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The larval alimentary canal of the Antarctic insect,Belgica antarcticaJames B.Nardi a ,*,Lou Ann Miller b ,Charles Mark Bee c ,Richard E.Lee,Jr.d ,David L.Denlinger eaDepartment of Entomology,University of Illinois,320Morrill Hall,505S.Goodwin Avenue,Urbana,IL 61801,USAbCenter for Microscopy and Imaging,College of Veterinary Medicine,University of Illinois,2001S.Lincoln Avenue,Urbana,IL 61801,USA cImaging Technology Group,Beckman Institute for Advanced Science and Technology,University of Illinois,405N Mathews Avenue,Urbana,IL 61801,USA dDepartment of Zoology,Miami University,Oxford,OH 45056,USA eDepartment of Entomology,Ohio State University,400Aronoff Laboratory,318West 12th Avenue,Columbus,OH 43210,USAa r t i c l e i n f oArticle history:Received 26October 2008Accepted 17April 2009Keywords:Alimentary canal Midge AntarcticaStomodeal valve MicrovilliRegenerative cellsa b s t r a c tOn the Antarctica continent the wingless midge,Belgica antarctica (Diptera,Chironomidae)occurs further south than any other insect.The digestive tract of the larval stage of Belgica that inhabits this extreme environment and feeds in detritus of penguin rookeries has been described for the first time.Ingested food passes through a foregut lumen and into a stomodeal valve representing an intussus-ception of the foregut into the midgut.A sharp discontinuity in microvillar length occurs at an interface separating relatively long microvilli of the stomodeal midgut region,the site where peritrophic membrane originates,from the midgut epithelium lying posterior to this stomodeal region.Although shapes of cells along the length of this non-stomodeal midgut epithelium are similar,the lengths of their microvilli increase over two orders of magnitude from anterior midgut to posterior ldings of the basal membranes also account for a greatly expanded interface between midgut cells and the hemocoel.The epithelial cells of the hindgut seem to be specialized for exchange of water with their environment,with the anterior two-thirds of the hindgut showing highly convoluted luminal membranes and the posterior third having a highly convoluted basal surface.The lumen of the middle third of the hindgut has a dense population of resident bacteria.Regenerative cells are scattered throughout the larval midgut epithelium.These presumably represent stem cells for the adult midgut,while a ring of cells,marked by a discontinuity in nuclear size at the midgut-hindgut interface,presumably represents stem cells for the adult hindgut.Ó2009Elsevier Ltd.All rights reserved.1.IntroductionDespite the dominance of insects and other terrestrial arthro-pods throughout the world,only a few species are found in Antarctica.Most are collembolans and mites,with the Class Insecta represented by only two endemic species of midges (Diptera:Chironomidae)(Convey and Block,1996).Of these,the range of the more abundant midge Belgica antarctica extends further south on the Antarctic Peninsula than that of any other insect.B.antarctica has a patchy distribution on the Peninsula,but it is particularly abundant near penguin rookeries on the small,off-shore islands near Palmer Station.In this habitat,midge larvae are subjected to a range of environmental stresses including desicca-tion,freezing,anoxia,pH fluctuation from the nitrogenous run-off,and inundation from seawater as well as fresh water fromprecipitation and ice melt.Numerous physiological adaptations are apparent in the larvae:heat shock proteins are continuously up-regulated (Rinehart et al.,2006),agents to counter oxidative stress are present in abundance (Lopez-Martinez et al.,2008),loss of a high percentage of body water is tolerated and in fact contributes to enhanced freeze tolerance (Hayward et al.,2007;Elnitsky et al.,2008).Dramatic changes in metabolites (Michaud et al.,2008)and gene expression (Lopez-Martinez et al.,2009)accompany these physiological responses to environmental stress.In addition to these distinctive biochemical features of cells of B.antarctica ,it is quite possible that structural features of this insect may also deviate somewhat from the patterns observed in insects at lower latitudes.The harsh environment of Antarctica obviously places great demands on the resiliency of cells that are exposed to periodic desiccation and freezing.To promote formation of ice crystals within extracellular spaces rather than within cells,insect cells must rapidly exchange water with their extracellular environments.Expansion of luminal and/or basal surface areas of epithelial cells would facilitate this rapid exchange.*Corresponding author.Tel.:þ12173336590;fax:þ12172443499E-mail address:j-nardi@ (J.B.Nardi).Contents lists available at ScienceDirectArthropod Structure &Developmentjournal homepage :www.else /locate/asd1467-8039/$–see front matter Ó2009Elsevier Ltd.All rights reserved.doi:10.1016/j.asd.2009.04.003Arthropod Structure &Development 38(2009)377–389Special emphasis in this manuscript has been placed on the cellular architecture of the three well-delineated epithelial regionsof the insect alimentary canal–foregut,midgut,and hindgut. Secretion from the midge’s large salivary gland cells aggregates detritus particles and facilitates uptake of detritus into the gut (Oliver,1971).After passage of ingested food through the midge larva’s short and narrow foregut,digestion and absorption of ingested material occurs across the peritrophic membrane and microvilli that line the lumen of the midgut.Subsequently digested food passes into the hindgut where ions,small molecules and water are absorbed across a cuticular lining.Comparisons of internal gut morphology of arthropods complement existing studies of external morphological features and molecular characters on which traditional phylogenetic relationships,representing genetic differences among organisms, are based.Although the alimentary canals of other species in the family Chironomidae have not been examined at the cellular level of organization examined in this manuscript,a compre-hensive comparison of internal morphological characters among related species would reveal differences that presumably are based on environmental adaptations.In this study we explore the possibility that the extreme environment in which these midge larvae live shapes the architecture of their gut epithelial cells.2.Materials and methodsLarvae of B.antarctica were collected from sites near penguin rookeries on Cormorant and Humble Islands,near Palmer Station, Antarctica(64 460S,64 040W)in January and February2007.The high nitrogen run-off from penguin rookeries provides the nutrient base for the microbes,algae(Prasiola crispa),lichens and moss with which midge larvae are usually rval development is restricted to the brief austral summer,from late December until mid-February;and larvae remain immobilized in the frozen substrate for the remainder of the year.Two years are required for the larva to complete its development(Usher and Edwards,1984),and adult life is compressed into a1–2week period in late December/early January(Sugg et al.,1983).Larvae collected in Antarctica were shipped to the laboratory at Ohio State University where they were maintained with their substrate at4 C.Digestive tracts and salivary glands from32individuals were dissected withfine watchmaker’s forceps in Grace’s insect culture medium.Tissues were immediatelyfixed at4 C in a primary fixative of2.5%glutaraldehyde(v/v)and0.5%paraformaldehyde (w/v)dissolved in a rinse buffer of0.1M cacodylate(pH7.4) containing0.18mM CaCl2and0.58mM sucrose.After3h in this fixative,tissues were washed three times with rinse buffer before being transferred to secondaryfixative(2%osmium tetroxide dissolved in rinse buffer,w/v)for4h.After thoroughly washing with rinse buffer,tissues were gradually dehydrated in a graded ethanol series(10–100%,v/v).From absolute ethanol,tissues were transferred to propylene oxide and infiltrated with mixtures of propylene oxide and resin before being embedded in pure LX112 resin.Semithin sections for light microscopy were mounted on glass slides and stained with0.5%toluidine blue in1%borax(w/v). Ultrathin sections were mounted on grids and stained briefly with saturated aqueous uranyl acetate and Luft’s lead citrate to enhance contrast.Images were taken with a Hitachi600transmission electron microscope operating at75kV.Whole mounts were prepared byfixing tissues at room temperature for30min in a4%solution of paraformaldehyde (w/v)dissolved in phosphate-buffered saline(PBS).After Fig.1.(a)Whole mount of larval gut with the three major divisions of the gut demarcated with arrows:fm¼foregut–midgut boundary;mh¼midgut–hindgut boundary.The stomodeal valve lies immediately posterior to fm(see Fig.4).The sclerotized head capsule is attached at the anterior end and four Malpighian tubules attach at the midgut–hindgut boundary.(b)Lateral view of the larva. Dorsal is to the right.Beneath the relatively translucent integument of the three thoracic segments(arrows point to prothoracic and metathoracic segments),lie imaginal discs for the three pairs of legs.Dorsal to these leg discs in the meso-thoracic and metathoracic segments are wing and haltere discs,respectively.Scale bar¼1.0mm.J.B.Nardi et al./Arthropod Structure&Development38(2009)377–389 378several rinses in PBS,nuclei of cells were labeled with1:1000 dilution of40,6-diamidino-2-phenylindole(DAPI,1mg/ml water)afterfirst permeabilizing cells for30min in a solution of 0.1%Triton X-100in PBS(v/v).Tissues were mounted under cover glasses in a solution of70%glycerin in0.1M Tris at pH 9.0(v/v).3.Results3.1.Global organization of the Belgica larval gutThe larval gut is a straight alimentary canal that is associated with a pair of salivary glands at its anterior end and four Malpighian tubules that converge with the alimentary canal at the junction of midgut and hindgut(Fig.1,mh).A prominent stomodeal valve occupies the interface between foregut and midgut(Fig.1,fm).The foregut occupies only about5%of the total length of the alimentary canal,while the endodermal midgut that occupies the region between fm and mh in Fig.1 clearly represents more than half the length of the alimentary canal.3.2.Salivary glands and foregutConspicuous salivary glands occupy the anterior end of the larval midge.These glands are both polyploid and polytene(Fig.2).Fig.3.Cuticles of foregut and epidermal epithelia have different stratification.At higher magnification,the internal folded foregut cuticle(a)is compared with the cuticle of the external epidermis(b).A bracket extends across the foregut cuticle.The gut lumen(*)is surrounded by relatively thin cuticle compared to the thicker epidermal cuticle in(b) epithelial cells(e),pigmented fat body(f).In(c)the convoluted integument of the foregut(arrowhead)is surrounded by muscles(arrows),tracheoles(t),neural tissue(n)and salivary gland(g).Scale bars:(a)1.0m m,(b)5m m,and(c)20mm.Fig.2.Whole mount of Belgica salivary gland as viewed with Nomarski optics(a)and after labeling DNA with DAPI(b).The salivary duct is located at the arrow.Scale bar¼50m m.J.B.Nardi et al./Arthropod Structure&Development38(2009)377–389379Like glands found in other larval members of the Chironomidae,these salivary glands secrete silken threads that entrap food particles.On the foregut’s apical surface,the cuticle lining the narrow foregut lumen is about 0.3–0.5m m thick (Fig.3a).Unlike the thicker,contiguous cuticle of the larva’s exoskeleton with its inner electron-dense layer (Fig.3b),this foregut cuticle is highly convoluted and its outermost layer is electron-dense.Conspicuous muscle layers surround the foregut.The large salivary glands and larval brain in turn surround these muscles on the basal surface of the larval foregut (Fig.3c).3.3.Stomodeal valve at foregut–midgut interfaceAfter being channeled through a foregut lumen lined by a convoluted cuticle,the contents of the gut pass through a conspicuous stomodeal valve into the endoperitrophic space of the midgut epithelium.The stomodeal valve represents anintussusception of the foregut epithelium into the midgut (Figs.4a–d and 5a–c).This folding of the foregut epithelium and its cuticle creates a caecum that is lined centrally by foregut cuticle and peripherally by midgut microvilli.The interface of foregut and midgut lies at the anterior end of the caecum.At this junction of foregut and midgut,a peritrophic membrane origi-nates and lines the lumen of the more posterior midgut epithelia.3.4.Spatial differentiation of the midgut epitheliumAn abrupt epithelial discontinuity marked by disparity in midgut microvillar length occurs at the interface between the stomodeal region and the more posterior midgut epithelium (Fig.4c and 5d).Certain cells at this interface are specialized for secretion (Fig.5d–f)and possibly are endocrine cells.These cells at the posterior edge of the stomodeal valve were the only cells of the midgut observed to contain conspicuous secretorygranulesFig.4.The stomodeal valve represents an intussusception of posterior foregut epithelium (fe)into anterior midgut epithelium (me).(a)The folded foregut epithelium is surrounded by the anterior midgut.Anterior is to the right.(b,c)Longitudinal sections show inner lumen cuticle (ic)and outer lumen cuticle (oc)of the foregut.Between these two cuticles lie two foregut epithelial layers and an enteric muscle layer (m).Midgut epithelium is the outermost layer of the valve.(c)Represents the region delimited by the rectangle in (b).The morphological discontinuity is indicated by the arrow.The peritrophic membrane (p)lies in the lumen separating foregut and midgut.(d)The concentric arrangement of three epithelia,two lumina and one muscle layer is shown in this transverse section of the valve.From periphery to center:(1)midgut epithelium with microvilli lining the lumen in which the peritrophic membrane forms;(2)foregut epithelium faces this lumen and (3)enteric muscles (m)occupy the space between this foregut epithelium and the foregut epithelium facing the innermost lumen.Scale bars:(a,b,d)50m m;(c)20m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389380Fig.5.At higher resolution,longitudinal sections of the stomodeal valve reveal details of peritrophic membrane formation and the presence of special secretory cells.(a)At the interface between the foregut epithelium and midgut epithelium lies a confluence of muscle (m),foregut epithelium covered by cuticle (fg)and secretory microvilli (arrows)of midgut epithelium.Anterior is at the bottom.(b,c)Copious secretion of peritrophic membrane material (*)occurs from the microvilli of midgut epithelial cells at the anterior end of the stomodeal valve.Note the high density of mitochondria in the adjacent midgut cells.In (b)the newly formed peritrophic membrane (arrow)lies between the foregut (fg)cuticle and the tips of the microvilli.(d)Distinctive secretory cells (arrow)lie within the midgut epithelium of the stomodeal valve at the border between midgut cells with microvilli and midgut cells without obvious microvilli (See Fig.4c).The gut lumen is at upper left.(e,f)Close-ups of the secretory cell showing the nucleus (n),rough enoplasmic reticulum (arrowhead)and the high density of secretory granules (*).Scale bars:(a)10m m;(b,c)2m m;(d)5m m;(e)1m m;and (f)0.2m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389381(Fig.5e and f).Posterior to the stomodeal valve,a striking gradient of microvillar length occurs along the antero-posterior (AP)axis of the midgut epithelium (Fig.6),with short (w 0.1to 0.2m m)microvilli occupying anterior regions of the midgut and extremely long,straight and densely packed (w 10m m,Figs.7and 9)microvilli occupying posterior regions of the midgut.This morphological gradient is evident in longitudinal sections of the midgut (Fig.6a–c)as well as the series of transverse sections from different locations along the AP axis of the Belgica gut (Figs.6d–f and 7–9).Underlying the antero-posterior topography revealed by the microvilli of the midgut is a parallel topography,at the base of the microvilli,reflected by contours of the apical surfaces of the midgut cells.These surfaces are most convoluted in regions of the midgut with the shortest microvilli and are least convoluted in regions of the midgut with the longest microvilli (Fig.6d–f).Rough endoplasmic reticulum (RER)is present throughout all regions of the midgut (Figs.7d,8d,and 9d).Stacks of large flattened sacs of endoplasmic reticulum are especially evident in the posterior region of the midgut epithelium.Some smooth endoplasmic reticulum (SER)is interspersed among the RER of the anterior third of the midgut,with little if any SER is observed in the middle third or the posterior third of the midgut.However,clearly defined Golgi complexes are not evident in any of the midgut cells.The lumen of the middle third of the Belgica midgut is lined with microvilli of intermediate length (w 1m m)that are associ-ated with electron-dense particles of uniform size (w 0.05m m).These particles lie within the ectoperitrophic space and show a strong affinity for the microvilli (Fig.8a–c).Within the cyto-plasm of the underlying midgut cells,electron-dense particles of identical size are concentrated in autophagic vacuoles,each delimited by a plasma membrane,and are presumed to enter these epithelial cells by endocytosis.Numerous coated vesicles atthe base of microvilli on the luminal surfaces of these midgut cells (Fig.8c)offer an obvious route for the cellular uptake of these electron-dense particles from the ectoperitrophic space of the gut lumen.Infoldings of the basal membranes of epithelial cells are most prominent in the anterior and the posterior regions of the midgut (Figs.7c,8e,and 9c);mitochondria are most conspicuous along the basal surface of the anterior midgut (Fig.7a,c);and infoldings of the basal plasma membrane contain numerous mitochondria and electron-lucent vacuoles (Figs.7c and 9c).Regenerative cells are scattered throughout the larval midgut epithelia and presumably represent imaginal stem cells that replace the larval epithelium at metamorphosis.These cells are located basally in the larval epithelium and are densely packed with ribosomes and endoplasmic reticulum (Fig.10).3.5.Contents of the midgut lumen3.5.1.Endoperitrophic spaceWithin the gut lumen,the peritrophic membrane separates an inner endoperitrophic space from an outer ectoperitrophic space (Terra and Ferreira,1994;Fig.6).The anterior endoperitrophic space of the midgut is packed with relatively intact multicellular microbial organisms.Gradual digestion of microbes is reflected in the disappearance of pigmentation from the gut lumen in the posterior third of the midgut (Fig.1a).Within the confines of the midgut’s peritrophic membrane,microbial cells arranged singly or in various aggregates can be readily discerned.These cells can be identified as predominantly nonbacterial microbes –i.e.,algae,fungi,lichens,protists (Fig.11a–c).3.5.2.Ectoperitrophic spaceThe surrounding ectoperitrophic space is lined by midgut epithelium with microvilli whose lengths are graded alongtheFig.6.Longitudinal (a–c)and transverse (d–f)sections of midgut epithelium posterior to the stomodeal valve show regional differences along the antero-posterior axis of the gut.Three equally spaced regions along this axis are illustrated:(a,d)anterior region;(b,e)middle region;(c,f)posterior region.In each image the microvillar surface and gut lumen are at top.The peritrophic membrane (arrow)is visible in (a,b,d,and e).Scale bars ¼20m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389382antero-posterior axis.Within one of the 10whole mounts of larval guts prepared,gregarines with distinctive appendages were found in this midgut zone (between the peritrophic matrix and midgut epithelial surface)(Fig.11d and e).Considering the isolation of these gregarines from other related host species,these protists most likely represent a distinct species of dipteran parasite.3.6.Spatial differentiation of the hindgut3.6.1.Ring of undifferentiated,presumptive adult hindgut epitheliumIn the images of the Belgica gut labeled with DAPI (Fig.12a),a discontinuity in nuclear labeling is observed at the midgut–hindgut boundary.At the anterior-most region of the larval hindgut,an imaginal ring of undifferentiated presumptive adult hindgut cells appears in whole mounts as a zone of cells with small nuclei among the polyploid nuclei in cells of the larval hindgut epithelium.Immediately posterior to the imaginal ring of epithelial cells,the anterior third of the hindgut is lined by a smooth cuticle approximately 0.25m m thick.This hindgut cuticle,like the foregut cuticle,is contiguous with the exoskeleton.Also,like the foregut cuticle,the hindgut cuticle secretes a well-delineated,electron-dense outermost cuticular layer.The arrangement of these different layers secreted by hindgut epithelial cells is distinct from the arrangement of the cuticular layers secreted by epidermal epithelia (Fig.3b).The anterior hindgut cuticle is secreted by attenuated,highly folded extensions of the apical surfaces of the hindgut epithelium containing conspicuous mitochondria and separated by large vacuoles that lack electron-density (Fig.12b andc).Fig.7.These are ultrastructural images of the anterior region of the midgut epithelium.Note the high concentration of mitochondria along the basal surface of the epithelium in (a)as well as the dark cell (arrow)at the basal surface of this epithelium.Lumen is marked with an asterisk (*).(b)The epithelial surface facing the lumen (*)is covered by short microvilli.(c)Mitochondria (arrows)are localized among membrane infoldings that lie adjacent to the basal lamina and enteric muscles (arrowhead).(d)Perinuclear region of midgut cell.Rough endoplasmic reticulum (ER)marked with arrowhead.Smooth ER marked with double arrowhead.Arrows point to mitochondria.n ¼nucleus.Scale bars:(a)5m m;(b,c)2m m;and (d)1m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389383While apical ends of epithelial cells in the anterior third of the hindgut have conspicuous large vacuoles,the central region of the hindgut is occupied by epithelial cells that lack vacuoles but that have extremely convoluted apical membranes characteristic of epithelial cells involved in active transport of ions and water (Fig.12d and e).Also in the central region of the hindgut,the presence of the electron-dense bacteria observed in high-resolu-tion images is reflected in the pigmentation of the central portion of the hindgut as viewed in whole mounts of larval guts (Fig.1a).In the posterior third of the hindgut or rectum,the highly convoluted cuticle lining the lumen mirrors the structure of the foregut.The apical surfaces of the epithelial cells of the rectum lack infolded membranes associated with mitochondria and are apparently not specialized for transport of ions and water.The basal surface of this region,by contrast,is highly infolded.Association of this basal surface with numerous muscles suggeststhis posterior-most hindgut epithelium serves a mechanical function.In this most posterior portion of the hindgut,the lumen is devoid of both resident microbes as well as ingested microbes (Fig.12f).3.7.Muscles associated with the gut epitheliaThe basal surface of the hindgut epithelium,like the foregut epithelium,is closely apposed to a uniformly thick layer of circum-ferential muscles (w 10m m)(Figs.3c,12e,f).By contrast,muscles associated with the midgut epithelium are sparsely but regularly distributed over the midgut’s basal surface (Figs.6–9).Relatively widely dispersed muscle cells lie on the basal surface of the midgut epithelium and are embedded in the matrix of the epithelial basal lamina.These represent the longitudinal muscles of the gut.Sparsely distributed circumferential muscles are alsopresent.Fig.8.Different magnifications of the middle region of the midgut are illustrated in (a–e).In images a and c,the midgut lumen is at the top;in e,it is down.Electron-dense particles occupy the space between the peritrophic membrane (arrow in a)and the microvillar parable particles are observed in autophagic vacuoles of midgut cells (arrowheads in b).(c)Higher resolution images suggest that these particles are taken up by endocytosis (arrows)at the microvillar surface.(d)Perinuclear region of midgut cell.Arrowheads indicate rough endoplasmic reticulum;arrows point to mitochondria;n ¼nucleus;me ¼membrane between two cells.(e)Basal lamina (arrowhead)and muscles (m)cover the basal surface of this ldings of the basal surface of plasma membrane are not conspicuous.Scale bars:(a)5m m;(b,c)1.0m m;(d)1m m;and (e)2m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–3893844.DiscussionThe study of insect diversity and evolution has been advanced by extensive surveys of molecular phylogeny and morphology of external integuments;however,knowledge and appreciation of insect diversity remain incomplete without adequate knowledge of the diversity of internal anatomy/physi-ology of insects and how this diversity is influenced by environment.With the paucity of information on the cellular architecture of insect guts,however,associating particular gut epithelial struc-tures with adaptation to particular diets and/or environments remains in a rudimentary state.Conventional descriptions of gut epithelial diversity (Lehane,1998;Noble-Nesbitt,1998;Terra et al.,1988)clearly do not consider the marked regional differ-entiation of microvilli on midgut cells of B.antarctica to be a common feature of epithelial cells of insect guts.Establishinghow general or how unique internal features are among insects,however,awaits additional structural studies on other related insect species.4.1.Differentiation of foregut–midgut boundary:structure of the peritrophic membrane and stomodeal valveA specialized luminal region at the foregut–midgut boundary can be visualized even in whole mounts of the alimentary canal (Fig.1a).In cross-sections and longitudinal sections of the alimentary canal at this boundary region,an inner concentric ring of folded foregut epithelium and associated muscle layers lies within the anterior midgut epithelium (Figs.4,5).Among the Diptera,the degree of specialization of foregut and midgut epithelial cells varies among the suborders.The most complex specialization of the foregut–midgut interface is found among the muscoid flies,in which specialized anteriormidgutFig.9.In a–c,the midgut lumen is to the left.Different magnifications of the posterior region of the midgut are illustrated.(a)Note numerous clear vacuoles (arrows)that lie between the luminal microvilli and the basal lamina (lower right).(b)The long microvilli are densely packed and extend approximately 10m m into the lumen.(c)The basal membranes of cells in this posterior region are highly folded.Basal lamina is indicated with arrowheads.Muscle ¼m.(d)Perinuclear region of midgut cell.Arrowheads indicate rough endoplasmic reticulum;arrows point to mitochondria.Scale bars:(a)10m m;(b)5m m;(c)2m m;and (d)1m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389385epithelium is closely apposed to the stomodeal valve to form the distinctive cardia (Eisemann et al.,2001;Binnington,1988);but the simplest specialization of the foregut–midgut interface is observed in the suborder Nematocera,of which Belgica is a member.In these flies,the foregut has been described as forming a short intussusception into the anterior midgut referred to as the stomodeal valve (King,1991;Wigglesworth,1930).For Belgica ,however,this intussusception of foregut as a percentage of total foregut surrounded by midgut is higher than that reported by Volf et al.(2004)for four other nem-atoceran Diptera in the families Culicidae (Culex pipiens )and Psychodidae (Lutzomyia longipalpis ,Phlebotomus duboscqi ,Phle-botomus papatasi ).Peritrophic structures for many insect species have often been described as chitinous,reticulated membranes with chitin micro-fibrils in a hexagonal or orthogonal arrangement (Lehane,1998).These peritrophic structures consist of chitin networks embedded in protein–carbohydrate matrices (Wang and Granados,2001;Tellam et al.,1999).The origin and consistency of peritrophic membranes,gels and matrices differ among the insects (Terra,2001;Binnington et al.,1998).The peritrophic structures of some insects,such as lepi-dopteran larvae,have traditionally been described as arising from cells along the length of the midgut epithelium (type I peritrophic matrix).Recent studies involving labeling of lepidopteran peri-trophic proteins have indicated that while one peritrophic protein (i.e.,invertebrate intestinal mucin)is secreted by epithelial cells throughout the length of the midgut (Harper and Granados,1999),certain peritrophic proteins recognized by an antibody raised against the peritrophic membrane of Heliothis virescens are produced by specialized cells near the foregut–midgut interface (Ryerse et al.,1992).At the junction of foregut and midgut epithelia in Diptera,the peritrophic structure (type II)arises from microvilli of midgut epithelia (Eisemann et al.,2001)and lines the lumen of the more posterior midgut epithelia.In Belgica ,the midgut epithelial cells of the stomodeal valve are the only cells observed to produce a copious secretion associated with a newly formed structure that represents a type II peritrophic membrane.4.2.Regional differentiation of midgut epitheliumAt least in some insects,the midgut is differentiated both structurally and functionally along its length (Lehane,1998;Marana et al.,1997;Ferreira et al.,1990;Terra et al.,1988;Dow,1981).The marked and graded differences in microvillar lengths observed for Belgica midgut epithelial cells,however,represent an extreme example of such regional differentiation (Fig.6).Extensive infolding of the basal epithelial surface of midgut and hindgut cells,however,as frequently observed in other insects,is only evident in certain regions (anterior third and posterior third)of the Belgica midgut and the posterior third (rectum)of its hindgut (Villaro et al.,1999;Lehane,1998;Marana et al.,1997).See Figs.7c,8e,9c and 12f.The high concentrations of electron-dense particles that occupy the ectoperitrophic space of the central region of the midgut are not observed elsewhere in the alimentary canal.The presence of comparable particles in autophagic vacuoles of these midgut cells suggests that these particles are taken up by cells rather than secreted by gut cells.The high concentration of particles in the gut lumen also implies that their movement proceeds toward the low concentration of particles observed within the midgut epithelial cells.Although regenerative cells have not been observed in midgut epithelia of certain immature arthropods such aslarvalFig.10.Regenerative cells (asterisks)of midgut epithelium are scattered throughout the larval epithelium.Cells from different regions along the antero-posterior axis are shown.(a)Anterior third.(b)Middle third.(c)Posterior third.Arrowheads point to basal laminae;m ¼muscles;n ¼nuclei of regenerative cells.Scale bars ¼2.0m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389386。

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在实际编程中用这一招解决了不少原本看来莫名其妙的问题。

比较麻烦的是每次都要去linux源代码里面查找错误代码的含义，现在把它贴出来，以后需要查时就来这里看了。

1-34号错误号是在内核源码的include/asm-generic/errno-base.h定义35-132则是在include/asm-generic/errno.h中定义剩下还有一些更大的错误号是留给内核级别的，如系统调用等，用户程序一般是看不见的这些号的，Ubuntu9.10中/usr/src/linux-headers-2.6.31-21-generic/include/linux/errno.h#ifndef _ASM_GENERIC_ERRNO_BASE_H#define _ASM_GENERIC_ERRNO_BASE_H#define EPERM 1 /＊Operation not permitted ＊/ #define ENOENT 2 /＊No such file or directory ＊/ #define ESRCH 3 /＊No such process ＊/#define EINTR 4 /＊Interrupted system call ＊/ #define EIO 5 /＊I/O error ＊/#define ENXIO 6 /＊No such device or address ＊/ #define E2BIG 7 /＊Argument list too long ＊/ #define ENOEXEC 8 /＊Exec format error ＊/ #define EBADF 9 /＊Bad file number ＊/#define ECHILD 10 /＊No child processes ＊/ #define EAGAIN 11 /＊Try again ＊/#define ENOMEM 12 /＊Out of memory ＊/#define EACCES 13 /＊Permission denied ＊/ #define EFAULT 14 /＊Bad address ＊/#define ENOTBLK 15 /＊Block device required ＊/ #define EBUSY16 /＊Device or resource busy ＊/ #define EEXIST 17 /＊File exists ＊/#define EXDEV 18 /＊Cross-device link ＊/#define ENODEV 19 /＊No such device ＊/#define ENOTDIR 20 /＊Not a directory ＊/#define EISDIR 21 /＊Is a directory ＊/#define EINVAL 22 /＊Invalid argument ＊/#define ENFILE 23 /＊File table overflow ＊/#define EMFILE 24 /＊Too many open files ＊/#define ENOTTY 25 /＊Not a typewriter ＊/#define ETXTBSY 26 /＊Text file busy ＊/#define EFBIG 27 /＊File too large ＊/#define ENOSPC 28 /＊No space left on device ＊/ #define ESPIPE 29 /＊Illegal seek ＊/#define EROFS 30 /＊Read-only file system ＊/#define EMLINK 31 /＊Too many links ＊/#define EPIPE 32 /＊Broken pipe ＊/#define EDOM 33 /＊Math argument out of domain of func ＊/#define ERANGE 34 /＊Math result not representable ＊/#endif#include#define EDEADLK 35 /＊Resource deadlock would occur ＊/ #define ENAMETOOLONG 36 /＊File name too long ＊/#define ENOLCK 37 /＊No record locks available ＊/ #define ENOSYS 38 /＊Function not implemented ＊/ #defineENOTEMPTY 39 /＊Directory not empty ＊/#define ELOOP 40 /＊Too many symbolic links encountered ＊/#define EWOULDBLOCK EAGAIN /＊Operation would block ＊/ #define ENOMSG 42 /＊No message of desired type ＊/ #define EIDRM 43 /＊Identifier removed ＊/#define ECHRNG 44 /＊Channel number out of range ＊/ #define EL2NSYNC 45 /＊Level 2 not synchronized ＊/ #define EL3HLT 46 /＊Level 3 halted ＊/#define EL3RST 47 /＊Level 3 reset ＊/#define ELNRNG 48 /＊Link number out of range ＊/#define EUNATCH 49 /＊Protocol driver not attached ＊/ #define ENOCSI 50 /＊No CSI structure available ＊/ #define EL2HLT 51 /＊Level 2 halted ＊/#define EBADE 52 /＊Invalid exchange ＊/#define EBADR 53 /＊Invalid request descriptor ＊/ #define EXFULL 54 /＊Exchange full ＊/#define ENOANO 55 /＊No anode ＊/#define EBADRQC 56 /＊Invalid request code ＊/ #define EBADSLT 57 /＊Invalid slot ＊/#define EDEADLOCK EDEADLK#define EBFONT 59 /＊Bad font file format ＊/#define ENOSTR 60 /＊Device not a stream ＊/#define ENODATA 61 /＊No data available ＊/#define ETIME 62 /＊Timer expired ＊/#define ENOSR 63 /＊Out of streams resources ＊/#define ENONET 64 /＊Machine is not on the network ＊/ #define ENOPKG 65 /＊Package not installed ＊/ #define EREMOTE 66 /＊Object is remote ＊/#define ENOLINK 67 /＊Link has been severed ＊/ #define EADV 68 /＊Advertise error ＊/#define ESRMNT 69 /＊Srmount error ＊/#define ECOMM 70 /＊Communication error on send ＊/ #define EPROTO 71 /＊Protocol error ＊/#define EMULTIHOP 72 /＊Multihop attempted ＊/#define EDOTDOT 73 /＊RFS specific error ＊/#define EBADMSG 74 /＊Not a data message ＊/#define EOVERFLOW 75 /＊Value too large for defined data type ＊/#define ENOTUNIQ 76 /＊Name not unique on network ＊/#define EBADFD 77 /＊File descriptor in bad state ＊/ #define EREMCHG 78 /＊Remote address changed ＊/ #define ELIBACC 79 /＊Can not access a needed shared library ＊/#define ELIBBAD 80 /＊Accessing a corrupted shared library ＊/ #define ELIBSCN 81 /＊ .lib section in a.out corrupted ＊/#define ELIBMAX 82 /＊Attempting to link in too many shared libraries ＊/#define ELIBEXEC 83 /＊Cannot exec a shared library directly ＊/ #define EILSEQ 84 /＊Illegal byte sequence ＊/#define ERESTART 85 /＊Interrupted system call should be restarted ＊/#define ESTRPIPE 86 /＊Streams pipe error ＊/#define EUSERS 87 /＊Too many users ＊/#define ENOTSOCK 88 /＊Socket operation on non-socket ＊/#define EDESTADDRREQ 89 /＊Destination address required ＊/ #define EMSGSIZE 90 /＊Message too long ＊/#define EPROTOTYPE 91 /＊Protocol wrong type for socket ＊/ #define ENOPROTOOPT 92 /＊Protocol not available ＊/#define EPROTONOSUPPORT 93 /＊Protocol not supported ＊/ #define ESOCKTNOSUPPORT 94 /＊Socket type not supported ＊/ #define EOPNOTSUPP 95 /＊Operation not supported on transport endpoint ＊/#define EPFNOSUPPORT 96 /＊Protocol family not supported ＊/ #define EAFNOSUPPORT 97 /＊Address family not supported by protocol ＊/#define EADDRINUSE 98 /＊Address already in use ＊/#define EADDRNOTAVAIL 99 /＊Cannot assign requested address ＊/#define ENETDOWN 100 /＊Network is down ＊/#define ENETUNREACH 101 /＊Network is unreachable ＊/#define ENETRESET 102 /＊Network dropped connection because of reset ＊/#define ECONNABORTED 103 /＊Software caused connection abort ＊/#define ECONNRESET 104 /＊Connection reset by peer ＊/#define ENOBUFS 105 /＊No buffer space available ＊/ #define EISCONN 106 /＊Transport endpoint is already connected ＊/#define ENOTCONN 107 /＊Transport endpoint is not connected ＊/#define ESHUTDOWN 108 /＊Cannot send after transport endpoint shutdown ＊/#define ETOOMANYREFS 109 /＊T oo many references: cannot splice ＊/#define ETIMEDOUT 110 /＊Connection timed out ＊/#define ECONNREFUSED 111 /＊Connection refused ＊/ #define EHOSTDOWN 112 /＊Host is down ＊/#define EHOSTUNREACH 113 /＊No route to host ＊/#define EALREADY 114 /＊Operation already in progress ＊/ #define EINPROGRESS 115 /＊Operation now in progress ＊/ #define ESTALE 116 /＊Stale NFS file handle ＊/ #define EUCLEAN 117 /＊Structure needs cleaning ＊/ #define ENOTNAM 118 /＊Not a XENIX named type file ＊/ #define ENAVAIL 119 /＊No XENIX semaphores available ＊/ #define EISNAM 120 /＊Is a named type file ＊/ #define EREMOTEIO 121 /＊Remote I/O error ＊/#define EDQUOT 122 /＊Quota exceeded ＊/#define ENOMEDIUM 123 /＊No medium found ＊/#define EMEDIUMTYPE 124 /＊Wrong medium type ＊#define ECANCELED 125 / ＊操作已取消＊/#define ENOKEY 126 / ＊必需的密钥不可用＊/ #define EKEYEXPIRED 127 / ＊密钥已过期＊/#define EKEYREVOKED 128 / ＊密钥已被撤销＊/#define EKEYREJECTED 129 / ＊密钥被服务拒绝＊// ＊用于强大的互斥体＊/#define EOWNERDEAD 130 / ＊所有者死亡＊/#define ENOTRECOVERABLE 131 / ＊状态不可恢复＊/#define ERFKILL 132 / ＊由于射频杀死＊/#ifdef __KERNEL__/ ＊＊用户程序切勿看到这些内容。

Bin Dec Hex 缩写/字符解释0000 0000 0 00 NUL (null) 空字符0000 0001 1 01 SOH (start of handing) 标题开始0000 0010 2 02 STX (start of text) 正文开始0000 0011 3 03 ETX (end of text) 正文结束0000 0100 4 04 EOT (end of transmission) 传输结束0000 0101 5 05 ENQ (enquiry) 请求0000 0110 6 06 ACK (acknowledge) 收到通知0000 0111 7 07 BEL (bell) 响铃0000 1000 8 08 BS (backspace) 退格0000 1001 9 09 HT (horizontal tab) 水平制表符0000 1010 10 0A LF (NL line feed, new line) 换行键0000 1011 11 0B VT (vertical tab) 垂直制表符0000 1100 12 0C FF (NP form feed, new page) 换页键0000 1101 13 0D CR (carriage return) 回车键0000 1110 14 0E SO (shift out) 不用切换0000 1111 15 0F SI (shift in) 启用切换0001 0000 16 10 DLE (data link escape) 数据链路转义0001 0001 17 11 DC1 (device control 1) 设备控制1 0001 0010 18 12 DC2 (device control 2) 设备控制2 0001 0011 19 13 DC3 (device control 3) 设备控制3 0001 0100 20 14 DC4 (device control 4) 设备控制4 0001 0101 21 15 NAK (negative acknowledge) 拒绝接收0001 0110 22 16 SYN (synchronous idle) 同步空闲0001 0111 23 17 ETB (end of trans. block) 传输块结束0001 1000 24 18 CAN (cancel) 取消0001 1001 25 19 EM (end of medium) 介质中断0001 1010 26 1A SUB (substitute) 替补0001 1011 27 1B ESC (escape) 溢出0001 1100 28 1C FS (file separator) 文件分割符0001 1101 29 1D GS (group separator) 分组符0001 1110 30 1E RS (record separator) 记录分离符0001 1111 31 1F US (unit separator) 单元分隔符0010 0000 32 20 空格0010 0001 33 21 !0010 0010 34 22 "0010 0011 35 23 #0010 0100 36 24 $0010 0101 37 25 %0010 0110 38 26 &0010 0111 39 27 '0010 1000 40 28 (0010 1001 41 29 )0010 1010 42 2A *0010 1100 44 2C , 0010 1101 45 2D - 0010 1110 46 2E . 0010 1111 47 2F / 0011 0000 48 30 0 0011 0001 49 31 1 0011 0010 50 32 2 0011 0011 51 33 3 0011 0100 52 34 4 0011 0101 53 35 5 0011 0110 54 36 6 0011 0111 55 37 7 0011 1000 56 38 8 0011 1001 57 39 9 0011 1010 58 3A : 0011 1011 59 3B ; 0011 1100 60 3C < 0011 1101 61 3D = 0011 1110 62 3E > 0011 1111 63 3F ? 0100 0000 64 40 @ 0100 0001 65 41 A 0100 0010 66 42 B 0100 0011 67 43 C 0100 0100 68 44 D 0100 0101 69 45 E 0100 0110 70 46 F 0100 0111 71 47 G 0100 1000 72 48 H 0100 1001 73 49 I 0100 1010 74 4A J 0100 1011 75 4B K 0100 1100 76 4C L 0100 1101 77 4D M 0100 1110 78 4E N 0100 1111 79 4F O 0101 0000 80 50 P 0101 0001 81 51 Q 0101 0010 82 52 R 0101 0011 83 53 S 0101 0100 84 54 T 0101 0101 85 55 U0101 0111 87 57 W0101 1000 88 58 X0101 1001 89 59 Y0101 1010 90 5A Z0101 1011 91 5B [0101 1100 92 5C \0101 1101 93 5D ]0101 1110 94 5E ^0101 1111 95 5F _0110 0000 96 60 `0110 0001 97 61 a0110 0010 98 62 b0110 0011 99 63 c0110 0100 100 64 d0110 0101 101 65 e0110 0110 102 66 f0110 0111 103 67 g0110 1000 104 68 h0110 1001 105 69 i0110 1010 106 6A j0110 1011 107 6B k0110 1100 108 6C l0110 1101 109 6D m0110 1110 110 6E n0110 1111 111 6F o0111 0000 112 70 p0111 0001 113 71 q0111 0010 114 72 r0111 0011 115 73 s0111 0100 116 74 t0111 0101 117 75 u0111 0110 118 76 v0111 0111 119 77 w0111 1000 120 78 x0111 1001 121 79 y0111 1010 122 7A z0111 1011 123 7B {0111 1100 124 7C |0111 1101 125 7D }0111 1110 126 7E ~0111 1111 127 7F DEL (delete) 删除。

DVADVA、、、。

，。

、DVA。

、 ，。

DVA……………………………………………………1-1…………………………………………………2-1 ，…………………………………………………………3-1………………………………………4-1……………………………………………5-1……………………………………6-1 DVA………………………………………7-1 …………………………………8-1 DVA…………………………………………9-1……………………………10-1：，。

，，。

U/T1，V/T2，W/T3AC。

，。

，DVADVA(DVA，■ ■3 . 7kW 380VDVS-001)，。

，。

R U N S T O PJ O G F W D R E V35MODEL : DVA-4T0037G/4T0055PINPUT : 3PH 380-460V 50/60Hz 10/14AS/N:Drive Electric Co.,Ltd.Made In ChinaFWD REV JOGRUNMODE PROG DATASTOP RESET42: A 4T 0 03 7 G V109000508 0100 1DV A - 4 T 0022 G7A220V 380VPG2 4(kW)T S0004 0007 0015 0022 0037 0055 0075 3150①：②： ③： ④： ⑤： ⑥： ⑦：，315。

1-11-2DVA DVA▲，，√√√√√、。

-20℃0%、。

+65℃，。

，：▲。

-10℃～50℃。

40℃，：：mm——LC-A05E95%58150mm50mm50mm131754 .5：，，（），。

150mm70▲▲▲▲、、、、。

☆☆LC - A0 5 E：D V A - 2 S 0 0 0 4 G～D V A - 2 S 0 0 3 7 G；D V A - 4 T 0 0 0 7 G～D V A - 4 T0 1 1 0 G。

C++ L2题解一维数组的初步认识
第2题查找跳绳成绩
一批同学参加跳绳比赛，体育老师已经将成绩记录好，后来有其他老师要查寻某个同学的成绩，请你帮助他。

输入格式
分三行，第一行参加跳绳的学生人数n，第二行是按序号排好的n个学生跳绳的成绩，最后一行是要查询的那个同学的序号。

输出格式
要查询的同学的序号和他跳绳的成绩.
输入/输出例子1
输入：
5
151 157 132 172 146
3
输出：
3 132
样例解释
无
参考答案
#include<bits/stdc++.h>
using namespace std;
int cj[10001],a,b,n,o;
int main(){
cin>>n;
for(int i=1;i<=n;i++)
cin>>cj[i];
cin>>o;
cout<<o<<" "<<cj[o];
return 0;
}。

第五章应用指令5.1 数据传送指令............................................................................5.1.1 MOV, MOVP, DMOV, DMOVP .....................................................5.1.2 CMOV, CMOVP, DCMOV, DCMOVP ...........................................5.1.3 GMOV, GMOVP ............................................................................5.1.4 FMOV, FMOVP ..............................................................................5.1.5 BMOV, BMOVP .............................................................................5.2 转换指令...................................................................................5.1.1 BCD, BCDP, DBCD, DBCDP .......................................................5.2.2 BIN, BINP, DBIN, DBINP .............................................................5.3 比较指令...................................................................................5.3.1 CMP, CMPP, DCMP, DCMPP ......................................................5.3.2 TCMP, TCMPP, DTCMP, DTCMPP ..............................................5.3.3 LD ( =, >, <, >=, <=, <> ) ..........................................................5.3.4 AND ( =, >, <, >=, <=, <>) .........................................................5.3.5 OR ( =, >, <, >=, <=, <>) ...........................................................5.4 增加/减少运算...........................................................................5.4.1 INC, INCP, DINC, DINCP .............................................................5.4.2 DEC, DECP, DDEC, DDECP .......................................................5.5 回转指令...................................................................................5.5.1 ROL, ROLP, DROL, DROLP ........................................................5.5.2 ROR, RORP, DROR, DRORP......................................................5.5.3 RCL, RCLP, DRCL, DRCLP .........................................................5.5.4 RCR, RCRP, DRCR, DRCRP ......................................................5.6 移位指令...................................................................................5.6.1 BSFT, BSFTP ................................................................................5.6.2 WSFT, WSFTP ..............................................................................5.6.3 SR ..................................................................................................5.7 交换指令...................................................................................5.7.1 XCHG, XCHGP, DXCHG, DXCHGP .............................................5.8 BIN 算术指令 ...........................................................................5.8.1 ADD, ADDP, DADD, DADDP .......................................................5.8.2 SUB, SUBP, DSUB, DSUBP ........................................................5.8.3 MUL, MULP, DMUL, DMULP .......................................................5.8.4 MULS, MULSP, DMULS, DMULSP ..............................................5.8.5 DIV, DIVP, DDIV, DDIVP ..............................................................5.8.6 DIVS, DIVSP, DDIVS, DDIVSP ....................................................5.9.1 ADDB, ADDBP, DADDB, DADDBP ..............................................5.9.2 SUBB, SUBBP, DSUBB, DSUBBP ..............................................5.9.3 MULB, MULBP, DMULB, DMULBP ..............................................5.9.4 DIVB, DIVBP, DDIVB, DDIVBP ....................................................5.10 逻辑算术指令 .......................................................................5.10.1 WAND, WANDP, DWAND, DWANDP ..........................................5.10.2 WOR, WORP, DWOR, DWORP ..................................................5.10.3 WXOR, WXORP, DWXOR, DWXORP .........................................5.10.4 WXNR, WXNRP, DWXNR, DWXNRP ..........................................5.11 数据处理指令............................................................................5.11.1 SEG, SEGP ...................................................................................5.11.2 ASC, ASCP ...................................................................................5.11.3 BSUM, BSUMP, DBSUM, DBSUMP ............................................5.11.4 ENCO, ENCOP .............................................................................5.11.5 DECO, DECOP .............................................................................5.11.6 FILR, FILRP, DFILR, DFILRP ......................................................5.11.7 FILW, FILWP, DFILW, DFILWP .....................................................5.11.8 DIS, DISP ......................................................................................5.11.9 UNI, UNIP ......................................................................................5.12 系统指令 ..............................................................................5.12.1 FALS ..............................................................................................5.12.2 DUTY .............................................................................................5.12.3 WDT, WDTP ..................................................................................5.12.4 OUTOFF ........................................................................................5.12.5 STOP .............................................................................................5.13 跳转指令 ..............................................................................5.13.1 JMP, JME ......................................................................................5.13.2 CALL, CALLP, SBRT, RET ...........................................................5.14 循环指令 ..............................................................................5.14.1 FOR, NEXT ...................................................................................5.14.2 BREAK ...........................................................................................5.15 标志指令 ..............................................................................5.15.1 STC, CLC ......................................................................................5.15.2 CLE ................................................................................................5.16 特殊模块指令 .......................................................................5.16.1 GET, GETP ....................................................................................5.16.2 PUT, PUTP ....................................................................................5.17.1 READ .............................................................................................5.17.2 WRITE............................................................................................5.17.3 RGET .............................................................................................5.17.4 RPUT .............................................................................................5.17.5 STATUS .........................................................................................5.18 中断指令 ..............................................................................5.18.1 EI, DI .............................................................................................5.18.2 TDINT, IRET ..................................................................................5.18.3 INT, IRET .......................................................................................5.19 符号反转指令 .......................................................................5.19.1 NEG, NEGP, DNEG, DNEGP .......................................................5.20 位接触指令...........................................................................5.20.1 BLD, BLDN ....................................................................................5.20.2 BAND, BANDN ..............................................................................5.20.3 BOR, BORN ..................................................................................5.20.4 BOUT .............................................................................................5.20.5 BSET, BRST ..................................................................................5.21 计算机连接模块指令.............................................................5.21.1 SND................................................................................................5.21.2 RCV................................................................................................5.22高速计数器指令....................................................................5.22.1 HSCNT ...........................................................................................5.22.2 HSC................................................................................................5.23 RS-485 通讯指令.................................................................5.23.1 RECV .............................................................................................5.23.2 SEND .............................................................................................5 应用指令5.1.1 MOV, MOVP , DMOV, DMOVP1) 功能-- DMOV(P) : 传送在指定设备[ S+1, S ]中的32位数据到指定的设备[ D+1, D ].16位+ + 16 位- 执行条件2)在P0205.1.2 CMOV, CMOVP1) 功能- CMOV(P) : [ S ]的每一位求反之后传送结果到 [ D ].P020MOVP, DMOVP 求反- DCMOV(P) : [ S+1, S ]中的每一位求反之后，结果传送至[ D+1, D ].16 位+ 1 求反求反- 执行条件2)-1) 功能- 从指定的设备[ S ]开始传送‘n ’字的内容，以块的形式传送‘n ’字至以指定的设备[ D ]为开始的区域。

单片机原理及应用课程一单选题 (共74题，总分值74分 )1. 在异步通信中，数据传输的单位是（）（1 分）A. 字节B. 字C. 帧D. 位2. 在MCS-51中,需要外加电路实现中断撤除的是（）（1 分）A. 定时中断B. 脉冲方式的外部中断C. 外部串行中断D. 电平方式的外部中断3. MCS－51单片机片要用传送指令访问片外数据存储器，它的指令操作码助记符是以下哪个？（）（1 分）A. MULB. MOVXC. MOVCD. MOV4. ＃data表示（）（1 分）A. 8位直接地址B. 16位地址C. 8位立即数D. 16位立即数5. 读片外部数据存储器时，不起作用的信号是（）（1 分）A. /RDB. /WEC. /PSEND. ALE6. 能用紫外线光擦除ROM中的程序的只读存储器为（）（1 分）A. 掩膜ROMB. PROMC. EPROMD. EEPROM7. 开机复位后,CPU使用的是第0组工作寄存器,地址范围是（）（1 分）A. 00H-10HB. 08H-0FHC. 10H-1FHD. 00H-07H8. 定时器/计数器工作方式1是（）。

（1 分）A. 8位计数器结构B. 2个8位计数器结构C. 13位计数结构D. 16位计数结构9. 有如下程序段： MOV 31H ，#24H ； MOV A ， 31H ； SWAP A ； ANL A ， #0F0H ；执行结果是（1 分）A. （A）=24HB. （A）=42HC. （A）=40HD. （A）=00H10. 8051有四个工作寄存器区，由PSW状态字中的RS1、RS0两位的状态来决定，单片机复位后，若执行 SETB RS0 指令，此时只能使用（）区的工作寄存器。

（1 分）A. 0区B. 1区C. 2区D. 3区11. 8051有四个工作寄存器区,由PSW状态字中的RS1和RS0两位的状态来决定,单片机复位后,若执行 SETB RS0 指令,此时只能使用（）区的工作寄存器。