Rigid three-dimensional Ni3S4 nanosheet frames: Controlled synthesis and their enhanced electrochemical performance

Rigid three-dimensional (3D) NiS nanosheet frames assembled from ultrathin nanosheets are synthesized via a facile solvothermal method. Compared to flat NiS sheets, 3D NiS nanosheet frames have both a high free volume and high compressive strength. They can deliver a very high specific capacitance of 1213 F g with good rate performance. In addition, these 3D NiS nanosheet frames are stabilized by plastically deformed ridges. The stabilized nanosheet frames did not unfold or collapse during electrochemical tests, and thus showed enhanced cycling ability

A potential induced degradation suppression method for photovoltaic systems

Potential induced degradation (PID) is regarded as one of leading causes of photovoltaic (PV) module degradation. A PID suppression method is proposed in this paper, in which a PID suppression unit is added between DC negative bus and ground. The idea is to regulate the output voltage of the added power supply, and then correspondingly raise the voltage of the PV module to the ground to suppress the PID effect. A high-value resistor is added in the proposed PID suppression unit for the safety of preventing electric shock. To determine the value of the high-value resistor, detailed analysis for PV module positive or negative terminals shorted to the ground is performed. The design of the added power supply is investigated, including topology selection, voltage setting, and close-loop control. Furthermore, detailed voltage analysis for the added power supply is implemented for the systems with front-end boost DC/DC converters and 3-level boost DC/DC converters, respectively. Additionally, in the proposed solution, a switch is used to control whether the PID suppression unit is connected to the system. Three requirements are explained, as well as the corresponding control for the switch. Finally, experimental results are presented to validate the proposed theory

Evaluation and Improvement of Backup Capacity for Household Electric Vehicle Uninterruptible Power Supply (EV-UPS) Systems

The use of electric vehicles (EVs) for household uninterruptible power supplies (UPSs), particularly in rural areas, can greatly improve household power reliability. However, because EVs are mobile, the evaluation of backup capacity for EV-UPS systems is completely different when compared to traditional UPSs. As a result, the focus of this paper is on the evaluation and improvement of backup capacity for EV-UPS systems. The architectures for EV-UPS systems are presented first. The methodology for calculating backup capacity for EV-UPS systems is then presented, followed by four detailed cases based on different grid failure times. Furthermore, the impact of system operating parameters on backup capacity, such as different load power, EV mobility pattern parameters, and grid outage durations, is investigated. The results of backup capacity in cases of different operating parameters are detailed using an EV mobility model. An improved strategy for increasing backup capacity is proposed, in which more backup energy can be released during a power outage. Meanwhile, the next trip requirement is unaffected. The backup capacity with the improved strategy is then calculated and compared to the results with the traditional strategy. Finally, a 5 kW EV-UPS experimental platform is constructed, and the experimental results are presented to validate the proposed method

A Current Control Method for Grid-Connected Inverters

It is simple to implement conventional current control with a proportional integral (PI) controller. However, system stability and dynamic performance are not perfect, particularly when operating under unfavorable conditions. In this paper, an improved control method is proposed by introducing a compensation unit. The compensation unit can effectively compensate the system’s phase around the crossover frequency, greatly enhancing the system’s phase margin and stability. It is also capable of handling weak-grid conditions. In this paper, the concept of the proposed compensation unit is explained first. Then, the corresponding mathematical model for the current control loop is built, and system bode diagrams for the conventional and proposed methods are compared. Furthermore, the effect of the parameters for the compensation unit is investigated, and an optimization method is proposed to determine optimal parameters. In addition, to handle weak-grid conditions, the proposed scheme is expanded by including the compensation unit in the grid’s feed-forward loop. Finally, an experimental platform is constructed, and the experimental results are presented to validate the proposed method

A calculation model for the head-on resistance of rock pipe jacking based on the rock breaking characteristics of the disc cutter

Jacking force is one of the most important parameters in the design and construction of pipe jacking. The accuracy of the jacking force will directly affect the success or failure of the pipe jacking project. Pipe jacking is increasingly applied to rock formations, but there are few calculation models for the jacking force in rock formations. To calculate the head-on resistance in the rock formation more accurately, a new calculation formula of the construction face resistance during pipe jacking is derived. The pipe jacking face is assumed to be stable; the rock pipe jacking force is analyzed by consideration of the rock breaking mechanism, force model and influence law of the rock pipe jacking machine cutter head hob. The results show that in rock pipe jacking, the compressive and shear strengths of the rock and the depth of the pipe jacking hob cut into the rock directly determine the value of the head-on resistance; after determining the appropriate hob spacing, the number of tools is not blindly increased; otherwise, the rock breaking effect of each hob will be affected. Moreover, the measured head-on resistance in engineering practice is consistent with the predicted value of the formula, which proves its applicability

The Official Website of the AMS Experiment

The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment installed on board the International Space Station (ISS). It has been operating since May 2011 and is expected to continue through 2028 or beyond. The AMS collaboration seeks to store, manage and present its research results as well as details about the detector and operations. An open-source content management framework is utilized as the platform to build the website. This platform allows management of a variety of information, such as institutes in the collaboration, physics results, publications, academic events, etc. This note discusses the motivation, strategy, infrastructure, web design techniques, custom modules, data sharing plan, and day-to-day operation. The resulting website is located at https://ams02.space

The Official Website of the AMS Experiment

The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment installed on board the International Space Station (ISS). It has been operating since May 2011 and is expected to continue through 2028 or beyond. The AMS collaboration seeks to store, manage and present its research results as well as details about the detector and operations. An open-source content management framework is utilized as the platform to build the website. This platform allows management of a variety of information, such as institutes in the collaboration, physics results, publications, academic events, etc. This note discusses the motivation, strategy, infrastructure, web design techniques, custom modules, data sharing plan, and day-to-day operation. The resulting website is located at https://ams02.space

Comprehensive Analysis of Differentially Expressed mRNA, lncRNA and circRNA and Their ceRNA Networks in the Longissimus Dorsi Muscle of Two Different Pig Breeds

Circular RNA (circRNA) and long non-coding RNA (lncRNA) are known to participate in adipogenesis and myogenic differentiation, but their impact on porcine muscle traits is not well understood. We compared their expressional profiles in the longissimus dorsi muscle of Chinese Huainan pigs (HN, the fat type) and Western commercial Duroc×(Landrace×Yorkshire) (DLY, the thin type) pigs, and 854 mRNAs, 233 lncRNAs, and 66 circRNAs (p < 0.05 and ｜log2FoldChange｜>1) were found to be differentially expressed. The differentially expressed mRNA and circRNA parental genes were enriched in the Wnt signaling pathway (adipogenesis), the transition between fast and slow fibers (myogenic differentiation), and alanine, aspartate and glutamate metabolism (pork flavor). The potential lncRNAs/circRNAs-miRNAs-mRNAs regulatory networks shared MYOD1, PPARD, miR-423-5p and miR-874, which were associated with skeletal muscle muscular proliferation, differentiation/regeneration and adipogenesis. Taken together, these differentially expressed non-coding RNAs may be involved in the molecular basis of muscle traits, acting as the competing endogenous RNA (ceRNA) for miRNAs