检索结果-南通市图书馆

Journal of Semiconductors 2024年第8期45卷 25-33页

作者： Fedor I.Manyakhin Dmitry o.Varlamov Vladimir P.Krylov Lyudmila o.Morketsova Arkady A.Skvortsov Vladimir K.Nikolaev Dinamics Strength of Machines and Resisance of MaterialsMoscow Polytechnic UniversityRussia Biomedical and Electronic Means and Technologies Vladimir State UniversityRussia Computer-Aided Design and Engineering National University of Science and Technology"MISiS"Russia

Herein,a physical and mathematical model of the voltage−current characteristics of a p−n heterostructure with quantum wells(QWs)is prepared using the Sah−Noyce−Shockley(SNS)recombination mechanism to show the SNS recombination rate of the correction function of the distribution of QWs in the space charge region of diode configuration.A comparison of the model voltage−current characteristics(VCCs)with the experimental ones reveals their *** technological parameters of the structure of the VCC model are determined experimentally using a nondestructive capacitive approach for determining the impurity distribution profile in the active region of the diode structure with a profile depth resolution of up to 10Å.The correction function in the expression of the recombination rate shows the possibility of determining the derivative of the VCCs of structures with QWs with a nonideality factor of up to 4.

关键词： light-emitting diodes with quantum wells voltage−current relation nonideality factor recombination mechanism Sah−Noyce−Shockley model

Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第6期36卷 13-19页

作者： Thomas M.Klapotke Stanisław Cudziło Waldemar A.Trzcinski Jozef Paszula Energetic Materials Research Department of ChemistryUniversity of Munich(LMU)Butenandtstrasse 5-13(D)81377MunichGermany Military University of Technology Faculty of Advanced Technologies and ChemistrySylwester Kaliski Str.200-908WarsawPoland

A direct comparison is made between the effectiveness of Al,Mg,and Be powders as additional fuels in model thermobaric compositions containing 20%fuel,20%ammonium perchlorate,and 60%RDX(1,3,5-Trinitro-1,3,5-triazacyclohexane)passivated with *** determined calorimetric measurements of the heat of detonation,along with the overpressure histories in an explosion chamber filled with nitrogen,were used to determine the quasi-static pressure(QSP)under anaerobic *** measurements were also performed in a semi-closed bunker,and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were *** calorimetry results,QSP values,and blast wave parameters(pressure amplitude,specific and total impulses)clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic *** heat of detonation of the RDXwax/AP/Be explosive mixture is over 40%and 50%higher than that of the mixture containing aluminum and magnesium instead of beryllium,***,the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66,while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to *** high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.

关键词： Thermobaric explosives Beryllium Heat of detonation Quasi-static overpressure Blast wave parameters

Steroidal scaffold decorations in Solanum alkaloid biosynthesis

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2024年第8期17卷 1236-1254页

作者： Rosalind Lucier Mohamed o.Kamileen Yoko Nakamura Sofiia Serediuk Ranjit Barbole Jens Wurlitzer Maritta Kunert Sarah Heinicke Sarah E.o'Connor Prashant D.Sonawane Department of Natural Product Biosynthesis Max Planck Institute for Chemical Ecology07745 JenaGermany Research group Biosynthesis and NMR Max Planck Institute for Chemical Ecology07745 JenaGermany Biochemical Sciences Division CSIR-National Chemical LaboratoryPune 411008MaharashtraIndia

Steroidal glycoalkaloids(SgAs)are specialized metabolites produced by hundreds of Solanum species,including important vegetable crops such as tomato,potato,and *** it has been known that SgAs play important roles in defense in plants and“anti-nutritional"effects(e.g.,toxicity and bitterness)to humans,many of these molecules have documented anti-cancer,anti-microbial,antiinflammatory,anti-viral,and anti-pyretic *** these,α-solasonine andα-solamargine isolated from black nightshade(Solanum nigrum)are reported to have potent anti-tumor,anti-proliferative,and anti-inflammatory ***,α-solasonine andα-solamargine,along with the core steroidal aglycone solasodine,are the most widespread SgAs produced among the Solanum ***,it is still unknown how plants synthesize these bioactive steroidal *** comparative metabolomictranscriptome-guided approach,biosynthetic logic,combinatorial expression in Nicotiana benthamiana,and functional recombinant enzyme assays,here we report the discovery of 12 enzymes from *** that converts the starting cholesterol precursorto solasodine aglycone,and the downstreamα-solasonine,α-solamargine,and malonyl-solamargine SgA *** further identified six enzymes from cultivated eggplant that catalyze the production ofα-solasonine,α-solamargine,and malonyl-solamargine SgAs from solasodine aglycone via glycosylation and atypical malonylation *** work provides the gene tool box and platform for engineering the production of high-value,steroidal bioactive molecules inheterologoushosts usingsyntheticbiology.

关键词： steroidal glycoalkaloids Solanum biosynthetic pathway α-solamargine malonyl-solamargine specialized metabolites

From the dust:extracellular vesicles as regulators of development and neuroregeneration

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第5期19卷 933-934页

作者： Leon g.Coleman Jr The University of North Carolina at Chapel Hill School of MedicineDepartment of PharmacologyBowles Center for Alcohol StudiesChapel HillNCUSA

First impressions can have a lasting *** science,this can be especially problematic,because our lack of understanding often causes us to mislabel and thus ignore important biological *** this vein,extracellular vesicles(EVs)were once considered to be“cellular dust”.Similar to the previous concept of“junk DNA”to describe protein non-coding regions,EVs are far more than just cellular *** fact,EVs are emerging as key mediators of intracellular communication across nearly all biological *** includes peripheral immune responses(e.g.,arthropathies and sepsis),intra-organ communication(Seim et al.,2023),and a host of other physiological and pathological states(Figure 1A and B).

关键词： Figure extracellular

基于改进MoPSo的RV减速器摆线轮齿廓多目标修形研究

在线全文

学校读者我要写书评

暂无评论

机床与液压 2024年第19期52卷 40-45页

作者：王程王士军冉川东王冠中山东理工大学机械工程学院山东淄博255000

在精密RV减速器摆线轮修形过程中,RV减速器回差和传动误差难以获得综合提升,且摆线轮的修形方式多为单目标修形或加权单目标修形,不符合实际工程情况。为此,采用TCA法建立传动误差模型和回差模型,提出一种带有指数型非线性递减惯性权重... 详细信息

在精密RV减速器摆线轮修形过程中,RV减速器回差和传动误差难以获得综合提升,且摆线轮的修形方式多为单目标修形或加权单目标修形,不符合实际工程情况。为此,采用TCA法建立传动误差模型和回差模型,提出一种带有指数型非线性递减惯性权重和迭代更新学习因子的多目标粒子群算法。以回差和传动误差为目标函数,利用改进算法进行复合修形量的优化,通过隶属度函数获得最优化解。利用Adams和MATLAB分别分析不同修形方法下RV减速器的回差和传动误差情况。结果表明:最终优化修形后的回差比等距、移距修形分别减少了0.02′、0.04′,传动误差分别减少了6.6%、7.8%。

关键词： RV减速器摆线轮改进多目标粒子群算法多目标修形

Alkali and Plasma-Treated guadua angustifolia Bamboo Fibers:A Study on Reinforcement Potential for Polymeric Matrices

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2024年第8期12卷 1399-1416页

作者： Patricia Luna Juan Lizarazo-Marriaga Alvaro Mariño Facultad de Ingeniería Universidad Nacional de ColombiaBogotá11001Colombia Facultad de Ciencias Universidad Nacional de ColombiaBogotá11001Colombia

This study focuses on treating guadua angustifolia bamboo fibers to enhance their properties for reinforcement applications in composite ***(alkali)and physical(dry etching plasma)treatments were used separately to augment compatibility of guadua angustifolia fibers with various composite *** influence of these treatments on the fibers’performance,chemical composition,and surface morphology were *** analysis indicated that alkali treatments reduced the tensile modulus of elasticity and strength of fibers by up to 40%and 20%,respectively,whereas plasma treatments maintain the fibers’mechanical *** spectroscopy revealed significant alterations in chemical composition due to alkali treatments,while plasma-treated fibers showed minimal *** examination through Scanning Electron Microscopy(SEM)revealed post-treatment modifications in both cases;alkali treatments served as a cleanser,eliminating lignin and hemicellulose from the fiber surface,whereas plasma treatments also produce rough *** results validate the impact of the treatments on the fiber mechanical performance,which opens up possibilities for using guadua angustifolia fibers as an alternative reinforcement in composite manufacturing.

关键词： Bamboo fibers guadua angustifolia alkali treatment dry etching plasma treatment composite reinforcement

Endotoxin-induced alterations of adipose tissue function:a pathway to bovine metabolic stress

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第4期15卷 1391-1407页

作者： Miguel Chirivi g.Andres Contreras Department of Large Animal Clinical Sciences Michigan State UniversityEast LansingMIUSA

During the periparturient period, dairy cows exhibit negative energy balance due to limited appetite and increased energy requirements for lactogenesis. The delicate equilibrium between energy availability and expenditure puts cows in a state of metabolic stress characterized by excessive lipolysis in white adipose tissues(AT), increased production of reactive oxygen species, and immune cell dysfunction. Metabolic stress, especially in AT, increases the risk for metabolic and inflammatory diseases. Around parturition, cows are also susceptible to endotoxemia. Bacterial-derived toxins cause endotoxemia by promoting inflammatory processes and immune cell infiltration in different organs and systems while impacting metabolic function by altering lipolysis, mitochondrial activity, and insulin sensitivity. In dairy cows, endotoxins enter the bloodstream after overcoming the defense mechanisms of the epithelial barriers, particularly during common periparturient conditions such as mastitis, metritis, and pneumonia, or after abrupt changes in the gut microbiome. In the bovine AT, endotoxins induce a pro-inflammatory response and stimulate lipolysis in AT, leading to the release of free fatty acids into the bloodstream. When excessive and protracted, endotoxin-induced lipolysis can impair adipocyte's insulin signaling pathways and lipid synthesis. Endotoxin exposure can also induce oxidative stress in AT through the production of reactive oxygen species by inflammatory cells and other cellular components. This review provides insights into endotoxins' impact on AT function, highlighting the gaps in our knowledge of the mechanisms underlying AT dysfunction, its connection with periparturient cows' disease risk, and the need to develop effective interventions to prevent and treat endotoxemia-related inflammatory conditions in dairy cattle.

关键词： Adipose tissue dysfunction Endotoxin Inflammation Insulin resistance

Interpreting siliciclastic sedimentation in the upper Paleozoic Mulargia-Escalaplano Basin(Sardinia, Italy):influence of tectonics on provenance

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第1期13卷 18-34页

作者： Luca g.Costamagna Sara Criniti Dipartimento di Scienze Chimiche e geologiche Citadella UniversitariaBlocco A09042 Monserrato CAItaly Dipartimento di Ingegneria dell'Ambiente Universita della Calabria87036 Arcavacata di Rende CSItaly

Late to post-Variscan molassic basins of Late Pennsylvanian-Permian age are exposed in Sardinia(Italy). Here, the compositional and stratigraphic evolution of the Mulargia-Escalaplano sedimentary basin(central Sardinia) has been investigated to highlight how the tectono-magmatic processes have influenced the sedimentation. Ruditic and arenitic samples were collected along well-characterized stratigraphic sections to provide a new insight into the impact of the tectono-magmatic processes on siliciclastic sedimentation. As a result, the conglomerates are mainly clast-supported, petromictic, and thus immature, with no defined maturity trend upwards. Nevertheless, pebble composition changes in times from Variscan basement pebble-rich to volcanic rock-rich, as a consequence of the basin widening and the dismantling and reworking of the coeval volcanic activity. The sandstone composition clearly changes from quartzolithic to feldspatholithic upwards, as a response to the same change of feeding and reworking of the volcanic rocks. occasionally, interbedded quartzolithic arenites suggest exceptional floods carrying debris from the far borders of the basin. Also, the immature sandstone composition has been interpreted as being controlled by a continuous supply of fresh debris and to a rapid burial rate. In addition, the disappearance of metaradiolarite(lydite AA) Paleozoic grains in the sandstone mineral suite could represent a distinctive marker of a progressive unroofing of the Variscan chain and a clastic supply from deeper tectonic units.

关键词： Petrography Stratigraphy Provenance Molassic basins Sardinia

Development of bismuth-based solutions for well plugging and abandonment:A review

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2024年第2期9卷 250-264页

作者： Lewaa Hmadeh Marcelo Anunciação Jaculli Behzad Elahifar Sigbjørn Sangesland Norwegian University of Science and Technology PTSValgrindaS.P.Andersens veg 15 ANorway

Plugging and abandonment(P&A)is a crucial step of the well life *** of how long one stretches the productive life of a well,P&A operations will have to be carried out *** current panorama of our industry includes many wells to be plugged and abandoned,with steep requirements to abide by both regulations and societal *** this context,we must guarantee that no leakage occurs with an eternal perspective in *** has been the prime material for this task,but recent studies have indicated the potential of degradation over time-especially in corrosive environments-and the creation of leaking paths due to its *** has opened up a path toward the usage of alternative *** of the emerging candidates is bismuth,a metal with the unique characteristic of expanding when *** a trait could improve the overall sealability of wellbores and especially during P&*** article discusses the current status of bismuth sealing technologies,introducing the basics of bismuth,the ongoing efforts to qualify it as a barrier material,its potential applications,and the challenges that still need to be *** latest research indicates promising results in terms of its usage as a barrier element.

关键词： Bismuth plugs Bismuth-tin alloys Well plugging and abandonment Well integrity

Music as medicine for traumatic brain injury:a perspective on future research directions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第10期19卷 2105-2106页

作者： Anthony E.Kline Eleni H.Moschonas Corina o.Bondi Department of Physical Medicine&Rehabilitation University of PittsburghPittsburghPAUSA Safar Center for Resuscitation Research University of PittsburghPittsburghPAUSA Center for Neuroscience University of PittsburghPittsburghPAUSA Department of Critical Care Medicine University of PittsburghPittsburghPAUSA Center for the Neural Basis of Cognition University of PittsburghPittsburghPAUSA Department of Psychology University of PittsburghPittsburghPAUSA Department of Neurobiology University of PittsburghPittsburghPAUSA

Traumatic brain injury(TBI) impacts 69 million individuals globally each year and is a leading cause of death and disability(Dewan et al.,2019).The majority of moderate-to-severe TBI survivors endure long-lasting disturbances in motor,cognitive,and affect that negatively impacts their *** a plethora of research on pharmacological interventions for TBI has been conducted,none has translated to the clinic,thus advocating for the evaluation of nonpharmacological therapeutic approaches that may increase translational success.

关键词： injury traumatic