【目的】从内蒙古种植向日葵的盐碱地中筛选高效溶磷真菌,为农业生产中增产节肥,开发耐盐、溶磷微生物肥料提供菌种资源。【方法】利用形态特征和ITS r DNA序列鉴定菌株;LC-MS技术测定菌株M2在液体培养基中分泌有机酸和植物激素含量,明...【目的】从内蒙古种植向日葵的盐碱地中筛选高效溶磷真菌,为农业生产中增产节肥,开发耐盐、溶磷微生物肥料提供菌种资源。【方法】利用形态特征和ITS r DNA序列鉴定菌株;LC-MS技术测定菌株M2在液体培养基中分泌有机酸和植物激素含量,明确菌株M2的溶磷和促生机理。采用液体摇床培养试验测定了鉴定菌株的溶磷能力。试验处理包括:在磷酸三钙、磷酸铝和5个磷矿的磷矿粉制备的100 m L难溶磷磷源(含5g/L难溶磷)中,接入1 m L灭菌培养液对照,和分别接种1 m L斜卧青霉菌P83和草酸青霉菌M2共15个处理。置于28℃、160 r/min摇床培养,分别于3、6和9 d,取菌液5 m L,在12000 r/min、4℃离心5 min,取上清液测定有效磷含量。采用含Na Cl的固体培养基测定菌株的耐盐性。Na Cl含量分别为0%、5%、7.5%、10%和12.5%的PDA平板中接入溶磷菌,置于28℃恒温培养箱中5 d,观察并记录菌丝的生长状况。采用盆栽试验方法检验了菌株的溶磷能力。以玉米种子(郑单958)为供试作物,以水稻土、黏性潮土、盐潮土和石灰性潮土为供试土壤,以Ca_3(PO_4)_2、AlPO_4和昆阳磷矿粉(RP)为供试磷源(磷源用量为1.0 g/kg土壤)。设置只加入灭菌草炭和Pikovskaya培养液对照,分别接种溶磷菌P83、M2,共计38个处理,144盆。玉米播种40天后收获,测定植株鲜重、干重和玉米根际土壤有效磷含量。田间试验以花生为供试作物,设置只加灭菌草炭和Pikovskaya培养液对照和分别接种ATCC20851、P83、M2溶磷菌剂三个处理。花生生长155 d后收获,称量花生植株鲜重和干重、花生果实鲜重和干重,同时采集花生根部土壤测定有效磷含量。【结果】溶磷菌株M2鉴定为草酸青霉(Penicillium oxalicum)。液体培养基摇床培养6 d后,接种菌株M2,以Ca_3(PO_4)_2为磷源的上清液中有效磷含量达972 mg/L,Ca_3(PO_4)_2溶解率为59.2%;以AlPO_4为磷源的有效磷含量达988 mg/L,溶解率�展开更多
Background： This study was to investigate the relationship among aortic artery calcification （AAC）, cardiac valve calcification （CVC）, and mortality in maintenance hemodialysis （MHD） patients. Methods： All MHD...Background： This study was to investigate the relationship among aortic artery calcification （AAC）, cardiac valve calcification （CVC）, and mortality in maintenance hemodialysis （MHD） patients. Methods： All MHD patients in Shanghai Ruijin Hospital in July 2011 were included. To follow up tbr 42 months, clinical data, predialysis blood tests, echocardiography, and lateral lumbar X-ray plain radiography results were collected. Plasma FGF23 level was measured using a C-terminal assay. Results： Totally, 110 MHD patients were involved in this study. Of which, 64 （58.2%） patients were male, the mean age was 55.2 ± 1.4 years old, and the median dialysis duration was 29.85 （3.0-225.5） months. About 25.5% of the 110 MHD patients had CVC from echocardiography while 61.8% of the patients had visible calcification of aorta from lateral lumbar X-ray plain radiography. After 42 months follow-up, 25 （22.7%） patients died. Kaplan-Meier analysis showed that patients with AAC or CVC had a significant greater number of all-cause and cardiovascular deaths than those without. In multivariate analyses, the presence of AAC was a significant factor associated with all-cause±mortality （hazard ratio [HR]： 3.149, P = 0.025） in addition to lower albumin level and lower 25-hydroxy Vitamin D （25（OH）D） level. The presence of CVC was a significant factor associated with cardiovascular mortality （HR： 3.800, P - 0.029） in addition to lower albumin level and lower 25（OH）D level. Conclusion： Lateral lumbar X-ray plain radiography and echocardiography are simple methods to detect AAC and CVC in dialysis patients. The presence of AAC and CVC was independently associated with mortality in MHD patients. Regular follow-up by X-ray and echocardiography could be a useful method to stratify mortality risk in MHD patients.展开更多
Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N ...Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.展开更多
Favorable agronomic traits are important to improve productivity of popcorn. In this study, a recombinant inbred line（RIL） population consisting of 258 lines was evaluated to identify quantitative trait loci（QTLs）...Favorable agronomic traits are important to improve productivity of popcorn. In this study, a recombinant inbred line（RIL） population consisting of 258 lines was evaluated to identify quantitative trait loci（QTLs） for nine agronomic traits（plant height, ear height, top height（plant height subtracted ear height）, top height/plant height, number of leaves above the top ear, leaf area, stalk diameter, number of tassel branches and the length of tassel） under three environments. Meta-analysis was conducted then to integrate QTLs identified across three generations（RIL, F2：3 and BC2F2） developed from the same crosses. In total, 179 QTLs and 36 meta-QTLs（m QTL） were identified. The percentage of phenotypic variation（R2） explained by any single QTL varied from 3.86 to 28.4%, and 24 QTLs with contributions over 15%. Nine common QTLs located in the same or similar chromosome regions were detected across three generations. Five meta-QTLs were identified including QTLs in three independent studies. Seven important m QTLs were composed of 11–26 QTLs for 4–7 traits, respectively. Only 11 m QTLs were commonly identified in the same or similar chromosome regions across agronomic traits, popping characteristics（popping fold, popping volume and popping rate） and grain yield components（ear weight per plant, grain weight per plant, 100-grain weight, ear length, kernel number per row, ear diameter, row number per ear and kernel ratio） by meta-QTL analysis. In conclusion, we identified a list of QTLs, some of which with much higher contributions to agronomic traits should be valuable for further study in improving both popping characteristics and grain yield components in popcorn.展开更多
The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive ...The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive formation. The knowledge of force response and mechanical specific energy (MSE) for the Stinger PDC cutter is of great importance for improving the cutter's performance and optimizing the hybrid PDC bit design. In this paper, 87 single cutter tests were conducted on the granite. A new method for precisely obtaining the rock broken volume was proposed. The influences of cutting depth, cutting angle, and cutting speed on cutting force and MSE were analyzed. Besides, a phenomenological cutting force model of the Stinger PDC cutter was established by regression of experimental data. Moreover, the surface topography and fracture morphology of the cutting groove and large size cuttings were measured by a 3D profilometer and a scanning electron microscope (SEM). Finally, the rock-breaking mechanism of the Stinger PDC cutter was illustrated. The results indicated that the cutting depth has the greatest influence on the cutting force and MSE, while the cutting speed has no obvious effects, especially at low cutting speeds. As the increase of cutting depth, the cutting force increases linearly, and MSE reduces with a quadratic polynomial relationship. When the cutting angle raises from 10° to 30°, the cutting force increases linearly, and the MSE firstly decreases and then increases. The optimal cutting angle for breaking rock is approximately 20°. The Stinger PDC cutter breaks granite mainly by high concentrated point loading and tensile failure, which can observably improve the rock breaking efficiency. The key findings of this work will help to reveal the rock-breaking mechanisms and optimize the cutter arrangement for the Stinger PDC cutter.展开更多
Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon di...Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.展开更多
The single polycrystalline diamond compact(PDC)cutter test is widely used to investigate the mecha-nism of rock-breaking.The generated cuttings and cutting force are important indexes reflecting the rock failure proce...The single polycrystalline diamond compact(PDC)cutter test is widely used to investigate the mecha-nism of rock-breaking.The generated cuttings and cutting force are important indexes reflecting the rock failure process.However,they were treated as two separate parameters in previous publications.In this study,through a series of rock block cutting tests,the relationship between them was investigated to obtain an in-depth understanding of the formation of cuttings.In addition,to validate the standpoints obtained in the aforementioned experiments,rock sheet cutting tests were conducted and the rock failure process was monitored by a high-speed camera frame by frame.The cutting force was recorded with the same sampling rate as the camera.By this design,every sampled point of cutting force can match a picture captured by the camera,which reflects the interaction between the rock and the cutter.The results indicate that the increase in cutting depth results in a transition of rock failure modes.At shallow cutting depth,ductile failure dominates and all the cuttings are produced by the compression of the cutter.The corresponding cutting force fluctuates slightly.However,beyond the critical depth,brittle failure occurs and chunk-like cuttings appear,which leads to a sharp decrease in cutting force.After that,the generation of new surface results in a significant decrease in actual cutting depth,a parameter proposed to reflect the interaction between the rock and the cutter.Consequently,ductile failure dominates again and a slight fluctuation of cutting force can be detected.As the cutter moves to the rock,the actual cutting depth gradually increases,which results in the subsequent generation of chunk-like cuttings.It is accompanied by an obvious cutting force drop.That is,ductile failure and brittle failure,one following another,present at large cutting depth.The transition of rock failure mode can be correlated with the variation of cutting force.Based on the results of this paper,the real-time monitoring of torque ma展开更多
The nuclear-encoded light-harvesting chlorophyll a/b-binding proteins（LHCPs） are specifically translocated from the stroma into the thylakoid membrane through the chloroplast signal recognition particle（cp SRP） pa...The nuclear-encoded light-harvesting chlorophyll a/b-binding proteins（LHCPs） are specifically translocated from the stroma into the thylakoid membrane through the chloroplast signal recognition particle（cp SRP） pathway. The cp SRP is composed of a cp SRP43 protein and a cp SRP54 protein, and it forms a soluble transit complex with LHCP in the chloroplast stroma. Here, we identified the YGL9 gene that is predicted to encode the probable rice cp SRP43 protein from a rice yellow-green leaf mutant. A phylogenetic tree showed that an important conserved protein family, cp SRP43, is present in almost all green photosynthetic organisms such as higher plants and green algae. Sequence analysis showed that YGL9 comprises a chloroplast transit peptide, three chromodomains and four ankyrin repeats, and the chromodomains and ankyrin repeats are probably involved in protein-protein interactions. Subcellular localization showed that YGL9 is localized in the chloroplast. Expression pattern analysis indicated that YGL9 is mainly expressed in green leaf sheaths and leaves. Quantitative real-time PCR analysis showed that the expression levels of genes associated with pigment metabolism, chloroplast development and photosynthesis were distinctly affected in the ygl9 mutant. These results indicated that YGL9 is possibly involved in pigment metabolism, chloroplast development and photosynthesis in rice.展开更多
Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained fr...Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained from liver magnetic resonance imaging(MRI)scan sequences.We aimed to establish a radiomics signature based on T2WI(T2-RS)for assessment of hepatic inflammation in people with nonalcoholic fatty liver disease(NAFLD).Methods:A total of 203 individuals with biopsy-confirmed NAFLD from two independent Chinese cohorts with liver MRI examination were enrolled in this study.The hepatic inflammatory activity score(IAS)was calculated by the unweighted sum of the histologic scores for lobular inflammation and ballooning.One thousand and thirty-two radiomics features were extracted from the localized region of interest(ROI)in the right liver lobe of T2WI and,subsequently,selected by minimum redundancy maximum relevance and least absolute shrinkage and selection operator(LASSO)methods.The T2-RS was calculated by adding the selected features weighted by their coefficients.Results:Eighteen radiomics features from Laplacian of Gaussian,wavelet,and original images were selected for establishing T2-RS.The T2-RS value differed significantly between groups with increasing grades of hepatic inflammation(P<0.01).The T2-RS yielded an area under the receiver operating characteristic(ROC)curve(AUROC)of 0.80[95%confidence interval(CI):0.71-0.89]for predicting hepatic inflammation in the training cohort with excellent calibration.The AUROCs of T2-RS in the internal cohort and external validation cohorts were 0.77(0.61-0.93)and 0.75(0.63-0.84),respectively.Conclusions:The T2-RS derived from radiomics analysis of T2WI shows promising utility for predicting hepatic inflammation in individuals with NAFLD.展开更多
Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （...Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （FE-SEM） and a MICROTEST-5000 tensile stage were used to carry out in-situ tension tests and observations. The crystallographic texture of the extruded sample changed from weak cube texture {001}〈100〉 to texture {018}〈081〉 during tension fracture. However, strong Brass {110}〈112〉 in the hot-rolled sample was modi-fied into a mixture texture component of Brass {110}〈112〉 and S {123}〈634〉 during tension fracture. Texture evolution in the two samples during tension can be explained by the rotation of grain orientation.展开更多
Laboratory uniaxial compression creep tests,with differential stress of 30 MPa hold for 3 h,were performed on Chang-7,Longmaxi(LMX)and Barnett shales to study the influence of SC-CO_(2)on short-term viscoelastic prope...Laboratory uniaxial compression creep tests,with differential stress of 30 MPa hold for 3 h,were performed on Chang-7,Longmaxi(LMX)and Barnett shales to study the influence of SC-CO_(2)on short-term viscoelastic properties.To this end,the wet shale samples were treated with SC-CO_(2)with a pressure of30 MPa and a temperature of 110℃for 14 days.We analyzed the creep data using the fractional Maxwell model.To investigate microscopic structural alterations,the surface morphology of the same location,before and after SC-CO_(2)-water exposure,was examined by SEM images.Compared with dry shales,dynamic and static elastic moduli decreased by up to 25.02%and 55.83%,respectively,but the creep deformation increased by 200%for LMX and Chang-7 shales,and 500%for the Barnett shale treated by SC-CO_(2).Compared to dry sample,there is an increase in calculated fractional orders of 0.02,0.07,0.22 for SC-CO_(2)treated samples,indicating that SC-CO_(2)treatment is likely to enhance shale creep.SEM investigation confirmed physicochemical mechanisms responsible for the observed elastic damage and creep enhancement,including mineral dissolution and swelling caused by SC-CO_(2).This work would further improve our current understanding of the time-dependent deformation of shale under chemicalmechanical coupling effects during CO_(2)capture utilization and storage.展开更多
文摘【目的】从内蒙古种植向日葵的盐碱地中筛选高效溶磷真菌,为农业生产中增产节肥,开发耐盐、溶磷微生物肥料提供菌种资源。【方法】利用形态特征和ITS r DNA序列鉴定菌株;LC-MS技术测定菌株M2在液体培养基中分泌有机酸和植物激素含量,明确菌株M2的溶磷和促生机理。采用液体摇床培养试验测定了鉴定菌株的溶磷能力。试验处理包括:在磷酸三钙、磷酸铝和5个磷矿的磷矿粉制备的100 m L难溶磷磷源(含5g/L难溶磷)中,接入1 m L灭菌培养液对照,和分别接种1 m L斜卧青霉菌P83和草酸青霉菌M2共15个处理。置于28℃、160 r/min摇床培养,分别于3、6和9 d,取菌液5 m L,在12000 r/min、4℃离心5 min,取上清液测定有效磷含量。采用含Na Cl的固体培养基测定菌株的耐盐性。Na Cl含量分别为0%、5%、7.5%、10%和12.5%的PDA平板中接入溶磷菌,置于28℃恒温培养箱中5 d,观察并记录菌丝的生长状况。采用盆栽试验方法检验了菌株的溶磷能力。以玉米种子(郑单958)为供试作物,以水稻土、黏性潮土、盐潮土和石灰性潮土为供试土壤,以Ca_3(PO_4)_2、AlPO_4和昆阳磷矿粉(RP)为供试磷源(磷源用量为1.0 g/kg土壤)。设置只加入灭菌草炭和Pikovskaya培养液对照,分别接种溶磷菌P83、M2,共计38个处理,144盆。玉米播种40天后收获,测定植株鲜重、干重和玉米根际土壤有效磷含量。田间试验以花生为供试作物,设置只加灭菌草炭和Pikovskaya培养液对照和分别接种ATCC20851、P83、M2溶磷菌剂三个处理。花生生长155 d后收获,称量花生植株鲜重和干重、花生果实鲜重和干重,同时采集花生根部土壤测定有效磷含量。【结果】溶磷菌株M2鉴定为草酸青霉(Penicillium oxalicum)。液体培养基摇床培养6 d后,接种菌株M2,以Ca_3(PO_4)_2为磷源的上清液中有效磷含量达972 mg/L,Ca_3(PO_4)_2溶解率为59.2%;以AlPO_4为磷源的有效磷含量达988 mg/L,溶解率�
基金This study was supported by Shanghai Science Foundation, China （No. 14ZR1425400）.
文摘Background： This study was to investigate the relationship among aortic artery calcification （AAC）, cardiac valve calcification （CVC）, and mortality in maintenance hemodialysis （MHD） patients. Methods： All MHD patients in Shanghai Ruijin Hospital in July 2011 were included. To follow up tbr 42 months, clinical data, predialysis blood tests, echocardiography, and lateral lumbar X-ray plain radiography results were collected. Plasma FGF23 level was measured using a C-terminal assay. Results： Totally, 110 MHD patients were involved in this study. Of which, 64 （58.2%） patients were male, the mean age was 55.2 ± 1.4 years old, and the median dialysis duration was 29.85 （3.0-225.5） months. About 25.5% of the 110 MHD patients had CVC from echocardiography while 61.8% of the patients had visible calcification of aorta from lateral lumbar X-ray plain radiography. After 42 months follow-up, 25 （22.7%） patients died. Kaplan-Meier analysis showed that patients with AAC or CVC had a significant greater number of all-cause and cardiovascular deaths than those without. In multivariate analyses, the presence of AAC was a significant factor associated with all-cause±mortality （hazard ratio [HR]： 3.149, P = 0.025） in addition to lower albumin level and lower 25-hydroxy Vitamin D （25（OH）D） level. The presence of CVC was a significant factor associated with cardiovascular mortality （HR： 3.800, P - 0.029） in addition to lower albumin level and lower 25（OH）D level. Conclusion： Lateral lumbar X-ray plain radiography and echocardiography are simple methods to detect AAC and CVC in dialysis patients. The presence of AAC and CVC was independently associated with mortality in MHD patients. Regular follow-up by X-ray and echocardiography could be a useful method to stratify mortality risk in MHD patients.
基金financial support from theNational Natural Science Foundation of China (31471443, 31501262)the Fundamental Research Funds for the Central Universities, China (KJQN201632)the Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University
文摘Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.
基金funded by the Plan for the Scientific Innovation Talent of Henan ProvinceChina(124200510003)+2 种基金the National High-Tech Research and Development Program of China(2012AA10A307)the Agricultural Science Creation in Henan Provincethe Modern Agricultural System in Industry and Technology of Henan Province,China(S2010-02-G01)
文摘Favorable agronomic traits are important to improve productivity of popcorn. In this study, a recombinant inbred line（RIL） population consisting of 258 lines was evaluated to identify quantitative trait loci（QTLs） for nine agronomic traits（plant height, ear height, top height（plant height subtracted ear height）, top height/plant height, number of leaves above the top ear, leaf area, stalk diameter, number of tassel branches and the length of tassel） under three environments. Meta-analysis was conducted then to integrate QTLs identified across three generations（RIL, F2：3 and BC2F2） developed from the same crosses. In total, 179 QTLs and 36 meta-QTLs（m QTL） were identified. The percentage of phenotypic variation（R2） explained by any single QTL varied from 3.86 to 28.4%, and 24 QTLs with contributions over 15%. Nine common QTLs located in the same or similar chromosome regions were detected across three generations. Five meta-QTLs were identified including QTLs in three independent studies. Seven important m QTLs were composed of 11–26 QTLs for 4–7 traits, respectively. Only 11 m QTLs were commonly identified in the same or similar chromosome regions across agronomic traits, popping characteristics（popping fold, popping volume and popping rate） and grain yield components（ear weight per plant, grain weight per plant, 100-grain weight, ear length, kernel number per row, ear diameter, row number per ear and kernel ratio） by meta-QTL analysis. In conclusion, we identified a list of QTLs, some of which with much higher contributions to agronomic traits should be valuable for further study in improving both popping characteristics and grain yield components in popcorn.
基金supported by the Joint Funds of The National Natural Science Foundation of China(Grant No.U19B6003-05)the National Key Research and Development Program of China(No.2019YFA0708302)+2 种基金the National Science Fund for Distinguished Young Scholars(Grant No.51725404)the Beijing Outstanding Young Scientist Program(Grant No.BJJWZYJH01201911414038)the Strategic Cooperation Technology Projects of CNPC and CUPB(Grant No.ZLZX2020-01).
文摘The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive formation. The knowledge of force response and mechanical specific energy (MSE) for the Stinger PDC cutter is of great importance for improving the cutter's performance and optimizing the hybrid PDC bit design. In this paper, 87 single cutter tests were conducted on the granite. A new method for precisely obtaining the rock broken volume was proposed. The influences of cutting depth, cutting angle, and cutting speed on cutting force and MSE were analyzed. Besides, a phenomenological cutting force model of the Stinger PDC cutter was established by regression of experimental data. Moreover, the surface topography and fracture morphology of the cutting groove and large size cuttings were measured by a 3D profilometer and a scanning electron microscope (SEM). Finally, the rock-breaking mechanism of the Stinger PDC cutter was illustrated. The results indicated that the cutting depth has the greatest influence on the cutting force and MSE, while the cutting speed has no obvious effects, especially at low cutting speeds. As the increase of cutting depth, the cutting force increases linearly, and MSE reduces with a quadratic polynomial relationship. When the cutting angle raises from 10° to 30°, the cutting force increases linearly, and the MSE firstly decreases and then increases. The optimal cutting angle for breaking rock is approximately 20°. The Stinger PDC cutter breaks granite mainly by high concentrated point loading and tensile failure, which can observably improve the rock breaking efficiency. The key findings of this work will help to reveal the rock-breaking mechanisms and optimize the cutter arrangement for the Stinger PDC cutter.
基金the National Key R&D Program of China(No.2019YFB1504102).
文摘Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.
基金support from the National Natural Science Foundation of China(52204004)the National Science Fund for Distinguished Young Scholars(51725404)。
文摘The single polycrystalline diamond compact(PDC)cutter test is widely used to investigate the mecha-nism of rock-breaking.The generated cuttings and cutting force are important indexes reflecting the rock failure process.However,they were treated as two separate parameters in previous publications.In this study,through a series of rock block cutting tests,the relationship between them was investigated to obtain an in-depth understanding of the formation of cuttings.In addition,to validate the standpoints obtained in the aforementioned experiments,rock sheet cutting tests were conducted and the rock failure process was monitored by a high-speed camera frame by frame.The cutting force was recorded with the same sampling rate as the camera.By this design,every sampled point of cutting force can match a picture captured by the camera,which reflects the interaction between the rock and the cutter.The results indicate that the increase in cutting depth results in a transition of rock failure modes.At shallow cutting depth,ductile failure dominates and all the cuttings are produced by the compression of the cutter.The corresponding cutting force fluctuates slightly.However,beyond the critical depth,brittle failure occurs and chunk-like cuttings appear,which leads to a sharp decrease in cutting force.After that,the generation of new surface results in a significant decrease in actual cutting depth,a parameter proposed to reflect the interaction between the rock and the cutter.Consequently,ductile failure dominates again and a slight fluctuation of cutting force can be detected.As the cutter moves to the rock,the actual cutting depth gradually increases,which results in the subsequent generation of chunk-like cuttings.It is accompanied by an obvious cutting force drop.That is,ductile failure and brittle failure,one following another,present at large cutting depth.The transition of rock failure mode can be correlated with the variation of cutting force.Based on the results of this paper,the real-time monitoring of torque ma
基金supported by the Special Fund for Industry of Ministry of Agriculture of China (201303129)the Fundamental Research Funds for the Central Universities, China (XDJK2013A023)+1 种基金the Key Program of Chongqing, China (cstc2012ggC 80002)the Upgrade Project of the Key Laboratory of Chongqing, China (cstc2014pt-sy80001)
文摘The nuclear-encoded light-harvesting chlorophyll a/b-binding proteins（LHCPs） are specifically translocated from the stroma into the thylakoid membrane through the chloroplast signal recognition particle（cp SRP） pathway. The cp SRP is composed of a cp SRP43 protein and a cp SRP54 protein, and it forms a soluble transit complex with LHCP in the chloroplast stroma. Here, we identified the YGL9 gene that is predicted to encode the probable rice cp SRP43 protein from a rice yellow-green leaf mutant. A phylogenetic tree showed that an important conserved protein family, cp SRP43, is present in almost all green photosynthetic organisms such as higher plants and green algae. Sequence analysis showed that YGL9 comprises a chloroplast transit peptide, three chromodomains and four ankyrin repeats, and the chromodomains and ankyrin repeats are probably involved in protein-protein interactions. Subcellular localization showed that YGL9 is localized in the chloroplast. Expression pattern analysis indicated that YGL9 is mainly expressed in green leaf sheaths and leaves. Quantitative real-time PCR analysis showed that the expression levels of genes associated with pigment metabolism, chloroplast development and photosynthesis were distinctly affected in the ygl9 mutant. These results indicated that YGL9 is possibly involved in pigment metabolism, chloroplast development and photosynthesis in rice.
基金supported by grants from the National Natural Science Foundation of China(82070588)High Level Creative Talents from Department of Public Health in Zhejiang Province(S2032102600032)+1 种基金Project of New Century 551 Talent Nurturing in Wenzhou.GT is supported in part by grants from the University School of Medicine of Verona,Verona,ItalyCDB is supported in part by the Southampton NIHR Biomedical Research Centre(IS-BRC-20004),UK.
文摘Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained from liver magnetic resonance imaging(MRI)scan sequences.We aimed to establish a radiomics signature based on T2WI(T2-RS)for assessment of hepatic inflammation in people with nonalcoholic fatty liver disease(NAFLD).Methods:A total of 203 individuals with biopsy-confirmed NAFLD from two independent Chinese cohorts with liver MRI examination were enrolled in this study.The hepatic inflammatory activity score(IAS)was calculated by the unweighted sum of the histologic scores for lobular inflammation and ballooning.One thousand and thirty-two radiomics features were extracted from the localized region of interest(ROI)in the right liver lobe of T2WI and,subsequently,selected by minimum redundancy maximum relevance and least absolute shrinkage and selection operator(LASSO)methods.The T2-RS was calculated by adding the selected features weighted by their coefficients.Results:Eighteen radiomics features from Laplacian of Gaussian,wavelet,and original images were selected for establishing T2-RS.The T2-RS value differed significantly between groups with increasing grades of hepatic inflammation(P<0.01).The T2-RS yielded an area under the receiver operating characteristic(ROC)curve(AUROC)of 0.80[95%confidence interval(CI):0.71-0.89]for predicting hepatic inflammation in the training cohort with excellent calibration.The AUROCs of T2-RS in the internal cohort and external validation cohorts were 0.77(0.61-0.93)and 0.75(0.63-0.84),respectively.Conclusions:The T2-RS derived from radiomics analysis of T2WI shows promising utility for predicting hepatic inflammation in individuals with NAFLD.
基金supported by the Innovation Fund of China Aerospace Science and Technology Corporation (2011)the Research Fund of the State Key Laboratory of Solidification Processing (No.42-QP-009)the 111 Project of China (No.B08040)
文摘Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （FE-SEM） and a MICROTEST-5000 tensile stage were used to carry out in-situ tension tests and observations. The crystallographic texture of the extruded sample changed from weak cube texture {001}〈100〉 to texture {018}〈081〉 during tension fracture. However, strong Brass {110}〈112〉 in the hot-rolled sample was modi-fied into a mixture texture component of Brass {110}〈112〉 and S {123}〈634〉 during tension fracture. Texture evolution in the two samples during tension can be explained by the rotation of grain orientation.
基金support of the National Science Fund for Distinguished Young Scholars(51925405)Beijing Outstanding Young Scientist Program(BJJWZYJH01201911414038)+3 种基金National Natural Science Foundation of China(52104050)National Natural Science Foundation of China(52174011)China Postdoctoral Science Foundation(2021M703579)China University of Petroleum,Beijing(ZX20200119)。
文摘Laboratory uniaxial compression creep tests,with differential stress of 30 MPa hold for 3 h,were performed on Chang-7,Longmaxi(LMX)and Barnett shales to study the influence of SC-CO_(2)on short-term viscoelastic properties.To this end,the wet shale samples were treated with SC-CO_(2)with a pressure of30 MPa and a temperature of 110℃for 14 days.We analyzed the creep data using the fractional Maxwell model.To investigate microscopic structural alterations,the surface morphology of the same location,before and after SC-CO_(2)-water exposure,was examined by SEM images.Compared with dry shales,dynamic and static elastic moduli decreased by up to 25.02%and 55.83%,respectively,but the creep deformation increased by 200%for LMX and Chang-7 shales,and 500%for the Barnett shale treated by SC-CO_(2).Compared to dry sample,there is an increase in calculated fractional orders of 0.02,0.07,0.22 for SC-CO_(2)treated samples,indicating that SC-CO_(2)treatment is likely to enhance shale creep.SEM investigation confirmed physicochemical mechanisms responsible for the observed elastic damage and creep enhancement,including mineral dissolution and swelling caused by SC-CO_(2).This work would further improve our current understanding of the time-dependent deformation of shale under chemicalmechanical coupling effects during CO_(2)capture utilization and storage.
