Fast, multicolor photodetection with graphene-contacted p-GaSe/n-InSe van der Waals heterostructures

The integration of different two-dimensional materials within a multilayer van der Waals (vdW) heterostructure offers a promising technology for high performance opto-electronic devices such as photodetectors and light sources. Here we report on the fabrication and electronic properties of vdW heterojunction diodes composed of the direct band gap layered semiconductors InSe and GaSe and transparent monolayer graphene electrodes. We show that the type II band alignment between the two layered materials and their distinctive spectral response, combined with the short channel length and low electrical resistance of graphene electrodes, enable efficient generation and extraction of photoexcited carriers from the heterostructure even when no external voltage is applied. Our devices are fast ( ~ 1 μs), self-driven photodetectors with multicolor photoresponse ranging from the ultraviolet to the near-infrared and offer new routes to miniaturized optoelectronics beyond present semiconductor materials and technologies

A simple all-fiber comb filter based on the combined effect of multimode interference and Mach-Zehnder interferometer

A polarization-dependent all-fiber comb filter based on a combination effect of multimode interference and Mach-Zehnder interferometer was proposed and demonstrated. The comb filter was composed with a short section of multimode fiber (MMF) fusion spliced with a conventional single mode fiber on the one side and a short section of a different type of optical fiber on the other side. The second type of optical fiber is spliced to the MMF with a properly designed misalignment. Different types and lengths of fibers were used to investigate the influence of fiber types and lengths on the performance of the comb filter. Experimentally, several comb filters with free spectral range (FSR) values ranging from 0.236 to 1.524 nm were achieved. The extinction ratio of the comb filter can be adjusted from 6 to 11.1 dB by varying polarization states of the input light, while maintaining the FSR unchanged. The proposed comb filter has the potential to be used in optical dense wavelength division multiplexing communication systems

A Simple All-fiber Comb Filter Based on the Combined Effect of Multimode Interference and Mach- Zehnder Interferometer

A polarization-dependent all-fiber comb filter based on a combination effect of multimode interference and Mach-Zehnder interferometer was proposed and demonstrated. The comb filter was composed with a short section of multimode fiber (MMF) fusion spliced with a conventional single mode fiber on the one side and a short section of a different type of optical fiber on the other side. The second type of optical fiber is spliced to the MMF with a properly designed misalignment. Different types and lengths of fibers were used to investigate the influence of fiber types and lengths on the performance of the comb filter. Experimentally, several comb filters with free spectral range (FSR) values ranging from 0.236 to 1.524 nm were achieved. The extinction ratio of the comb filter can be adjusted from 6 to 11.1 dB by varying polarization states of the input light, while maintaining the FSR unchanged. The proposed comb filter has the potential to be used in optical dense wavelength division multiplexing communication systems

Simultaneous occurrence of extralobar pulmonary sequestration, esophageal duplication, and bronchogenic cysts in a Chinese child: a rare case report

The occurrence of simultaneous extralobar pulmonary sequestration, esophageal duplication, and bronchogenic cysts is relatively low. We report the case of a 9-month-old Chinese child who had a right lung cyst, detected in utero and was closely monitored until birth. At age 9 months, contrast-enhanced computed tomography revealed right mediastinal extralobar pulmonary sequestration and two cysts. The patient did not exhibit any abnormalities. However, the parents were concerned about the disease. Following positive psychological counseling to the parents, surgery was the strong desire. Subsequently, successful thoracoscopic surgery was performed, excising the three lesions. No postoperative complications occurred. Postoperative pathology confirmed extralobar pulmonary sequestration syndrome combined with esophageal duplication and bronchogenic cysts. The patient was followed-up at 1 and 12 months postoperatively and recovered well with no abnormal space occupation. In such cases, preoperative imaging examinations should be carefully performed, and intraoperative exploration should correspond to that before surgery to avoid lesion omission

Study on out-of-plane shear behavior of new tubular roof prefabricated structures

The tubular roof prefabricated (TPR) structures consist of steel tubular roof and reinforced concrete. To make full use of tubular roof materials in the structures, the TPR structure is innovated by replacing stirrups with tie bars. This paper performed tests on two specimens with transverse reinforcement ratio as parameter to investigate the shear behavior of new TRP structure members. The results show that the number of transverse reinforcement influences the members’ failure model and shear-bearing capacity. Three-dimensional finite element (FE) models were developed to simulate the shear behavior of new TRP members, and the FE results were in good agreement with the experimental results in the tests. Based on this model, the sensitivity of different factors on the shear performance of new TRP members were analyzed. The main influencing factors were determined, and the suitability of the shear capacity calculation formulas in different codes for new TRP structure members is verified

Autonomous and Privacy-preserving Energy Trading Based on Redactable Blockchain in Smart Grid

With the development of information and communication technologies in smart grid, peer-to-peer (P2P) energy trading for distributed energy resources (DER) has achieved an efficient two-way flow of information and power. The adoption of blockchain technology makes the P2P energy trading more secure and transparent. Considering that users with extra energy may be reluctant to participate in the energy trading due to privacy concerns, many researchers have focused on potential privacy issues. However, most of the existing works are built on top of a semi-decentralized energy blockchain in which only a few certified third-party nodes are authorized to manage and verify transactions - once these authorized nodes are attacked, the system will be threatened. In this paper, we use the Ciphertext Policy Attribute-Based Encryption (CP-ABE) scheme to establish a blockchain based P2P energy trading approach with privacy preservation, which allows peer nodes, including sellers and purchasers, to manage and verify transactions autonomously without needing any additional third-party nodes. In addition, we introduce the redactable blockchain technology into our scheme to ensure users can modify their sensitive information uploaded to the blockchain. Furthermore, we improve the CP-ABE scheme to provide low latency in the system. The experimental evaluations show that our scheme is efficient and practical.This work is supported by National Natural Science Foundation of China (61972148)

Inducing factors and deformation mechanism of the Zhangjiacitang landslide in the Three Gorges Reservoir Area

Abstract Landslides are the most widely distributed geological hazards in the Three Gorges Reservoir Area (TGRA). Understanding the deformation mechanism and evolution of landslides is of great significance for their prevention and control. In this study, we focused on the Zhangjiacitang landslide, a typical bank landslide in the TGRA. We analyzed the relationship between landslide deformation and water level fluctuations and rainfall, based on accumulated displacement monitoring data, to clarify their triggering factors and deformation mechanism. The results show that the Zhangjiacitang landslide is a large-scale accumulation landslide. Under the influence of cyclic water level fluctuations and periodic rainfall, the accumulated displacement–time curve shows a “stepped” characteristic. Heavy rainfall emerged as the primary factor influencing the deformation of the Zhangjiacitang landslide, leading to substantial deformation throughout different periods. The deformation of the landslide exhibited a positive correlation with the intensity of rainfall. In contrast, the impact of water level changes on the landslide deformation was more intricate. A rapid water level drop (> 0.3 m/d) tended to intensify the landslide deformation, while the slow water level drop period (< 0.3 m/d) did not exhibit such an effect. This study emphasizes the need for closely monitoring the landslide status during heavy rainfall periods and rapid water level decline periods. The findings of this study provide a certain reference for landslide monitoring, early warning, prevention and control in the TGRA

Initial experience of thoracoscopic segmentectomy of basal segment through the inferior pulmonary ligament approach in treating congenital lung malformations in children

Abstract Purpose This study aimed to evaluate the feasibility and limitations of thoracoscopic segmentectomy of the basal segment (S10). Methods Clinical data of 15 children with congenital lung malformations (CLM) who underwent thoracoscopic segmentectomy of S10 via the inferior pulmonary ligament approach from January to October 2022 were retrospectively analyzed. The demographics, clinical presentation, intraoperative time, blood loss, postoperative events, and follow-up duration were assessed. Results There were 15 patients in this group (nine males and six females). Age ranges from 4.3 to 96.0 months (median, 7.7 months). Fourteen patients underwent S10 segmentectomy, with one undergoing right S10 segmentectomy and right S6 partial wedge resection. The surgical time was 57–125 min (median, 80 min), intraoperative bleeding volume (5–20 ml; median, 10 ml), postoperative drainage tube indwelling (2–4 d; median, 3 d), and postoperative hospitalization time (4–7 d; median, 5 d). No intraoperative conversions, surgical mortalities, or major complications were observed among these patients. Subcutaneous emphysema appeared in three patients; however, it disappeared following conservative observation without pneumothorax or bronchopleural fistula occurrence. Conclusions Thoracoscopic segmentectomy of S10 via the inferior pulmonary ligament approach is technically feasible for treating CLM; however, this surgical approach may have certain limitations for CLM with large cysts