. Nine SSR markers （P〈0.01） were associated with the value of the response to photoperiod and temperature （VRPT） caused by days to flowering （DF）, among which, Satt308 （LG M）, Sattl50 （LG M） and Satt440 （LG l）, were identified in both 2006 and 2007. Twelve SSR markers （P〈0.01） were associated with VRPT caused by days to maturity （DM）, among which three markers, Satt387 （LG N）, Satt307 （LG C2） and AW310961 （LG J）, were detected in both 2006 and 2007. In addition, a total of 20 elite alleles were screened out over 2006 and 2007 for being associated with an insensitive response to photoperiod and temperature （IRPT） caused by DF and a total of seven different elite alleles were screened out for being associated with IRPT caused by DM. Among these elite alleles, five alleles, Satt150-244, Satt308-164, Satt308-206, Satt440-176, and Satt440-206, were associated with IRPT caused by DF and were identified in both years, but only one allele, Satt307-170, was identified as being associated with an IRPT caused by DM. Based on these elite alleles, a set of typical accessions were screened out. The result about the genetic basis of IRPT is meaningful for soybean wide adaption breeding.
