Tractive performance evaluation of seafloor tracked trencher based on laboratory mechanical measurements

Wang, Meng,Wang, Xuyang,Sun, Yuanhong,Gu, Zhimin The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.2

To evaluate the tractive performance of tracked trencher on seafloor surface, a new shear stress-displacement empirical model was proposed for saturated soft-plastic soil (SSP model). To validate the SSP model, a test platform, where track segment shear test can be performed in seafloor soil simulacrum (bentonite water mixture), was built. Series shear tests were carried out. Test results indicate that the SSP model can describe the mechanical behavior of track segment with good approximation in seafloor soil simulacrum. Through analyzing the main external forces applied to seafloor tracked trencher during the uniform linear trenching process, a drawbar pull prediction model was deduced with the SSP model. A tracked walking mechanism of the seafloor tracked trencher prototype was built, and verification tests were carried out. Test results indicate that this prediction model was feasible and effective; moreover, from another side, this conclusion also proved that the SSP model was effective.

Tractive performance evaluation of seafloor tracked trencher based on laboratory mechanical measurements

Meng Wang,Xuyang Wang,Yuanhong Sun,Zhimin Gu 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.2

To evaluate the tractive performance of tracked trencher on seafloor surface, a new shear stress-displacement empirical model was proposed for saturated soft-plastic soil (SSP model). To validate the SSP model, a test platform, where track segment shear test can be performed in seafloor soil simulacrum (bentonite water mixture), was built. Series shear tests were carried out. Test results indicate that the SSP model can describe the mechanical behavior of track segment with good approximation in seafloor soil simulacrum. Through analyzing the main external forces applied to seafloor tracked trencher during the uniform linear trenching process, a drawbar pull prediction model was deduced with the SSP model. A tracked walking mechanism of the seafloor tracked trencher prototype was built, and verification tests were carried out. Test results indicate that this prediction model was feasible and effective; moreover, from another side, this conclusion also proved that the SSP model was effective.

Three-Dimensional Hierarchically Ternary Iron Tungsten Nitride Nanosheets with Slight Ratio of Nickel Modulation for Oxygen Evolution Reaction

Xuyang Zhang,Hangjia Shen,Babak Rezaei Moghadam,Siqi Liu,Yuejin Zhu,Jiacheng Wang,Minghui Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Practical application of oxygen evolution reaction (OER) in energy conversion devices, such as water splitting and metal-air batteries, relies on the development of highly efficient and stable electrocatalysts and is still challengeable. Here, Nickel modulated ternary Iron tungsten nitride (Ni-FeWN2) nanosheets are synthesized through a facile hydrothermal growth method and subsequently nitriding process for boosting OER. A potential of 1.57V at the current density of 10 mA/cm2 and Tafel slope (40 mV/dec) are achieved on Ni-FeWN2, much lower than that on Ni-free FeWN2 and commercial IrO2. More importantly, Ni-FeWN2 nanosheets display high stability and electrocatalytic activity toward driving oxygen evolution efficiently in alkaline media.

Altered lipid metabolism promoting cardiac fibrosis is mediated by CD34+ cell-derived FABP4+ fibroblasts

Du Luping,Wang Xuyang,Guo Yan,Tao Tingting,Wu Hong,Xu Xiaodong,Zhang Bohuan,Chen Ting,Xu Qingbo,Guo Xiaogang 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Hyperlipidemia and hypertension might play a role in cardiac fibrosis, in which a heterogeneous population of fibroblasts seems important. However, it is unknown whether CD34+ progenitor cells are involved in the pathogenesis of heart fibrosis. This study aimed to explore the mechanism of CD34+ cell differentiation in cardiac fibrosis during hyperlipidemia. Through the analysis of transcriptomes from 50,870 single cells extracted from mouse hearts and 76,851 single cells from human hearts, we have effectively demonstrated the evolving cellular landscape throughout cardiac fibrosis. Disturbances in lipid metabolism can accelerate the development of fibrosis. Through the integration of bone marrow transplantation models and lineage tracing, our study showed that hyperlipidemia can expedite the differentiation of non-bone marrow-derived CD34+ cells into fibroblasts, particularly FABP4+ fibroblasts, in response to angiotensin II. Interestingly, the partial depletion of CD34+ cells led to a notable reduction in triglycerides in the heart, mitigated fibrosis, and improved cardiac function. Furthermore, immunostaining of human heart tissue revealed colocalization of CD34+ cells and fibroblasts. Mechanistically, our investigation of single-cell RNA sequencing data through pseudotime analysis combined with in vitro cellular studies revealed the crucial role of the PPARγ/Akt/Gsk3β pathway in orchestrating the differentiation of CD34+ cells into FABP4+ fibroblasts. Through our study, we generated valuable insights into the cellular landscape of CD34+ cell-derived cells in the hypertrophic heart with hyperlipidemia, indicating that the differentiation of non-bone marrow-derived CD34+ cells into FABP4+ fibroblasts during this process accelerates lipid accumulation and promotes heart failure via the PPARγ/Akt/Gsk3β pathway.

Freezing Hu ram semen: influence of different penetrating cryoprotectants and egg yolk level on the post-thaw quality of sperm

Zhang Liuming,Jiang Caiyu,Wang Xuyang,Sohail Tariq,Sun Yuxuan,Sun Xiaomei,Wang Jian,Li Yongjun 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.9

Objective: The Hu sheep is a renowned breed known for its high reproductive rate. It is in estrus all year round, and its breeding population is gradually expanding. However, the current techniques for cryopreserving semen have limited effectiveness, which hinders the continuous development of this species. The purpose of this study is to explore the effects of different penetrating cryoprotectants (CPAs) and egg yolk (EY) concentrations on the cryopreservation of Hu ram semen to determine the most effective combination.Methods: In this study, the effects of glycerol (GLY), ethylene glycol (EG), dimethylacetamide, dimethyl sulfoxide, different proportions of GLY and EG, EY on sperm quality after thawing were investigated by detecting sperm total motility (TM), progressive motility (PM), straight-line velocity, curvilinear velocity, average path velocity, amplitude of lateral head displacement, wobble movement coefficient, average motion degree, functional integrity (plasma membrane integrity, acrosome integrity) and reactive oxygen species (ROS) level.Results: When GLY and EG were added together, compared to other concentration groups, 6% GLY significantly (p<0.05) increased TM, PM, plasma membrane integrity, and acrosome integrity of thawed sperm. Additionally, it significantly (p<0.05) decreased the ROS level of sperm. In this study, the TM, PM, and membrane integrity of the 6% EG were significantly (p<0.05) higher than those of the control, 1% GLY+5% EG and 6% GLY+6% EG groups. Compared to other concentration groups, 20% EY significantly (p<0.05) improved the TM, PM, and plasma membrane integrity of thawed sperm. However, the integrity of the acrosome increased with the higher concentration of EY.Conclusion: In conclusion, the post-thawed Hu ram semen diluted with a diluent containing 6% GLY and 20% EY exhibited higher quality compared to the other groups. Objective: The Hu sheep is a renowned breed known for its high reproductive rate. It is in estrus all year round, and its breeding population is gradually expanding. However, the current techniques for cryopreserving semen have limited effectiveness, which hinders the continuous development of this species. The purpose of this study is to explore the effects of different penetrating cryoprotectants (CPAs) and egg yolk (EY) concentrations on the cryopreservation of Hu ram semen to determine the most effective combination. Methods: In this study, the effects of glycerol (GLY), ethylene glycol (EG), dimethylacetamide, dimethyl sulfoxide, different proportions of GLY and EG, EY on sperm quality after thawing were investigated by detecting sperm total motility (TM), progressive motility (PM), straight-line velocity, curvilinear velocity, average path velocity, amplitude of lateral head displacement, wobble movement coefficient, average motion degree, functional integrity (plasma membrane integrity, acrosome integrity) and reactive oxygen species (ROS) level. Results: When GLY and EG were added together, compared to other concentration groups, 6% GLY significantly (p<0.05) increased TM, PM, plasma membrane integrity, and acrosome integrity of thawed sperm. Additionally, it significantly (p<0.05) decreased the ROS level of sperm. In this study, the TM, PM, and membrane integrity of the 6% EG were significantly (p<0.05) higher than those of the control, 1% GLY+5% EG and 6% GLY+6% EG groups. Compared to other concentration groups, 20% EY significantly (p<0.05) improved the TM, PM, and plasma membrane integrity of thawed sperm. However, the integrity of the acrosome increased with the higher concentration of EY. Conclusion: In conclusion, the post-thawed Hu ram semen diluted with a diluent containing 6% GLY and 20% EY exhibited higher quality compared to the other groups.

A Hydrogel-based First-Aid Tissue Adhesive with Effective Hemostasis and Anti-bacteria for Trauma Emergency Management

Dongjie Zhang,Li Mei,Yuanping Hao,Bingcheng Yi,Jilin Hu,Danyang Wang,Yaodong Zhao,Zhe Wang,Hailin Huang,Yongzhi Xu,Xuyang Deng,Cong Li,Xuewei Li,Qihui Zhou,Yun Lu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Clinical tissue adhesives remain some critical drawbacks for managing emergency injuries, such as inadequate adhesive strength and insufficient anti-infection ability. Herein, a novel, self-healing, and antibacterial carboxymethyl chitosan/polyaldehyde dextran (CMCS/PD) hydrogel is designed as the first-aid tissue adhesive for effective trauma emergency management. Methods We examined the gel-forming time, porosity, self-healing, antibacterial properties, cytotoxicity, adhesive strength, and hemocompatibility. Liver hemorrhage, tail severance, and skin wound infection models of rats are constructed in vivo, respectively. Results Results demonstrate that the CMCS/PD hydrogel has the rapid gel-forming (~ 5 s), good self-healing, and effective antibacterial abilities, and could adhere to tissue firmly (adhesive strength of ~ 10 kPa and burst pressure of 327.5 mmHg) with excellent hemocompatibility and cytocompatibility. This suggests the great prospect of CMCS/ PD hydrogel in acting as a first-aid tissue adhesive for trauma emergency management. The CMCS/PD hydrogel is observed to not only achieve rapid hemostasis for curing liver hemorrhage and tail severance in comparison to commercial hemostatic gel (Surgiflo ®) but also exhibit superior anti-infection for treating acute skin trauma compared with clinical disinfectant gel (Prontosan ®). Conclusions Overall, the CMCS/PD hydrogel offers a promising candidate for first-aid tissue adhesives to manage the trauma emergency. Because of the rapid gel-forming time, it could also be applied as a liquid first-aid bandage for mini-invasive surgical treatment.

Effect of crossflow velocity on underwater bubble swarms

Xu, Yang,Aliyu, Aliyu Musa,Seo, Hyunduk,Wang, Jin-Jun,Kim, Kyung Chun Elsevier 2018 International journal of multiphase flow Vol.105 No.-

<P><B>Abstract</B></P> <P>We investigate the effect of crossflow velocity on submerged bubble plumes or swarms by employing the use of high-speed photography and an image-processing method to measure bubble rise velocities. Particle image velocimetry (PIV) was used to accurately determine the crossflow freestream velocity as well as boundary layer information. We varied the gas flow rates from 2 to 25 L/min. This range exceeds those of previous studies we could find in the open literature which were mostly less than 5 L/min and involved isolated bubbles. Combined with the crossflow velocities, this resulted in the investigation of a wide range of flow conditions providing a database of 36 experimental data points and constitutes a substantial addition to the bubble swarm/crossflow literature. Because our experiments involved larger gas flow rates than previously reported, we had to develop a digital image-processing algorithm using standard functions in Matlab to measure swarm rise velocities, and angles of inclination under crossflow. Results were validated against reported data at similar experimental conditions. It was established that increasing freestream velocity strongly suppressed bubble rise velocities and resulted in bubble breakup. Relationships for predicting rise velocity and inclination angle were derived as non-dimensional functions of the crossflow velocity, fluid properties and inlet gas flow rates. These showed good agreement with the current as well as reported experimental data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bubble swarm experiments performed in a channel with water crossflow. </LI> <LI> High-speed visualization at various gas flow rates and liquid velocities. </LI> <LI> Image processing used to extract trajectory and velocity of swarm. </LI> <LI> Bubble motion is quasilinear and correlation developed to model trajectory. </LI> <LI> Improved velocity correlation derived to capture our wide range of flow conditions. </LI> </UL> </P>

A Family of New Zero-Voltage-Transition PWM Converter with Zero-Current Turnoff Auxiliary Switch

Xu Yang,Zhaoan Wang 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

The shortcomings of zero-volltage-transition PWM converter is discussed ,and a new family of topologies of zero-voltage-transition PWM converter with soft-switched auxiliary switch is introduced The experiments on a 290W boost converter and a 100W forward converter are carried out to prove the circuit The efficiency increment of the new circuits are 2-5% comparing to hard switching circuits,and the switching noise is also greatly reduced.<br/>

Pressure Contact Interconnection for High Reliability Medium Power Integrated Power Electronic Modules

Xu Yang,Wenjie Chen,Xiaoyu He,Xiangjun Zeng,Zhaoan Wang 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

This paper presents a novel spring pressure contact interconnect technique for medium power integrated power electronics modules (IPEMs). The key technology of this interconnection is a spring which is made from Be-Cu alloy. By means of the string pressure contact, sufficient press-contact force and good electrical interconnection can be achieved. Another important advantage is that the spring exhibits excellent performance in enduring thermo-mechanical stress. In terms of manufacture procedure, it is also comparatively simple. A 4 ㎾ half-bridge power inverter module is fabricated to demonstrate the performance of the proposed pressure contact technique. Electrical, thermal and mechanical test results of the packaged device are reported. The results of both the simulation and experiment have proven that a good performance can be achieved by the proposed pressure contact technique for the medium power IPEMs.