Comparison of Perovskite Systems Based on AFeO_(3)(A=Ce,La,Y)in CO_(2) Hydrogenation to CO

CO_(2) is the most cost-eff ective and abundant carbon resource,while the reverse water-gas reaction(rWGS)is one of the most eff ective methods of CO_(2) utilization.This work presents a comparative study of rWGS activity for perovskite systems based on AFeO_(3)(where A=Ce,La,Y).These systems were synthesized by solution combustion synthesis(SCS)with diff erent ratios of fuel(glycine)and oxidizer(φ),diff erent amounts of NH 4 NO_(3),and the addition of alumina or silica as supports.Various techniques,including X-ray diff raction analysis,thermogravimetric analysis,Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy,energy-dispersive X-ray spectroscopy,N 2-physisorption,H_(2) temper-ature-programmed reduction,temperature-programmed desorption of H_(2) and CO_(2),Raman spectroscopy,and in situ FTIR,were used to relate the physicochemical properties with the catalytic performance of the obtained composites.Each specifi c perovskite-containing system(either bulk or supported)has its own optimalφand NH_(4) NO_(3) amount to achieve the highest yield and dispersion of the perovskite phase.Among all synthesized systems,bulk SCS-derived La-Fe-O systems showed the highest resistance to reducing environments and the easiest hydrogen desorption,outperforming La-Fe-O produced by solgel combustion(SGC).CO_(2) conversion into CO at 600°C for bulk ferrite systems,depending on the A-cation type and preparation method,follows the order La(SGC)<Y<Ce<La(SCS).The diff erences in properties between La-Fe-O obtained by the SCS and SGC methods can be attributed to diff erent ratios of oxygen and lanthanum vacancy contributions,hydroxyl coverage,morphology,and free iron oxide presence.In situ FTIR data revealed that CO_(2) hydrogenation occurs through formates generated under reaction conditions on the bulk system based on La-Fe-O,obtained by the SCS method.γ-Al_(2)O_(3) improves the dispersion of CeFeO_(3) and LaFeO_(3) phases,the specifi c surface area,and the quantity of adsorbed H_(2) and CO_(2).This led to a signifi cant increase in CO_(2) conversion for supported CeFeO_(3) but not for the La-based system compared to bulk and SiO_(2)-supported perovskite catalysts.However,adding alumina increased the activity per mass for both Ce-and La-based perovskite systems,reducing the amount of rare-earth components in the catalyst and thereby lowering the cost without substantially compromising stability.

First results of turbulence investigation on Globus-M2 using radial correlation Doppler reflectometry

The first results of investigation of the turbulence structure using Doppler backscattering(DBS)on the Globus-M2 tokamak are presented.A one-channel DBS system with a variable probing frequency within the 18–26 GHz range was installed to investigate the edge plasma at normalized minor radiiρ=0.9–1.1.Radial correlation Doppler reflectometry was used to study the changes in turbulence eddies after the LH transition.Correlation analysis was applied to the phase derivative of complex in-phase and quadrature(IQ)signals of the DBS diagnostic as it contains information about the poloidal plasma rotation velocity.In L-mode,the radial correlation length L_(r)is estimated to be 3 cm and after transition to H-mode reduces to approximately 2 cm.Gyrokinetic modelling in a linear local approximation using code GENE indicates that the instability with positive growth rate at the normalized minor radiusρ=0.75 in L-mode and H-mode on Globus-M2 was the ion temperature gradient(ITG)mode.

Isochrone Fitting of Galactic Globular Clusters—Ⅵ.High-latitude Clusters NGC 5024 (M53),NGC 5053,NGC 5272 (M3),NGC 5466,and NGC7099 (M30)

We fit various color–magnitude diagrams(CMDs) of the high-latitude Galactic globular clusters NGC 5024(M53),NGC 5053,NGC 5272(M3),NGC 5466,and NGC 7099(M30) by isochrones from the Dartmouth Stellar Evolution Database and Bag of Stellar Tracks and Isochrones for α–enrichment [α/Fe] = +0.4.For the CMDs,we use data sets from Hubble Space Telescope,Gaia,and other sources utilizing,at least,25 photometric filters for each cluster.We obtain the following characteristics with their statistical uncertainties for NGC 5024,NGC 5053,NGC 5272,NGC 5466,and NGC 7099,respectively:metallicities [Fe/H] =-1.93 ± 0.02,-2.08 ± 0.03,-1.60 ± 0.02,-1.95 ± 0.02,and-2.07 ± 0.04 dex with their systematic uncertainty 0.1 dex;ages 13.00 ± 0.11,12.70 ± 0.11,11.63 ± 0.07,12.15 ± 0.11,and 12.80 ± 0.17 Gyr with their systematic uncertainty 0.8 Gyr;distances(systematic uncertainty added) 18.22 ± 0.06 ± 0.60,16.99 ± 0.06 ± 0.56,10.08 ± 0.04 ± 0.33,15.59 ±0.03 ± 0.51,and 8.29 ± 0.03 ± 0.27 kpc;reddenings E(B-V) = 0.023 ± 0.004,0.017 ± 0.004,0.023 ± 0.004,0.023 ± 0.003,and 0.045 ± 0.002 mag with their systematic uncertainty 0.01 mag;extinctions AV= 0.08 ± 0.01,0.06 ± 0.01,0.08 ± 0.01,0.08 ± 0.01,and 0.16 ± 0.01 mag with their systematic uncertainty 0.03 mag,which suggest the total Galactic extinction AV= 0.08 across the whole Galactic dust to extragalactic objects at the North Galactic Pole.The horizontal branch morphology difference of these clusters is explained by their different metallicity,age,mass-loss efficiency,and loss of low-mass members in the evolution of the core-collapse cluster NGC 7099 and loose clusters NGC 5053 and NGC 5466.

What Mice Can Teach Us about How to Stop Drug-Resistant Tuberculosis:Correct Chemotherapy Regimen and Patient Compliance are the Key

Despite well-known limitations,mice remain useful as model animals to study tuberculosis(TB)pathogenesis,the basic immune response,the extent of lung pathology as well as efficacy of new drugs against Mycobacterium tuberculosis[1,2].There are four routes of tuberculosis infection in mice:aerosol generation and exposition,intravenous injection,intranasal administration,and subcutaneous administration[3].

The sudden ocean warming and its potential influences on earlyfrozen landfast ice in the Prydz Bay, East Antarctica

The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar regions.An integrated high-frequency ice-ocean observation system,including Acoustic Doppler Velocimeter,Conductivity-Temperature-Depth Sensor,and Sea Ice Mass Balance Array(SIMBA),was deployed in the landfast ice region close to the Chinese Zhongshan Station in Antarctica.A sudden ocean warming of 0.14℃(p<0.01)was observed beneath early-frozen landfast ice,from(−1.60±0.03)℃during April 16-19 to(−1.46±0.07)℃during April 20-23,2021,which is the only significant warming event in the nearly 8-month records.The sudden ocean warming brought a double rise in oceanic heat flux,from(21.7±11.1)W/m^(2) during April 16-19 to(44.8±21.3)W/m^(2) during April 20-23,2021,which shifted the original growth phase at the ice bottom,leading to a 2 cm melting,as shown from SIMBA and borehole observations.Simultaneously,the slowdown of ice bottom freezing decreased salt rejection,and the daily trend of observed ocean salinity changed from+0.02 d^(-1) during April 16-19,2021 to+0.003 d^(-1) during April 20-23,2021.The potential reasons are increased air temperature due to the transit cyclones and the weakened vertical ocean mixing due to the tide phase transformation from semi-diurnal to diurnal.The high-frequency observations within the ice-ocean boundary layer enhance the comprehensive investigation of the ocean’s influence on ice evolution at a daily scale.

Systemic juvenile idiopathic arthritis–associated lung disease: A retrospective cohort study

BACKGROUND Lung damage in systemic juvenile arthritis(sJIA)is one of the contemporary topics in pediatric rheumatology.Several previous studies showed the severe course and fatal outcomes in some patients.The information about interstitial lung disease(ILD)in the sJIA is scarce and limited to a total of 100 cases.AIM To describe the features of sJIA patients with ILD in detail.METHODS In the present retrospective cohort study,information about 5 patients less than 18-years-old with sJIA and ILD were included.The diagnosis of sJIA was made according to the current 2004 and new provisional International League of Associations for Rheumatology criteria 2019.ILD was diagnosed with chest computed tomography with the exclusion of other possible reasons for concurrent lung involvement.Macrophage activation syndrome(MAS)was diagnosed with HLH-2004 and 2016 EULAR/ACR/PRINTO Classification Criteria and hScores were calculated during the lung involvement.RESULTS The onset age of sJIA ranged from 1 year to 10 years.The time interval before ILD ranged from 1 mo to 3 years.The disease course was characterized by the prevalence of the systemic features above articular involvement,intensive rash(100%),persistent and very active MAS(hScore range:194-220)with transaminitis(100%),and respiratory symptoms(100%).Only 3 patients(60%)developed a clubbing phenomenon.All patients(100%)had pleural effusion and 4 patients(80%)had pericardial effusion at the disease onset.Two patients(40%)developed pulmonary arterial hypertension.Infusion-related reactions to tocilizumab were observed in 3(60%)of the patients.One patient with trisomy 21 had a fatal disease course.Half of the remaining patients had sJIA remission and 2 patients had improvement.Lung disease improved in 3 patients(75%),but 1 of them had initial deterioration of lung involvement.One patient who has not achieved the sJIA remission had the progressed course of ILD.No cases of hyper-eosinophilia were noted.Four patients(80%)received canakinumab and one(20%)tocilizumab at the last follow-up visit.CONCLUSION ILD is a severe life-threatening complication of sJIA that may affect children of different ages with different time intervals since the disease onset.Extensive rash,serositis(especially pleuritis),full-blown MAS with transaminitis,lymphopenia,trisomy 21,eosinophilia,and biologic infusion reaction are the main predictors of ILD.The following studies are needed to find the predictors,pathogenesis,and treatment options,for preventing and treating the ILD in sJIA patients.

Samples of the Collection of Old Medicine Raw Materials of the Department of Pharmacognosy of St.Petersburg Chemical Pharmaceutical University,Which Can Be Used in Food

In the world there are many collections of the pharmaceutical trend.In America,the exhibits of this profile are in the Smithsonian Museum of Natural History in Washington,in Europe these are collections of pharmacy museums in Heidelberg(Germany),Krakow and Warsaw(Poland),Basel(Switzerland),Riga(Latvia),and others.Some of them have many thousands of exhibits.There are also separate collections of pharmaceutical items for educational institutions,for example,a collection of old medicinal raw materials in Vigan’s Cabinet,Queen College,Cambridge(Great Britain).All these meetings,however,have long been known and described in detail.Most of them do not have a strict orientation and are presented,along with old medicinal raw materials,as well as tools and appliances,dishes,books,herbaria and various auxiliary items.All the more interesting is the collection indicated in the title of the article,which arose literally from non-existence.She was transferred to the educational institution at its creation,and this year she,like him,turns a hundred years old.It has a strict focus and is represented almost exclusively by medicinal raw materials.Studying the samples of this old collection,as a whole of medical profile,makes it possible to understand that many plants,which initially had only food use,gradually became pharmaceutical objects.Probably,it was the long practice of food use,with the fixing of associated pharmacological effects in the memory,that became the reason for choosing certain types of raw materials as medicinal.Ordinary foods,protein and starchy,began to be perceived as strengthening,mucous—as enveloping and anti-ulcer,some fruits and herbs—as antiscorbutic,sharp—as appetizing and improving the work of the stomach,and so on.

High-temperature annealing of(201)β-Ga_(2)O_(3) substrates for reducing structural defects after diamond sawing

A commercial epi-ready(201)β-Ga_(2)O_(3) wafer was investigated upon diamond sawing into pieces measuring 2.5×3 mm^(2).The defect structure and crystallinity in the cut samples has been studied by X-ray diffraction and a selective wet etching technique.The density of defects was estimated from the average value of etch pits calculated,including near-edge regions,and was obtained close to 109 cm^(-2).Blocks with lattice orientation deviated by angles of 1-3 arcmin,as well as non-stoichiometric fractions with a relative strain about(1.0-1.5)×10^(-4)in the[201]direction,were found.Crystal perfection was shown to decrease significantly towards the cutting lines of the samples.To reduce the number of structural defects and increase the crystal perfection of the samples via increasing defect motion mobility,the thermal annealing was employed.Polygonization and formation of a mosaic structure coupled with dislocation wall appearance upon 3 h of annealing at 1100℃ was observed.The fractions characterized by non-stoichiometry phases and the block deviation disappeared.The annealing for 11 h improved the homogeneity and perfection in the crystals.The average density of the etch pits dropped down significantly to 8×10^(6) cm^(-2).

Constructing Representative Collective Signature Protocols Using The GOST R34.10-1994 Standard

The representative collective digital signature,which was suggested by us,is built based on combining the advantages of group digital signature and collective digital signature.This collective digital signature schema helps to create a unique digital signature that deputizes a collective of people representing different groups of signers and may also include personal signers.The advantage of the proposed collective signature is that it can be built based on most of the well-known difficult problems such as the factor analysis,the discrete logarithm and finding modulo roots of large prime numbers and the current digital signature standards of the United States and Russian Federation.In this paper,we use the discrete logarithmic problem on prime finite fields,which has been implemented in the GOST R34.10-1994 digital signature standard,to build the proposed collective signature protocols.These protocols help to create collective signatures:Guaranteed internal integrity and fixed size,independent of the number of members involved in forming the signature.The signature built in this study,consisting of 3 components(U,R,S),stores the information of all relevant signers in the U components,thus tracking the signer and against the“disclaim of liability”of the signer later is possible.The idea of hiding the signer’s public key is also applied in the proposed protocols.This makes it easy for the signing group representative to specify which members are authorized to participate in the signature creation process.

Valley-dependent topological edge states in plasma photonic crystals

Plasma photonic crystals designed in this paper are composed of gas discharge tubes to control the flow of electromagnetic waves.The band structures calculated by the finite element method are consistent with the experimental results which have two distinct attenuation peaks in the ranges of 1-2.5 GHz and 5-6 GHz.Electromagnetic parameters of the plasma are extracted by the Nicolson-Ross-Weir method and effective medium theory.The measured electron density is between 1×1011 cm-3 and1×1012 cm-3,which verifies the correctness of the parameter used in the simulation,and the collision frequency is near 1.5×1010 Hz.As the band structures are corroborated by the measured scattering parameters,we introduce the concept of photonic topological insulator based on the quantum Valley Hall effect into the plasma photonic crystal.A valley-dependent plasma photonic crystal with hexagonal lattice is constructed,and the phase transition of the valley K(K’)occurs by breaking the spatial inversion symmetry.Valley-spin locked topological edge states are generated and excited by chiral sources.The frequency of the non-bulk state can be dynamically regulated by the electron density.This concept paves the way for novel,tunable topological edge states.More interestingly,the Dirac cone is broken when the electron density increases to 3.1×1012 cm-3,which distinguishes from the methods of applying a magnetic field and changing the symmetry of the point group.

Influence of relative compaction and degree of saturation on the deformation characteristics of bentonite under freeze-thaw cycles

Bentonite,consisting of clay minerals of the montmorillonite group,has been widely used as an adsorbent and backfill material in nuclear waste disposal and groundwater remediation.It is challenging to use bentonite as a filling material in cold regions since bentonite is highly sensitive to thermal environmental changes,during which its bulk volume and microstructure change significantly.In this study,a series of one-dimensional and three-dimensional freeze-thaw tests were carried out within a closed system to investigate the influencing factors of the deformation of bentonite under freeze-thaw cycles.Results show that the initial soil water content greatly impacts bentonite's deformation during freeze-thaw cycles.For an initial higher degree of saturation(Sr),the expansion caused by the formation of ice lenses has a greater impact than the shrinkage induced by dehydration,ice-cementation,and so on.Conversely,bentonite tends to shrink at a lower degree of saturation during freezing.And the critical degree of saturation that determines bentonite's behavior of frost heave or frost shrinkage seems to be roughly 0.8.As the number of freeze-thaw cycles rises,initially uncompacted bentonite clay becomes more compacted,and initially compacted bentonite clay remains unchanged.

Chondroitin sulfate and glucosamine combination in patients with knee and hip osteoarthritis:A long-term observational study in Russia

BACKGROUND Oral treatment of glucosamine(GA) combined with chondroitin sulfate(CS) was reportedly effective for pain relief and function improvement in osteoarthritis patients with moderate to severe knee pain in clinical trials. While the effectiveness of GA and CS on both clinical and radiological findings has been demonstrated, only a few high-quality trials exist. Therefore, controversy regarding their effectiveness in real-world clinical practice remains.AIM To investigate the impact of GA + CS on clinical outcomes of patients with knee and hip osteoarthritis in routine clinical practice.METHODS A multicenter prospective observational cohort study included 1102 patients of both genders with knee or hip osteoarthritis(Kellgren & Lawrence grades Ⅰ-Ⅲ) in 51 clinical centers in the Russian Federation from November 20, 2017, to March 20,2020, who had started to receive oral capsules of glucosamine hydrochloride 500 mg and CS 400mg according to the approved patient information leaflet starting from 3 capsules daily for 3 wk,followed by a reduced dosage of 2 capsules daily before study inclusion(minimal recommended treatment duration is 3-6 mo). Changes in subscale scores [Pain, Symptoms, Function, and Quality of Life(QOL)] of the Knee Injury and Osteoarthritis Outcome Score(KOOS)/Hip Disability and Osteoarthritis Outcome Score(HOOS) questionnaires during the observational period(up to 54-64wk with a total of 4 visits). Patients’ treatment satisfaction, data on the combined oral use of glucosamine hydrochloride and CS, concomitant use of non-steroidal anti-inflammatory drugs(NSAIDs), and adverse events(AEs) were also evaluated.RESULTS A total of 1102 patients with knee and hip osteoarthritis were included in the study. The mean patient age was 60.4 years, most patients were women(87.8%), and their average body mass index was 29.49 kg/m2. All subscale scores(Pain, Symptoms, Function, and QOL) of the KOOS and HOOS demonstrated clinically and statistically significant improvements. In patients with knee osteoarthritis, the mean score increases from baseline to the end of Week 64 were 22.87, 20.78,16.60, and 24.87 on Pain, Symptoms, Physical Function(KOOS-PS), and QOL subscales(P < 0.001for all), respectively. In patients with hip osteoarthritis, the mean score increases were 22.81, 19.93,18.77, and 22.71 on Pain, Symptoms, Physical Function(HOOS-PS), and QOL subscales(P < 0.001for all), respectively. The number of patients using any NSAIDs decreased from 43.1% to 13.5%(P < 0.001) at the end of the observation period. Treatment-related AEs occurred in 2.8% of the patients and mainly included gastrointestinal disorders [25 AEs in 24(2.2%) patients]. Most patients(78.1%) were satisfied with the treatment.CONCLUSION Long-term oral GA + CS was associated with decreased pain, reduced concomitant NSAID therapy, improved joint function and QOL in patients with knee and hip osteoarthritis in routine clinical practice.

Diagnostic value ultrasound signs of stones less than or equal to 10 mm and clinicoradiological variants of ureteric colic

Objective:To determine the diagnostic value of ultrasound signs of urinary stones less than or equal to 10 mm and to determine clinico-radiological variants of ureteric colic.Methods:A total of 455 ultrasound investigations were performed in patients referring to emergency department with urolithiasis and symptoms suspected of ureteric colic between January 2021 and May 2021.In addition to microscopic evaluation of urine sediment to detect different crystals and non-contrast spiral computed tomography to detect stones,B-mode and color Doppler sonography was performed to assess the presence of acoustic shadow(AS)and twinkle artifacts(TA)as possible signs of stone(s)in ureter.Results:While the sensitivity and specificity of AS and TA were higher than 90%in patients with stones greater than 5 mm;positive prognostic values of these parameters were found to be extremely low for stones with sizes of 1-3 mm with specificity and sensitivity values not exceeding 53%.The sensitivity and specificity of AS and TA in the upper and lower ureters were higher for stones greater than or equal to 5 than for compared to those less than 5 mm.At the same time,the diagnostic values of TA and AS for middle ureter stones were very limited.The most prevalent clinico-radiological variants of ureteric colic were types I,III,and V being observed in 39%,28% and 21% cases,respectively.Conclusion:Our results demonstrate that TA and AS parameters seem to have a very low sensitivity and specificity in the diagnosis of urinary stones less than 5 mm.The diagnostic value of TA and AS increase significantly in stones greater than or equal to 5 mm.Therefore,clinicians need to be very careful for overestimating the diagnostic values of TA and AS for stones less than 5 mm and non-contrast spiral computed tomography must be the method of choice for patients presenting to emergency department with ureteric colic.

Causal Circular Narrative and Time-Space Construction of the Movie Little Big Woman

Chinese film Little Big Woman takes the father’s funeral as the main line to tell the story of family affection and real-life emotional entanglements.In the narrative with multiple clues,we go back to find the hidden reasons,and the gradually clear reflection of the past is related to the real situation of the characters.Causal cycle narrative is not only a narrative strategy,but also a narrative logic with deep Chinese traditional cultural and philosophical connotations.

长江口滨海湿地有机碳循环过程及影响因素研究进展

滨海湿地是“蓝碳生态系统”的重要组成部分。综述了长江口滨海湿地土壤有机碳时空分布及含量、碳汇速率、有机碳横向输入输出通量及量化方法、有机碳循环定量分析模型以及有机碳储量和组分对不同影响因素所做出的动态响应规律,发现在土壤有机碳水平空间分布上,崇西湿地>崇明东滩>九段沙>南汇潮滩;有机碳通量和浓度变化主要受到植物生物量和结构、水和土壤的理化性质、陆源输入和潮汐动力、间隙水交换以及人类活动和全球气候变化的影响。未来应加强长江口湿地土壤碳库和有机碳输运通量统一观测,准确量化各主要因素对有机碳的贡献,这对研究盐沼湿地的碳循环机理和碳汇评估具有重要意义。

高温后再生保温混凝土损伤劣化数值分析

【目的】内部多孔且高温稳定的玻化微珠(glazed hollow beads,GHB)可在一定程度上减缓混凝土的高温损伤劣化,提升混凝土的抗火性能。为了进一步明确GHB改善混凝土抗火性能的机理,从细观尺度出发,提出一种可考虑初始缺陷和再生骨料(recycled coarse aggregate,RCA)取代率的再生保温混凝土(recycled aggregate concrete mixed with glazed hollow beads,RATIC)细观模型的建模方法。【方法】利用现阶段比较常用的塑性损伤模型,探究了RCA取代率(0,50%,100%)、GHB含量(0,70%,100%)和孔隙率(0,2%,4%)对于高温后RATIC力学性能的影响。【结果】结果表明:随着受火温度的提高,荷载作用下RATIC试件的损伤分布均呈现出逐渐加剧的趋势,且500℃后,试件的损伤分布较400℃之前严重。GHB的加入可在一定程度上缓减混凝土内部的损伤劣化,而RCA的加入会加剧此现象。此外,随着孔隙率增大,RATIC试件的强度逐渐变低。

十九至二十世纪之交俄罗斯的中亚考察与奥登堡的敦煌探险

19—20世纪之交,中亚是英俄两国角逐的舞台。为了获得新市场和原材料来源地的控制权,沙俄开始对中亚进行了一系列的探险考察。在此背景下,谢尔盖·奥登堡(S.F.Oldenburg,1863—1934)先后主导了前往中国新疆和敦煌的两次探险。1914—1915年,奥登堡率领探险队前往敦煌对莫高窟进行了详细的考古调查,并通过各种方式收集了大量古代文献与文物。奥登堡敦煌探险收集品后来分藏于埃尔米塔什博物馆、俄罗斯科学院档案馆圣彼得堡分馆和俄罗斯科学院东方文献研究所,自那以来关于该收集品已有大量研究成果问世。

丙酮盐酸混合液提取土壤腐殖质组分的光谱学特征

采用丙酮盐酸混合液提取土壤胡敏酸(HA)和胡敏素(HU)组分,利用元素分析、紫外-可见漫反射光谱和红外光谱进行结构表征。元素分析表明,HA中C、H、N和S含量均高于HU,O含量低于HU。原子比分析表明HA的缩合度相对较高,分子结构相对复杂,HU的缩合度相对较低,分子结构相对简单。紫外-可见漫反射光谱分析表明,由于腐殖质(HS)的组成复杂,多种官能团互相干扰,HA和HU紫外-可见漫反射光谱无明显特征峰,吸光度值随着波长的增加呈下降趋势,且HA包含的吸光有机成分较多,化学组成较复杂。HA和HU紫外特征参数SUV254和E4/E6比较分析表明,与HU相比,HA芳香性较大,腐殖化程度较高。红外光谱分析表明,HA和HU具有相似的红外光谱,各研究对象特征吸收峰的吸收强度不同,其中开垦黑土20~40 cm和未开垦灰土18~37 cm土层HA的振动幅度较大,说明其包含的酚类化合物、含羟基化合物、脂肪族化合物和羧酸,以及含羰基的醛、酮、醚等化合物的含量较多。开垦黑土10~20 cm土层和未开垦灰土18~37 cm土层HU在各特征吸收峰振动幅度较大,说明其包含的酚类化合物、羧酸、脂肪烃和糖类化合物含量较多。红外光谱各吸收峰强度比较分析表明,开垦后黑土HA和HU酚类化合物、羟基官能团和脂肪族化合物等含量增加,而开垦后灰土HA和HU酚类化合物、羧酸和脂肪族化合物含量下降,表明开垦对黑土土壤有机质影响相对较小,并且在一定程度上增加了土壤有机质含量,而促进了灰土土壤有机质的分解。综上所述,丙酮盐酸混合液提取法为HS生物化学和生理活性的研究提供了新的技术手段,为合理利用土壤资源提供理论依据。

Radiation of a TM mode from an open end of a three-layer dielectric capillary

Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.

Cross-method Analysis of Corotation Radii Data Set for Spiral Galaxies

A corotation radius is a key characteristic of disk galaxies that is essential to determine the angular speed of the spiral structureΩ_p,and therefore understand its nature.In the literature,there are plenty of methods to estimate this value,but do these measurements have any consistency?In this work,we collected a data set of corotation radius measurements for 547 galaxies,300 of which had at least two values.An initial analysis reveals that most objects have rather inconsistent corotation radius positions.Moreover,a significant fraction of galactic disks is distinguished by a large error coverage and almost uniform distribution of measurements.These findings do not have any relation to spiral type,Hubble classification,or presence of a bar.Among other reasons,obtained results could be explained by the transient nature of spirals in a considerable part of galaxies.We have made our collected data sample publicly available,and have demonstrated on one example how it could be useful for future research by investigating a winding time value for a sample of galaxies with possible multiple spiral arm patterns.