Scanning Tunneling Microscopic and Scanning Tunneling Spectroscopic Studies of Nanocrystalline CdSe Thin Film

Nanocrystalline CdSe thin film prepared by chemical solution deposition was imaged in air with a scanning tunnelling microscope(STM). Scanning tunnelling current spectroscopy(STS) was taken at a fixed tip - sample separation. Tunnelling current(i) - voltage(v) curve and differential conductance spectrum show an n-type schottky rectifying behaviour and yield a direct measure of band gap energy. An increase of bandgap energy (1.8 - 2.1eV) was measured indicating energy quantization of this particular thin film.,

A high precision profilometer based on vertical scanning microscopic interferometry

A profilometer used for 3 dimension measurement of micro-surface topography is presented. The instrument is based on the vertical scanning microscopic interferometry （VSMI）. A Linnik type interference microscope is used and the interferograms which present changes of surface profile are recorded with a CCD camera. A developed nano-positioning work stage with an integrated optical grating displacement measuring system realizes the precise vertical scanning motion during profile measurement. By a white-light phase shifting algorithm of arbitrary step, frames of interferograms are processed by a computer to rebuild and evaluate the measured profile. Because of the specialty of VSMI, the profilometer is suitable for both smooth and rough surface measurement. It can also be used to measure curved surfaces, dimension of micro electro mechanical systems （MEMS）, etc. The vertical resolution of the profilometer is 0.5 nm, and lateral resolution 0.5 μm.

Scanning Electron Microscopic Observation on Morphologic Characteristics of Sperms in Uremic Patients

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.

Scanning Electron Microscopically Study of Sesame Seeds Infected with Macrophomina phaseolina

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.

COEXISTENCE OF OSTEOARTHRITIS AND OSTEOPOROSIS IN FEMORAL HEAD: A SCANNING ELECTRON MICROSCOPIC STUDY

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.

Solidification process of conventional superalloy by confocal scanning laser microscope

The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and temperature in reference with the in-situ observation. The characteristics of L→γ transformation were analyzed and the γ growing rate of each stage was also calculated. Scheil equation was employed to predict the segregation behavior, and the predict results are in consistence with the experimental results. As a result, the confocal scanning laser microscope shows a great potential for solidification process research.

Obsevation for Epidermal Ultrastructure of Nostoc sphaeroides Kutzing under Scanning Electron Microscope

[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.

Observation of Helicotylenchus digonicus by Scanning Electron Microscope

[ 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.

A Highly Stable Electrochemical Scanning Tunneling Microscope

We demonstrate a home-built electrochemical scanning tunneling microscope （ECSTM）. The ECSTM exhibits highly stable performance. The drifting rates in XY and Z directions of the ECSTM are about 67 and 55.6 pm/min, respectively. Moreover, a specially designed scanner unit successfully solves the well-known problem of large leakage current in high humidity atmosphere. The mechanical structure of the ECSTM is described in detail. The excellent performances of the system are demonstrated by the measured STM images （in copper sulfate solution）, including clean and well-ordered large area morphology of Au（111） and the atomically resolved image of highly oriented pyrolytic graphite.

Compact Scanning Tunneling Microscope with Large Scale Searching Capability for Mmultidisciplinary Applications

We present the design and performance of a home-built scanning tunneling microscope （STM）, which is compact （66 mm tall and 25 mm in diameter）, yet equipped with a 3D atomic precision piezoelectric motor in which the Z coarse approach relies on a high simplic-ity friction-type walker （of our own invention） driven by an axially cut piezoelectric tube. The walker is vertically inserted in a piezoelectric scanner tube （PST） with its brim laying at on the PST end as the inertial slider （driven by the PST） for the XZ （sample plane） motion. The STM is designed to be capable of searching rare microscopic targets （defects, dopants, boundaries, nano-devices, etc.） in a macroscopic sample area （square millimeters） under extreme conditions （low temperatures, strong magnetic elds, etc.） in which it ts. It gives good atomic resolution images after scanning a highly oriented pyrolytic graphite sample in air at room temperature.

Bacteriological and electron microscopic examination of primary intrahepatic stones

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.

In situ observation of the dissolution kinetics of Al_(2)O_(3) particles in CaO–Al_(2)O_(3)–SiO_(2) slags using laser confocal scanning microscopy

The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.

Chalkiness Characters and Scanning Electron Microscope Observation of Rice Grain Endosperm of Japonica Varieties in Southern Henan

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.

Experimental Study on Meiotic Spindles and Chromosomes of Mouse Mature (MⅡ) Stage Oocytes under Laser Scanning Confocal Microscopy

Taking the mouse as a model, the experimental method of observing the morphology of meiotic spindles and chromosomes in mature oocytes were investigated in order to evaluate the effects of various interventions on the quality of oocytes accurately and rapidly. Laser scanning confocal microscope （LSCM） was used to examine the meiotic spindles and chromosomes by the technologies of optical section and three-dimensional （3D） image reconstruction. The results showed that the configurations of meiotic spindles and chromosomes could be observed clearly by LSCM. The normal rate of meiotic spindles and chromosomes was 82% and 86% respectively. It was concluded that the LSCM was a valid instrument to observe the meiotic spindles and chromosomes of mature oocytes and could be used as a valid method to evaluate the quality of MⅡocytes.

Confocal Laser Scanning Microscope Evaluation of Early Bacterial Colonization on Zirconium Oxide and Titanium Surfaces:An in vivo Study

To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.

A novel phase-sensitive scanning near-field optical microscope

Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.

A Simple,Compact and Rigid Scanning Tunneling Microscope

We present a homebuilt scanning tunneling microscope(STM)which employs an inner-wall polished sapphire guiding tube as a rail for the scanner to form a short tip-sample mechanical loop.The scanner is mounted on a square rod which is housed in the guiding tube and held by a spring strip.The stiff sapphire guiding tube allows the STM body to be made in a simple,compact and rigid form.Also the material of sapphire improves the thermal stability of the STM for its good thermal conductivity.To demonstrate the performance of the STM,high quality atomic-resolution STM images of high oriented pyrolytic graphite were given.

Retrieving analog images from a scanning electron microscopewith a synchronous data acquisition method

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.

Vibration Compensation for Scanning Tunneling Microscope

The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano measuring field.Starting with the research of sensitivity to vibration of scanning tunneling microscope(STM),the theory,techniques and realization methods of nano vibration sensor based on tunnel effect are initially investigated,followed by developing the experimental devices.The experiments of the vibration detection and vibration compensation are carried out.The experimental results show that vibration sensor based on tunnel effect is characterized by high sensitivity,good frequency characteristic and the same vibratory response characteristic consistent with STM.

Fabrication of grating-like polystyrene latex monolayer structure as three-dimensional calibration standards for scanning probe microscope

This paper illuminates the preparation of grating-like polystyrene latex monolayer structure, which can minimize the effects of the size deviation of spheres and the defect transfer on the accuracy as calibration samples for micro-scopes. The latex films are grown on freshly cleaved mica substrates by vertical deposition method. The concentration dependence of the structure and the topography of latex films is characterized by optical microscope, ultraviolet- visible transmission spectrum and scanning probe microscope. The origination of such a grating-like structure is also discussed.