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Fine-tuned, molecular-composite, organosilica membranes were fabricated via the co-condensation of organosilica precursors bis(triethoxysilyl)acetylene (BTESA) and bis(triethoxysilyl)benzene (BTESB). Fourier transform infrared and UV–vis spectra confirmed the co-condensation behaviors of BTESA and BTESB. The evolution of the network structure indicated that the incorporated BTESB decreased the membrane pore size, which was determined by a modified gas translation model according to the steric effect of the phenyl groups. The incorporation of BTESB to BTESA finely tuned the membrane structure and endowed the resultant composite membrane with improved separation properties. The BTESAB 9:1 membrane (molar ratio of BTESA/BTESB was 9:1) exhibited high C3H6 permeance at 4.5 × 10−8 mol m−2 s−1 Pa−1 and a C3H6/C3H8 permeance ratio of 33 at 50°C. One of the most important developments of this study involved clearly defining the relationship between membrane pore size and C3H6/C3H8 separation performance for organosilica membranes in single and binary separation systems.  相似文献   
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The soldier crab appears in great numbers and feeds while wandering during daytime low tide. When they see an approaching object, they screw themselves into the sand. The mechanism of formation of mass wandering has not been clarified. In this study, to investigate if the soldier crabs use visual images of neighbors as a stimulus for wandering, dummy crabs were presented to crabs. In the experiments, one, two, four, or eight dummies were placed in a circle on a sand arena. Each crab was placed in the center of the arena and observed whether it burrowed into the sand or wandered. The proportions of wandering individuals in each experimental treatment were compared with the expected value. Significantly more crabs were wanderers when only two and four dummies were present. This result suggests that soldier crabs chose burrowing or wandering depending on visual image of the distribution of the neighbors.  相似文献   
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We report on the improvement in the water splitting efficiency of a WO3/BiVO4 composite photoelectrode by the application of an improved auto-combustion method to the preparation of porous BiVO4 thin films. The unique feature of this preparation method is the addition of both NH4NO3, as a strong oxidizing agent, and an organic additive into BiVO4 precursor solution. The local decomposition heat of the organic additive and oxidizing agent created a porous film with small, highly crystalline BiVO4 particles. The photoelectrode has many advantages over existing ones, such as the high light-harvesting efficiency (LHE), a single BiVO4 phase, the facile access of the holes to the photoelectrode/electrolyte interface, and the ease of water and oxygen diffusion. The maximum incident photon-to-current efficiency (IPCE) was estimated to be 64% (at 440 nm, 1.23 V vs. RHE) and the applied bias photon-tocurrent efficiency (ABPE) reached as high as 1.28%. This ABPE value is highest among all oxide semiconductor photoelectrodes reported previously, except for the case of a stacking photoelectrode system.  相似文献   
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An automatically guided vehicle, traveling without fixed guide ways, has been developed. In this paper, the construction of the vehicle, the control algorithm, and its general performance are described.  相似文献   
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Although the number of applications of conductive staining for SEM has recently increased investigations or discussions on the features of these methods are scanty, and so it could not be said that its features are sufficiently understood. In the present studies employing the tannin-osmium method as the conductive stain, the authors compared it with an ion-sputtering method that they use for metal coating. Besides the prevention of masking by the coating metal, there are other advantages to the conductive staining method.
  • 1 The appearance of the tissue “transparency”, which allows three-dimensional observations of sub-surface structures to be made.
  • 2 Any damage associated with metal coating can be avoided since the specimen itself is conductive.
  • 4 Hardening of specimens by the conductive stain enhances the resistance of structures to mechanical damage during preparation.
Especially the tissue transparency produced by the conductive stain might suggest new possibilities for SEM.  相似文献   
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OBJECTIVE: To determine the value of cytology in the follow-up of cervical cancer. STUDY DESIGN: The study group consisted of 230 patients with invasive cervical carcinoma who were followed for one to seven years. Forty-four patients developed recurrences or metastases. During this period, cytologic investigations involved 795 exfoliative smears from the cervix or vaginal vault, 10 fine needle aspirates and 5 fluids. RESULTS: Thirty-three patients had positive or inconclusive cervical or vault smears that were histologically proven to be recurrences, and the other 11 patients had clinically obvious recurrences that were not smeared. Cytology first alerted the clinicians to recurrence in eight patients. Of 25 cervical or vault smears reported as malignant, 24 (96%) were histologically confirmed, and 1 showed radiation change on biopsy. In all 22 cases of smears reported as inconclusive, a biopsy followed, and in 9 (41%) of these, recurrence was demonstrated histologically. Inability to distinguish radiation change from recurrent malignancy was the chief cause of inconclusive smears. Five fluids and seven fine needle aspirates were diagnosed as malignant, saving patients an invasive diagnostic procedure. CONCLUSION: Cytology is a useful, cost-effective, noninvasive and accurate investigation in the follow-up of cervical cancer.  相似文献   
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The distribution and organization of odontoblast processes in young human dentin was examined with a scanning electron microscope. By applying the HCl-collagenase method, the extracellular matrix of dentin was almost completely removed, thereby exposing the odontoblast processes and their branches to direct observation. The odontoblast processes are located close to the dentinoenamel junction. In the middle and outer zones of dentin the processes bear numerous branches. Some of these appeared to bridge the space between the processes and connect them.  相似文献   
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