The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%eth...The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%ethanol,and these extracts were concentrated and then diluted to a constant volume.The content of total flavonoids,total polyphenols and total proteins was tested and analyzed.In addition,DPPH free radical scavenging,inhibition of the formation of advanced glycation end products,and inhibitory activity against elastase was measured to compare their skin care efficacy in anti-oxidation,anti-glycation,anti-wrinkling and firming.The results showed that,based on the dry weight of CJF,the content of total flavonoids and total proteins of the CJF at high altitude was approximately 1.5 times of the CJF at low altitude,while the content of total polyphenols was approximately 2.4 times that of the CJF at low altitude.The skin care efficacy of CJF at high altitude was significantly better than that of the CJF at low altitude.This work could provide theoretical basis for the selection and application of Camellia japonica flowers in the field of cosmetics.展开更多
Sea surface temperature(SST)in the Yellow Sea Warm Current(YSWC)pathway is sensitive to the East Asian Winter Monsoon(EAWM)and YSWC.However,the role of the YSWC in the evolution of regional SST remains unclear.Here,we...Sea surface temperature(SST)in the Yellow Sea Warm Current(YSWC)pathway is sensitive to the East Asian Winter Monsoon(EAWM)and YSWC.However,the role of the YSWC in the evolution of regional SST remains unclear.Here,we present new U 37 k′based SST and grain size sequences spanning the last 6092 years in the sediment core Z1,which was retrieved from the central Yellow Sea muddy area.Overall,U 37 k′-SST gradually increased since 6.1 ka BP,with a series of centennial-scale fl uctuations.Its variation was mainly caused by EAWM when YSWC was weak between 6.1 and~3.9 ka BP,as shown by the end-member content of grain size.However,after YSWC was fully developed,i.e.,since~3.9 ka BP,it exerted critical eff ects on SST evolution in its pathway.The 1010-and 538-year cycles of the SST sequence indicated a basic control of solar activity on the oceanic conditions in the Yellow Sea.It is suggested that the variation of total solar irradiance was amplifi ed by thermohaline circulation and then transmitted to the Yellow Sea through the EAWM.Meanwhile,the tropical Pacifi c signal of El Niño was transmitted to the YSWC through the Kuroshio Current.The dual properties of warm water transported by YSWC to compensate the EAWM and driving by Kuroshio Current closely linked the variation of SST in the YSWC pathway to the Northern Hemisphere high latitude climate and the tropical Pacifi c.These fi ndings highlight the signifi cance of YSWC on regional SST evolution and its teleconnection to high and low latitude forcing,which grains a better understanding of the long-term evolution of SST in the middle latitude Yellow Sea.展开更多
The harmonic analysis method based on high and low water levels is discussed in this paper. In order to make full use of the information of high and low water observations (the time derivative of water level at the ob...The harmonic analysis method based on high and low water levels is discussed in this paper. In order to make full use of the information of high and low water observations (the time derivative of water level at the observation time is zero), the weight coefficient, w, is introduced to control the importance of the part related to this information in the error formula. The major diurnal constituents, O 1 and K 1, and semi diurnal constituents, N 2, M 2 and S 2 are selected directly from the monthly data analysis, and some other important constituents, P 1, ν 2 and K 2, are included as the inferred constituents. The obtained harmonic constants of the major constituents are very close to those obtained from the analysis of hourly data, and this shows that high and low water data can be used to extract tidal constants with high accuracy. The analysis result also shows that the inference and the weighting coefficient are important in the high and low water data analysis, and it is suggested that w ≥1 should be taken in monthly high and low water data analysis. This analysis method can be used directly to analyze altimetric data with w =0.展开更多
Relationships between large-scale zonal wind anomalies and annual frequency of NW Pacific tropical cyclones and possible mechanisms are investigated with the methods of correlation and composition. It is indicated tha...Relationships between large-scale zonal wind anomalies and annual frequency of NW Pacific tropical cyclones and possible mechanisms are investigated with the methods of correlation and composition. It is indicated that when A U2oo- A U850 〉0 in the eastern tropical Pacific and A U2oo- A U850 〈0 in western tropical Pacific, the Walker cell is stronger in the Pacific tropical region and the annual frequency of NW Pacific tropical cyclone are above normal. In the years with zonal wind anomalies, the circulation of high and low troposphere and the vertical motions in the troposphere have significant characteristics. In the time scale of short-range climate prediction, zonal wind anomalies in high and low troposphere are useful as a preliminary signal of the annual frequency prediction of NW Pacific tropical cyclones.展开更多
The increasing severity of ground subsidence,ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management.A significa...The increasing severity of ground subsidence,ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management.A significant contributing factor to the challenges faced is the inadequacy of existing soil mechanics experimental instruments in providing effective indicators,creating a bottleneck in comprehensively understanding the mechanisms of land subsidence.It is urgent to develop a multi-field and multi-functional soil mechanics experimental system to address this issue.Based soil mechanics theories,the existing manufacturing capabilities of triaxial apparatus and the practical demands of the test system,a set of multi-field coupled high-pressure triaxial system is developed tailored for testing deep soils(at depths of approximately 3000 m)and soft rock.This system incorporates specialized design elements such as high-pressure chamber and horizontal deformation testing devices.In addition to the conventional triaxial tester functions,its distinctive feature encompass a horizontal deformation tracking measuring device,a water release testing device and temperature control device for the sample.This ensemble facilitates testing of horizontal and vertical deformation water release and other parameters of samples under a specified stress conditions,at constant or varying temperature ranging from-40℃–90℃.The accuracy of the tested parameters meets the requirements of relevant current specifications.The test system not only provides scientifically robust data for revealing the deformation and failure mechanism of soil subjected to extreme temperature,but also offers critical data support for major engineering projects,deep exploration and mitigation efforts related to soil deformation-induced disaster.展开更多
Created a new damage model for explosive for LS-DYNA3D,taking advantageof the Taylor method aimed at the high gassy and low permeability coal seam,and numericallysimulated and analyzed the deep-hole presplitting explo...Created a new damage model for explosive for LS-DYNA3D,taking advantageof the Taylor method aimed at the high gassy and low permeability coal seam,and numericallysimulated and analyzed the deep-hole presplitting explosion.The entire processof explosion was represented,including cracks caused by dynamic pressure,transmissionand vibration superposition of stress waves,as well as cracks growth driven by gas generatedby explosion.The influence of the cracks generated in the process of explosion andthe performance of improving permeability caused by the difference of interval between.explosive holes were analyzed.A reasonable interval between explosive holes of deepholepresplitting explosions in high gassy and low permeability coal seams was proposed,and the resolution of gas drainage in high gassy and low permeability coal seam was putforward.展开更多
The electrical properties of polycrystaltine CaB6 are revealed by in-situ resistance measurements under high pressure and low temperature. Due to the existence of grain boundaries, polycrystalline CaB6 behaves with se...The electrical properties of polycrystaltine CaB6 are revealed by in-situ resistance measurements under high pressure and low temperature. Due to the existence of grain boundaries, polycrystalline CaB6 behaves with semiconducting transport properties, which is different from the semimetallic CaB6 single crystals. The temperaturedependent resistance measurement results show that before the structural phase transition at 12.3 GPa the high pressure first induces the metallization at 6.5 GPa for CAB6. Moreover, the phase diagram for CaB6 is drawn based on the investigated electric conducting properties and at least three different conducting phases are found even at moderate high pressure and low temperature, indicating that the electric nature of CaB6 is very sensitive to the environment.展开更多
We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the thre...We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.展开更多
To analyze the relation of matrix metalloproteinase-2(MMP-2) and Fibronection (FN) mRNA expression with metastasis of breast cancer and elucidate the role of MMP-2 and FN in breast cancer metastasis.Methods The expres...To analyze the relation of matrix metalloproteinase-2(MMP-2) and Fibronection (FN) mRNA expression with metastasis of breast cancer and elucidate the role of MMP-2 and FN in breast cancer metastasis.Methods The expression of MMP-2 and FN mRNA in breast cancer cell lines was detected by fluorescence-quantitative RT-PCR.The expression of MMP-2 and FN protein was detected by Western blots.Results The expression of MMP-2 and FN mRNA was down-regulated in high metastatic cell lines MDA-MB-231,MDA-MB-435,but up-regulated in low metastatic cell lines MDA-453,T47D,SK-BR-3 and non-metastatic cell line MCF-7,ZR-75-30.The protein expression of MMP-2 and FN was up-regulated in high mestastic cell lines,and down-regulated in low metastatic cell lines.Conclusion The mRNA and protein expression of MMP-2 and FN was related with breast cancer metastasis.The mRNA expression of MMP-2 and FN is feed-back regulated with protein expression.6 refs,4 figs,2 tabs.展开更多
<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the applica...<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>展开更多
This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed ...This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed Newsprint Paper)fibres.To enhance the composite properties,the addition of highly grafted maleic anhydride polyethylene wax,as CA(Coupling Agent),and semi crystalline copolymer of propylene and ethylene,as IM(Impact Modifier),was included into the material formulation by a twin-screw extruder.Mechanical and morphological properties were studied on tensile test specimens,prepared by injection moulding,by tensile testing machine and SEM(Scanning Electron Microscope),respectively.Thermal properties,i.e.melting and crystallization behaviour,were investigated by DSC(Differential Scanning Calorimetry).Mechanical analysis showed that the addition of rNP in both composites increased the young modulus and significantly decreased the elongation at break.The DSC results revealed that the addition of the rNP in the rHDPE matrix led to a substantial decrease of crystallinity,which consequently affects the tensile strength of the composite(17 MPa)in contrast to the neat rHDPE(25 MPa).On the contrary,fibre addition in rPE HD/LD matrix had no specific impact on the crystallinity index,but did contribute to the increased tensile strength(26 MPa)when compared with neat rPE HD/LD(16 MPa).SEM photomicrographs of the impact fracture surfaces demonstrated a solid adhesion bond between the natural fibres and the rPE HD/LD matrix.Reclaimed newsprint fibres can thus be considered as a perspective alternative to the inorganic fillers in the rPE HD/LD composite.展开更多
A waterproof nanocrystalline soft magnetic alloy core with a size of O.D.850 mm×I.D.316 mm×H.25 mm for radio frequency acceleration was successfully developed by winding 18μm 1k107b MA ribbons.Theμ'_(p...A waterproof nanocrystalline soft magnetic alloy core with a size of O.D.850 mm×I.D.316 mm×H.25 mm for radio frequency acceleration was successfully developed by winding 18μm 1k107b MA ribbons.Theμ'_(p)Qf products reached 7.5,10,and 12 GHz at 1,3,and 5 MHz,respectively.Theμ'_(p)Qf products of the MA core(O.D.250 mm×I.D.100 mm×H.25 mm)manufactured using a 13μm MA ribbon further increased by 30%.Detailed improvements on the MA core manufacture process are discussed herein.Continuous high-power tests on the new MA cores demonstrated its good performance of waterproofness,particularly its stability of highμ'_(p)Qf products.The MA core with highμ'pQf product and large size can operate under a high average RF power,high electric field,and in deionized water,which will be used in the China Spallation Neutron Source PhaseⅡ(CSNS-Ⅱ).展开更多
[Objectives]To establish a non-toxic and efficient method for extracting DNA and total RNA from peanuts and laying a solid foundation for the molecular biology study of peanuts.[Methods]Based on the principle and meth...[Objectives]To establish a non-toxic and efficient method for extracting DNA and total RNA from peanuts and laying a solid foundation for the molecular biology study of peanuts.[Methods]Based on the principle and method of purifying nucleic acids by silica gel adsorption at high salt and low pH condition,a non-toxic and efficient method to extract peanut DNA and total RNA using cetyltrimethyl ammonium bromide(CTAB)extraction solution was designed.The quality and purity of nucleic acids were detected by agarose gel electrophoresis and nucleic acids protein analyzer,respectively.The quality of DNA was further verified by enzyme digestion and PCR amplification using molecular marker techniques.The quality of total RNA was further verified by reverse transcription(RT)-PCR of actin gene and cDNA-SCoT gene differential display technique.[Results]The agarose gel electrophoresis test showed that the peanut DNA extracted by a low-toxic and effective method is free of contamination and degradation.Through the detection by the nucleic acid protein analyzer,the DNA concentration,yield,A260/A280 and A260/A230 of 5 peanut varieties were 419.6-498.2 ng/μL,20.98-24.91μg/g,1.89-1.96 and 2.03-2.28,respectively.The DNA was of high quality and can be completely digested by EcoRI restriction enzymes,and also can be used for SCoT and SRAP molecular marker technology analysis.The RNA extracted from different tissues of peanuts showed no visible DNA bands by non-denaturing agarose gel electrophoresis.The separated 28S bands were brighter than 18S.The ratio of A260/A280 and A260/A230 showed that the RNA quality was good and can be used for reverse transcription,RT-PCR of actin gene and amplification of cDNA-SCoT gene differential display technique.[Conclusions]This experiment established a low-toxic and effective method for extracting DNA and total RNA from peanuts.Compared with traditional methods,this method is more time-saving and cheaper than commercial kits.The most important point is that this method does not use toxic reagents such as phenol,chloroform and isopropanol.Thus,it is expected to be widely applied in molecular biology research.展开更多
X-ray security equipment is currently a more commonly used dangerous goods detection tool, due to the increasing security work tasks, the use of target detection technology to assist security personnel to carry out wo...X-ray security equipment is currently a more commonly used dangerous goods detection tool, due to the increasing security work tasks, the use of target detection technology to assist security personnel to carry out work has become an inevitable trend. With the development of deep learning, object detection technology is becoming more and more mature, and object detection framework based on convolutional neural networks has been widely used in industrial, medical and military fields. In order to improve the efficiency of security staff, reduce the risk of dangerous goods missed detection. Based on the data collected in X-ray security equipment, this paper uses a method of inserting dangerous goods into an empty package to balance all kinds of dangerous goods data and expand the data set. The high-low energy images are combined using the high-low energy feature fusion method. Finally, the dangerous goods target detection technology based on the YOLOv7 model is used for model training. After the introduction of the above method, the detection accuracy is improved by 6% compared with the direct use of the original data set for detection, and the speed is 93FPS, which can meet the requirements of the online security system, greatly improve the work efficiency of security personnel, and eliminate the security risks caused by missed detection.展开更多
Objective:To observe the clinical effect of high suspension and low incision(HSLI)surgery on mixed haemorrhoids,compared with Milligan-Morgan haemorrhoidectomy.Methods:A multi-centre,randomized,singleblind,non-inferio...Objective:To observe the clinical effect of high suspension and low incision(HSLI)surgery on mixed haemorrhoids,compared with Milligan-Morgan haemorrhoidectomy.Methods:A multi-centre,randomized,singleblind,non-inferiority clinical trial was performed.Participants with mixed haemorrhoids from Xiyuan Hospital of China Academy of Chinese Medical Sciences,Beijing Rectum Hospital,Air Force Medical Center of People's Liberation Army of China,and Puyang Hospital of Traditional Chinese Medicine were enrolled from September 2016 to March 2018.By using a blocked randomization scheme,participants were assigned to two groups.The experimental group was treated with HSLI,while the control group was treated with Milligan-Morgan haemorrhoidectomy.The primary outcome was the clinical effect evaluated at 12 weeks after operation.The secondary outcomes included the number of haemorrhoids treated during the operation,pain scores,use of analgesics,postoperative oedema,wound healing,incidence of anal stenosis,anorectal manometry after operation,as well as surgical duration,length of stay and total hospitalization expenses.A safety evaluation was also conducted.Results:In total,246 eligible participants were enrolled,with 123 cases in each group.There was no significant difference in the clinical effect between the two groups(100.00% vs.99.19%,P>0.05).Compared with the control group,the number of external haemorrhoids treated during the operation and the pain scores after operation were significantly reduced in the experimental group(P<0.05 or P<0.01);the patient number with wound healing at 2 weeks after operation and the functional length of anal canal at 12 weeks after operation were significantly increased in the experimental group(P<0.05).There was no significant difference in the incidence of anal stenosis,the numbers of patients using analgesics and patients with postoperative oedema between the two groups after operation(P>0.05).The surgical duration and length of stay in the experimental group were significantly longer than those in the control group,and the total hospitalization expense was significantly higher than that in the control group(all P<0.05).No adverse events were reported in either group during the whole trial or follow-up period.Conclusion:HSLI had the advantages of preserving the skin of anal canal completely,alleviating postsurgical pain and promoting rapid recovery after operation.(Registration No.Chi CTR1900022883).展开更多
From June 18th to June 19th of 2009,Heilongjiang Province was hit by the regional rainstorm rarely paralleled in history.According to the findings based upon the conventional observation data,the precipitation occurre...From June 18th to June 19th of 2009,Heilongjiang Province was hit by the regional rainstorm rarely paralleled in history.According to the findings based upon the conventional observation data,the precipitation occurred under the double-blocking situation of Ural Mountains and the Sea of Okhotsk.The main influencing systems were the upper vortex and northward low-pressure that came from Hetao area,accompanied by the delivery of high and low level jet stream.The results showed that the evolvement of blocking high,transfer of water vapor and configuration of high and low level jet stream were the key factors resulting in the rainfall process.展开更多
Using a mesoscale model,a numerical study on a heavy rainfall case occurring in the Changjiang-Huaihe River Basin is made in this paper.The influence of the intensity of northeasterly wind in front of the Qinghai-Xiza...Using a mesoscale model,a numerical study on a heavy rainfall case occurring in the Changjiang-Huaihe River Basin is made in this paper.The influence of the intensity of northeasterly wind in front of the Qinghai-Xizang high at upper level on the low level wind field and development of mesoscale systems as well as heavy rainfall is investigated.The model well reproduced the heavy rainfall process and the weather systems associated.And it indicates that the strong northeasterly flow around the high at upper troposphere will bring about not only the strengthening of low level southeasterly wind,but also the appearance of shear-line and mesoscale vortex at low level.The coupling of northerly wind at upper level and southerly wind at lower level constructs a vertical indirect circulation which is most favourable for the development of convective motions.Its ascending branch in the shear-line area is very strong and shows a pronounced mesoscale characteristic.展开更多
Based on conventional radiosonde data, surface encrypted observation data and so forth, the diagnostic analysis of a heavy rainstorm in the central and east of Henan Province on June 29, 2006 was carried out from the ...Based on conventional radiosonde data, surface encrypted observation data and so forth, the diagnostic analysis of a heavy rainstorm in the central and east of Henan Province on June 29, 2006 was carried out from the aspects of its large-scale background, environmental field and physical characteristics. The results showed that under the effect of a favorable large-scale environmental field, the rainstorm was caused by a mesoscale system. The high-east and low-west circulation pattern, the eastward movement of high-level low trough, low-level shear lines and strengthening of low-level jet streams directly resulted in the occurrence of the heavy rainstorm.展开更多
Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors.However,graphene sheets are prone to slips under repeated compression due t...Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors.However,graphene sheets are prone to slips under repeated compression due to inadequate chemical con-nections.In addition,the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research,making it difficult to perform real-temperature detections.To address these issues,a hyperelastic polyimide fiber/graphene aerogel(PINF/GA)with a three-dimensional interconnected structure was fabricated by simple one-pot compound-ing and in-situ welding methods.The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers,which can effectively avoid slidings between fibers to form reinforced ribs,preventing graphene from damage during compression.In particular,the inner core of the fiber maintains its macromolecular chain structure and toughness during welding.Thus,PINF/GA has good structural stabilities under a large strain compression(99%).Moreover,the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains,with its thermal-conductivity change ratio reaching up to 9.8.Hyperelastic PINF/GA,with dynamically stable thermal and electrical conductivity,as well as high heat tolerance,shows broad applica-tion prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.展开更多
文摘The active ingredients of Camellia japonica flowers(CJF)at high and low altitudes,as well as their skin care efficacy were compared.The dried red CJF at high and low altitudes were ultrasonically extracted with 70%ethanol,and these extracts were concentrated and then diluted to a constant volume.The content of total flavonoids,total polyphenols and total proteins was tested and analyzed.In addition,DPPH free radical scavenging,inhibition of the formation of advanced glycation end products,and inhibitory activity against elastase was measured to compare their skin care efficacy in anti-oxidation,anti-glycation,anti-wrinkling and firming.The results showed that,based on the dry weight of CJF,the content of total flavonoids and total proteins of the CJF at high altitude was approximately 1.5 times of the CJF at low altitude,while the content of total polyphenols was approximately 2.4 times that of the CJF at low altitude.The skin care efficacy of CJF at high altitude was significantly better than that of the CJF at low altitude.This work could provide theoretical basis for the selection and application of Camellia japonica flowers in the field of cosmetics.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the National Natural Science Foundation of China(Nos.41830539,42076051)the Open Fund Project of the Key Laboratory of Marine Sedimentology and Environmental Geology,Ministry of Natural Resources(No.MASEG201901),and the Taishan Scholar Project。
文摘Sea surface temperature(SST)in the Yellow Sea Warm Current(YSWC)pathway is sensitive to the East Asian Winter Monsoon(EAWM)and YSWC.However,the role of the YSWC in the evolution of regional SST remains unclear.Here,we present new U 37 k′based SST and grain size sequences spanning the last 6092 years in the sediment core Z1,which was retrieved from the central Yellow Sea muddy area.Overall,U 37 k′-SST gradually increased since 6.1 ka BP,with a series of centennial-scale fl uctuations.Its variation was mainly caused by EAWM when YSWC was weak between 6.1 and~3.9 ka BP,as shown by the end-member content of grain size.However,after YSWC was fully developed,i.e.,since~3.9 ka BP,it exerted critical eff ects on SST evolution in its pathway.The 1010-and 538-year cycles of the SST sequence indicated a basic control of solar activity on the oceanic conditions in the Yellow Sea.It is suggested that the variation of total solar irradiance was amplifi ed by thermohaline circulation and then transmitted to the Yellow Sea through the EAWM.Meanwhile,the tropical Pacifi c signal of El Niño was transmitted to the YSWC through the Kuroshio Current.The dual properties of warm water transported by YSWC to compensate the EAWM and driving by Kuroshio Current closely linked the variation of SST in the YSWC pathway to the Northern Hemisphere high latitude climate and the tropical Pacifi c.These fi ndings highlight the signifi cance of YSWC on regional SST evolution and its teleconnection to high and low latitude forcing,which grains a better understanding of the long-term evolution of SST in the middle latitude Yellow Sea.
基金supported by the project of NSFC(No.49906001)the Excellent Young Teacher Award Foundation of State Education Ministry[2000](No.6).
文摘The harmonic analysis method based on high and low water levels is discussed in this paper. In order to make full use of the information of high and low water observations (the time derivative of water level at the observation time is zero), the weight coefficient, w, is introduced to control the importance of the part related to this information in the error formula. The major diurnal constituents, O 1 and K 1, and semi diurnal constituents, N 2, M 2 and S 2 are selected directly from the monthly data analysis, and some other important constituents, P 1, ν 2 and K 2, are included as the inferred constituents. The obtained harmonic constants of the major constituents are very close to those obtained from the analysis of hourly data, and this shows that high and low water data can be used to extract tidal constants with high accuracy. The analysis result also shows that the inference and the weighting coefficient are important in the high and low water data analysis, and it is suggested that w ≥1 should be taken in monthly high and low water data analysis. This analysis method can be used directly to analyze altimetric data with w =0.
基金Research on predictive signals and methods for short-short climate of annual frequency oftyphoons, a project from the research fund on typhoons of 2003 – 2004 at Shanghai Typhoon Institute
文摘Relationships between large-scale zonal wind anomalies and annual frequency of NW Pacific tropical cyclones and possible mechanisms are investigated with the methods of correlation and composition. It is indicated that when A U2oo- A U850 〉0 in the eastern tropical Pacific and A U2oo- A U850 〈0 in western tropical Pacific, the Walker cell is stronger in the Pacific tropical region and the annual frequency of NW Pacific tropical cyclone are above normal. In the years with zonal wind anomalies, the circulation of high and low troposphere and the vertical motions in the troposphere have significant characteristics. In the time scale of short-range climate prediction, zonal wind anomalies in high and low troposphere are useful as a preliminary signal of the annual frequency prediction of NW Pacific tropical cyclones.
基金supported by National Natural Science Foundation(No.41272301 and No.42007171)Nature Fund of Hebei(No.D2021504034)Chinese Academy of Geological Sciences(No.YYWF201628).
文摘The increasing severity of ground subsidence,ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management.A significant contributing factor to the challenges faced is the inadequacy of existing soil mechanics experimental instruments in providing effective indicators,creating a bottleneck in comprehensively understanding the mechanisms of land subsidence.It is urgent to develop a multi-field and multi-functional soil mechanics experimental system to address this issue.Based soil mechanics theories,the existing manufacturing capabilities of triaxial apparatus and the practical demands of the test system,a set of multi-field coupled high-pressure triaxial system is developed tailored for testing deep soils(at depths of approximately 3000 m)and soft rock.This system incorporates specialized design elements such as high-pressure chamber and horizontal deformation testing devices.In addition to the conventional triaxial tester functions,its distinctive feature encompass a horizontal deformation tracking measuring device,a water release testing device and temperature control device for the sample.This ensemble facilitates testing of horizontal and vertical deformation water release and other parameters of samples under a specified stress conditions,at constant or varying temperature ranging from-40℃–90℃.The accuracy of the tested parameters meets the requirements of relevant current specifications.The test system not only provides scientifically robust data for revealing the deformation and failure mechanism of soil subjected to extreme temperature,but also offers critical data support for major engineering projects,deep exploration and mitigation efforts related to soil deformation-induced disaster.
基金Supported by the National Science Foundation of China(50534090,2007BAK28B01,2007BAK29B06)the Science Foundation of Anhui Province(050440403)Creative Team Plan for High School of Anhui(2006KJ005TD)
文摘Created a new damage model for explosive for LS-DYNA3D,taking advantageof the Taylor method aimed at the high gassy and low permeability coal seam,and numericallysimulated and analyzed the deep-hole presplitting explosion.The entire processof explosion was represented,including cracks caused by dynamic pressure,transmissionand vibration superposition of stress waves,as well as cracks growth driven by gas generatedby explosion.The influence of the cracks generated in the process of explosion andthe performance of improving permeability caused by the difference of interval between.explosive holes were analyzed.A reasonable interval between explosive holes of deepholepresplitting explosions in high gassy and low permeability coal seams was proposed,and the resolution of gas drainage in high gassy and low permeability coal seam was putforward.
基金Supported by the National Basic Research Program of China under Grant No 2011CB808204the National Natural Science Foundation of China under Grant Nos 11374121 and 11404133
文摘The electrical properties of polycrystaltine CaB6 are revealed by in-situ resistance measurements under high pressure and low temperature. Due to the existence of grain boundaries, polycrystalline CaB6 behaves with semiconducting transport properties, which is different from the semimetallic CaB6 single crystals. The temperaturedependent resistance measurement results show that before the structural phase transition at 12.3 GPa the high pressure first induces the metallization at 6.5 GPa for CAB6. Moreover, the phase diagram for CaB6 is drawn based on the investigated electric conducting properties and at least three different conducting phases are found even at moderate high pressure and low temperature, indicating that the electric nature of CaB6 is very sensitive to the environment.
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801 and 2013CB632803the National Natural Science Foundation of China under Grant Nos 61435014,61306058 and 61274094the Beijing Natural Science Foundation under Grant No 4144086
文摘We report on the room-temperature cascade laser (QCL) at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback (DFB) quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.
文摘To analyze the relation of matrix metalloproteinase-2(MMP-2) and Fibronection (FN) mRNA expression with metastasis of breast cancer and elucidate the role of MMP-2 and FN in breast cancer metastasis.Methods The expression of MMP-2 and FN mRNA in breast cancer cell lines was detected by fluorescence-quantitative RT-PCR.The expression of MMP-2 and FN protein was detected by Western blots.Results The expression of MMP-2 and FN mRNA was down-regulated in high metastatic cell lines MDA-MB-231,MDA-MB-435,but up-regulated in low metastatic cell lines MDA-453,T47D,SK-BR-3 and non-metastatic cell line MCF-7,ZR-75-30.The protein expression of MMP-2 and FN was up-regulated in high mestastic cell lines,and down-regulated in low metastatic cell lines.Conclusion The mRNA and protein expression of MMP-2 and FN was related with breast cancer metastasis.The mRNA expression of MMP-2 and FN is feed-back regulated with protein expression.6 refs,4 figs,2 tabs.
文摘<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>
文摘This study investigates the mechanical,thermal and morphological properties of rHDPE(Recycled High Density Polyethylene)and a mixture of rPE HD/LD(High and Low Density Polyethylene),both reinforced with rNP(Reclaimed Newsprint Paper)fibres.To enhance the composite properties,the addition of highly grafted maleic anhydride polyethylene wax,as CA(Coupling Agent),and semi crystalline copolymer of propylene and ethylene,as IM(Impact Modifier),was included into the material formulation by a twin-screw extruder.Mechanical and morphological properties were studied on tensile test specimens,prepared by injection moulding,by tensile testing machine and SEM(Scanning Electron Microscope),respectively.Thermal properties,i.e.melting and crystallization behaviour,were investigated by DSC(Differential Scanning Calorimetry).Mechanical analysis showed that the addition of rNP in both composites increased the young modulus and significantly decreased the elongation at break.The DSC results revealed that the addition of the rNP in the rHDPE matrix led to a substantial decrease of crystallinity,which consequently affects the tensile strength of the composite(17 MPa)in contrast to the neat rHDPE(25 MPa).On the contrary,fibre addition in rPE HD/LD matrix had no specific impact on the crystallinity index,but did contribute to the increased tensile strength(26 MPa)when compared with neat rPE HD/LD(16 MPa).SEM photomicrographs of the impact fracture surfaces demonstrated a solid adhesion bond between the natural fibres and the rPE HD/LD matrix.Reclaimed newsprint fibres can thus be considered as a perspective alternative to the inorganic fillers in the rPE HD/LD composite.
基金supported by the funds of the National Natural Science Foundation of China (Nos. 11175194, 11875270, and U1832210)Youth Innovation Promotion Association CAS (No. 2018015)Guangdong Basic and Applied Basic Research Foundation (No.2019B1515120046)
文摘A waterproof nanocrystalline soft magnetic alloy core with a size of O.D.850 mm×I.D.316 mm×H.25 mm for radio frequency acceleration was successfully developed by winding 18μm 1k107b MA ribbons.Theμ'_(p)Qf products reached 7.5,10,and 12 GHz at 1,3,and 5 MHz,respectively.Theμ'_(p)Qf products of the MA core(O.D.250 mm×I.D.100 mm×H.25 mm)manufactured using a 13μm MA ribbon further increased by 30%.Detailed improvements on the MA core manufacture process are discussed herein.Continuous high-power tests on the new MA cores demonstrated its good performance of waterproofness,particularly its stability of highμ'_(p)Qf products.The MA core with highμ'pQf product and large size can operate under a high average RF power,high electric field,and in deionized water,which will be used in the China Spallation Neutron Source PhaseⅡ(CSNS-Ⅱ).
基金Projects of National Natural Science Foundation of China(3166042831960409+2 种基金31960416)Projects of Guangxi Natural Science Foundation of China(2018GXNSFDA281027,2018GXNSFDA294004,2017GXNSFAA198032)Science and Technology Development Fund Project of Guangxi Academy of Agricultural Sciences(Gui Nong Ke 2018YM06,Gui Nong Ke 2017JZ13,31960409,Gui Nong Ke 2018YT12).
文摘[Objectives]To establish a non-toxic and efficient method for extracting DNA and total RNA from peanuts and laying a solid foundation for the molecular biology study of peanuts.[Methods]Based on the principle and method of purifying nucleic acids by silica gel adsorption at high salt and low pH condition,a non-toxic and efficient method to extract peanut DNA and total RNA using cetyltrimethyl ammonium bromide(CTAB)extraction solution was designed.The quality and purity of nucleic acids were detected by agarose gel electrophoresis and nucleic acids protein analyzer,respectively.The quality of DNA was further verified by enzyme digestion and PCR amplification using molecular marker techniques.The quality of total RNA was further verified by reverse transcription(RT)-PCR of actin gene and cDNA-SCoT gene differential display technique.[Results]The agarose gel electrophoresis test showed that the peanut DNA extracted by a low-toxic and effective method is free of contamination and degradation.Through the detection by the nucleic acid protein analyzer,the DNA concentration,yield,A260/A280 and A260/A230 of 5 peanut varieties were 419.6-498.2 ng/μL,20.98-24.91μg/g,1.89-1.96 and 2.03-2.28,respectively.The DNA was of high quality and can be completely digested by EcoRI restriction enzymes,and also can be used for SCoT and SRAP molecular marker technology analysis.The RNA extracted from different tissues of peanuts showed no visible DNA bands by non-denaturing agarose gel electrophoresis.The separated 28S bands were brighter than 18S.The ratio of A260/A280 and A260/A230 showed that the RNA quality was good and can be used for reverse transcription,RT-PCR of actin gene and amplification of cDNA-SCoT gene differential display technique.[Conclusions]This experiment established a low-toxic and effective method for extracting DNA and total RNA from peanuts.Compared with traditional methods,this method is more time-saving and cheaper than commercial kits.The most important point is that this method does not use toxic reagents such as phenol,chloroform and isopropanol.Thus,it is expected to be widely applied in molecular biology research.
文摘X-ray security equipment is currently a more commonly used dangerous goods detection tool, due to the increasing security work tasks, the use of target detection technology to assist security personnel to carry out work has become an inevitable trend. With the development of deep learning, object detection technology is becoming more and more mature, and object detection framework based on convolutional neural networks has been widely used in industrial, medical and military fields. In order to improve the efficiency of security staff, reduce the risk of dangerous goods missed detection. Based on the data collected in X-ray security equipment, this paper uses a method of inserting dangerous goods into an empty package to balance all kinds of dangerous goods data and expand the data set. The high-low energy images are combined using the high-low energy feature fusion method. Finally, the dangerous goods target detection technology based on the YOLOv7 model is used for model training. After the introduction of the above method, the detection accuracy is improved by 6% compared with the direct use of the original data set for detection, and the speed is 93FPS, which can meet the requirements of the online security system, greatly improve the work efficiency of security personnel, and eliminate the security risks caused by missed detection.
基金Supported by the Capital Featured Clinical Application and Promotion Project(No.Z151100004015082)Basic Research Business Fees Independent Selection Project of China Academy of Chinese Medical Sciences(No.ZZ0908002)Cultivation Project of National Natural Science Foundation of China in Xiyuan Hospital,China Academy of Chinese Medical Sciences(No.XY20-16)。
文摘Objective:To observe the clinical effect of high suspension and low incision(HSLI)surgery on mixed haemorrhoids,compared with Milligan-Morgan haemorrhoidectomy.Methods:A multi-centre,randomized,singleblind,non-inferiority clinical trial was performed.Participants with mixed haemorrhoids from Xiyuan Hospital of China Academy of Chinese Medical Sciences,Beijing Rectum Hospital,Air Force Medical Center of People's Liberation Army of China,and Puyang Hospital of Traditional Chinese Medicine were enrolled from September 2016 to March 2018.By using a blocked randomization scheme,participants were assigned to two groups.The experimental group was treated with HSLI,while the control group was treated with Milligan-Morgan haemorrhoidectomy.The primary outcome was the clinical effect evaluated at 12 weeks after operation.The secondary outcomes included the number of haemorrhoids treated during the operation,pain scores,use of analgesics,postoperative oedema,wound healing,incidence of anal stenosis,anorectal manometry after operation,as well as surgical duration,length of stay and total hospitalization expenses.A safety evaluation was also conducted.Results:In total,246 eligible participants were enrolled,with 123 cases in each group.There was no significant difference in the clinical effect between the two groups(100.00% vs.99.19%,P>0.05).Compared with the control group,the number of external haemorrhoids treated during the operation and the pain scores after operation were significantly reduced in the experimental group(P<0.05 or P<0.01);the patient number with wound healing at 2 weeks after operation and the functional length of anal canal at 12 weeks after operation were significantly increased in the experimental group(P<0.05).There was no significant difference in the incidence of anal stenosis,the numbers of patients using analgesics and patients with postoperative oedema between the two groups after operation(P>0.05).The surgical duration and length of stay in the experimental group were significantly longer than those in the control group,and the total hospitalization expense was significantly higher than that in the control group(all P<0.05).No adverse events were reported in either group during the whole trial or follow-up period.Conclusion:HSLI had the advantages of preserving the skin of anal canal completely,alleviating postsurgical pain and promoting rapid recovery after operation.(Registration No.Chi CTR1900022883).
文摘From June 18th to June 19th of 2009,Heilongjiang Province was hit by the regional rainstorm rarely paralleled in history.According to the findings based upon the conventional observation data,the precipitation occurred under the double-blocking situation of Ural Mountains and the Sea of Okhotsk.The main influencing systems were the upper vortex and northward low-pressure that came from Hetao area,accompanied by the delivery of high and low level jet stream.The results showed that the evolvement of blocking high,transfer of water vapor and configuration of high and low level jet stream were the key factors resulting in the rainfall process.
基金This work was supported by the National Natural Science Foundation of China under the auspices of Project Contract No.49335061.
文摘Using a mesoscale model,a numerical study on a heavy rainfall case occurring in the Changjiang-Huaihe River Basin is made in this paper.The influence of the intensity of northeasterly wind in front of the Qinghai-Xizang high at upper level on the low level wind field and development of mesoscale systems as well as heavy rainfall is investigated.The model well reproduced the heavy rainfall process and the weather systems associated.And it indicates that the strong northeasterly flow around the high at upper troposphere will bring about not only the strengthening of low level southeasterly wind,but also the appearance of shear-line and mesoscale vortex at low level.The coupling of northerly wind at upper level and southerly wind at lower level constructs a vertical indirect circulation which is most favourable for the development of convective motions.Its ascending branch in the shear-line area is very strong and shows a pronounced mesoscale characteristic.
文摘Based on conventional radiosonde data, surface encrypted observation data and so forth, the diagnostic analysis of a heavy rainstorm in the central and east of Henan Province on June 29, 2006 was carried out from the aspects of its large-scale background, environmental field and physical characteristics. The results showed that under the effect of a favorable large-scale environmental field, the rainstorm was caused by a mesoscale system. The high-east and low-west circulation pattern, the eastward movement of high-level low trough, low-level shear lines and strengthening of low-level jet streams directly resulted in the occurrence of the heavy rainstorm.
基金supported by National Key R&D Program of China(No.2022YFB3805702)National Natural Science Foundation of China(Grant Nos.52173078,52130303,51973158,51803151,and 51973152)the Science Foundation for Distinguished Young Scholars in Tianjin(No.19JCJQJC61700).
文摘Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors.However,graphene sheets are prone to slips under repeated compression due to inadequate chemical con-nections.In addition,the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research,making it difficult to perform real-temperature detections.To address these issues,a hyperelastic polyimide fiber/graphene aerogel(PINF/GA)with a three-dimensional interconnected structure was fabricated by simple one-pot compound-ing and in-situ welding methods.The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers,which can effectively avoid slidings between fibers to form reinforced ribs,preventing graphene from damage during compression.In particular,the inner core of the fiber maintains its macromolecular chain structure and toughness during welding.Thus,PINF/GA has good structural stabilities under a large strain compression(99%).Moreover,the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains,with its thermal-conductivity change ratio reaching up to 9.8.Hyperelastic PINF/GA,with dynamically stable thermal and electrical conductivity,as well as high heat tolerance,shows broad applica-tion prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.