Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample...Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample pretreatments due to the isobaric interferences from ^(99)Ru and ^(98)Mo^(1)H. Herein, capillary electrophoresis(CE) was applied as sample introduction system for the sensitive, and interferencefree determination of ^(99)TcO_(4)^(-) from RuO_(4)^(-), and MoO_(4)^(2-) by ICP-MS with a simple sample treatment. Compared to the conventional methods, the hyphenated CE-ICP-MS avoids the use of expensive separation resins and reduces the consumption of mineral acid, representing a simpler, more efficient and environmentally benign approach. Moreover, the proposed method exhibits higher accuracy compared with the mathematical correction method using the natural isotope ratio of ^(99)Ru and ^(101)Ru, and significantly reduces sample consumption and the amount of waste, thus remarkably alleviating the radioactive exposure to operators and the pressure of radioactive waste treatment. Under the optimized conditions, the detection limits of 25 μg/L and 0.06 μg/L were obtained for RuO_(4)^(-) and ReO_(4)^(-)(Tc was replaced by Re), respectively, with relative standard deviation(RSD) lower than 5%. In addition, efficient recoveries of RuO_(4)^(-),ReO_(4)^(-),and ^(99)TcO_(4)^(-) from simulated Hanford site groundwater were achieved. The method is expected to be a promising candidate for sensitive and accurate analysis of ^(99)Tc from contaminated environmental samples.展开更多
The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fi...The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.展开更多
Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was t...Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was thin-layer chromatography scanning(TLCS),using a developing solvent composed of ethyl acetate–methanol–strong ammonia water(17:2:1).The plates were heated at 105°C for 5 minutes,then sprayed with a mixture of dilute bismuth potassium iodide and 1%ferric chloride in ethanol(10:1),and scanned at a wavelength of 500 nm.Results:Peimine showed good linearity in the concentration range of 0.21–2.1μg with a correlation coefficient of r=0.9997,and Peiminine also exhibited good linearity in the same range with r=0.9995.The accuracy was≥95.0%,and the relative standard deviation(RSD)was≤5.0%(n=6).Conclusion:This method allows for the simultaneous determination of peimine and peiminine,providing a reliable reference for the quality control of the product.展开更多
Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheles...Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheless,these works predominantly centered on the formation and utilization of hydroxyl radicals(•OH)in the process,neglecting the evolution of oxidant and reductant due to the difficulty in the simultaneous determination of these two components.By employing the quenching-iodometric method,we could simultaneously determine the concentrations of HSO_(3)-and peroxydisulfate(PDS).This method first employed an excess of peroxymonosulfate(PMS)to effectively quench HSO_(3)-,and then used the iodometric spectrophotometry to simultaneously determine the concentrations of PMS and PDS in the reaction system.Finally,through precise stoichiometric relationships,we could accurately calculate the concentration of HSO_(3)-.Based on this method,we achieved concentration measurements that,upon linear fitting,yielded a correlation coefficient(R^(2))surpassing 0.99,unequivocally affirming the method’s accuracy and trustworthiness.In this work,an innovation approach for determining the concentrations of HSO_(3)-(reductant)and PDS(oxidant)was explored.Additionally,the resilience of the method was verified across different pH levels and in the presence of diverse impurity ions.The results ensured precise concentration measure-ments in the real wastewater.This method was characterized by its simplicity,rapid analysis,and environmental friendliness,offering a newanalytical strategy for the determination of PDS and HSO_(3)-in environmental samples.The method enables more meticulous monitoring of chemical usage in water treatment,facilitating optimized dosing strategies and assessments of reductant-enhanced Fenton or Fenton-like system in water purification.展开更多
In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupt...In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupture area and displacement,which are intimately linked to the seismic moment,are hard to derive from paleoseismic studies.Our preceding study identified two earthquake sites in Huoshan and Guzhen,Anhui Province.While we qualitatively described the timing of these occurrences and the characteristics of sand veins,dislocations,and earthquake-induced cracks,we did not provide quantitative estimates of their magnitude or seismogenic faults.Consequently,these findings were insufficient for assessing regional seismic risks or determining the potential magnitude of specific faults.This study employs two empirical relationships:one between the farthest distribution distance based on liquefaction from earthquake-induced events and magnitude,and the other concerning the intensityepicenter distance-magnitude relationship.Through these relationships,we analyze the sandy soil liquefaction and earthquake-induced cracks quantitatively.The analysis includes magnitude estimation and seismogenic fault evaluation for the sandy soil liquefaction and crack remnants of the Huoshan Daijiayuan earthquake,as well as the dislocation and crack remnants of the Guzhen Gaixia earthquake.The findings indicate that the Huoshan Daijiayuan site records two paleoseismic events.The first event transpired after 850 BC,and the second after 550 BC,with a gap of approximately 300 years between them;both had a seismic magnitude(M_(S))of around 6.0.The likely seismogenic fault for the Huoshan Daijiayuan earthquake is the Luoerling-Tudiling fault.Meanwhile,the paleoseismic site in Guzhen Gaixia documents two seismic events occurring during 2350-2050 BC,both with a seismic magnitude(MS)of approximately 6½.The Tancheng-Lujiang fault zone is likely the seismogenic fault associated with the Guzhen Gaixia earthquake site.展开更多
Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori at...Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori attitude information replacing the code measurements to enhance the successful rate for ambiguity resolution.However,there exists a key limitation that this method relies on considerable Monte Carlo sampling particles to construct the pdf of ambiguities,resulting in significant computational burdens.To address this limitation,this paper provides a rapid single-epoch GNSS attitude determination method based on a priori attitude information.It utilizes a second-order Taylor expansion to analytically estimate the covariance of the baseline conditioned on a priori attitude information.This is followed by deriving the float solution and covariance of ambiguities,which are then processed using the standard LAMBDA method for integer ambiguity resolution.Experimental results demonstrate that our method is both efficient and accurate,significantly reducing computational costs compared to previous methods,thereby enhancing its applicability for GNSS-based attitude determination.展开更多
This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollu...This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.展开更多
The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arisin...The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.展开更多
Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,...Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.展开更多
[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)w...[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)with ShimNex CS C 18 as the column;column temperature:35℃;wavelength:270 nm;methanol-0.1%phosphoric acid solution as the mobile phase with gradient elution.[Results]The 12 components of the retention of Longqing Capsule showed good linearity within the investigated range(r≥0.9995),with the average spiked recoveries of 97.83%-100.52%and the RSD of 0.9%-2.1%.[Conclusions]The method is exclusive,sensitive,reproducible,simple and easy to use,and can provide a reference for the construction of the quality standard and control system of Longqing Capsule based on the theory of traditional Chinese medicine.展开更多
The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current re...The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current research is focused on Doppler positioning techniques,which require the collaboration of multiple satellites(≥3).However,the dynamic changes of LEO satellites weaken the generalization ability of Doppler positioning.In this paper,a direct position determination(DPD)method with uniform circular array(UCA)is proposed for UAV positioning from the perspective of the spatial spectrum estimation of LEO-SOPs.The proposed method employs the orthogonality between the signal and noise subspaces of the covariance matrix of the different received SOPs to establish the cost function for UAV’s coordinate.Instead of the multiple dimen-sional search,a root mean square propagation(RM-SProp)gradient optimizer with an adaptive learning rate is developed to find the coordinate of UAV.The effectiveness and robustness of the proposed method are verified using numerical data generated from the systems tool kit(STK).展开更多
Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific ...Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific approach has been a successful strategy for survival of a large variety of species including humans, the fidelity of sex determination leading to 100% cis-binary outcomes is not achieved in many species, with evidence for homosexual or bisexual behaviour evident in more than 1500 species. Thus, such outcomes indicates that sex determination is a multi-step process and not a single event, and as such, could lead to the appearance of variants during the process which developed much earlier than humans. Variants could arise either due to intrinsic variation in the steps of determination, or also be influenced by environmental factors of a biological or psychological nature. In contrast to homosexual variants which do not require interventions such as hormone therapy or surgery, expression of gender dysphoria, is more based in psychology, but also has biological underpinnings and can be influenced by such hormonal interventions and surgery. While the numbers of those with gender dysphoria is small (~0.6% - 1.0% of population), the attention given to this issue raises the possibility of biological and psychological environmental factors impacting the emergence of some of those expressing gender dysphoria. Furthermore, transitioning from male-to-female or female-to-male can have consequences regarding disease risks latter in life, including the appearance of autoimmune diseases. This review will attempt to review some of the evidence regarding sex determination, discuss why the system has potentially not been improved upon during evolution, how a potential role for sex chromosome function on neurodevelopment may be central to variation in humans, and how commitment to the current strategy is likely integrated into other sex-related events such as puberty, pregnancy, and menopause to ensure species survival. It will also discuss how variants in sex determination could contribute to sex differences in disease risk and how epigenetic modifications could play a role in such risk. .展开更多
In this study, we swiftly determined the focal parameters(focal mechanism, seismic imaging process, magnitude)of the Jishishan earthquake, leveraging a solved fault model to assess the intensity field and casualties p...In this study, we swiftly determined the focal parameters(focal mechanism, seismic imaging process, magnitude)of the Jishishan earthquake, leveraging a solved fault model to assess the intensity field and casualties promptly.The investigation began by retrieving the source mechanism through the P-wave initial motion and W-phase method. This enabled us to chart the spatial and temporal distribution of energy release in the source area via the back-projection technique. Following this, we estimated the earthquake's intensity field by merging the source inversion findings with the ground motion prediction equation. This analysis facilitated the evaluation of earthquake casualties, utilizing the theoretical intensity field and a casualty assessment model. Our findings indicate that the fault type is a thrust fault, characterized by a unilateral rupture in the direction of NW, with a rupture length spanning approximately 10–15 km and a duration ranging between 8 and 10 s. The earthquake's magnitude varied from M 5.9 to M 6.2. The demarcated high-intensity areas, as per our intensity assessment, align closely with the actual survey results. Furthermore, the predicted total casualties and identified critical rescue zones closely match the real-world casualty figures. These insights offer crucial technical support for governmental emergency command and rescue operations.展开更多
Once a satellite experiences extreme abnormal conditions,it may face serious consequences such as structural damages,material low-temperature failures,propellant freezing,and even whole satellite failures if it is not...Once a satellite experiences extreme abnormal conditions,it may face serious consequences such as structural damages,material low-temperature failures,propellant freezing,and even whole satellite failures if it is not rescued in time.Therefore,it is significantly important to study emergency recovery technologies for satellites.The research progress on attitude determination and control technologies during satellite emergency recovery is reviewed in detail.Moreover,the research achievements in the design and implementation of satellite emergency modes are summarized.By synthesizing and analyzing relevant literature,this paper aims to provide reference and guidance for emergency recovery technologies in response to extremely abnormal satellite states.展开更多
transformer is a switch gene for sex determination in many insects, which cooperates with transformer-2 that is expressed in both sexes to regulate female differentiation, particularly in dipterans. Zeugodacus cucurbi...transformer is a switch gene for sex determination in many insects, which cooperates with transformer-2 that is expressed in both sexes to regulate female differentiation, particularly in dipterans. Zeugodacus cucurbitae(Coquillett) is a very destructive pest worldwide, however, its sex determination pathway remains largely uncharacterized. Here, we show that the female sex ratio is sharply reduced with knockdown of either transformer or transformer-2 by RNA interference in early embryos of Z. cucurbitae. Most of the males grown from the embryos with transient transformer and transformer-2 suppression mated with wild-type females and produced mixed sex progeny, with one exception that produced only female progeny, and all of the few remaining males failed to mate with wild-type females and produced no progeny. The exceptional male and those males with mating failure were XX pseudomales as determined by the detection of Y chromosome-linked Maleness-on-the-Y, indicating that most XX pseudomales are not viable. The phenotypes of transformer and transformer-2 suggest that they play a key role in regulating sex determination and are required for female sexual development of Z. cucurbitae. Our results will be beneficial to the understanding of sex determination in Z. cucurbitae and can facilitate the development of genetic sexing strains for its biological control.展开更多
As a type of new carbon-based nanomaterials,carbon dots(CDs)possess exceptional optical properties,making them highly desirable for use in fluorescent sensors.However,the CDs with deep-red(DR)or near-infrared(NIR)emis...As a type of new carbon-based nanomaterials,carbon dots(CDs)possess exceptional optical properties,making them highly desirable for use in fluorescent sensors.However,the CDs with deep-red(DR)or near-infrared(NIR)emission have rarely been reported.In this work,we prepared deep-red emissive fluorine-doped carbon quantum dots(F-CDs)by introducing a precursor simultaneously containing fluorine and amidogen.The synergistic effect of nitrogen doping and D-π-A pattern production contributed to the maximum emission of F-CDs at 636 nm with an absolute quantum yield of 36.00%±0.68%.Moreover,we designed an F-CDs-based fluorescence assay to determine the content of hypochlorite(ClO^(-)),with a limit of detection(LOD)as low as 15.4 nmol/L,indicating the high sensitivity of F-CDs to ClO^(-).In real samples,the F-CDs-based fluorescent sensor exhibited excellent sensitivity and selectivity in the detection of ClO^(-),with an error below 2%,suggesting their great potential in daily life.In cancer cell imaging,the F-CDs not only demonstrated high sensitivity to ClO^(-)but also exhibited excellent mitochondria targeting,as evidenced by the high Pearson's correlation coefficient(PCC)of 0.93 in colocalization analysis.The work presented here suggests the great potential of replacing commercial dyes with F-CDs for highly specific mitochondria labeling and cell imaging.展开更多
The identification of sex chromosomes is fundamental for exploring the mechanism and evolution of sex determination.Platichthys stellatus,a species exhibiting clear sexual dimorphism and homomorphic chromosome pairs,h...The identification of sex chromosomes is fundamental for exploring the mechanism and evolution of sex determination.Platichthys stellatus,a species exhibiting clear sexual dimorphism and homomorphic chromosome pairs,has received limited research concerning its sex determination mechanisms.Clarifying the sex chromosome of P.stellatus will enhance our understanding of sex chromosome evolution in Pleuronectiformes.This study employed whole-genome resequencing to investigate the sex chromosome and sex determination system in P.stellatus.Notably,Chr23 was identified as the sex chromosome in P.stellatus,with the sex-determining region(SDR)occupying 48.1%of the chromosome and featuring an XX/XY system.Sex chromosome turnover was observed within Pleuronectiformes,with P.stellatus,Verasper variegatus,and Hippoglossus hippoglossus sharing a common ancestral karyotype.No inversions were detected within the SDR of P.stellatus,although chromosomal rearrangements between sex chromosomes and autosomes were identified.Additionally,a sex-specific marker for P.stellatus was ascertained,enabling genetic sex identification,with significant implications for improving breeding programs and aquaculture practices.展开更多
In reptiles,such as the red-eared slider turtle(Trachemys scripta elegans),gonadal sex determination is highly dependent on the environmental temperature during embryonic stages.This complex process,which leads to dif...In reptiles,such as the red-eared slider turtle(Trachemys scripta elegans),gonadal sex determination is highly dependent on the environmental temperature during embryonic stages.This complex process,which leads to differentiation into either testes or ovaries,is governed by the finely tuned expression of upstream genes,notably the testis-promoting gene Dmrt1 and the ovary-promoting gene Foxl2.Recent studies have identified epigenetic regulation as a crucial factor in testis development,with the H3K27me3 demethylase KDM6B being essential for Dmrt1 expression in T.s.elegans.However,whether KDM6B alone can induce testicular differentiation remains unclear.In this study,we found that overexpression of Kdm6b in T.s.elegans embryos induced the male development pathway,accompanied by a rapid increase in the gonadal expression of Dmrt1 at 31°C,a temperature typically resulting in female development.Notably,this sex reversal could be entirely rescued by Dmrt1 knockdown.These findings demonstrate that Kdm6b is sufficient for commitment to the male pathway,underscoring its role as a critical epigenetic regulator in the sex determination of the red-eared slider turtle.展开更多
Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for ang...Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.展开更多
基金the National Natural Science Foundation of China (Nos. U1867205, 21622508, and 21575092)Study on Physical/Chemical Characteristics Related to the Migration of Key Nuclides under Simulated Disposal Conditions (Phase Ⅱ) (Contract No. KGES 2019(170), dated February 21, 2019.) for financial support。
文摘Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample pretreatments due to the isobaric interferences from ^(99)Ru and ^(98)Mo^(1)H. Herein, capillary electrophoresis(CE) was applied as sample introduction system for the sensitive, and interferencefree determination of ^(99)TcO_(4)^(-) from RuO_(4)^(-), and MoO_(4)^(2-) by ICP-MS with a simple sample treatment. Compared to the conventional methods, the hyphenated CE-ICP-MS avoids the use of expensive separation resins and reduces the consumption of mineral acid, representing a simpler, more efficient and environmentally benign approach. Moreover, the proposed method exhibits higher accuracy compared with the mathematical correction method using the natural isotope ratio of ^(99)Ru and ^(101)Ru, and significantly reduces sample consumption and the amount of waste, thus remarkably alleviating the radioactive exposure to operators and the pressure of radioactive waste treatment. Under the optimized conditions, the detection limits of 25 μg/L and 0.06 μg/L were obtained for RuO_(4)^(-) and ReO_(4)^(-)(Tc was replaced by Re), respectively, with relative standard deviation(RSD) lower than 5%. In addition, efficient recoveries of RuO_(4)^(-),ReO_(4)^(-),and ^(99)TcO_(4)^(-) from simulated Hanford site groundwater were achieved. The method is expected to be a promising candidate for sensitive and accurate analysis of ^(99)Tc from contaminated environmental samples.
基金supported by the National Key R&D Program of China 2022YFB2404300the National Natural Science Foundation of China U22B2069the China Postdoctoral Science Foundation 2024M761006。
文摘The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.
文摘Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was thin-layer chromatography scanning(TLCS),using a developing solvent composed of ethyl acetate–methanol–strong ammonia water(17:2:1).The plates were heated at 105°C for 5 minutes,then sprayed with a mixture of dilute bismuth potassium iodide and 1%ferric chloride in ethanol(10:1),and scanned at a wavelength of 500 nm.Results:Peimine showed good linearity in the concentration range of 0.21–2.1μg with a correlation coefficient of r=0.9997,and Peiminine also exhibited good linearity in the same range with r=0.9995.The accuracy was≥95.0%,and the relative standard deviation(RSD)was≤5.0%(n=6).Conclusion:This method allows for the simultaneous determination of peimine and peiminine,providing a reliable reference for the quality control of the product.
基金supported by National Natural Scienc Foundation of China(No.52400097)the Nanqiang Young Talents Supporting Program from Xiamen University.
文摘Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheless,these works predominantly centered on the formation and utilization of hydroxyl radicals(•OH)in the process,neglecting the evolution of oxidant and reductant due to the difficulty in the simultaneous determination of these two components.By employing the quenching-iodometric method,we could simultaneously determine the concentrations of HSO_(3)-and peroxydisulfate(PDS).This method first employed an excess of peroxymonosulfate(PMS)to effectively quench HSO_(3)-,and then used the iodometric spectrophotometry to simultaneously determine the concentrations of PMS and PDS in the reaction system.Finally,through precise stoichiometric relationships,we could accurately calculate the concentration of HSO_(3)-.Based on this method,we achieved concentration measurements that,upon linear fitting,yielded a correlation coefficient(R^(2))surpassing 0.99,unequivocally affirming the method’s accuracy and trustworthiness.In this work,an innovation approach for determining the concentrations of HSO_(3)-(reductant)and PDS(oxidant)was explored.Additionally,the resilience of the method was verified across different pH levels and in the presence of diverse impurity ions.The results ensured precise concentration measure-ments in the real wastewater.This method was characterized by its simplicity,rapid analysis,and environmental friendliness,offering a newanalytical strategy for the determination of PDS and HSO_(3)-in environmental samples.The method enables more meticulous monitoring of chemical usage in water treatment,facilitating optimized dosing strategies and assessments of reductant-enhanced Fenton or Fenton-like system in water purification.
基金supported by the Spark Program of Earthquake Sciences(No.XH23020YA)Joint Open Fund of Mengcheng National Geophysical Observatory(No.MEMGO-202411)Hefei government special technology research project(2024BFFFD02048).
文摘In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupture area and displacement,which are intimately linked to the seismic moment,are hard to derive from paleoseismic studies.Our preceding study identified two earthquake sites in Huoshan and Guzhen,Anhui Province.While we qualitatively described the timing of these occurrences and the characteristics of sand veins,dislocations,and earthquake-induced cracks,we did not provide quantitative estimates of their magnitude or seismogenic faults.Consequently,these findings were insufficient for assessing regional seismic risks or determining the potential magnitude of specific faults.This study employs two empirical relationships:one between the farthest distribution distance based on liquefaction from earthquake-induced events and magnitude,and the other concerning the intensityepicenter distance-magnitude relationship.Through these relationships,we analyze the sandy soil liquefaction and earthquake-induced cracks quantitatively.The analysis includes magnitude estimation and seismogenic fault evaluation for the sandy soil liquefaction and crack remnants of the Huoshan Daijiayuan earthquake,as well as the dislocation and crack remnants of the Guzhen Gaixia earthquake.The findings indicate that the Huoshan Daijiayuan site records two paleoseismic events.The first event transpired after 850 BC,and the second after 550 BC,with a gap of approximately 300 years between them;both had a seismic magnitude(M_(S))of around 6.0.The likely seismogenic fault for the Huoshan Daijiayuan earthquake is the Luoerling-Tudiling fault.Meanwhile,the paleoseismic site in Guzhen Gaixia documents two seismic events occurring during 2350-2050 BC,both with a seismic magnitude(MS)of approximately 6½.The Tancheng-Lujiang fault zone is likely the seismogenic fault associated with the Guzhen Gaixia earthquake site.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(Nos.25202520,15214523)the Fundamental Research Funds for the Central Universities,China(No.YWF-22-L-805)。
文摘Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori attitude information replacing the code measurements to enhance the successful rate for ambiguity resolution.However,there exists a key limitation that this method relies on considerable Monte Carlo sampling particles to construct the pdf of ambiguities,resulting in significant computational burdens.To address this limitation,this paper provides a rapid single-epoch GNSS attitude determination method based on a priori attitude information.It utilizes a second-order Taylor expansion to analytically estimate the covariance of the baseline conditioned on a priori attitude information.This is followed by deriving the float solution and covariance of ambiguities,which are then processed using the standard LAMBDA method for integer ambiguity resolution.Experimental results demonstrate that our method is both efficient and accurate,significantly reducing computational costs compared to previous methods,thereby enhancing its applicability for GNSS-based attitude determination.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(RS-202300243390 and 2020R1A5A1018052)supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(2022R1A3B1078163)supported by the Technology Innovation Program(Publicprivate joint investment semiconductor R&D program[K-CHIPS])to foster high-quality human resources(RS-2023-00235484)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187770)。
文摘This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.
基金supported by the National Natural Science Foundation of China(No.22090041)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2017ZT07C069)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022B1515120014)the Natural Science Foundation of Zhejiang Province(No.LQ21A040010).
文摘The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.
文摘Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.
基金Supported by Provincial University Scientific Research Platform Team Project of Guizhou Provincial Department of Education(Qianjiaoji[2022]No.010).
文摘[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)with ShimNex CS C 18 as the column;column temperature:35℃;wavelength:270 nm;methanol-0.1%phosphoric acid solution as the mobile phase with gradient elution.[Results]The 12 components of the retention of Longqing Capsule showed good linearity within the investigated range(r≥0.9995),with the average spiked recoveries of 97.83%-100.52%and the RSD of 0.9%-2.1%.[Conclusions]The method is exclusive,sensitive,reproducible,simple and easy to use,and can provide a reference for the construction of the quality standard and control system of Longqing Capsule based on the theory of traditional Chinese medicine.
基金supported by Jiangsu Province Fron-tier Leading Technology Basic Research Project(BK20222013)partly supported by National Natural Science Foundation of China(No.62101251)+1 种基金Fundamental Research Funds for the Central Universities(No.NS20240240)partly supported by Post-graduate Research&Practice Innovation Program of NUAA(No.016001)。
文摘The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current research is focused on Doppler positioning techniques,which require the collaboration of multiple satellites(≥3).However,the dynamic changes of LEO satellites weaken the generalization ability of Doppler positioning.In this paper,a direct position determination(DPD)method with uniform circular array(UCA)is proposed for UAV positioning from the perspective of the spatial spectrum estimation of LEO-SOPs.The proposed method employs the orthogonality between the signal and noise subspaces of the covariance matrix of the different received SOPs to establish the cost function for UAV’s coordinate.Instead of the multiple dimen-sional search,a root mean square propagation(RM-SProp)gradient optimizer with an adaptive learning rate is developed to find the coordinate of UAV.The effectiveness and robustness of the proposed method are verified using numerical data generated from the systems tool kit(STK).
文摘Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific approach has been a successful strategy for survival of a large variety of species including humans, the fidelity of sex determination leading to 100% cis-binary outcomes is not achieved in many species, with evidence for homosexual or bisexual behaviour evident in more than 1500 species. Thus, such outcomes indicates that sex determination is a multi-step process and not a single event, and as such, could lead to the appearance of variants during the process which developed much earlier than humans. Variants could arise either due to intrinsic variation in the steps of determination, or also be influenced by environmental factors of a biological or psychological nature. In contrast to homosexual variants which do not require interventions such as hormone therapy or surgery, expression of gender dysphoria, is more based in psychology, but also has biological underpinnings and can be influenced by such hormonal interventions and surgery. While the numbers of those with gender dysphoria is small (~0.6% - 1.0% of population), the attention given to this issue raises the possibility of biological and psychological environmental factors impacting the emergence of some of those expressing gender dysphoria. Furthermore, transitioning from male-to-female or female-to-male can have consequences regarding disease risks latter in life, including the appearance of autoimmune diseases. This review will attempt to review some of the evidence regarding sex determination, discuss why the system has potentially not been improved upon during evolution, how a potential role for sex chromosome function on neurodevelopment may be central to variation in humans, and how commitment to the current strategy is likely integrated into other sex-related events such as puberty, pregnancy, and menopause to ensure species survival. It will also discuss how variants in sex determination could contribute to sex differences in disease risk and how epigenetic modifications could play a role in such risk. .
基金supported by the Fundamental Research Funds of the Institute of Earthquake Predic-tion, China Earthquake Administration (2023IESLZ04)the Gansu Provincial Key Talent Project。
文摘In this study, we swiftly determined the focal parameters(focal mechanism, seismic imaging process, magnitude)of the Jishishan earthquake, leveraging a solved fault model to assess the intensity field and casualties promptly.The investigation began by retrieving the source mechanism through the P-wave initial motion and W-phase method. This enabled us to chart the spatial and temporal distribution of energy release in the source area via the back-projection technique. Following this, we estimated the earthquake's intensity field by merging the source inversion findings with the ground motion prediction equation. This analysis facilitated the evaluation of earthquake casualties, utilizing the theoretical intensity field and a casualty assessment model. Our findings indicate that the fault type is a thrust fault, characterized by a unilateral rupture in the direction of NW, with a rupture length spanning approximately 10–15 km and a duration ranging between 8 and 10 s. The earthquake's magnitude varied from M 5.9 to M 6.2. The demarcated high-intensity areas, as per our intensity assessment, align closely with the actual survey results. Furthermore, the predicted total casualties and identified critical rescue zones closely match the real-world casualty figures. These insights offer crucial technical support for governmental emergency command and rescue operations.
基金supported by the Na⁃tional Natural Science Foundation of China(No.62373125).
文摘Once a satellite experiences extreme abnormal conditions,it may face serious consequences such as structural damages,material low-temperature failures,propellant freezing,and even whole satellite failures if it is not rescued in time.Therefore,it is significantly important to study emergency recovery technologies for satellites.The research progress on attitude determination and control technologies during satellite emergency recovery is reviewed in detail.Moreover,the research achievements in the design and implementation of satellite emergency modes are summarized.By synthesizing and analyzing relevant literature,this paper aims to provide reference and guidance for emergency recovery technologies in response to extremely abnormal satellite states.
基金supported by the Hainan Provincial Natural Science Foundation of China(321CXTD435)the National Natural Science Foundation of China(31860523,31660339,31702059,and 32260665)the National Key R&D Program of China(2022YFC2601400)。
文摘transformer is a switch gene for sex determination in many insects, which cooperates with transformer-2 that is expressed in both sexes to regulate female differentiation, particularly in dipterans. Zeugodacus cucurbitae(Coquillett) is a very destructive pest worldwide, however, its sex determination pathway remains largely uncharacterized. Here, we show that the female sex ratio is sharply reduced with knockdown of either transformer or transformer-2 by RNA interference in early embryos of Z. cucurbitae. Most of the males grown from the embryos with transient transformer and transformer-2 suppression mated with wild-type females and produced mixed sex progeny, with one exception that produced only female progeny, and all of the few remaining males failed to mate with wild-type females and produced no progeny. The exceptional male and those males with mating failure were XX pseudomales as determined by the detection of Y chromosome-linked Maleness-on-the-Y, indicating that most XX pseudomales are not viable. The phenotypes of transformer and transformer-2 suggest that they play a key role in regulating sex determination and are required for female sexual development of Z. cucurbitae. Our results will be beneficial to the understanding of sex determination in Z. cucurbitae and can facilitate the development of genetic sexing strains for its biological control.
基金supported by the National Natural Science Foundation of China(Nos.82222035 and 81602489)the Guangdong Basic and Applied Basic Research Foundation(Nos.2021A1515111036 and 2022A1515110308)+1 种基金the Medical Scientific Research Foundation of Guangdong Province of China(No.A2023274)the Basic Research Program of Shenzhen Innovation Council(No.JCYJ20210324105609024)。
文摘As a type of new carbon-based nanomaterials,carbon dots(CDs)possess exceptional optical properties,making them highly desirable for use in fluorescent sensors.However,the CDs with deep-red(DR)or near-infrared(NIR)emission have rarely been reported.In this work,we prepared deep-red emissive fluorine-doped carbon quantum dots(F-CDs)by introducing a precursor simultaneously containing fluorine and amidogen.The synergistic effect of nitrogen doping and D-π-A pattern production contributed to the maximum emission of F-CDs at 636 nm with an absolute quantum yield of 36.00%±0.68%.Moreover,we designed an F-CDs-based fluorescence assay to determine the content of hypochlorite(ClO^(-)),with a limit of detection(LOD)as low as 15.4 nmol/L,indicating the high sensitivity of F-CDs to ClO^(-).In real samples,the F-CDs-based fluorescent sensor exhibited excellent sensitivity and selectivity in the detection of ClO^(-),with an error below 2%,suggesting their great potential in daily life.In cancer cell imaging,the F-CDs not only demonstrated high sensitivity to ClO^(-)but also exhibited excellent mitochondria targeting,as evidenced by the high Pearson's correlation coefficient(PCC)of 0.93 in colocalization analysis.The work presented here suggests the great potential of replacing commercial dyes with F-CDs for highly specific mitochondria labeling and cell imaging.
基金supported by the National Key Research and Development Program of China(2022YFD2400100)National Natural Science Foundation of Shandong Province of China(ZR2023QC006)National Natural Science Foundation of China(32403053)。
文摘The identification of sex chromosomes is fundamental for exploring the mechanism and evolution of sex determination.Platichthys stellatus,a species exhibiting clear sexual dimorphism and homomorphic chromosome pairs,has received limited research concerning its sex determination mechanisms.Clarifying the sex chromosome of P.stellatus will enhance our understanding of sex chromosome evolution in Pleuronectiformes.This study employed whole-genome resequencing to investigate the sex chromosome and sex determination system in P.stellatus.Notably,Chr23 was identified as the sex chromosome in P.stellatus,with the sex-determining region(SDR)occupying 48.1%of the chromosome and featuring an XX/XY system.Sex chromosome turnover was observed within Pleuronectiformes,with P.stellatus,Verasper variegatus,and Hippoglossus hippoglossus sharing a common ancestral karyotype.No inversions were detected within the SDR of P.stellatus,although chromosomal rearrangements between sex chromosomes and autosomes were identified.Additionally,a sex-specific marker for P.stellatus was ascertained,enabling genetic sex identification,with significant implications for improving breeding programs and aquaculture practices.
基金supported by the National Natural Science Foundation of China(32325049,U22A20529,32303000)Zhejiang Provincial Natural Science Foundation(LQ24C190009)+1 种基金Ningbo Natural Science Foundation(2022J192)Zhejiang Provincial Top Key Discipline of Biological Engineering(1741000592)。
文摘In reptiles,such as the red-eared slider turtle(Trachemys scripta elegans),gonadal sex determination is highly dependent on the environmental temperature during embryonic stages.This complex process,which leads to differentiation into either testes or ovaries,is governed by the finely tuned expression of upstream genes,notably the testis-promoting gene Dmrt1 and the ovary-promoting gene Foxl2.Recent studies have identified epigenetic regulation as a crucial factor in testis development,with the H3K27me3 demethylase KDM6B being essential for Dmrt1 expression in T.s.elegans.However,whether KDM6B alone can induce testicular differentiation remains unclear.In this study,we found that overexpression of Kdm6b in T.s.elegans embryos induced the male development pathway,accompanied by a rapid increase in the gonadal expression of Dmrt1 at 31°C,a temperature typically resulting in female development.Notably,this sex reversal could be entirely rescued by Dmrt1 knockdown.These findings demonstrate that Kdm6b is sufficient for commitment to the male pathway,underscoring its role as a critical epigenetic regulator in the sex determination of the red-eared slider turtle.
基金supported by the National Natural Science Foundation of China (12272168)the Foundation of Science and Technology on Space Intelligent Control Laboratory (HTKJ2023KL502015)。
文摘Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.
