Weighted total least squares(WTLS)have been regarded as the standard tool for the errors-in-variables(EIV)model in which all the elements in the observation vector and the coefficient matrix are contaminated with rand...Weighted total least squares(WTLS)have been regarded as the standard tool for the errors-in-variables(EIV)model in which all the elements in the observation vector and the coefficient matrix are contaminated with random errors.However,in many geodetic applications,some elements are error-free and some random observations appear repeatedly in different positions in the augmented coefficient matrix.It is called the linear structured EIV(LSEIV)model.Two kinds of methods are proposed for the LSEIV model from functional and stochastic modifications.On the one hand,the functional part of the LSEIV model is modified into the errors-in-observations(EIO)model.On the other hand,the stochastic model is modified by applying the Moore-Penrose inverse of the cofactor matrix.The algorithms are derived through the Lagrange multipliers method and linear approximation.The estimation principles and iterative formula of the parameters are proven to be consistent.The first-order approximate variance-covariance matrix(VCM)of the parameters is also derived.A numerical example is given to compare the performances of our proposed three algorithms with the STLS approach.Afterwards,the least squares(LS),total least squares(TLS)and linear structured weighted total least squares(LSWTLS)solutions are compared and the accuracy evaluation formula is proven to be feasible and effective.Finally,the LSWTLS is applied to the field of deformation analysis,which yields a better result than the traditional LS and TLS estimations.展开更多
Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represente...Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,respectively.After in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning microscope.Effects of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA sequencing.All the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty acids.The MD 5s group exhibited higher α-diversity than the MD 0s and 60s groups.Abundances of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s group.These bacteria were also positively correlated with the SCFAs production via Spearman correlation analysis.In vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.展开更多
BACKGROUND Although the etiology of nonalcoholic fatty liver disease(NAFLD)has not been thoroughly understood,the emerging roles of anthropometric indicators in assessing and predicting the risk of NAFLD have been hig...BACKGROUND Although the etiology of nonalcoholic fatty liver disease(NAFLD)has not been thoroughly understood,the emerging roles of anthropometric indicators in assessing and predicting the risk of NAFLD have been highlighted by accumulating evidence.AIM To evaluate the causal relationships between five anthropometric indicators and NAFLD employing Mendelian randomization(MR)design.METHODS The Anthropometric Consortium provided genetic exposure data for five anthropometric indicators,including hip circumference(HC),waist circumference(WC),waist-to-hip ratio(WHR),body mass index(BMI),and body fat percentage(BF).Genetic outcome data for NAFLD were obtained from the United Kingdom Biobank and FinnGen Consortium.Genome-wide significant single nucleotide polymorphisms were chosen as instrumental variables.Univariable MR(UVMR)and multivariable MR(MVMR)designs with analytical approaches,including inverse variance weighted(IVW),MR-Egger,weighted median(WM),and weighted mode methods,were used to assess the causal relationships between anthropometric indicators and NAFLD.RESULTS Causal relationships were revealed by UVMR,indicating that a higher risk of NAFLD was associated with a perunit increase in WC[IVW:odds ratio(OR)=2.67,95%CI:1.42-5.02,P=2.25×10^(−3)],and BF was causally associated with an increased risk of NAFLD(WM:OR=2.23,95%CI:1.07-4.66,P=0.033).The presence of causal effects of WC on the decreased risk of NAFLD was supported by MVMR after adjusting for BMI and smoking.However,no causal association between BF and NAFLD was observed.In addition,other causal relationships of HC,WHR(BMI adjusted),and BMI with the risk of NAFLD were not retained after FDR correction.CONCLUSION This study establishes a causal relationship,indicating that an increase in WC is associated with a higher risk of NAFLD.This demonstrates that a suitable decrease in WC is advantageous for preventing NAFLD.展开更多
Objective:This paper aims to compare the effect of skin staple suture and traditional silk suture in scalp suture surgery.Methods:A total of 80 craniocerebral surgery patients were included in this study,and the patie...Objective:This paper aims to compare the effect of skin staple suture and traditional silk suture in scalp suture surgery.Methods:A total of 80 craniocerebral surgery patients were included in this study,and the patients were randomly divided into observation group and control group,with 40 cases in each group.The observation group used disposable skin stapler to suture the scalp incision,and the control group used conventional silk suture to suture the incision.Statistical analysis was carried out on 6 indicators including suturing speed,healing under-scab,incision necrosis,incision cerebrospinal fluid(CSF)leakage,incision infection,and postoperative“centipede-shaped”scar incidence rate of the two suture methods.Results:There was no significant difference between the groups in terms of postoperative healing under-scab,incision necrosis,incision CSF leakage,and intracranial infection(P>0.05).The suturing speed in the observation group was 15.2±0.7 cm/min,which was significantly faster than 7.4±0.3 cm/min in the control group(P<0.05).The incidence of“centipede-shaped”scars in the observation group was significantly lower than that in the control group at 1 to 6 months after operation(P<0.05).Conclusion:Compared with traditional silk suture,skin staple suture has obvious advantages in suture speed and cosmetic effect.展开更多
Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of o...Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of only 372 mAh·g?1,which cannot meet the everincreasing demand of LIBs for high energy density.Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites.Synthesis of nanoscale Si in a facile,cost-effective way,however,still poses a great challenge.In this work,nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source.It was found that the nanoscale Si prepared under optimized conditions(800°C,10 h)can deliver a high initial specific capacity(3053 mAh·g?1 on discharge,2519 mAh·g?1 on charge)with a high first coulombic efficiency(82.5%).When using sand-milled diatomite as a precursor,the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency(85.6%).The Si–C(Si:graphite=1:7 in weight)composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 mAh·g?1 at 100 mA·g?1),good rate capability(587 mAh·g?1 at 500 mA·g?1),and a long cycle life(480 mAh·g?1 after 200 cycles at 500 mA·g?1).This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.展开更多
A binder-free Ni_3S_2 electrode was prepared directly on a graphene-coated Ni foam(G/Ni) substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni_3S_2 showed a flower-l...A binder-free Ni_3S_2 electrode was prepared directly on a graphene-coated Ni foam(G/Ni) substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni_3S_2 showed a flower-like morphology and was uniformly distributed on the G/Ni surface. The flower-like Ni_3S_2 was composed of cross-arrayed nanoflakes with a diameter and a thickness of 1-2 μm and ~50 nm, respectively. The free space in the flowers and the thin feature of Ni_3S_2 buffered the volume changes and relieved mechanical strain during repeated cycling. The intimate contact with the Ni substrate and the fixing effect of graphene maintained the structural stability of the Ni_3S_2 electrode during cycling. The G/Ni-supported Ni_3S_2 maintained a reversible capacity of 250 mAh·g^(-1) after 100 cycles at 50 mAh^(-1), demonstrating the good cycling stability as a result of the unique microstructure of this electrode material.展开更多
Olivine-structured pure LiFePO4 and doped Li(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate tha...Olivine-structured pure LiFePO4 and doped Li(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate that the as-prepared LiFePO4 is well-crystallized nanopowders without any detectable impurity phases. The electronic conductivity of LiFePO4 is enhanced by around 1-3 orders by doping. It was found that doping alone is not suffcient for the high-rate performance of LiFePO4 and surface coating with such as carbon should be needed. The best dopant for LiFePO4 is Nd among those studied in the present work. Accordingly, doping with 1 mol fraction Nd leads to an increase in 70 mAh/g at 0.1 C for the hydrothermally synthesized sample and 50 mAh/g at 1.0 C after carbon-coating in comparison with the undoped samples.展开更多
At present,the principal data processing methods involving complex observations are based on two strategies according to characteristics of the observation process,i.e.,step-by-step and direct resolution.However,these...At present,the principal data processing methods involving complex observations are based on two strategies according to characteristics of the observation process,i.e.,step-by-step and direct resolution.However,these strategies have some limitations,e.g.they cannot consider statistical observation error information,redundant observations and so on.This paper applies least squares methods to complex data processing to extend surveying adjustment theory from real to complex number space.We compared the two adjustment criteria for a complex domain in a quantitative way.In order to understand the effectiveness of complex least squares,tree height inversion from PolInSAR data is taken as an example.We firstly established both a complex adjustment function model and a stochastic model for PolInSAR tree height inversion,and then applied the complex least squares method to estimate tree height.Results show that the complex least squares approach is reliable and outperforms other classic tree height retrieval methods;the method is simple and easy to implement.展开更多
Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondar...Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries were investigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materials. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemical impedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.展开更多
Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrol...Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrolyte and electrodes causes continuous performance degradation.Here,we report a unique design of a double-layer composite solid-state electrolyte(D-CSE),where each layer,composed of both polymer and ceramics,is electrochemically compatible with its contacting electrode(Li anode or LiCoO_(2)cathode).The D-CSE has a small thickness(50μm),high thermal stability(up to 160℃ without noticeable deformation),and good flexibility even at a high ceramics content(66.7 wt%).Large-area selfstanding film can be obtained by a facile coating route.The electrolyte/electrode interface can be further enhanced via forming a soft interface by in-situ polymerization.Quasi-solid-state Li|D-CSE|LiCoO_(2)coin cells with the cathode-supported D-CSE can deliver a high initial discharge capacity of 134 mAh g^(-1) and a high capacity retention of 83%after 200 cycles at 0.5 C and 60℃.Quasi-solid-state Li|D-CSE|LiCoO_(2)pouch cells(designed capacity 8.6 mAh)with the self-standing D-CSE have a high retention of80%after 180 cycles at 2 mA charge and 4 mA discharge.At a high cathode loading(19.1 mg cm^(-2)),the Li|D-CSE|LiCoO_(2)pouch cell still can be stably cycled,and can withstand abuse tests of folding,cutting and nail penetration,indicating practical applications of the D-CSE.展开更多
Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metall...Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling,while a facile method to solve this issue is still lacking.In this work,we report an effective,environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable,NaF-rich solid electrolyte interface(SEI)layer on metallic Na via adding a small amount(~3 wt%)of fluorinated graphene(FG)in bulk Na.Inspired by the forging processing,a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes.The Na/FG–Na/FG half cell exhibits a low voltage hysteresis of 110–140 mV over 700 h at a current density up to 5 mA cm^(-2) with an areal capacity as high as 5 mAh cm^(-2).Na–CO_(2) full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g^(-1).Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na.Both experiments and density functional theory(DFT)calculations confirm the formation of the NaF-rich SEI layer.The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.展开更多
A three-dimensional viscous code has been developed to solve Reynolds-averaged Navier-Stokes equations. The governing equations in finite volume form are solved by two-step Runge-Kutta scheme with implicit residual sm...A three-dimensional viscous code has been developed to solve Reynolds-averaged Navier-Stokes equations. The governing equations in finite volume form are solved by two-step Runge-Kutta scheme with implicit residual smoothing. The eddy viscous is obtained using the Baldwin-Lomax model. A prediction of the 3-D turbulent flow and the performance in the “all-over controlled vortex distribution” centrifugal impeller with a vaneless diffuser has been made for the compressor at design and off-design condition. The predicted effi-ciency is a little higher than the experiment data. These results suggest that the present calculation code is able to determine the flow development in the impeller and also the turbulence model in the centrifugal im-peller should be improved.展开更多
Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate c...Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate change and pollution of water bodies are putting increasing pressure on these resources. In this context, understanding the contribution of water to the economy and environment is crucial for its conservation. To meet this need, the World Bank launched a program aiming at improving valuation and accounting systems of natural resources in Turkey. As part of this program, this article estimates in monetary terms the economic value of water in Bey?ehir Lake, the largest freshwater lake in Turkey. Valuation is based on the Total Economic Value concept, which includes use and non-use values. The results show that the economic value of water is about seven times higher than its financial value. In addition, the economic value of water allocated for municipal use (TL5/m<sup>3</sup>) is substantially greater than that supplied for irrigation (TL0.5/m<sup>3</sup>). The analysis suggests that allocation of water from Bey?ehir Lake among different uses is inefficient. To validate this conclusion and improve allocation, a more comprehensive assessment of the economic benefits of water resources is needed, particularly of water supply for irrigation, municipal use, recreation and biodiversity. The analysis also indicates that economic valuation can be a powerful tool to improve water management at the river basin level.展开更多
Efficient adsorption of gaseous radioiodine is pivotal for the sustainable development of nuclear energy and the long-termradiation safety of the ecological system.However,state-of-the-art adsorbents(e.g.metal-organic...Efficient adsorption of gaseous radioiodine is pivotal for the sustainable development of nuclear energy and the long-termradiation safety of the ecological system.However,state-of-the-art adsorbents(e.g.metal-organic frameworks and covalent-organic frameworks)currently under exploration suffer severely from limited adsorption capacity,especially under a real-world scenariowith extremely lowradioiodine concentration and elevated temperature.This mostly originates from the relatively weak sorption driving forces mainly determinedby the iodine-adsorbent interaction consistingof noncovalent interactionswith a small fraction of strong chemical bonding.Here,we document the discovery of an open metal-sulfide framework((NH_(4))_(2)(Sn_(3)S_(7)),donated as SCU-SnS)constructed by three different types of active sites as a superior iodine adsorbent.Benefiting from the ability of iodine for pre-enrichment into the framework by charge-balancing NH_(4)^(+)through N-H···I interaction,the efficient reduction of I^(2)affording I^(-)by S^(2-),and extremely high binding affinity between Sn_(4)^(+)and I^(-),SCU-SnS exhibit a record-breaking iodine adsorption capacity(2.12 g/g)under dynamic breakthrough conditions and the highest static capacity(6.12 g/g)among all reported inorganic adsorbents,both at 348 K.Its facile synthesis and low cost endow SCU-SnS with powerful application potential for the nuclear industry.展开更多
To the Editor:A 35-year-old man who smoked for 15 years suffered from chest pain 12 days ago before admission.He was diagnosed as myocardial infarction.Thrombolytic therapy was given consequently.The electrocardiogram...To the Editor:A 35-year-old man who smoked for 15 years suffered from chest pain 12 days ago before admission.He was diagnosed as myocardial infarction.Thrombolytic therapy was given consequently.The electrocardiogram showed sub-acute inferior wall myocardial infarction.Echocardiogram showed attenuated constriction of the inferior wall with an ejection fraction of 59％.On September 5,2013,he was treated with a XINSORB scaffold in right coronary artery (RCA).展开更多
Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3...Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOFs)包覆的FeOOH(FeOOH@MIL-100(Fe))作为前驱体和自牺牲模板,通过高温热处理制备得到一种能良好继承前驱体形貌的中空海胆状碳包覆的Fe2O3(Fe2O3@MOFC)复合材料.在热处理过程中,外部的MOF层很好地保护了内部Fe2O3结构的完整性,并以原位转化的方式衍生为均匀分布在纳米粒子外部的碳涂层.在0.1 Ag^-1的电流密度下,Fe2O3@MOFC可提供高达1366.9 mA hg^-1的初始放电容量,且充放电循环200次后,仍能保持大约1551.3 mA hg^-1的高放电容量.在1 Ag^-1的高电流密度下循环300次后,其比容量仍可保持在1208.6 mA hg^-1.展开更多
有机醌类化合物因其具有高的理论容量值而引起了人们的广泛关注.本文合成了一种新型的环状大分子Calix[6]quinone(C6Q),它由6个对苯醌单元组成,可提供12个电化学位点,是一种极具发展前景的锂离子正极材料.C6Q在0.1 C的电流密度下展示了...有机醌类化合物因其具有高的理论容量值而引起了人们的广泛关注.本文合成了一种新型的环状大分子Calix[6]quinone(C6Q),它由6个对苯醌单元组成,可提供12个电化学位点,是一种极具发展前景的锂离子正极材料.C6Q在0.1 C的电流密度下展示了高达423 mA h g^-1的初始放电比容量(理论放电比容量为447 mA h g^-1).经过100圈充放电循环之后,它的容量保持在216 mA h g^-1;经过300次循环之后,仍然拥有195 mA h g^-1的高容量.C6Q具有高容量和宽的电化学窗口,因此可以提供高达1201 W h kg^-1的能量密度.此外,使用有序介孔碳CMK-3固载C6Q的方法可以进一步提高C6Q的电化学性能.展开更多
In this work, a facile, one-pot route has been applied to synthesize nanohybrids based on mixed oxide Ni Fe2O4 and reduced graphene oxide(r GO). The hybrid is constructed by nanosized Ni Fe2O4 crystals confined by few...In this work, a facile, one-pot route has been applied to synthesize nanohybrids based on mixed oxide Ni Fe2O4 and reduced graphene oxide(r GO). The hybrid is constructed by nanosized Ni Fe2O4 crystals confined by fewlayered r GO sheets. The formation mechanism and microstructure of the hybrids have been clarified by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy.Electrochemical tests show that the performance of Ni Fe2O4 can be considerably improved by r GO incorporation. The performance improvement can be attributed to the two-dimensional conductive channels and the unique hybrid structure r GO constructed. The easy synthesis and good electrochemical performance of Ni Fe2O4/r GO hybrid make it a promising anode material for Li-ion batteries.展开更多
Nano structured LiFexMn1-xPO4(x=0,0.2,0.4) materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were c...Nano structured LiFexMn1-xPO4(x=0,0.2,0.4) materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO 4 could be largely increased by Fe2+ substitution. At a current rate of C/20, the capacity of the three samples (x=0,0.2,0.4) were 47, 107 and 150 mA·h·g-1 , respectively. CV result showed that the Fe2+ substitution could decrease the polarization during charging/discharging, accelerating the electrochemical process. EIS result showed that the Fe2+ substitution could decrease the charge transfer resistance between the electrode and electrolyte,展开更多
基金the financial support of the National Natural Science Foundation of China(Grant No.42074016,42104025,42274057and 41704007)Hunan Provincial Natural Science Foundation of China(Grant No.2021JJ30244)Scientific Research Fund of Hunan Provincial Education Department(Grant No.22B0496)。
文摘Weighted total least squares(WTLS)have been regarded as the standard tool for the errors-in-variables(EIV)model in which all the elements in the observation vector and the coefficient matrix are contaminated with random errors.However,in many geodetic applications,some elements are error-free and some random observations appear repeatedly in different positions in the augmented coefficient matrix.It is called the linear structured EIV(LSEIV)model.Two kinds of methods are proposed for the LSEIV model from functional and stochastic modifications.On the one hand,the functional part of the LSEIV model is modified into the errors-in-observations(EIO)model.On the other hand,the stochastic model is modified by applying the Moore-Penrose inverse of the cofactor matrix.The algorithms are derived through the Lagrange multipliers method and linear approximation.The estimation principles and iterative formula of the parameters are proven to be consistent.The first-order approximate variance-covariance matrix(VCM)of the parameters is also derived.A numerical example is given to compare the performances of our proposed three algorithms with the STLS approach.Afterwards,the least squares(LS),total least squares(TLS)and linear structured weighted total least squares(LSWTLS)solutions are compared and the accuracy evaluation formula is proven to be feasible and effective.Finally,the LSWTLS is applied to the field of deformation analysis,which yields a better result than the traditional LS and TLS estimations.
基金supported by the National Natural Science Foundation of China (32202051)the Shanghai Sailing Program (21YF1431800, 20YF1433400)+1 种基金Shanghai Agriculture Applied Technology Development Program, China (2021-02-08-0012-F00780 )the National Key R&D Program of China (2022YFF1100104, 2023YFF1103404)。
文摘Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,respectively.After in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning microscope.Effects of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA sequencing.All the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty acids.The MD 5s group exhibited higher α-diversity than the MD 0s and 60s groups.Abundances of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s group.These bacteria were also positively correlated with the SCFAs production via Spearman correlation analysis.In vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.
基金Supported by Science and Technology Research Project of Sichuan Administration of Traditional Chinese Medicine,No.2023MS419.
文摘BACKGROUND Although the etiology of nonalcoholic fatty liver disease(NAFLD)has not been thoroughly understood,the emerging roles of anthropometric indicators in assessing and predicting the risk of NAFLD have been highlighted by accumulating evidence.AIM To evaluate the causal relationships between five anthropometric indicators and NAFLD employing Mendelian randomization(MR)design.METHODS The Anthropometric Consortium provided genetic exposure data for five anthropometric indicators,including hip circumference(HC),waist circumference(WC),waist-to-hip ratio(WHR),body mass index(BMI),and body fat percentage(BF).Genetic outcome data for NAFLD were obtained from the United Kingdom Biobank and FinnGen Consortium.Genome-wide significant single nucleotide polymorphisms were chosen as instrumental variables.Univariable MR(UVMR)and multivariable MR(MVMR)designs with analytical approaches,including inverse variance weighted(IVW),MR-Egger,weighted median(WM),and weighted mode methods,were used to assess the causal relationships between anthropometric indicators and NAFLD.RESULTS Causal relationships were revealed by UVMR,indicating that a higher risk of NAFLD was associated with a perunit increase in WC[IVW:odds ratio(OR)=2.67,95%CI:1.42-5.02,P=2.25×10^(−3)],and BF was causally associated with an increased risk of NAFLD(WM:OR=2.23,95%CI:1.07-4.66,P=0.033).The presence of causal effects of WC on the decreased risk of NAFLD was supported by MVMR after adjusting for BMI and smoking.However,no causal association between BF and NAFLD was observed.In addition,other causal relationships of HC,WHR(BMI adjusted),and BMI with the risk of NAFLD were not retained after FDR correction.CONCLUSION This study establishes a causal relationship,indicating that an increase in WC is associated with a higher risk of NAFLD.This demonstrates that a suitable decrease in WC is advantageous for preventing NAFLD.
文摘Objective:This paper aims to compare the effect of skin staple suture and traditional silk suture in scalp suture surgery.Methods:A total of 80 craniocerebral surgery patients were included in this study,and the patients were randomly divided into observation group and control group,with 40 cases in each group.The observation group used disposable skin stapler to suture the scalp incision,and the control group used conventional silk suture to suture the incision.Statistical analysis was carried out on 6 indicators including suturing speed,healing under-scab,incision necrosis,incision cerebrospinal fluid(CSF)leakage,incision infection,and postoperative“centipede-shaped”scar incidence rate of the two suture methods.Results:There was no significant difference between the groups in terms of postoperative healing under-scab,incision necrosis,incision CSF leakage,and intracranial infection(P>0.05).The suturing speed in the observation group was 15.2±0.7 cm/min,which was significantly faster than 7.4±0.3 cm/min in the control group(P<0.05).The incidence of“centipede-shaped”scars in the observation group was significantly lower than that in the control group at 1 to 6 months after operation(P<0.05).Conclusion:Compared with traditional silk suture,skin staple suture has obvious advantages in suture speed and cosmetic effect.
基金the National Natural Science Foundation of China(No.51572238)Zhejiang Provincial Natural Science Foundation(No.LY19E020013)the Joint Research Project of Zhejiang University with Zotye Automobile Corporation Limited on Si-Based Anode Materials(No.P-ZH-2018-003).
文摘Li-ion batteries(LIBs)have demonstrated great promise in electric vehicles and hybrid electric vehicles.However,commercial graphite materials,the current predominant anodes in LIBs,have a low theoretical capacity of only 372 mAh·g?1,which cannot meet the everincreasing demand of LIBs for high energy density.Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites.Synthesis of nanoscale Si in a facile,cost-effective way,however,still poses a great challenge.In this work,nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source.It was found that the nanoscale Si prepared under optimized conditions(800°C,10 h)can deliver a high initial specific capacity(3053 mAh·g?1 on discharge,2519 mAh·g?1 on charge)with a high first coulombic efficiency(82.5%).When using sand-milled diatomite as a precursor,the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency(85.6%).The Si–C(Si:graphite=1:7 in weight)composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 mAh·g?1 at 100 mA·g?1),good rate capability(587 mAh·g?1 at 500 mA·g?1),and a long cycle life(480 mAh·g?1 after 200 cycles at 500 mA·g?1).This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.
基金financially supported by the Scientific and Technological Project of State Grid Corporation of China
文摘A binder-free Ni_3S_2 electrode was prepared directly on a graphene-coated Ni foam(G/Ni) substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni_3S_2 showed a flower-like morphology and was uniformly distributed on the G/Ni surface. The flower-like Ni_3S_2 was composed of cross-arrayed nanoflakes with a diameter and a thickness of 1-2 μm and ~50 nm, respectively. The free space in the flowers and the thin feature of Ni_3S_2 buffered the volume changes and relieved mechanical strain during repeated cycling. The intimate contact with the Ni substrate and the fixing effect of graphene maintained the structural stability of the Ni_3S_2 electrode during cycling. The G/Ni-supported Ni_3S_2 maintained a reversible capacity of 250 mAh·g^(-1) after 100 cycles at 50 mAh^(-1), demonstrating the good cycling stability as a result of the unique microstructure of this electrode material.
基金supported by the Science-Technology Foundation of Zhejiang Province under grant No.2007C21100
文摘Olivine-structured pure LiFePO4 and doped Li(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate that the as-prepared LiFePO4 is well-crystallized nanopowders without any detectable impurity phases. The electronic conductivity of LiFePO4 is enhanced by around 1-3 orders by doping. It was found that doping alone is not suffcient for the high-rate performance of LiFePO4 and surface coating with such as carbon should be needed. The best dopant for LiFePO4 is Nd among those studied in the present work. Accordingly, doping with 1 mol fraction Nd leads to an increase in 70 mAh/g at 0.1 C for the hydrothermally synthesized sample and 50 mAh/g at 1.0 C after carbon-coating in comparison with the undoped samples.
基金The National Natural Science Foundation of China(41274010,40974007,40901172)National Key Basic Research and Development Program of China(2012AA121301)+2 种基金Hunan Provincial Natural Science Foundation of China(12JJ4035)Postgraduate Autonomous Exploration Project of Central South University(2013zzts055)China Scholarship Council(201406370079).
文摘At present,the principal data processing methods involving complex observations are based on two strategies according to characteristics of the observation process,i.e.,step-by-step and direct resolution.However,these strategies have some limitations,e.g.they cannot consider statistical observation error information,redundant observations and so on.This paper applies least squares methods to complex data processing to extend surveying adjustment theory from real to complex number space.We compared the two adjustment criteria for a complex domain in a quantitative way.In order to understand the effectiveness of complex least squares,tree height inversion from PolInSAR data is taken as an example.We firstly established both a complex adjustment function model and a stochastic model for PolInSAR tree height inversion,and then applied the complex least squares method to estimate tree height.Results show that the complex least squares approach is reliable and outperforms other classic tree height retrieval methods;the method is simple and easy to implement.
基金This work is supported by the N ational Natural Science Foundation of China(No.50201014)RFDP of the Education Ministry of China(No.20010335045).
文摘Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries were investigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materials. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemical impedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.
基金supported by the National Natural Science Foundation of China(Grant No.51572238,51725102)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY19E020013)Hunan Provincial Science and Technology Major Project of China(Grant Nos.2020GK1014,2021GK2018)。
文摘Solid-state lithium metal batteries are promising next-generation batteries for both micro-scale integrated electronic devices and macro-scale electric vehicles.However,electrochemical incompatibility between electrolyte and electrodes causes continuous performance degradation.Here,we report a unique design of a double-layer composite solid-state electrolyte(D-CSE),where each layer,composed of both polymer and ceramics,is electrochemically compatible with its contacting electrode(Li anode or LiCoO_(2)cathode).The D-CSE has a small thickness(50μm),high thermal stability(up to 160℃ without noticeable deformation),and good flexibility even at a high ceramics content(66.7 wt%).Large-area selfstanding film can be obtained by a facile coating route.The electrolyte/electrode interface can be further enhanced via forming a soft interface by in-situ polymerization.Quasi-solid-state Li|D-CSE|LiCoO_(2)coin cells with the cathode-supported D-CSE can deliver a high initial discharge capacity of 134 mAh g^(-1) and a high capacity retention of 83%after 200 cycles at 0.5 C and 60℃.Quasi-solid-state Li|D-CSE|LiCoO_(2)pouch cells(designed capacity 8.6 mAh)with the self-standing D-CSE have a high retention of80%after 180 cycles at 2 mA charge and 4 mA discharge.At a high cathode loading(19.1 mg cm^(-2)),the Li|D-CSE|LiCoO_(2)pouch cell still can be stably cycled,and can withstand abuse tests of folding,cutting and nail penetration,indicating practical applications of the D-CSE.
基金supported by the National Natural Science Foundation of China(No.51572238)Zhejiang Provincial Natural Science Foundation of China under Grant no.LY19E020013Hunan Provincial Science and Technology Major Project of China(2020GK1014).
文摘Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling,while a facile method to solve this issue is still lacking.In this work,we report an effective,environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable,NaF-rich solid electrolyte interface(SEI)layer on metallic Na via adding a small amount(~3 wt%)of fluorinated graphene(FG)in bulk Na.Inspired by the forging processing,a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes.The Na/FG–Na/FG half cell exhibits a low voltage hysteresis of 110–140 mV over 700 h at a current density up to 5 mA cm^(-2) with an areal capacity as high as 5 mAh cm^(-2).Na–CO_(2) full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g^(-1).Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na.Both experiments and density functional theory(DFT)calculations confirm the formation of the NaF-rich SEI layer.The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.
文摘A three-dimensional viscous code has been developed to solve Reynolds-averaged Navier-Stokes equations. The governing equations in finite volume form are solved by two-step Runge-Kutta scheme with implicit residual smoothing. The eddy viscous is obtained using the Baldwin-Lomax model. A prediction of the 3-D turbulent flow and the performance in the “all-over controlled vortex distribution” centrifugal impeller with a vaneless diffuser has been made for the compressor at design and off-design condition. The predicted effi-ciency is a little higher than the experiment data. These results suggest that the present calculation code is able to determine the flow development in the impeller and also the turbulence model in the centrifugal im-peller should be improved.
文摘Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate change and pollution of water bodies are putting increasing pressure on these resources. In this context, understanding the contribution of water to the economy and environment is crucial for its conservation. To meet this need, the World Bank launched a program aiming at improving valuation and accounting systems of natural resources in Turkey. As part of this program, this article estimates in monetary terms the economic value of water in Bey?ehir Lake, the largest freshwater lake in Turkey. Valuation is based on the Total Economic Value concept, which includes use and non-use values. The results show that the economic value of water is about seven times higher than its financial value. In addition, the economic value of water allocated for municipal use (TL5/m<sup>3</sup>) is substantially greater than that supplied for irrigation (TL0.5/m<sup>3</sup>). The analysis suggests that allocation of water from Bey?ehir Lake among different uses is inefficient. To validate this conclusion and improve allocation, a more comprehensive assessment of the economic benefits of water resources is needed, particularly of water supply for irrigation, municipal use, recreation and biodiversity. The analysis also indicates that economic valuation can be a powerful tool to improve water management at the river basin level.
基金The authors gratefully acknowledge the financial support from the National Key R&D Program of China(grant nos.2021YFB3200400 and 2018YFB1900203)the National Natural Science Foundation of China(grant nos.21825601,21790374,22176139,21906113,and 22176163)+2 种基金the Young Taishan Scholars Program(grant no.tsqn201909082)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(grant no.KYCX22_3212)This work is dedicated to Prof.Zhifang Chai on the occasion of his 80th birthday.
文摘Efficient adsorption of gaseous radioiodine is pivotal for the sustainable development of nuclear energy and the long-termradiation safety of the ecological system.However,state-of-the-art adsorbents(e.g.metal-organic frameworks and covalent-organic frameworks)currently under exploration suffer severely from limited adsorption capacity,especially under a real-world scenariowith extremely lowradioiodine concentration and elevated temperature.This mostly originates from the relatively weak sorption driving forces mainly determinedby the iodine-adsorbent interaction consistingof noncovalent interactionswith a small fraction of strong chemical bonding.Here,we document the discovery of an open metal-sulfide framework((NH_(4))_(2)(Sn_(3)S_(7)),donated as SCU-SnS)constructed by three different types of active sites as a superior iodine adsorbent.Benefiting from the ability of iodine for pre-enrichment into the framework by charge-balancing NH_(4)^(+)through N-H···I interaction,the efficient reduction of I^(2)affording I^(-)by S^(2-),and extremely high binding affinity between Sn_(4)^(+)and I^(-),SCU-SnS exhibit a record-breaking iodine adsorption capacity(2.12 g/g)under dynamic breakthrough conditions and the highest static capacity(6.12 g/g)among all reported inorganic adsorbents,both at 348 K.Its facile synthesis and low cost endow SCU-SnS with powerful application potential for the nuclear industry.
基金a grant from National Natural Science Foundation of China，the National Basic Research Program of China （No.2011CB503905） from the Ministry of Science and Technology of China,the Specialized Research Fund for the Doctoral Program of Higher Education of China，the Science and Technology Commission of Shanghai,China （No.12DZ1940604）.Conflict of Interest：None
文摘To the Editor:A 35-year-old man who smoked for 15 years suffered from chest pain 12 days ago before admission.He was diagnosed as myocardial infarction.Thrombolytic therapy was given consequently.The electrocardiogram showed sub-acute inferior wall myocardial infarction.Echocardiogram showed attenuated constriction of the inferior wall with an ejection fraction of 59％.On September 5,2013,he was treated with a XINSORB scaffold in right coronary artery (RCA).
基金financially supported by the National Key R&D Program of China (2017YFA0403402 and 2019YFA0405601)the National Natural Science Foundation of China(21773222,U1732272 and U1932214)the DNL Cooperation Fund,and Chinese Academy of Sciences (DNL180201)
文摘Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOFs)包覆的FeOOH(FeOOH@MIL-100(Fe))作为前驱体和自牺牲模板,通过高温热处理制备得到一种能良好继承前驱体形貌的中空海胆状碳包覆的Fe2O3(Fe2O3@MOFC)复合材料.在热处理过程中,外部的MOF层很好地保护了内部Fe2O3结构的完整性,并以原位转化的方式衍生为均匀分布在纳米粒子外部的碳涂层.在0.1 Ag^-1的电流密度下,Fe2O3@MOFC可提供高达1366.9 mA hg^-1的初始放电容量,且充放电循环200次后,仍能保持大约1551.3 mA hg^-1的高放电容量.在1 Ag^-1的高电流密度下循环300次后,其比容量仍可保持在1208.6 mA hg^-1.
基金the financial support of the National Natural Science Foundation of China (21875206 and 21403187)China Postdoctoral Science Foundation (2015T80229)the Natural Science Foundation of Hebei Province (B2019203487)
文摘有机醌类化合物因其具有高的理论容量值而引起了人们的广泛关注.本文合成了一种新型的环状大分子Calix[6]quinone(C6Q),它由6个对苯醌单元组成,可提供12个电化学位点,是一种极具发展前景的锂离子正极材料.C6Q在0.1 C的电流密度下展示了高达423 mA h g^-1的初始放电比容量(理论放电比容量为447 mA h g^-1).经过100圈充放电循环之后,它的容量保持在216 mA h g^-1;经过300次循环之后,仍然拥有195 mA h g^-1的高容量.C6Q具有高容量和宽的电化学窗口,因此可以提供高达1201 W h kg^-1的能量密度.此外,使用有序介孔碳CMK-3固载C6Q的方法可以进一步提高C6Q的电化学性能.
基金supported by the National Basic Research Program of China (No.2013CB934001)the Fundamental Research Funds for the Central Universities (No.2014XZZX002-03)+2 种基金the National Natural Science Foundation of China (No.51101139)Key Science and Technology Innovation Team of Zhejiang Province under Grant No.2010R50013Program for Innovative Research Team in University of Ministry of Education of China (No.IRT13037)
文摘In this work, a facile, one-pot route has been applied to synthesize nanohybrids based on mixed oxide Ni Fe2O4 and reduced graphene oxide(r GO). The hybrid is constructed by nanosized Ni Fe2O4 crystals confined by fewlayered r GO sheets. The formation mechanism and microstructure of the hybrids have been clarified by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy.Electrochemical tests show that the performance of Ni Fe2O4 can be considerably improved by r GO incorporation. The performance improvement can be attributed to the two-dimensional conductive channels and the unique hybrid structure r GO constructed. The easy synthesis and good electrochemical performance of Ni Fe2O4/r GO hybrid make it a promising anode material for Li-ion batteries.
基金supported by Zijin Program of Zhejiang University, Chinathe Fundamental Research Funds for the Central Universities (No. 2010QNA4003)+3 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No. 20100101120024)the Foundation of Education Office of Zhejiang Province, China (No. Y201016484)the Qianjiang Talents Project of Science Technology Department of Zhejiang Province, China (No. 2011R10021)the National Natural Science Foundation of China (No.51101139)
文摘Nano structured LiFexMn1-xPO4(x=0,0.2,0.4) materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO 4 could be largely increased by Fe2+ substitution. At a current rate of C/20, the capacity of the three samples (x=0,0.2,0.4) were 47, 107 and 150 mA·h·g-1 , respectively. CV result showed that the Fe2+ substitution could decrease the polarization during charging/discharging, accelerating the electrochemical process. EIS result showed that the Fe2+ substitution could decrease the charge transfer resistance between the electrode and electrolyte,
