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家禽的免疫抑制疾病

浙江畜牧兽医 1988年第1期 53-54+37页

作者： f.t.w.jordan 徐辉

免疫抑制可定义为免疫系统对某种抗原的反应低于正常状态,它可能与多种或单一的特异性抗原有关,从而表现出部分或完全的、短暂或持久的免疫耐受性。引起免疫抑制的因素很多,物理、化学、遗传、环境等因子均与此有关,但在环境适宜,营养... 详细信息

免疫抑制可定义为免疫系统对某种抗原的反应低于正常状态,它可能与多种或单一的特异性抗原有关,从而表现出部分或完全的、短暂或持久的免疫耐受性。引起免疫抑制的因素很多,物理、化学、遗传、环境等因子均与此有关,但在环境适宜,营养充足的情况下,最主要的免疫抑制疾病与病毒和其他微生物的感染及黄曲霉毒素有关。本文摘要介绍与传染病和霉菌毒素有关的几种免疫抑制疾病。

关键词：免疫抑制疾病胸腺淋巴组织法氏囊淋巴器官腔上囊雏火鸡

Inflow and outflow permeability tests in a very soft clay under low stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3270-3283页

作者： J.w.S.Vargas f.A.B.Danziger f.R.Lopes t.Lunne federal University of Rio de Janeiro Rio de JaneiroBrazil Norwegian Geotechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the BAt probe at SarapuíII soft clay test site are presented.A description of the BAt permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low *** pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe *** show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading *** sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests *** are presented concerning the relationship between index parameters and the in situ coefficient of permeability for SarapuíII clay,which plot outside the range of existing databases.

关键词： Permeability test Soft clay BAt probe Inflow and outflow tests

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.t.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

the superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Oxidative dissolution of Cr(OH)_(3) and mixed fe-Cr(Ⅲ)phases by aqueous Mn(Ⅲ)-pyrophosphate complex

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Journal of Environmental Sciences 2024年第5期139卷 105-113页

作者： Mismel Ruiz-Garcia jordan Stanberry Giovanna Ballerini Ribeiro Vasileios Anagnostopoulos Department of Chemistry University of Central FloridaOrlando FL 32816USA

the key role of manganese(Mn)in the biogeochemical cycle of trace elements has been of great interest in recent ***,the redox properties of aqueous Mn(Ⅲ)have been studied to a lesser ***(Ⅲ)is not stable in solution by ***,when complexed with inorganic ligands,it has shown potential to oxidize and reduce trace *** the present study,we are exploring the redox characteristics of the complex Mn(Ⅲ)-Pyrophosphate(Mn(Ⅲ)-PP).this complex is stable over a wide range of pH values but requires the ratio of Mn:PP to be less than 1:***,the redox reaction of chromium(Cr(Ⅲ))and Mn(Ⅲ)-PP is investigated.A solid,Cr(OH)_(3),is used as a source of Cr(Ⅲ).for this reaction,environmentally relevant parameters,such as pH,ionic strength,ratio Mn(Ⅲ)/Cr(Ⅲ),and excess of ligand,were *** showed that Mn(Ⅲ)can effectively oxidize Cr(Ⅲ)to Cr(Ⅵ),taking about 15 days for the reaction to *** reaction occurs only under acidic conditions(pH4),and with a low excess of *** initial Mn(Ⅲ)concentration decreases as the Cr(Ⅵ)is produced,and Cr(Ⅵ)can be adsorbed back into the Cr(OH)_(3)surface,limiting the mobility of this toxic *** this adsorption,significant amounts of Cr(VI)are release in the aqueous *** study shows the importance of a mobile species(Mn-PP complex)in the oxidation of Cr(Ⅲ)and the release of Cr(Ⅵ)to the environment.

关键词： Chromium Manganese Pyrophosphate complex Sorption Ionic strength Redox

A Preliminary Comparative Study on the Centering Algorithms for CassiniISS NAC Images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： t.Liang Q.-f.Zhang G.-M.Liu w.-H.Zhu C.-S.wang Department of Computer Science Jinan UniversityGuangzhou 510632China Sino-french Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China School of Computer Science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow Angle Camera(NAC)of the Cassini Imaging Science Subsystem(ISS).Selecting the best centering algorithm is key to enhancing astrometric *** this study,we compared the accuracy of five centering algorithms:Gaussian fitting,the modified moments method,and three point-spread function(PSf)fitting methods(effective PSf(ePSf),PSfEx,and extended PSf(x PSf)from the Cassini Imaging Central Laboratory for Operations(CICLOPS)).we assessed these algorithms using 70 ISS NAC star field images taken with CL1 and CL2 filters across different stellar *** ePSf method consistently demonstrated the highest accuracy,achieving precision below 0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PSf method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPSf model provided by CICLOPS had lower precision than the ***,the ePSf exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPSf focusing on photometry rather than *** findings highlight the necessity of constructing PSf models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these ISS NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

SMILE soft X-ray Imager flight model CCD370 pre-flight device characterisation

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Earth and Planetary Physics 2024年第1期8卷 25-38页

作者： S.Parsons D.J.Hall O.Hetherington t.w.Buggey t.Arnold M.w.J.Hubbard A.Holland Centre for Electronic Imaging the Open UniversityMilton KeynesMK76AAUK

throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their *** order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance *** CCDs have been characterised,the two flight devices and the flight spa *** has been carried out at the Open University in a bespo ke cleanroom measure ment *** results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe *** at the nominal ope rating tempe rature(-120℃) it is within the procure ment ***,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science *** se rial charge transfer inefficiency degrades with temperature in full frame *** any charge losses are recovered when binning/frame transfer is implemented.

关键词： CCD soft X-ray imager characterisation SMILE

Effects of dust controls on respirable coal mine dust composition and particle sizes:case studies on auxiliary scrubbers and canopy air curtain

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International Journal of Coal Science & technology 2024年第3期11卷 86-101页

作者： f.Animah C.Keles w.R.Reed E.Sarver Department of Mining and Minerals Engineering Virginia Polytechnic Institute&State UniversityBlacksburgVAUSA National Institute of Occupational Safety and Health(NIOSH) PittsburghPAUSA

Control of dust in underground coal mines is critical for mitigating both safety and health *** decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal *** studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator *** detailed dust characterization was not a focus of such studies,this is a growing area of *** preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size *** this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive *** indicate that dust composition was not appreciably affected by either scrubber or the ***,the wet scrubber and CAC appeared to decrease the overall particle size *** an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return *** from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

关键词： Respirable dust Dust control SEM–EDX Scrubber Canopy air curtain Silica

the CCD instrument background of the SMILE SXI

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Earth and Planetary Physics 2024年第1期8卷 15-24页

作者： M.w.J.Hubbard O.Hetherington D.J.Hall t.w.Buggey S.Parsons t.Arnold A.Holland C.Pagani S.Sembay Centre for Electronic Imaging The Open UniversityMilton KeynesMK76AAUK X-ray and Observational Astronomy Group Department of Physics&AstronomyUniversity of LeicesterLE17RHUK

the ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation *** Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is *** shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen ***,two radiation environments can be approximated based on the shutter door position:open and *** instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two *** to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two *** results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar *** is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.

关键词： instrument background X-ray astronomy space radiation

Microstructure evolution and shape memory behaviors of Ni_(47)ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & technology 2024年第4期171卷 80-93页

作者： Y.H.Zhang H.Li Z.w.Yang X.Liu Q.f.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision forming technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the Niti matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density offaustenite twins form in the specimen with a larger prestrain of 16%.with increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(t)upon heating increases first and then ***ε_(re)^(t)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(t)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(t)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)ti_(44)Nb_(9)shape memory alloy wide transformation hysteresis thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning