The prevalence of malignant transformation of endometriotic lesions is estimated between 0.3% and 1%. Malignant transformations of endometriosis occur in the colorectum is rarer, accounting for ...0.25%. Because the malignant transformation of colorectal endometriosis rarely involves mucosa, it is difficult to obtain abnormal tissue by routine endoscopic biopsy. In this case, we evaluated a patient with a rectal mass by endorectal ultrasound (ERUS) and performed endorectal ultrasound‐guided biopsy (EGB). Malignant transformations of endometriosis were confirmed by histological result. For patients with rectal tumors but with negative findings on colonoscopy and biopsy, ERUS and EGB contribute to preoperative diagnosis.
Malignant transformations of endometriosis were confirmed by endorectal ultrasound‐guided biopsy. For patients with rectal tumors but with negative findings on colonoscopy and biopsy, endorectal ultrasound and endorectal ultrasound‐guided biopsy contribute to preoperative diagnosis.
Constructing perovskite-based van der Waals heterostructures (vdWHs) have rapidly advanced the field of optoelectronics and solar cells due to their unprecedented property to integrate excellent ...characteristics of different materials. In general, the perovskite-based vdWHs have various functional properties due to their different band alignments for Type I, Type II and Type III. However, it is challenging to realize the flexible switch of band alignments in heterostructure for diverse applications. In this paper, we systematically investigate the electronic and optical properties of novel heterostructure system composed of emerging two-dimensional material Pd2Se3 and all-inorganic halide perovskite CsSnBr3 for the first time. A Type I–Type II transition of band alignments in Pd2Se3/CsSnBr3 vdWH is achieved by partly replacing the Pd atom in Pd2Se3 monolayer with Ni atom, facilitating the highly efficient separation of photo-generated carriers. Meanwhile, the heavy hole effective mass along 1 0 0 direction is greatly reduced due to the transition of band alignment, which will improve the photoelectric conversion efficiency. Our works indicate that such a controllable band alignment of Pd2Se3/CsSnBr3 heterostructure holds a significant potential for future photoelectric applications.
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•The Pd2Se3/CsSnBr3 heterostructure was theoretically studied for the first time.•A Type I - Type II transition of band alignments in heterostructure was achieved.•The heavy hole effective masses of heterostructure was greatly reduced.•The excellent light absorption properties of heterostructure was preserved.
Inspired by the high efficiency of mixed halide perovskite CH3NH3PbI3-xClx due to the long diffusion and superior optical property, we pay our attention to the mixed halide germanium perovskite. In ...this paper, we present a detail theoretical investigation of geometric and electronic structure of mixed halide perovskite CH3NH3GeI3-xClx to predict its charge transport and optical properties. The calculated results show that this system exhibits tunable direct bandgap from 1.9 eV for CH3NH3GeI3 to 2.8 eV for CH3NH3GeCl3 compounds. With the increase of iodine atom doping ratio, the transport and optical properties significantly improve. In addition, we systematically discuss how the electronic structure depends on the doping position of iodine atoms by taking mixed halide CH3NH3GeI1Cl2 compound as examples. The results prove the mixed halide CH3NH3GeI1Cl2 demonstrates more superior transport and optical properties by doping iodine atoms at polar plane. This work will help to deepen the understanding of halogen doping mechanism by changing the doping proportion and doping position and these findings may lay foundation for experimental design to obtain higher photovoltaic properties in future.
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•Varying rules of geometric construction, optical absorption spectra, transport properties of mixed halide MAGeI3-xClx.•The systems exhibit more superior transport properties along c(z) axis.•I atoms distributing in the polar planes contributes to improving the photovoltaic properties.
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It was still a great challenge to design high performance of rectification characteristic for the rectifier diode. Lately, a new approach was proposed experimentally to tune the ...Schottky barrier height (SBH) by inserting an ultrathin insulated tunneling layer to form metal–insulator-semiconductor (MIS) heterostructures. However, the electronic properties touching off the high performance of these heterostructures and the possibility of designing more efficient applications for the rectifier diode were not presently clear. In this paper, the structural, electronic and interfacial properties of the novel MIS diode with the graphene/hexagonal boron nitride/monolayer molybdenum disulfide (GBM) heterostructure had been investigated by first-principle calculations. The calculated results showed that the intrinsic properties of graphene and MoS2 were preserved due to the weak van der Waals contact. The height of interfacial Schottky barrier can be tuned by the different thickness of hBN layers. In addition, the GBM Schottky diode showed more excellent rectification characteristic than that of GM Schottky diode due to the interfacial band bending caused by the epitaxial electric field. Based on the electronic band structure, we analyzed the relationship between the electronic structure and the nature of the Schottky rectifier, and revealed the potential of utilizing GBM Schottky diode for the higher rectification characteristic devices.
•Studied numerically the bundle effect and mechanism in falling film heat transfer.•Analyzed microscopically the mechanisms of solitary wave, droplet and liquid bridge.•Clarified the trigger ...mechanisms of solitary wave, droplet and liquid bridge.•Compared fluid flow and heat transfer results for various tube bundle arrangements.•Recommended the key parameters and factors for a higher heat transfer performance.
Falling film heat transfer, an advanced technology, has been widely applied in the refrigeration and desalination system and beyond. Numerical simulations are conducted aiming to investigate the impacts of liquid flow rate, distributor height, tube pitch and tube bundle arrangement on the falling film hydrodynamics and heat transfer performance in the tube bundles. The liquid film thickness (LFT), heat transfer coefficient (HTC) and bundle effect are obtained under various conditions. The results indicated that: (1) the calculation results are in good consistent with the previous studies in both LFT and HTC; (2) various inter-column flow patterns, solitary wave, droplet and liquid bridge are widely observed; (3) the velocity fluctuation due to the pulsatile droplet impacting or liquid column impingement is one of the fundamental causes of bundle effect; (4) bundle effect universally exists in the falling film tube bundle, and varies with the liquid flow rate, distributor height, tube pitch and tube bundle arrangement; (5) the triangular and square tube bundles behave the best and the worst in the average HTC of the tube bundle, respectively, while the square tube bundle and rotated square tube bundle provide the largest and the smallest bundle effect, respectively.
With the increasing popularity of electric vehicles, cable-driven serial manipulators have been applied in auto-charging processes for electric vehicles. To ensure the safety of the physical ...vehicle-robot interaction in this scenario, this paper presents a model-independent collision localization and classification method for cable-driven serial manipulators. First, based on the dynamic characteristics of the manipulator, data sets of terminal collision are constructed. In contrast to utilizing signals based on torque sensors, our data sets comprise the vibration signals of a specific compensator. Then, the collected data sets are applied to construct and train our collision localization and classification model, which consists of a double-layer CNN and an SVM. Compared to previous works, the proposed method can extract features without manual intervention and can deal with collision when the contact surface is irregular. Furthermore, the proposed method is able to generate the location and classification of the collision at the same time. The simulated experiment results show the validity of the proposed collision localization and classification method, with promising prediction accuracy.
In this letter, a novel low-profile dual-band and dual circularly polarized (CP) microstrip antenna is proposed. The antenna consists of two circular eccentric rings (CECRs) with different sizes. The ...two eccentric rings each work as a single-band circular polarization radiator and are simultaneously excited by an arc-shaped strip. A lumped equivalent circuit model is developed to analyze the operation mechanism of the antenna. In order to simplify the design procedure, empirical formulas are derived based on the physical parameters of the antenna. The proposed structure has been examined by both simulation and experiment, and both results agree very well.
The cosmopolitan pest Aphis gossypii (Glover) causes considerable economic losses on various crops by its feeding damage and transmitting diseases around the world. Flupyradifurone is a novel ...butenolide pesticide; its toxicity on A. gossypii parent generation (F0) was estimated following treatment with LC25 concentration for 48 h. The adult longevity and fecundity of the F0 individuals treated by flupyradifurone showed no significant decrease in comparison with the control. Life table method was used to evaluate the sublethal effects on progeny population (F1). Results showed that the development time of the fourth instar and the preadult as well as the total pre-reproductive period were significantly prolonged, while their fecundity was significantly decreased compared with the control. Additionally, the intrinsic rate of increase (r), the finite rate of increase (λ), and the net reproductive rate (R0) of F1 were all significantly lower in the group treated by LC25 than in the control group.These results reveal that the sublethal concentration of flupyradifurone could suppress the population growth of A. gossypii and indicate that this novel insecticide may be as a useful tool in pest management.
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Ferroelectric polarizationhas been considered to be an key factor to tune the structural and photoelectric properties of perovskites and their heterostructures. While there has been ...growing researches made in the novel phenomena originating from interface formed between oxide perovskites, the effects of ferroelectric polarization on the electronic properties of halide perovskites and their heterostructures are rarely studied. Herein, by using first-principles calculations, all-inorganic halide perovskite heterostructure composed of 3D perovskite tetragonal CsPbBr3 and 2D Ruddlesden-Popper (RP) perovskite Cs2PbI2Cl2 is constructed for disclosing the relationship between the intrinsic polarization of tetragonal CsPbBr3 and electronic band structure of heterostructure. Cs atoms and Pb atoms of tetragonal CsPbBr3 in heterostructure are artificially moved away from the equivalent centers to simulate increased polarization. Our results show that with the spontaneous polarization of tetragonal CsPbBr3 increasing, the bandgap of heterostructure decreases, and the band alignment switches from staggered type-II to broken-gap type-III. Moreover, large cation–anion displacements along z-direction in tetragonal CsPbBr3 can be observed when tensile strains (≥5%) are applied, indicating a increased ferroelectric polarization, which also facilitates the decreasing of bandgap in heterostructure and the type-II-type-III transition of band alignment. Our study suggests that control over the polarization of ferroelectric materials is of great importance to tune the photoelectric properties of perovskite-based devices.
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