[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to com...[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.展开更多
[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild an...[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.展开更多
[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron micro...[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron microscope, and its morphological structure was confmned under optical microscope. [ Resuit]The nematode specimens fixed by glutaraldehyde and osmium tetroxide and prepared by critical point drying were unmodified and unshrinkable with clear mor- phological structure, which could be scanned very well by scanning electron microscope. [ Conclusion ] The study provided reference for study and control of H. digonicus.展开更多
Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important ...Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here,we have investigated the chalkiness characters such as chalkiness rate,chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore,the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties,the biggest difference is the chalkiness rate,the second is the chalkiness area,and the last is the chalkiness degree. Moreover,there is a certain correlation between the distribution of starch granules,the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety,the starch granules of chalky and non-chalky grains have obvious difference,while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice.展开更多
In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output...In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.展开更多
Common bean (Phaseolus vulgaris L.) is an economic important crop and one of the major grain legumes for human consumption in Latin America, Africa and Asia. A morphological study of shoot induced from embryonic axes ...Common bean (Phaseolus vulgaris L.) is an economic important crop and one of the major grain legumes for human consumption in Latin America, Africa and Asia. A morphological study of shoot induced from embryonic axes development in four Costa Rican bean varieties (Brunca, Huetar, Guaymi and Bribri) cultivated on MS media with or without 5 mg·L–1 de N6-benzylaminopurine (BAP) by scanning electron microscopy (SEM) was developed in the present work. Micrographs showed similarities and differences in the ultrastructure of the apical dome, epidermal surface, stomata and different types of trichomes in the varieties cultivated on organogenesis media. Genotypes with advantageous morphological characteristics for genetic transformation, in particular an exposed apical dome, were identified. This work will contribute to the optimization of the in vitro regeneration of four common bean varieties.展开更多
Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lph...Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage展开更多
Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and th...Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and there are methods that change curly or wavy hair into straight hair. Hair damage as a result of winding, combing, and using high-temperature hairdressing irons is also often seen. By using scanning electron micrographs (SEM) we showed broken hairs and hair damage caused by permanent wave solutions. The hair damage is obvious when comparisons are made with the condition of the hair surface, condition of the cuticle, etc. Hair swelling by permanent wave solutions, manipulations such as winding, etc., inadequate rinsing with water, procedures on injured hair at the outset, etc., are considered possible reasons for any of these types of injury.展开更多
Three types of osteoblast-like cells with different cnfigurations could be ob-tained through culturing fetal chicken calvaria in vitro. They were spindle-shaped cells,globular cells, and polygonal or squamous cells. W...Three types of osteoblast-like cells with different cnfigurations could be ob-tained through culturing fetal chicken calvaria in vitro. They were spindle-shaped cells,globular cells, and polygonal or squamous cells. With passage of culture time, there werechanges in configuration so that the spindle-shaped cells and the globular cells turnedgradually into squamous cells, in quantity which increased greatly to produce confluenceand multi-layer formation of cells, and in function as evidenced by emergence ofintracytoplasmic granules, reflecting collagen synthesis.展开更多
To observe the morphologic characteristics of spermatozoon ultramicroscopic structure in uremic subjects.Method Semen sample from lO patients with uremia and 5 healthy men were observed under light microscope and scan...To observe the morphologic characteristics of spermatozoon ultramicroscopic structure in uremic subjects.Method Semen sample from lO patients with uremia and 5 healthy men were observed under light microscope and scanning electronic microscope.Results Abnormalities were found in sperms of uremic patients either in the sperm head （acrosome, acrosomic deficit, nuclear abnormality, pointed head, headless and double head of spermatozoon）, neck （rupture, separation and enlargement）, or tail （mitochondrial swelling, mitochondrial deficit, tailless, double tail, short tail and curled tail）; whereas none of the above-mentioned abnormalities was observed in healthy men. Conclusion Sperms of uremic patients had many morphologic and structural abnormalities in the head, neck and tail.展开更多
Two postpartum cows were used to study the ultrastructural changes of uterine endometrium by using scanning electron microscope.The results showed that the process of repair of uterine endometrium after calving was de...Two postpartum cows were used to study the ultrastructural changes of uterine endometrium by using scanning electron microscope.The results showed that the process of repair of uterine endometrium after calving was demonstrated by scanning electron microscope through a series of endometrium biopsy.Some part of the endometrium was damaged after calving and its adjacent endometrium cells became necrosis and exfoliated during the first 7 days post-partum;the cilium and microvillus of the epithelial cell in the undamaged area of the endometrium disappeared.By 26 days postpartum the damaged area reduced and the cilium and microvillus increased in their numbers.The damaged tissues were all repaired by day 60 postpartum.展开更多
In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically ...In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically shown by a rise of the photon count as a function of the bias voltage between the tip and the substrate.It remains a challenge to determine the precise rise position of the current due to possible experimental noise.In this work,we propose an alternating current version of STML to resolve the fine structures in the photon count measurement.The measured photon count and the current at the long-time limit show a sinusoidal oscillation.The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of the bias voltage.We propose to measure the energy level with discontinuity of the first derivative of such a zero-frequency component.The current method will extend the application of STML in terms of measuring molecular properties.展开更多
The direct impact of seed-borne fungi on seed is considerable. Many fungi are serious parasites of seed primordial and maturing seeds and reduce yield of seed both quantitatively and qualitatively. Other fungi, includ...The direct impact of seed-borne fungi on seed is considerable. Many fungi are serious parasites of seed primordial and maturing seeds and reduce yield of seed both quantitatively and qualitatively. Other fungi, including saprophytes and very weak parasites, may lower the quality of seeds by causing discoloration which may seriously depreciate the commercial value of seeds, particularly of grain when graded for consumption. Studies by using scanning electron microscopy （SEM） confirmed the importance of the seed coat, and seed cells as infection sites as well as location of the mycelium of the investigated fungus. Macrophominaphaseolina The present investigation is undertaken to study the colonization, infection and fungal establishment on different sesame seed parts by （SEM）. A successful colonization of M. phaseolina to seed tissues was also detected. Different forms of pycnidial shapes were also observed.展开更多
Objective To ascertain the coexistence of osteoarthritis and osteoporosis in the femoral head. Methods During total hip replacement for osteoarthritis of hip joint in 12 female patients with an average age of 56 years...Objective To ascertain the coexistence of osteoarthritis and osteoporosis in the femoral head. Methods During total hip replacement for osteoarthritis of hip joint in 12 female patients with an average age of 56 years, the femoral heads were procured. After processing the femoral had, specimens were studied under scanning electron microscope. Results Different degrees of osteoarthritic lesions (characterized by degeneration of articular cartilage and hyperplasia of subchondral bone tissues) could coexust with osteoporotic lesions (characterized by icicle-like trabeculae ) in the femoral had. The hyperplas- tic bone tissues of osteoarthritis lay in the vicinity of icicle-like trabeculae. However, they did not care into contact, nor did they exert influence on each other. Coexistence of these two different lesions covered a brood territory extending from the deep surface of subchondral bone plate to the head-neck junction of femoral head. Conclusion The results suggest that osteoarthritis and osteoporosis do coexist in the femoral head.展开更多
Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyze...Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.展开更多
BACKGROUND:Primary intrahepatic cholelithiasis is usually combined with biliary tract infection.This research was undertaken to investigate the relationship between intrahepatic stones and biliary tract infection.METH...BACKGROUND:Primary intrahepatic cholelithiasis is usually combined with biliary tract infection.This research was undertaken to investigate the relationship between intrahepatic stones and biliary tract infection.METHODS:Thirty-five bile samples and 30 stones specimens were cultured for bacteria and 12 stones specimens were examined with a scan electron microscope(SEM)or a transmission electron microscope(TEM).RESULT:94.2%bile samples and 96.7%stones specimens were positive in bacteria culture.Bacteria were found in stones under SEM and TEM.CONCLUSION:Bacteria in stones are associated with the infection of the biliary tract.展开更多
The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy（SEM）,transmission electron m...The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and M（o｜¨）ssbauer spectroscopy.The experimental results reveal that two types of thermal-induced martensites,e（hcp） andα＇（bcc） martensites,are formed in the as-quenched condition,and these transformations have athermal characters.Mo addition to the Fe-Mn alloy does not change the coexistence ofεandα＇ martensites with the Mn content between 10wt%and 15wt%.Besides,M（o｜¨）ssbauer spectra reveal a paramagnetic character with a singlet for theγ（fcc） austenite andεmartensite phases and a ferromagnetic character with a broad sextet for theα＇ martensite phase. The volume fraction ofα＇ martensite forming in the quenched alloy is much more than that of theεmartensite.展开更多
The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have b...The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have been measured and their variation with concentration of the metal ion has been investigated. The resistivity of doped mullite decreases rapidly in the shorter temperature range and sharply in the higher temperature range. The decreasing resistivity is due to the 3d orbital electrons and the concentration of metal ions present. X-ray analysis confirms the presence of metal ions in mullite, which entered in the octahedral site. The Fe2+ and Cu2+ ions will substitute Al3+ ion in the octahedral site of mullite structure and most probably will be responsible for reducing the resistivity as well as the activation energy. Transition metal ion doped mullite-based ceramic can be considered as promising material as a substrate in the electronic industry, because of its reasonable atom density, its low activation characteristics, low thermal expansion coefficient and high mechanical strength. The present material we have developed has an activation energy of resistivity/band gap energy, Eg, 1.11 eV at 0.04 M concentration for Cu2+ ion.展开更多
文摘[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.
文摘[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.
文摘[ Objective] The paper was to observe Helicotylenchus digonicus by scanning electron microscope （SEM）. [ Method ] H. digonicus collected from Changxing of Zhejiang Province was observed under scanning electron microscope, and its morphological structure was confmned under optical microscope. [ Resuit]The nematode specimens fixed by glutaraldehyde and osmium tetroxide and prepared by critical point drying were unmodified and unshrinkable with clear mor- phological structure, which could be scanned very well by scanning electron microscope. [ Conclusion ] The study provided reference for study and control of H. digonicus.
基金Supported by Key Project of Science and Technology in Henan Province(152102110100,152102110036)National Natural Science Foundation of China(U1604110,U1404319,31270727,31600992)+3 种基金Nanhu Scholars Program for Young Scholars of XYNU(2016056)Major Science and Technology Project in Henan Province(121100110200)Students Scientific Research Fund of Xinyang Normal University(2015-DXS-158)Fund of Institute for Conservation and Utilization of Agro-bioresources in Dabie Mountains(2016020)
文摘Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here,we have investigated the chalkiness characters such as chalkiness rate,chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore,the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties,the biggest difference is the chalkiness rate,the second is the chalkiness area,and the last is the chalkiness degree. Moreover,there is a certain correlation between the distribution of starch granules,the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety,the starch granules of chalky and non-chalky grains have obvious difference,while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice.
文摘In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.
文摘Common bean (Phaseolus vulgaris L.) is an economic important crop and one of the major grain legumes for human consumption in Latin America, Africa and Asia. A morphological study of shoot induced from embryonic axes development in four Costa Rican bean varieties (Brunca, Huetar, Guaymi and Bribri) cultivated on MS media with or without 5 mg·L–1 de N6-benzylaminopurine (BAP) by scanning electron microscopy (SEM) was developed in the present work. Micrographs showed similarities and differences in the ultrastructure of the apical dome, epidermal surface, stomata and different types of trichomes in the varieties cultivated on organogenesis media. Genotypes with advantageous morphological characteristics for genetic transformation, in particular an exposed apical dome, were identified. This work will contribute to the optimization of the in vitro regeneration of four common bean varieties.
文摘Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage
文摘Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and there are methods that change curly or wavy hair into straight hair. Hair damage as a result of winding, combing, and using high-temperature hairdressing irons is also often seen. By using scanning electron micrographs (SEM) we showed broken hairs and hair damage caused by permanent wave solutions. The hair damage is obvious when comparisons are made with the condition of the hair surface, condition of the cuticle, etc. Hair swelling by permanent wave solutions, manipulations such as winding, etc., inadequate rinsing with water, procedures on injured hair at the outset, etc., are considered possible reasons for any of these types of injury.
文摘Three types of osteoblast-like cells with different cnfigurations could be ob-tained through culturing fetal chicken calvaria in vitro. They were spindle-shaped cells,globular cells, and polygonal or squamous cells. With passage of culture time, there werechanges in configuration so that the spindle-shaped cells and the globular cells turnedgradually into squamous cells, in quantity which increased greatly to produce confluenceand multi-layer formation of cells, and in function as evidenced by emergence ofintracytoplasmic granules, reflecting collagen synthesis.
文摘To observe the morphologic characteristics of spermatozoon ultramicroscopic structure in uremic subjects.Method Semen sample from lO patients with uremia and 5 healthy men were observed under light microscope and scanning electronic microscope.Results Abnormalities were found in sperms of uremic patients either in the sperm head （acrosome, acrosomic deficit, nuclear abnormality, pointed head, headless and double head of spermatozoon）, neck （rupture, separation and enlargement）, or tail （mitochondrial swelling, mitochondrial deficit, tailless, double tail, short tail and curled tail）; whereas none of the above-mentioned abnormalities was observed in healthy men. Conclusion Sperms of uremic patients had many morphologic and structural abnormalities in the head, neck and tail.
基金The projectis supported financially by Heilongjiang( C- 970 2 ) and Chinese national( 39870 572 ) natural and scientificfunds.
文摘Two postpartum cows were used to study the ultrastructural changes of uterine endometrium by using scanning electron microscope.The results showed that the process of repair of uterine endometrium after calving was demonstrated by scanning electron microscope through a series of endometrium biopsy.Some part of the endometrium was damaged after calving and its adjacent endometrium cells became necrosis and exfoliated during the first 7 days post-partum;the cilium and microvillus of the epithelial cell in the undamaged area of the endometrium disappeared.By 26 days postpartum the damaged area reduced and the cilium and microvillus increased in their numbers.The damaged tissues were all repaired by day 60 postpartum.
基金the National Natural Science Foundation of China(NSFC)(Grant No.11875049)the NSAF(Grant Nos.U1730449 and U1930403)the National Basic Research Program of China(Grant No.2016YFA0301201).
文摘In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically shown by a rise of the photon count as a function of the bias voltage between the tip and the substrate.It remains a challenge to determine the precise rise position of the current due to possible experimental noise.In this work,we propose an alternating current version of STML to resolve the fine structures in the photon count measurement.The measured photon count and the current at the long-time limit show a sinusoidal oscillation.The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of the bias voltage.We propose to measure the energy level with discontinuity of the first derivative of such a zero-frequency component.The current method will extend the application of STML in terms of measuring molecular properties.
文摘The direct impact of seed-borne fungi on seed is considerable. Many fungi are serious parasites of seed primordial and maturing seeds and reduce yield of seed both quantitatively and qualitatively. Other fungi, including saprophytes and very weak parasites, may lower the quality of seeds by causing discoloration which may seriously depreciate the commercial value of seeds, particularly of grain when graded for consumption. Studies by using scanning electron microscopy （SEM） confirmed the importance of the seed coat, and seed cells as infection sites as well as location of the mycelium of the investigated fungus. Macrophominaphaseolina The present investigation is undertaken to study the colonization, infection and fungal establishment on different sesame seed parts by （SEM）. A successful colonization of M. phaseolina to seed tissues was also detected. Different forms of pycnidial shapes were also observed.
文摘Objective To ascertain the coexistence of osteoarthritis and osteoporosis in the femoral head. Methods During total hip replacement for osteoarthritis of hip joint in 12 female patients with an average age of 56 years, the femoral heads were procured. After processing the femoral had, specimens were studied under scanning electron microscope. Results Different degrees of osteoarthritic lesions (characterized by degeneration of articular cartilage and hyperplasia of subchondral bone tissues) could coexust with osteoporotic lesions (characterized by icicle-like trabeculae ) in the femoral had. The hyperplas- tic bone tissues of osteoarthritis lay in the vicinity of icicle-like trabeculae. However, they did not care into contact, nor did they exert influence on each other. Coexistence of these two different lesions covered a brood territory extending from the deep surface of subchondral bone plate to the head-neck junction of femoral head. Conclusion The results suggest that osteoarthritis and osteoporosis do coexist in the femoral head.
基金National Natural Science Foundation of China(Grant No.51804318)the China Postdoctoral Science Foundation Founded Project(Grant No.2019M650963)National Key Basic Research and Development Program of China(Grant No.2014CB239203).
文摘Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.
文摘BACKGROUND:Primary intrahepatic cholelithiasis is usually combined with biliary tract infection.This research was undertaken to investigate the relationship between intrahepatic stones and biliary tract infection.METHODS:Thirty-five bile samples and 30 stones specimens were cultured for bacteria and 12 stones specimens were examined with a scan electron microscope(SEM)or a transmission electron microscope(TEM).RESULT:94.2%bile samples and 96.7%stones specimens were positive in bacteria culture.Bacteria were found in stones under SEM and TEM.CONCLUSION:Bacteria in stones are associated with the infection of the biliary tract.
基金supported by the Kirikkale University Scientific Research Fund(Nos.2008/34 and 2008/35)
文摘The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and M（o｜¨）ssbauer spectroscopy.The experimental results reveal that two types of thermal-induced martensites,e（hcp） andα＇（bcc） martensites,are formed in the as-quenched condition,and these transformations have athermal characters.Mo addition to the Fe-Mn alloy does not change the coexistence ofεandα＇ martensites with the Mn content between 10wt%and 15wt%.Besides,M（o｜¨）ssbauer spectra reveal a paramagnetic character with a singlet for theγ（fcc） austenite andεmartensite phases and a ferromagnetic character with a broad sextet for theα＇ martensite phase. The volume fraction ofα＇ martensite forming in the quenched alloy is much more than that of theεmartensite.
文摘The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have been measured and their variation with concentration of the metal ion has been investigated. The resistivity of doped mullite decreases rapidly in the shorter temperature range and sharply in the higher temperature range. The decreasing resistivity is due to the 3d orbital electrons and the concentration of metal ions present. X-ray analysis confirms the presence of metal ions in mullite, which entered in the octahedral site. The Fe2+ and Cu2+ ions will substitute Al3+ ion in the octahedral site of mullite structure and most probably will be responsible for reducing the resistivity as well as the activation energy. Transition metal ion doped mullite-based ceramic can be considered as promising material as a substrate in the electronic industry, because of its reasonable atom density, its low activation characteristics, low thermal expansion coefficient and high mechanical strength. The present material we have developed has an activation energy of resistivity/band gap energy, Eg, 1.11 eV at 0.04 M concentration for Cu2+ ion.
