Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digit...Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digital radiographic testing and fully evaluate the integrated system inspection ability of equipment,personnel,and processes,a scientific and standardized evaluation method to the system is very necessary.Here investigates the precedents of relevant non-destructive testing evaluation methods at home and abroad,considers the testing characteristics of DR equipment,develops a complete set of DR testing system evaluation procedures.It deeply studies the adaptability methods of program processes from defect production to slicing processing and data statistical calculation for digital radiographic testing evaluation.To check the repeatability and reliability of the detectable system,five process welds with 200 real metallographic defects were fabricated in the laboratory.From the detected results,the DR system has good repeatability in image quality,and the detectable defect size reaches 0.85 mm under achieving 90%detection probability at a confidence level of 95%,the error of detected defect length is±2 mm,and the error of detected defect localization is±5 mm.The qualitative and quantitative detection of defects are accurate and reliable.The test further confirmed the reliable detection ability of the DR detection system,and fully validated the scientific and practical evaluation method designed.The research on the evaluation test method can serve as an important link in the quality control system for the on-site application of digital ray equipment in long-distance pipelines.The designed program,test,and evaluation content can serve as an important basis for the formulation of relevant specifications or standards.展开更多
Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact ...Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.展开更多
The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of...The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.展开更多
Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F...Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F-box and leucine-rich repeat 6(FBXL6)regulates KRAS and KRAS^(G12D)activity in hepatocellular carcinoma(HCC).Methods:We constructed transgenic mouse strains LC(LSL-Fbxl6^(KI/+);Alb-Cre,n=13),KC(LSL-Kras^(G12D/+);Alb-Cre,n=10)and KLC(LSL-Kras^(G12D/+);LSL-Fbxl6^(KI/+);Alb-Cre,n=12)mice,and then monitored HCC for 320 d.Multiomics approaches and pharmacological inhibitors were used to determine oncogenic signaling in the context of elevated FBXL6 and KRAS activation.Co-immunoprecipitation(Co-IP),Western blotting,ubiquitination assay,and RAS activity detection assay were employed to investigate the underlying molecular mechanism by which FBXL6 activates KRAS.The pathological relevance of the FBXL6/KRAS/extracellular signal-regulated kinase(ERK)/mammalian target of rapamycin(mTOR)/proteins of relevant evolutionary and lymphoid interest domain 2(PRELID2)axis was evaluated in 129 paired samples from HCC patients.Results:FBXL6 is highly expressed in HCC as well as other human cancers(P<0.001).Interestingly,FBXL6 drives HCC in transgenic mice.Mechanistically,elevated FBXL6 promotes the polyubiquitination of both wild-type KRAS and KRAS^(G12D)at lysine 128,leading to the activation of both KRAS and KRAS^(G12D)and promoting their binding to the serine/threonine-protein kinase RAF,which is followed by the activation of mitogen-activated protein kinase kinase(MEK)/ERK/mTOR signaling.The oncogenic activity of the MEK/ERK/mTOR axis relies on PRELID2,which induces reactive oxygen species(ROS)generation.Furthermore,hepatic FBXL6 upregulation facilitates KRAS^(G12D)to induce more severe hepatocarcinogenesis and lung metastasis via the MEK/ERK/mTOR/PRELID2/ROS axis.Dual inhibition of MEK and mTOR effectively suppresses tumor growth and metastasis in this subtype of cancer in vivo.In clinical samples,FBXL6 expression positively correlates with p-ERK(χ^(2)=85.067,P<0.001),p-mTOR(χ^(2)=66.919,P<0.001)and PRELID2(χ^(2)=20.891,P<0.001).The Kaplan-Meier survival analyses suggested that HCC patients with high FBXL6/p-ERK levels predicted worse overall survival(log-rank P<0.001).Conclusions:FBXL6 activates KRAS or KRAS^(G12D)via ubiquitination at the site K128,leading to activation of the ERK/mTOR/PRELID2/ROS axis and tumorigenesis.Dual inhibition of MEK and mTOR effectively protects against FBXL6-and KRAS^(G12D)-induced tumorigenesis,providing a potential therapeutic strategy to treat this aggressive subtype of liver cancer.展开更多
Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The hig...Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.展开更多
Sailors and pilots need three things to find their way: they musthave the correct time; they must know the exact position of the starsoverhead; and they must have a book that tells what the future positionof the stars...Sailors and pilots need three things to find their way: they musthave the correct time; they must know the exact position of the starsoverhead; and they must have a book that tells what the future positionof the stars will be. The information makes possible the science ofnavigation. And it is the job of the United States Naval Observatory tocollect and publish this information. The Headquarters of the展开更多
Continuous phase plate（CPP）,which has a function of beam shaping in laser systems,is one kind of important diffractive optics.Based on the Fourier transform of the Gerchberg-Saxton（G-S） algorithm for designing CPP...Continuous phase plate（CPP）,which has a function of beam shaping in laser systems,is one kind of important diffractive optics.Based on the Fourier transform of the Gerchberg-Saxton（G-S） algorithm for designing CPP,we proposed an optical diffraction method according to the real system conditions.A thin lens can complete the Fourier transform of the input signal and the inverse propagation of light can be implemented in a program.Using both of the two functions can realize the iteration process to calculate the near-field distribution of light and the far-field repeatedly,which is similar to the G-S algorithm.The results show that using the optical diffraction method can design a CPP for a complicated laser system,and make the CPP have abilities of beam shaping and phase compensation for the phase aberration of the system.The method can improve the adaptation of the phase plate in systems with phase aberrations.展开更多
Flexible blue light emitting diodes(LEDs)were fabricated by using poly(N-vinylcarbazole)(PVK)doped with high fluorescence dye,1,1,4,4-tetraphen1-1,3-butadiene(TPB),as a emitter layer,a layer of tris(8-quinolino1ato)al...Flexible blue light emitting diodes(LEDs)were fabricated by using poly(N-vinylcarbazole)(PVK)doped with high fluorescence dye,1,1,4,4-tetraphen1-1,3-butadiene(TPB),as a emitter layer,a layer of tris(8-quinolino1ato)aluminum(Ⅲ)(Alq3)as an electron-transporting layer,and a layer of 2-(4-biphenylyl)-5-(4-tertbutypheny)-1-3,4-oxadiazole(PBD)as hole-blocking layer;a cell structure of flexible substrate/indium-tin-oxide/PVK:TPB/PBD/Alq3/Al was employed.In this cell structure,carrier injection from the electrodes to the doped PVK layer and concomitant electroluminescence from doped PVK were observed at room temperature with dcbias voltage of 4V.Blue emission peaks at about 465nm.This kind of LED is about 200μm thick and can be curled or bent repeatedly at sharp angles without failure.展开更多
A Q-switched YAG laser is used to act repeatedly upon a charge-coupled devices(CCD)having metal-oxide-semiconductor structure,and plasmas in the process are investigated by a Mach-Zehnder interferomcter.According to t...A Q-switched YAG laser is used to act repeatedly upon a charge-coupled devices(CCD)having metal-oxide-semiconductor structure,and plasmas in the process are investigated by a Mach-Zehnder interferomcter.According to the production and development of the plasmas,the damage mechanism of the optoelectronic device is analyzed.展开更多
“The reasonable man adapts himself to the world;the unreasonable one persists in trying to adapt the world to himself.Therefore all progress depends on the unreasonable man.”-Maxims for Revolutionists,George Bernard...“The reasonable man adapts himself to the world;the unreasonable one persists in trying to adapt the world to himself.Therefore all progress depends on the unreasonable man.”-Maxims for Revolutionists,George Bernard Shaw(1903).In the twenty years since the Budapest Open Access Initiative(BOAI,2002)defined the term“open access”(OA)and laid out the unanswerable case in its favour,the growth of OA has been inexorable.Legacy publishers,dependent on the revenue stream provided by subscriptions,have repeatedly attempted to stem this tide,and have certainly succeeded in delaying it-to no-one’s benefit but their own.But OA progresses despite this rearguard action,especially in recent years through the adoption by many major research funders of the Plan S declaration(Plan S,2018),that open-access publication is a condition of grant funding.At the time of writing,over half of all newly published papers are open access either immediately or within a few months(Piwowar,Priem,&Orr,2019),and the proportion continues to increase rapidly.展开更多
Gu Yangang joined the work at a time when Petrochina Changqing Oilfield Company(PCOC)launched a sprint to the target of 20 million tons of oil and gas equivalent.She worshipped the technical expert Yan Minli as her te...Gu Yangang joined the work at a time when Petrochina Changqing Oilfield Company(PCOC)launched a sprint to the target of 20 million tons of oil and gas equivalent.She worshipped the technical expert Yan Minli as her teacher,modestly sought advice from her master every day,practised assiduously and repeatedly,and participated in technical competitions many times.In 2012,she successively won the gold medal in the skill competition of Petrochina Changqing Oilfield Company and the third oil production plant.In the same year,she was granted the May 1 Labour Medal of Gansu Province and the honour of Technical Expert of Gansu Province.展开更多
In the past few years,we have repeatedly discussed what consumers need most.What kind of things will they pay for?The result always tells us that consumers will only pay for goods that are good-looking,cheap and famou...In the past few years,we have repeatedly discussed what consumers need most.What kind of things will they pay for?The result always tells us that consumers will only pay for goods that are good-looking,cheap and famous.Consumers are always greedy,but this accords with people's general psychology.展开更多
文摘Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digital radiographic testing and fully evaluate the integrated system inspection ability of equipment,personnel,and processes,a scientific and standardized evaluation method to the system is very necessary.Here investigates the precedents of relevant non-destructive testing evaluation methods at home and abroad,considers the testing characteristics of DR equipment,develops a complete set of DR testing system evaluation procedures.It deeply studies the adaptability methods of program processes from defect production to slicing processing and data statistical calculation for digital radiographic testing evaluation.To check the repeatability and reliability of the detectable system,five process welds with 200 real metallographic defects were fabricated in the laboratory.From the detected results,the DR system has good repeatability in image quality,and the detectable defect size reaches 0.85 mm under achieving 90%detection probability at a confidence level of 95%,the error of detected defect length is±2 mm,and the error of detected defect localization is±5 mm.The qualitative and quantitative detection of defects are accurate and reliable.The test further confirmed the reliable detection ability of the DR detection system,and fully validated the scientific and practical evaluation method designed.The research on the evaluation test method can serve as an important link in the quality control system for the on-site application of digital ray equipment in long-distance pipelines.The designed program,test,and evaluation content can serve as an important basis for the formulation of relevant specifications or standards.
文摘Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.
基金the Fundamental Research Funds for the Central Universities(Grant No.30920041102)National Natural Science Foundation of China(Grant No.11802134).
文摘The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.
基金supported by the National Natural Science Foundation of China(82370631)the Talent Foundations from Army Medical University(4174C6),the Chongqing Government(CQYC20220303727)to Xie CMthe National Natural Science Foundation of China(31900449)to Xiong HJ.
文摘Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F-box and leucine-rich repeat 6(FBXL6)regulates KRAS and KRAS^(G12D)activity in hepatocellular carcinoma(HCC).Methods:We constructed transgenic mouse strains LC(LSL-Fbxl6^(KI/+);Alb-Cre,n=13),KC(LSL-Kras^(G12D/+);Alb-Cre,n=10)and KLC(LSL-Kras^(G12D/+);LSL-Fbxl6^(KI/+);Alb-Cre,n=12)mice,and then monitored HCC for 320 d.Multiomics approaches and pharmacological inhibitors were used to determine oncogenic signaling in the context of elevated FBXL6 and KRAS activation.Co-immunoprecipitation(Co-IP),Western blotting,ubiquitination assay,and RAS activity detection assay were employed to investigate the underlying molecular mechanism by which FBXL6 activates KRAS.The pathological relevance of the FBXL6/KRAS/extracellular signal-regulated kinase(ERK)/mammalian target of rapamycin(mTOR)/proteins of relevant evolutionary and lymphoid interest domain 2(PRELID2)axis was evaluated in 129 paired samples from HCC patients.Results:FBXL6 is highly expressed in HCC as well as other human cancers(P<0.001).Interestingly,FBXL6 drives HCC in transgenic mice.Mechanistically,elevated FBXL6 promotes the polyubiquitination of both wild-type KRAS and KRAS^(G12D)at lysine 128,leading to the activation of both KRAS and KRAS^(G12D)and promoting their binding to the serine/threonine-protein kinase RAF,which is followed by the activation of mitogen-activated protein kinase kinase(MEK)/ERK/mTOR signaling.The oncogenic activity of the MEK/ERK/mTOR axis relies on PRELID2,which induces reactive oxygen species(ROS)generation.Furthermore,hepatic FBXL6 upregulation facilitates KRAS^(G12D)to induce more severe hepatocarcinogenesis and lung metastasis via the MEK/ERK/mTOR/PRELID2/ROS axis.Dual inhibition of MEK and mTOR effectively suppresses tumor growth and metastasis in this subtype of cancer in vivo.In clinical samples,FBXL6 expression positively correlates with p-ERK(χ^(2)=85.067,P<0.001),p-mTOR(χ^(2)=66.919,P<0.001)and PRELID2(χ^(2)=20.891,P<0.001).The Kaplan-Meier survival analyses suggested that HCC patients with high FBXL6/p-ERK levels predicted worse overall survival(log-rank P<0.001).Conclusions:FBXL6 activates KRAS or KRAS^(G12D)via ubiquitination at the site K128,leading to activation of the ERK/mTOR/PRELID2/ROS axis and tumorigenesis.Dual inhibition of MEK and mTOR effectively protects against FBXL6-and KRAS^(G12D)-induced tumorigenesis,providing a potential therapeutic strategy to treat this aggressive subtype of liver cancer.
基金This paper was supported by Northeast Forestry University.
文摘Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.
文摘Sailors and pilots need three things to find their way: they musthave the correct time; they must know the exact position of the starsoverhead; and they must have a book that tells what the future positionof the stars will be. The information makes possible the science ofnavigation. And it is the job of the United States Naval Observatory tocollect and publish this information. The Headquarters of the
文摘Continuous phase plate（CPP）,which has a function of beam shaping in laser systems,is one kind of important diffractive optics.Based on the Fourier transform of the Gerchberg-Saxton（G-S） algorithm for designing CPP,we proposed an optical diffraction method according to the real system conditions.A thin lens can complete the Fourier transform of the input signal and the inverse propagation of light can be implemented in a program.Using both of the two functions can realize the iteration process to calculate the near-field distribution of light and the far-field repeatedly,which is similar to the G-S algorithm.The results show that using the optical diffraction method can design a CPP for a complicated laser system,and make the CPP have abilities of beam shaping and phase compensation for the phase aberration of the system.The method can improve the adaptation of the phase plate in systems with phase aberrations.
文摘Flexible blue light emitting diodes(LEDs)were fabricated by using poly(N-vinylcarbazole)(PVK)doped with high fluorescence dye,1,1,4,4-tetraphen1-1,3-butadiene(TPB),as a emitter layer,a layer of tris(8-quinolino1ato)aluminum(Ⅲ)(Alq3)as an electron-transporting layer,and a layer of 2-(4-biphenylyl)-5-(4-tertbutypheny)-1-3,4-oxadiazole(PBD)as hole-blocking layer;a cell structure of flexible substrate/indium-tin-oxide/PVK:TPB/PBD/Alq3/Al was employed.In this cell structure,carrier injection from the electrodes to the doped PVK layer and concomitant electroluminescence from doped PVK were observed at room temperature with dcbias voltage of 4V.Blue emission peaks at about 465nm.This kind of LED is about 200μm thick and can be curled or bent repeatedly at sharp angles without failure.
文摘A Q-switched YAG laser is used to act repeatedly upon a charge-coupled devices(CCD)having metal-oxide-semiconductor structure,and plasmas in the process are investigated by a Mach-Zehnder interferomcter.According to the production and development of the plasmas,the damage mechanism of the optoelectronic device is analyzed.
文摘“The reasonable man adapts himself to the world;the unreasonable one persists in trying to adapt the world to himself.Therefore all progress depends on the unreasonable man.”-Maxims for Revolutionists,George Bernard Shaw(1903).In the twenty years since the Budapest Open Access Initiative(BOAI,2002)defined the term“open access”(OA)and laid out the unanswerable case in its favour,the growth of OA has been inexorable.Legacy publishers,dependent on the revenue stream provided by subscriptions,have repeatedly attempted to stem this tide,and have certainly succeeded in delaying it-to no-one’s benefit but their own.But OA progresses despite this rearguard action,especially in recent years through the adoption by many major research funders of the Plan S declaration(Plan S,2018),that open-access publication is a condition of grant funding.At the time of writing,over half of all newly published papers are open access either immediately or within a few months(Piwowar,Priem,&Orr,2019),and the proportion continues to increase rapidly.
文摘Gu Yangang joined the work at a time when Petrochina Changqing Oilfield Company(PCOC)launched a sprint to the target of 20 million tons of oil and gas equivalent.She worshipped the technical expert Yan Minli as her teacher,modestly sought advice from her master every day,practised assiduously and repeatedly,and participated in technical competitions many times.In 2012,she successively won the gold medal in the skill competition of Petrochina Changqing Oilfield Company and the third oil production plant.In the same year,she was granted the May 1 Labour Medal of Gansu Province and the honour of Technical Expert of Gansu Province.
文摘In the past few years,we have repeatedly discussed what consumers need most.What kind of things will they pay for?The result always tells us that consumers will only pay for goods that are good-looking,cheap and famous.Consumers are always greedy,but this accords with people's general psychology.
