Uniaxial compression tests and cyclic loading acoustic emission tests were conducted on 20%,40%,60%,80%,dry and saturated muddy sandstone by using a creep impact loading system to investigate the mechanical properties...Uniaxial compression tests and cyclic loading acoustic emission tests were conducted on 20%,40%,60%,80%,dry and saturated muddy sandstone by using a creep impact loading system to investigate the mechanical properties and acoustic emission characteristics of soft rocks with different water contents under dynamic disturbance.The mechanical properties and acoustic emission characteristics of muddy sandstones at different water contents were analysed.Results of experimental studies show that water is a key factor in the mechanical properties of rocks,softening them,increasing their porosity,reducing their brittleness and increasing their plasticity.Under uniaxial compression,the macroscopic damage characteristics of the muddy sandstone change from mono-bevel shear damage and‘X’type conjugate bevel shear damage to a roadway bottom-drum type damage as the water content increases.Dynamic perturbation has a strengthening effect on the mechanical properties of samples with 60%and less water content,and a weakening effect on samples with 80%and more water content,but the weakening effect is not obvious.Macroscopic damage characteristics of dry samples remain unchanged,water samples from shear damage and tensile–shear composite damage gradually transformed into cleavage damage,until saturation transformation monoclinic shear damage.The evolution of acoustic emission energy and event number is mainly divided into four stages:loading stage(I),dynamic loading stage(II),yield failure stage(III),and post-peak stage(IV),the acoustic emission characteristics of the stages were different for different water contents.The characteristic value of acoustic emission key point frequency gradually decreases,and the damage degree of the specimen increases,corresponding to low water content—high main frequency—low damage and high water content—low main frequency—high damage.展开更多
[Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experimen...[Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experiments were designed to optimize the extraction process of total flavonoids from P.chinense Pursh with the volume fraction of ethanol,the ratio of material to liquid,heating reflux extraction time and extraction times as factors,and the content of total flavonoids as the index.A verification test was carried out.The optimized extraction process was adopted to compare the contents of total flavonoids from different parts of P.chinense Pursh.[Results]The best extraction process was extracting the powder of P.chinense Pursh for 2.0 h with 20 times of 55%ethanol by reflux twice.Under this condition,the contents of total flavonoids were 3.63%,8.90%,11.28%,and 4.36%from stems,leaves,flowers and whole grass of P.chinense Pursh,respectively.[Conclusions]The process is reasonable,feasible and stable,and can effectively extract total flavonoids from P.chinense Pursh.The contents of total flavonoids from different parts of P.chinense Pursh were quite different,and the value was higher in the leaves and flowers,so the proportions of leaves and flowers should be paid attention to in the industrial processing of P.chinense Pursh.展开更多
Water injection, as a widely used technique to prevent coal burst, can restrain the fractured coal seam and released the energy storage. In this study, laboratory tests were frstly carried out on standard coal specime...Water injection, as a widely used technique to prevent coal burst, can restrain the fractured coal seam and released the energy storage. In this study, laboratory tests were frstly carried out on standard coal specimens with fve diferent water contents (i.e., 0%, 0.6%, 1.08%, 1.5%, 2.0%, and 2.3%). The failure mode, fragment size, and energy distribution characteristics of coal specimens were investigated. Experimental results show that strength, elastic strain energy, dissipated energy, brittleness index, as well as impact energy index decrease with increasing water content. Besides, the failure mode transitions gradually from splitting ejection to tensile-shear mixed failure mode as water content increases, and average fragment size shows positively related to water content. Moreover, scanning electron microscope tests results indicate that water in coal sample mainly causes the mineral softening and defects increase. Furthermore, a numerical model containing roadway excavation was established considering the water on coal burst prevention. Modelling results revealed that water injection can reduce degree of coal burst and ejection velocity of coal blocks, while it will raise up the depth of crack zone and surface displacement of roadway. Combined with laboratory tests and numerical results, the micro mechanism, energy mechanism, and engineering signifcance of water injection on coal burst prevention were fnally analyzed.展开更多
In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular ...In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular elements varied widely among different phytoplankton.We found that temperature is one of the important factors affecting the carbon,nitrogen,and sulfur contents in phytoplankton cells;however,the degree of influence of temperature is different for different kinds of phytoplankton.By measuring the nitrogen content in cells,we found that the C:N ratio indirectly measured in the experiment fluctuated in the range of 3.50-8.97,and the average C:N ratio was 5.52.In this experiment,we accurately measured the cell elemental contents at different temperatures and transformed the cell count results into carbon,nitrogen,and sulfur contents to express the biomass.This method ensures that the contribution of species that are small in number but with a large cell volume in biomass is considered.Moreover,this method comprehensively considers the interspecific differences of species and the uneven distribution of elements in phytoplankton cells,which is of significance in the estimation of marine carbon and nitrogen budget.The distribution of nitrogen content in marine phytoplankton can well indicate the marine eutrophication caused by human activities.Climate change can affect the community structure and element composition of marine phytoplankton,meanwhile marine carbon and nitrogen element can regulate the climate to a certain extent.展开更多
When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining str...When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining structures become unpredictable.This necessitates the determination of lateral pressure coefficient at rest(k_(0) value)for expansive soils in landfill.Considering compaction,excavation of expansive soils,as well as construction of landfill in different seasons,series of stepwise loading and unloading consolidation tests at various moisture contents were carried out in this work to explore the evolution characteristics of k_(0) value and assess the dependence of k_(0) value on vertical stress and moisture content.Besides,scanning electron microscope(SEM)was used to track the change in microstructural features with vertical stresses.The results indicated that the k_(0) value of expansive soil shows a pronounced nonlinearity and is inextricably linked with vertical stress and moisture content,based on which a prediction formula to estimate the variation in k_(0) value with vertical stress during loading stage was proposed;there is a significant exponential increase in k_(0) value with overconsolidation ratio(OCR)during unloading stage,and OCR dominates the release of horizontal stress of expansive soil;SEM results revealed that with an increase in vertical stress,the anisotropy of expansive soil microstructure increases dramatically,causing a significant directional readjustment,which is macroscopically manifested as an initially rapid increase in k_(0) value;but when vertical stress increases to a critical value,the anisotropy of microstructure increases marginally,indicating a stable orientation occurring in the soil microstructure,which causes the k_(0) value to maintain a relatively stable value.展开更多
The thermal expansion behavior of sintered Nd–Fe–B magnets is a crucial parameter for production and application.However, this aspect has not been thoroughly investigated. In this study, three different sintered Nd...The thermal expansion behavior of sintered Nd–Fe–B magnets is a crucial parameter for production and application.However, this aspect has not been thoroughly investigated. In this study, three different sintered Nd–Fe–B magnets with varying Co content(Co = 0, 6, 12 wt%) were prepared using the conventional powder metallurgy method, and four magnets oriented under different magnetic fields were prepared to compare. The thermal expansion behavior for the magnets was investigated using a linear thermal dilatometry in the temperature range of 20℃–500℃. It was found that, the coefficient of thermal expansion(CTE) increases with the increase of Co contents, while the anisotropy of thermal expansion decreases.The introduction of Co leads to continuous changes from negative to positive thermal expansion in the vertically oriented direction, which is important for the development of zero thermal expansion magnets. The thermal expansion of nonoriented magnets was found to be isotropic. Additionally, the anisotropy of thermal expansion increases with the increase of orientation degree. These results have important implications for the development of sintered Nd–Fe–B with controllable CTE.展开更多
The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative...The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative coal seam with multiple sections (A1, A2, and A3) in the Sydney basin, where the CO_(2) composition exceeds 90%. The fast direct desorption method and associated devices were described in detail and employed to measure the in-situ gas components (Q_(1), Q_(2), and Q_(3)) of the coal seam. The results show that in-situ total gas content (Q_(T)) ranges from 9.48 m^(3)/t for the A2 section to 14.80 m^(3)/t for the A3 section, surpassing the Level 2 outburst threshold limit value, thereby necessitating gas drainage measures. Among the gas components, Q_(2) demonstrates the highest contribution to Q_(T), ranging between 55% and 70%. Furthermore, high-pressure isothermal gas sorption experiments were conducted on coal samples from each seam section to explore their gas sorption capacity. The Langmuir model accurately characterizes CO_(2) sorption behavior, with ft coefcients (R^(2)) greater than 0.99. Strong positive correlations are observed between in-situ gas content and Langmuir volume, as well as between residual gas content (Q_(3)) and sorption hysteresis. Notably, the A3 seam section is proved to have a higher outburst propensity due to its higher Q_(1) and Q_(2) gas contents, lower sorption hysteresis, and reduced coal toughness f value. The insights derived from the study can contribute to the development of efective gas management strategies and enhance the safety and efciency of coal mining operations.展开更多
The growing interest in the potential biological activity of polyphenols and flavonoids has highlighted necessity to assess their content in fresh and dried pepper from Ivory Coast. The total polyphenol content was de...The growing interest in the potential biological activity of polyphenols and flavonoids has highlighted necessity to assess their content in fresh and dried pepper from Ivory Coast. The total polyphenol content was determined using the Folin-Ciocalteu test and the total flavonoid content was also measured spectrophotometrically using the aluminum chloride colorimetric test. The results obtained indicate the total polyphenol levels of fresh and dried peppers are higher in the samples collected in Danane (0.8 ± 0.05 mg GAE/100g) and in Azaguie (0.4 ± 0.08 mg GAE/100g). The lowest concentrations were obtained with fresh and dried pepper samples collected in N’douci (0.22 ± 0.02 mg GAE/100g) and in PK 103 (0.22 ± 0.02 mg GAE/100g). The highest content of total flavonoids was revealed in the locality of PK 103 (1.85 ± 0.62 mg EC/100g) followed by the locality of Maféré (1.37 ± 0.25 mg EC/100g) respectively for black pepper and green pepper. Then, the lowest flavonoid contents were obtained in the dried pepper of Lopou (0.57 ± 0.03 mg EC/100g) and the fresh pepper of PK 103 (0.47 ± 0.03 mg EC/100g). The results obtained highlight the importance of these black spices as promising sources of phenolic compounds and could be used in pharmaceutical treatments and in food.展开更多
[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragran...[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.展开更多
The global physical and biogeochemical environment has been substantially altered in response to increased atmospheric greenhouse gases from human activities.In 2023,the sea surface temperature(SST)and upper 2000 m oc...The global physical and biogeochemical environment has been substantially altered in response to increased atmospheric greenhouse gases from human activities.In 2023,the sea surface temperature(SST)and upper 2000 m ocean heat content(OHC)reached record highs.The 0–2000 m OHC in 2023 exceeded that of 2022 by 15±10 ZJ(1 Zetta Joules=1021 Joules)(updated IAP/CAS data);9±5 ZJ(NCEI/NOAA data).The Tropical Atlantic Ocean,the Mediterranean Sea,and southern oceans recorded their highest OHC observed since the 1950s.Associated with the onset of a strong El Niño,the global SST reached its record high in 2023 with an annual mean of~0.23℃ higher than 2022 and an astounding>0.3℃ above 2022 values for the second half of 2023.The density stratification and spatial temperature inhomogeneity indexes reached their highest values in 2023.展开更多
Fragrant rice has a high market value,and it is a popular rice type among consumers owing to its pleasant flavor.Plantation methods,nitrogen(N)fertilizers,and silicon(Si)fertilizers can affect the grain yield and frag...Fragrant rice has a high market value,and it is a popular rice type among consumers owing to its pleasant flavor.Plantation methods,nitrogen(N)fertilizers,and silicon(Si)fertilizers can affect the grain yield and fragrance of fragrant rice.However,the core commercial rice production attributes,namely the head rice yield(HRY)and 2-acetyl-1-pyrroline(2-AP)content of fragrant rice,under various nitrogen and silicon(N-Si)fertilization levels and different plantation methods remain unknown.The field experiment in this study was performed in the early seasons of 2018 and 2019 with two popular indica fragrant rice cultivars(Yuxiangyouzhan and Xiangyaxiangzhan).They were grown under six N-Si fertilization treatments(combinations of two levels of Si fertilizer,0 kg Si ha^(−1)(Si0)and 150 kg Si ha^(−1)(Si1),and three levels of N fertilizer,0 kg N ha^(−1)(N0),150 kg N ha^(−1)(N1),and 220 kg N ha^(−1)(N2))and three plantation methods(artificial transplanting(AT),mechanical transplanting(MT),and mechanical direct-seeding(MD)).The results showed that the N-Si fertilization treatments and all the plantation methods significantly affected the HRY and 2-AP content and related parameters of the two different fragrant rice cultivars.Compared with the Si0N0 treatment,the N-Si fertilization treatments resulted in higher HRY and 2-AP contents.The rates of brown rice,milled rice,head rice,and chalky rice of the fragrant rice also improved with the N-Si fertilization treatments.The N-Si fertilization treatments increased the activities of N metabolism enzymes and the accumulation of N and Si in various parts of the fragrant rice,and affected their antioxidant response parameters.The key parameters for the HRY and 2-AP content were assessed by redundancy analysis.Furthermore,the structural equation model revealed that the Si and N accumulation levels indirectly affected the HRY by affecting the N metabolism enzyme activity,N use efficiency,and grain quality of fragrant rice.Moreover,high N and Si accumulation directly promoted the 2-AP content or affected the antioxidant response parameters and indirectly regulated 2-AP synthesis.The interactions of the MT method with the N-Si fertilization treatments varied in the fragrant rice cultivars in terms of the HRY and 2-AP content,whereas the MD method was beneficial to the 2-AP content in both fragrant rice cultivars under the N-Si fertilization treatments.展开更多
本文从专家推荐网站入手对学科网站进行研究,以气象学为例,通过检索ISI Current Contents Connect数据库,对学科网站的地理分布、语种分布、信息来源、出版者及关键词进行统计分析,总结出学科网站的一些特点。最后对目前学科网络信息资...本文从专家推荐网站入手对学科网站进行研究,以气象学为例,通过检索ISI Current Contents Connect数据库,对学科网站的地理分布、语种分布、信息来源、出版者及关键词进行统计分析,总结出学科网站的一些特点。最后对目前学科网络信息资源研究提出了自己的看法。展开更多
The global ionosphere maps(GIM)provided by the International GNSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical application.Assessing the credibility of G...The global ionosphere maps(GIM)provided by the International GNSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical application.Assessing the credibility of GIM products in data-sparse regions is of paramount importance.In this study,measurements from the Crustal Movement Observation Network of China(CMONOC)are leveraged to evaluate the suitability of IGS-GIM products over China region in 2013-2014.The indices of mean error(ME),root mean square error(RMSE),and normalized RMSE(NRMSE)are then utilized to quantify the accuracy of IGS-GIM products.Results revealed distinct local time and latitudinal dependencies in IGS-GIM errors,with substantially high errors at nighttime(NRMSE:39%)and above 40°latitude(NRMSE:49%).Seasonal differences also emerged,with larger equinoctial deviations(NRMSE:33.5%)compared with summer(20%).A preliminary analysis implied that the irregular assimilation of sparse IGS observations,compounded by China’s distinct geomagnetic topology,may manifest as error variations.These results suggest that modeling based solely on IGS-GIM observations engenders inadequate representations across China and that a thorough examination would proffer the necessary foundation for advancing regional total electron content(TEC)constructions.展开更多
Examination of the food habits and seasonal variation of the stomach contents of adult tongue sole, Cynoglossus semilaevisGunther) taken in July 1982-July 1983 from Laizhou Bay and the Huanghe River estuary of the Boh...Examination of the food habits and seasonal variation of the stomach contents of adult tongue sole, Cynoglossus semilaevisGunther) taken in July 1982-July 1983 from Laizhou Bay and the Huanghe River estuary of the Bohai Sea showed Crustacea, bivalvia and small fishes comprised the main prey. Invertebrates such as polychaeta, cephalopoda, gastropoda, echinodermata and actiniaria were also intermittently found in them. They intensively fed all the year round (monthly feeding rate of over 80%). The main food items were Alpheus japonica, Alpheus distinguendus, Oratosquilla oratorio, Eucrate crenata and Carcinoplax vestitus, etc. In summer and autumn, the portion of bivalvia such as Cultellus attenuatus and Musculus senhousei increased steadily. From summer to winter, a stable proportion of small fishes such as Rhinogobius pflaumi and Setipinna taty was in the diet.展开更多
Objective:To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol,flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al ...Objective:To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol,flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al Jabal Al Akhdar,Nizwa.Sultanate of Oman.Methods:The leave sample was extracted with methanol and evaporated.Then it was defatted with water and extracted with different polarities organic solvents with increasing polarities.The prepare hexane,chloroform,ethyl acetate,hutanol and methanol crude extracts were used for their evaluation of total phenol,flavonoids contents and phytochemical screening study.The established conventional metliods were used for quantitative determination of total phenol,flavonoids contents and phytochemical screening.Results:Phytochemical screening for various crude extracts were tested and shown positive result for flavonoids,saponins and steroids compounds.The result for total phenol content was the highest in hutanol and the lowest in methanol crude extract whereas the total flavonoids contents was the highest in methanol and the lowest hexane crude extract.Conclusions:The crude extracts from locally grown Thymus vulgaris showed high concentration of flavonoids and it could be used as antibiotics for different curable and uncurable diseases.展开更多
Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stabilit...Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability.In the present study,we have evaluated the effects of foliar applied plant growth regulators,i.e.,moringa leaf extract(MLE)and mepiquat chloride(MC)alone and in combination MC and MLE on the conventional cotton cultivar(CIM 573)and transgenic one(CIM 598).The growth regulators were applied at the start of bloom,45 and 90 days after blooming.Results The application of MC and MLE at 90 days after blooming significantly improved the relative growth rate,net assimilation rate,the number of bolls per plant,and seed cotton yield.Likewise,the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules,as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars.The application of MLE alone has considerably improved the nitrogen uptake in leaves,and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars.Similarly,Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents.Treatment in combination(MLE+MC)at 90 days after blooming produced considerably higher micronaire value,fiber strength,and staple length in conventional cultivar.Conclusion The natural growth enhancer,MLE is a rich source of minerals and zeatin,improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.展开更多
Amylose content(AC)is a crucial determinant of the eating and cooking quality(ECQ)of rice,with low AC varieties exhibiting a softer texture and greater stickiness-attributes that enhance palatability and are desirable...Amylose content(AC)is a crucial determinant of the eating and cooking quality(ECQ)of rice,with low AC varieties exhibiting a softer texture and greater stickiness-attributes that enhance palatability and are desirable in specific culinary contexts.To harness these traits,significant efforts have been made to manipulate AC to improve rice ECQ.Our research utilized the MutMap+approach to identify LAC6/TL1,a gene that is an allele of Du13,responsible for low AC.LAC6 encodes a C2H2 zinc finger protein,which specifically increases the splicing efficiency of the Wxb allele without affecting the Wxa allele.Functional studies of LAC6 revealed that its proper integration could rectify the undesirable AC phenotype,whereas mutations within this gene led to reduced AC and were associated with shorter grain length and decreased thousand-grain weight.Despite these drawbacks,such mutations positively impact rice palatability,presenting a trade-off between grain size and eating quality.To address the challenges posed by the reduced grain weight associated with LAC6 mutations,we developed a specific molecular marker for LAC6,which has been effectively used in breeding programs to select lac6/tl1/du13 homozygous individuals with larger grain size.Our findings demonstrate that the“small grain”trait associated with lac6/tl1/du13 can be effectively mitigated through combined phenotype-based and marker-assisted selection.This study highlights the potential of lac6/tl1/du13 as a valuable gene for breeding novel,high-quality soft rice varieties through targeted breeding strategies.展开更多
Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin re...Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin responsible for the variation of properties remains poorly understood.In the present work,we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins.Specifically,we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl(Tl is the liquidus temperature)to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating.We found that glass transition temperature,Tg,increases by as much as 36 K,and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl.The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys.The incorporated oxygen and silicon can both enhance the interactions between atoms,which renders the cooperative rearrangements of atoms difficult,and thus enhances the kinetic stability of the MGs.展开更多
Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting control...Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore fluid.We employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying KC.These artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different directions.Observations revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of kerogen.All elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC variations.In the range of low KC(<10%),the V_(P)/V_(S) ratio demonstrated a linearly negative correlation with KC,and the V_(P)/V_(S) ratio magnitude of less than 1.75may serve as a significant characterization for highly organic-rich(>10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.展开更多
基金National Natural Science Foundation of China (No. 52204101)Natural Science Foundation of Shandong Province (No. ZR2022QE137)Open Project of State Key Laboratory for Geomechanics and Deep Underground Engineering in CUMTB (No. SKLGDUEK2023).
文摘Uniaxial compression tests and cyclic loading acoustic emission tests were conducted on 20%,40%,60%,80%,dry and saturated muddy sandstone by using a creep impact loading system to investigate the mechanical properties and acoustic emission characteristics of soft rocks with different water contents under dynamic disturbance.The mechanical properties and acoustic emission characteristics of muddy sandstones at different water contents were analysed.Results of experimental studies show that water is a key factor in the mechanical properties of rocks,softening them,increasing their porosity,reducing their brittleness and increasing their plasticity.Under uniaxial compression,the macroscopic damage characteristics of the muddy sandstone change from mono-bevel shear damage and‘X’type conjugate bevel shear damage to a roadway bottom-drum type damage as the water content increases.Dynamic perturbation has a strengthening effect on the mechanical properties of samples with 60%and less water content,and a weakening effect on samples with 80%and more water content,but the weakening effect is not obvious.Macroscopic damage characteristics of dry samples remain unchanged,water samples from shear damage and tensile–shear composite damage gradually transformed into cleavage damage,until saturation transformation monoclinic shear damage.The evolution of acoustic emission energy and event number is mainly divided into four stages:loading stage(I),dynamic loading stage(II),yield failure stage(III),and post-peak stage(IV),the acoustic emission characteristics of the stages were different for different water contents.The characteristic value of acoustic emission key point frequency gradually decreases,and the damage degree of the specimen increases,corresponding to low water content—high main frequency—low damage and high water content—low main frequency—high damage.
基金Supported by Key Research and Development Program of Sichuan Province(2022YFS0436)Natural Science Foundation of Sichuan Province(2022NSFSC1738)+4 种基金Science and Technology Planning Project of Luzhou City(2021-JYJ-109,2023SYF120)Special Project of Traditional Chinese Medicine Scientific Research of Sichuan Provincial Administration of Traditional Chinese Medicine(2020CP0029)Southwest Medical University-Luzhou Hospital of Traditional Chinese Medicine Base Project(2019-LH003)Open Subject of Luzhou Key Laboratory of Fine Chemical Application Technology(HYJY-2106-B)Southwest Medical University Undergraduate Student Innovation and Entrepreneurship Training Program(202310632074).
文摘[Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experiments were designed to optimize the extraction process of total flavonoids from P.chinense Pursh with the volume fraction of ethanol,the ratio of material to liquid,heating reflux extraction time and extraction times as factors,and the content of total flavonoids as the index.A verification test was carried out.The optimized extraction process was adopted to compare the contents of total flavonoids from different parts of P.chinense Pursh.[Results]The best extraction process was extracting the powder of P.chinense Pursh for 2.0 h with 20 times of 55%ethanol by reflux twice.Under this condition,the contents of total flavonoids were 3.63%,8.90%,11.28%,and 4.36%from stems,leaves,flowers and whole grass of P.chinense Pursh,respectively.[Conclusions]The process is reasonable,feasible and stable,and can effectively extract total flavonoids from P.chinense Pursh.The contents of total flavonoids from different parts of P.chinense Pursh were quite different,and the value was higher in the leaves and flowers,so the proportions of leaves and flowers should be paid attention to in the industrial processing of P.chinense Pursh.
基金supported by the National Natural Science Foundation of China(Grant No:51974289)Natural Science Foundation of Anhui Province(Grant No:2108085ME155).
文摘Water injection, as a widely used technique to prevent coal burst, can restrain the fractured coal seam and released the energy storage. In this study, laboratory tests were frstly carried out on standard coal specimens with fve diferent water contents (i.e., 0%, 0.6%, 1.08%, 1.5%, 2.0%, and 2.3%). The failure mode, fragment size, and energy distribution characteristics of coal specimens were investigated. Experimental results show that strength, elastic strain energy, dissipated energy, brittleness index, as well as impact energy index decrease with increasing water content. Besides, the failure mode transitions gradually from splitting ejection to tensile-shear mixed failure mode as water content increases, and average fragment size shows positively related to water content. Moreover, scanning electron microscope tests results indicate that water in coal sample mainly causes the mineral softening and defects increase. Furthermore, a numerical model containing roadway excavation was established considering the water on coal burst prevention. Modelling results revealed that water injection can reduce degree of coal burst and ejection velocity of coal blocks, while it will raise up the depth of crack zone and surface displacement of roadway. Combined with laboratory tests and numerical results, the micro mechanism, energy mechanism, and engineering signifcance of water injection on coal burst prevention were fnally analyzed.
基金supported by the National Natural Science Foundation of China-Shandong Joint Foundation(No.U1806211)。
文摘In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular elements varied widely among different phytoplankton.We found that temperature is one of the important factors affecting the carbon,nitrogen,and sulfur contents in phytoplankton cells;however,the degree of influence of temperature is different for different kinds of phytoplankton.By measuring the nitrogen content in cells,we found that the C:N ratio indirectly measured in the experiment fluctuated in the range of 3.50-8.97,and the average C:N ratio was 5.52.In this experiment,we accurately measured the cell elemental contents at different temperatures and transformed the cell count results into carbon,nitrogen,and sulfur contents to express the biomass.This method ensures that the contribution of species that are small in number but with a large cell volume in biomass is considered.Moreover,this method comprehensively considers the interspecific differences of species and the uneven distribution of elements in phytoplankton cells,which is of significance in the estimation of marine carbon and nitrogen budget.The distribution of nitrogen content in marine phytoplankton can well indicate the marine eutrophication caused by human activities.Climate change can affect the community structure and element composition of marine phytoplankton,meanwhile marine carbon and nitrogen element can regulate the climate to a certain extent.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1509901)。
文摘When expansive soils in the original location are artificially transferred to landfill in different seasons,and subject to engineering activities afterwards,the corresponding deformation and stability of retaining structures become unpredictable.This necessitates the determination of lateral pressure coefficient at rest(k_(0) value)for expansive soils in landfill.Considering compaction,excavation of expansive soils,as well as construction of landfill in different seasons,series of stepwise loading and unloading consolidation tests at various moisture contents were carried out in this work to explore the evolution characteristics of k_(0) value and assess the dependence of k_(0) value on vertical stress and moisture content.Besides,scanning electron microscope(SEM)was used to track the change in microstructural features with vertical stresses.The results indicated that the k_(0) value of expansive soil shows a pronounced nonlinearity and is inextricably linked with vertical stress and moisture content,based on which a prediction formula to estimate the variation in k_(0) value with vertical stress during loading stage was proposed;there is a significant exponential increase in k_(0) value with overconsolidation ratio(OCR)during unloading stage,and OCR dominates the release of horizontal stress of expansive soil;SEM results revealed that with an increase in vertical stress,the anisotropy of expansive soil microstructure increases dramatically,causing a significant directional readjustment,which is macroscopically manifested as an initially rapid increase in k_(0) value;but when vertical stress increases to a critical value,the anisotropy of microstructure increases marginally,indicating a stable orientation occurring in the soil microstructure,which causes the k_(0) value to maintain a relatively stable value.
基金the National Key Research and Development Program of China (Grant No. 2021YFB3502900)the National Natural Science Foundation of China (Grant No. 51871063)+1 种基金the Key Technology Research and Development Program of Shandong Province, China (Grant No. 2019JZZY020210)the Major Projects in Inner Mongolia Autonomous Region, China。
文摘The thermal expansion behavior of sintered Nd–Fe–B magnets is a crucial parameter for production and application.However, this aspect has not been thoroughly investigated. In this study, three different sintered Nd–Fe–B magnets with varying Co content(Co = 0, 6, 12 wt%) were prepared using the conventional powder metallurgy method, and four magnets oriented under different magnetic fields were prepared to compare. The thermal expansion behavior for the magnets was investigated using a linear thermal dilatometry in the temperature range of 20℃–500℃. It was found that, the coefficient of thermal expansion(CTE) increases with the increase of Co contents, while the anisotropy of thermal expansion decreases.The introduction of Co leads to continuous changes from negative to positive thermal expansion in the vertically oriented direction, which is important for the development of zero thermal expansion magnets. The thermal expansion of nonoriented magnets was found to be isotropic. Additionally, the anisotropy of thermal expansion increases with the increase of orientation degree. These results have important implications for the development of sintered Nd–Fe–B with controllable CTE.
基金supported by China Scholarship Council(202006430006)the International Postgraduate Tuition Award(IPTA)of the University of Wollongongthe research funding provided by the Mine A,ACARP Project C35015 and Coal Services Health and Safety Trust.
文摘The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative coal seam with multiple sections (A1, A2, and A3) in the Sydney basin, where the CO_(2) composition exceeds 90%. The fast direct desorption method and associated devices were described in detail and employed to measure the in-situ gas components (Q_(1), Q_(2), and Q_(3)) of the coal seam. The results show that in-situ total gas content (Q_(T)) ranges from 9.48 m^(3)/t for the A2 section to 14.80 m^(3)/t for the A3 section, surpassing the Level 2 outburst threshold limit value, thereby necessitating gas drainage measures. Among the gas components, Q_(2) demonstrates the highest contribution to Q_(T), ranging between 55% and 70%. Furthermore, high-pressure isothermal gas sorption experiments were conducted on coal samples from each seam section to explore their gas sorption capacity. The Langmuir model accurately characterizes CO_(2) sorption behavior, with ft coefcients (R^(2)) greater than 0.99. Strong positive correlations are observed between in-situ gas content and Langmuir volume, as well as between residual gas content (Q_(3)) and sorption hysteresis. Notably, the A3 seam section is proved to have a higher outburst propensity due to its higher Q_(1) and Q_(2) gas contents, lower sorption hysteresis, and reduced coal toughness f value. The insights derived from the study can contribute to the development of efective gas management strategies and enhance the safety and efciency of coal mining operations.
文摘The growing interest in the potential biological activity of polyphenols and flavonoids has highlighted necessity to assess their content in fresh and dried pepper from Ivory Coast. The total polyphenol content was determined using the Folin-Ciocalteu test and the total flavonoid content was also measured spectrophotometrically using the aluminum chloride colorimetric test. The results obtained indicate the total polyphenol levels of fresh and dried peppers are higher in the samples collected in Danane (0.8 ± 0.05 mg GAE/100g) and in Azaguie (0.4 ± 0.08 mg GAE/100g). The lowest concentrations were obtained with fresh and dried pepper samples collected in N’douci (0.22 ± 0.02 mg GAE/100g) and in PK 103 (0.22 ± 0.02 mg GAE/100g). The highest content of total flavonoids was revealed in the locality of PK 103 (1.85 ± 0.62 mg EC/100g) followed by the locality of Maféré (1.37 ± 0.25 mg EC/100g) respectively for black pepper and green pepper. Then, the lowest flavonoid contents were obtained in the dried pepper of Lopou (0.57 ± 0.03 mg EC/100g) and the fresh pepper of PK 103 (0.47 ± 0.03 mg EC/100g). The results obtained highlight the importance of these black spices as promising sources of phenolic compounds and could be used in pharmaceutical treatments and in food.
基金Supported by Key R&D Program of Hainan Province in 2021(ZDYF2021XDNY152).
文摘[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42076202, 42122046, 42206208 and 42261134536)the Open Research Cruise NORC2022-10+NORC2022-303 supported by NSFC shiptime Sharing Projects 42149910+7 种基金the new Cornerstone Science Foundation through the XPLORER PRIZE, DAMO Academy Young Fellow, Youth Innovation Promotion Association, Chinese Academy of SciencesNational Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (EarthLab)sponsored by the US National Science Foundationsupported by NASA Awards 80NSSC17K0565, 80NSSC21K1191, and 80NSSC22K0046by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S. Department of Energy’s Office of Biological & Environmental Research (BER) via National Science Foundation IA 1947282supported by NOAA (Grant No. NA19NES4320002 to CISESS-MD at the University of Maryland)supported by the Young Talent Support Project of Guangzhou Association for Science and Technologyfunded by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in agreement between INGV, ENEA, and GNV SpA shipping company that provides hospitality on its commercial vessels
文摘The global physical and biogeochemical environment has been substantially altered in response to increased atmospheric greenhouse gases from human activities.In 2023,the sea surface temperature(SST)and upper 2000 m ocean heat content(OHC)reached record highs.The 0–2000 m OHC in 2023 exceeded that of 2022 by 15±10 ZJ(1 Zetta Joules=1021 Joules)(updated IAP/CAS data);9±5 ZJ(NCEI/NOAA data).The Tropical Atlantic Ocean,the Mediterranean Sea,and southern oceans recorded their highest OHC observed since the 1950s.Associated with the onset of a strong El Niño,the global SST reached its record high in 2023 with an annual mean of~0.23℃ higher than 2022 and an astounding>0.3℃ above 2022 values for the second half of 2023.The density stratification and spatial temperature inhomogeneity indexes reached their highest values in 2023.
基金This project was financially supported by the National Natural Science Foundation of China(31601244 and 31971843)the Guangdong Provincial Key Field Research and Development Plan Project,China(2019B020221003)the Modern Agricultural Industrial Technology System of Guangdong Province,China(2020KJ105).
文摘Fragrant rice has a high market value,and it is a popular rice type among consumers owing to its pleasant flavor.Plantation methods,nitrogen(N)fertilizers,and silicon(Si)fertilizers can affect the grain yield and fragrance of fragrant rice.However,the core commercial rice production attributes,namely the head rice yield(HRY)and 2-acetyl-1-pyrroline(2-AP)content of fragrant rice,under various nitrogen and silicon(N-Si)fertilization levels and different plantation methods remain unknown.The field experiment in this study was performed in the early seasons of 2018 and 2019 with two popular indica fragrant rice cultivars(Yuxiangyouzhan and Xiangyaxiangzhan).They were grown under six N-Si fertilization treatments(combinations of two levels of Si fertilizer,0 kg Si ha^(−1)(Si0)and 150 kg Si ha^(−1)(Si1),and three levels of N fertilizer,0 kg N ha^(−1)(N0),150 kg N ha^(−1)(N1),and 220 kg N ha^(−1)(N2))and three plantation methods(artificial transplanting(AT),mechanical transplanting(MT),and mechanical direct-seeding(MD)).The results showed that the N-Si fertilization treatments and all the plantation methods significantly affected the HRY and 2-AP content and related parameters of the two different fragrant rice cultivars.Compared with the Si0N0 treatment,the N-Si fertilization treatments resulted in higher HRY and 2-AP contents.The rates of brown rice,milled rice,head rice,and chalky rice of the fragrant rice also improved with the N-Si fertilization treatments.The N-Si fertilization treatments increased the activities of N metabolism enzymes and the accumulation of N and Si in various parts of the fragrant rice,and affected their antioxidant response parameters.The key parameters for the HRY and 2-AP content were assessed by redundancy analysis.Furthermore,the structural equation model revealed that the Si and N accumulation levels indirectly affected the HRY by affecting the N metabolism enzyme activity,N use efficiency,and grain quality of fragrant rice.Moreover,high N and Si accumulation directly promoted the 2-AP content or affected the antioxidant response parameters and indirectly regulated 2-AP synthesis.The interactions of the MT method with the N-Si fertilization treatments varied in the fragrant rice cultivars in terms of the HRY and 2-AP content,whereas the MD method was beneficial to the 2-AP content in both fragrant rice cultivars under the N-Si fertilization treatments.
基金the National Key R&D Program of China(Grant No.2022YFF0503702)the National Natural Science Foundation of China(Grant Nos.42074186,41831071,42004136,and 42274195)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20211036)the Specialized Research Fund for State Key Laboratories,and the University of Science and Technology of China Research Funds of the Double First-Class Initiative(Grant No.YD2080002013).
文摘The global ionosphere maps(GIM)provided by the International GNSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical application.Assessing the credibility of GIM products in data-sparse regions is of paramount importance.In this study,measurements from the Crustal Movement Observation Network of China(CMONOC)are leveraged to evaluate the suitability of IGS-GIM products over China region in 2013-2014.The indices of mean error(ME),root mean square error(RMSE),and normalized RMSE(NRMSE)are then utilized to quantify the accuracy of IGS-GIM products.Results revealed distinct local time and latitudinal dependencies in IGS-GIM errors,with substantially high errors at nighttime(NRMSE:39%)and above 40°latitude(NRMSE:49%).Seasonal differences also emerged,with larger equinoctial deviations(NRMSE:33.5%)compared with summer(20%).A preliminary analysis implied that the irregular assimilation of sparse IGS observations,compounded by China’s distinct geomagnetic topology,may manifest as error variations.These results suggest that modeling based solely on IGS-GIM observations engenders inadequate representations across China and that a thorough examination would proffer the necessary foundation for advancing regional total electron content(TEC)constructions.
文摘Examination of the food habits and seasonal variation of the stomach contents of adult tongue sole, Cynoglossus semilaevisGunther) taken in July 1982-July 1983 from Laizhou Bay and the Huanghe River estuary of the Bohai Sea showed Crustacea, bivalvia and small fishes comprised the main prey. Invertebrates such as polychaeta, cephalopoda, gastropoda, echinodermata and actiniaria were also intermittently found in them. They intensively fed all the year round (monthly feeding rate of over 80%). The main food items were Alpheus japonica, Alpheus distinguendus, Oratosquilla oratorio, Eucrate crenata and Carcinoplax vestitus, etc. In summer and autumn, the portion of bivalvia such as Cultellus attenuatus and Musculus senhousei increased steadily. From summer to winter, a stable proportion of small fishes such as Rhinogobius pflaumi and Setipinna taty was in the diet.
基金Supported by Central Instrument Laboratory,College of Agriculture and Marine Sciences,Sultan Qaboos University,Sultanate of Oma(Grant No.507/SOP/OB/1/2013)
文摘Objective:To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol,flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al Jabal Al Akhdar,Nizwa.Sultanate of Oman.Methods:The leave sample was extracted with methanol and evaporated.Then it was defatted with water and extracted with different polarities organic solvents with increasing polarities.The prepare hexane,chloroform,ethyl acetate,hutanol and methanol crude extracts were used for their evaluation of total phenol,flavonoids contents and phytochemical screening study.The established conventional metliods were used for quantitative determination of total phenol,flavonoids contents and phytochemical screening.Results:Phytochemical screening for various crude extracts were tested and shown positive result for flavonoids,saponins and steroids compounds.The result for total phenol content was the highest in hutanol and the lowest in methanol crude extract whereas the total flavonoids contents was the highest in methanol and the lowest hexane crude extract.Conclusions:The crude extracts from locally grown Thymus vulgaris showed high concentration of flavonoids and it could be used as antibiotics for different curable and uncurable diseases.
文摘Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability.In the present study,we have evaluated the effects of foliar applied plant growth regulators,i.e.,moringa leaf extract(MLE)and mepiquat chloride(MC)alone and in combination MC and MLE on the conventional cotton cultivar(CIM 573)and transgenic one(CIM 598).The growth regulators were applied at the start of bloom,45 and 90 days after blooming.Results The application of MC and MLE at 90 days after blooming significantly improved the relative growth rate,net assimilation rate,the number of bolls per plant,and seed cotton yield.Likewise,the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules,as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars.The application of MLE alone has considerably improved the nitrogen uptake in leaves,and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars.Similarly,Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents.Treatment in combination(MLE+MC)at 90 days after blooming produced considerably higher micronaire value,fiber strength,and staple length in conventional cultivar.Conclusion The natural growth enhancer,MLE is a rich source of minerals and zeatin,improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.
基金supported by the National Key Research and Development Program of China(2023YFD1200901)the National Natural Science Foundation of China(32230074 and 32161143004)+3 种基金the Research Programs from Jiangsu Government(JBGS[2021]001,BZ2021017,and Qing Lan Project)the Foreign Expert Project(G2023014064L)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_3239)the Yangzhou University High-end Talent Program.
文摘Amylose content(AC)is a crucial determinant of the eating and cooking quality(ECQ)of rice,with low AC varieties exhibiting a softer texture and greater stickiness-attributes that enhance palatability and are desirable in specific culinary contexts.To harness these traits,significant efforts have been made to manipulate AC to improve rice ECQ.Our research utilized the MutMap+approach to identify LAC6/TL1,a gene that is an allele of Du13,responsible for low AC.LAC6 encodes a C2H2 zinc finger protein,which specifically increases the splicing efficiency of the Wxb allele without affecting the Wxa allele.Functional studies of LAC6 revealed that its proper integration could rectify the undesirable AC phenotype,whereas mutations within this gene led to reduced AC and were associated with shorter grain length and decreased thousand-grain weight.Despite these drawbacks,such mutations positively impact rice palatability,presenting a trade-off between grain size and eating quality.To address the challenges posed by the reduced grain weight associated with LAC6 mutations,we developed a specific molecular marker for LAC6,which has been effectively used in breeding programs to select lac6/tl1/du13 homozygous individuals with larger grain size.Our findings demonstrate that the“small grain”trait associated with lac6/tl1/du13 can be effectively mitigated through combined phenotype-based and marker-assisted selection.This study highlights the potential of lac6/tl1/du13 as a valuable gene for breeding novel,high-quality soft rice varieties through targeted breeding strategies.
基金The work was financially supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0703600,2021YFA0716302,and 2021YFA0718703)the National Natural Science Foundation of China(Grant Nos.51825104 and 52192602)China Postdoctoral Science Foundation(Grant No.2022T150691).
文摘Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin responsible for the variation of properties remains poorly understood.In the present work,we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins.Specifically,we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl(Tl is the liquidus temperature)to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating.We found that glass transition temperature,Tg,increases by as much as 36 K,and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl.The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys.The incorporated oxygen and silicon can both enhance the interactions between atoms,which renders the cooperative rearrangements of atoms difficult,and thus enhances the kinetic stability of the MGs.
基金supported by the National Natural Science Foundation of China(42004112,42274175,42030812,41974160)Natural Science Foundation of Sichuan Province(2023NSFSC0764)。
文摘Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and development.Conducting controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore fluid.We employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying KC.These artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different directions.Observations revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of kerogen.All elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC variations.In the range of low KC(<10%),the V_(P)/V_(S) ratio demonstrated a linearly negative correlation with KC,and the V_(P)/V_(S) ratio magnitude of less than 1.75may serve as a significant characterization for highly organic-rich(>10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.