Experimental Research on Crack Resistance of Steel-Polyvinyl Alcohol Hybrid Fiber-Reinforced Concrete.

This paper investigates the effects of steel fiber and PVA fiber hybrid blending on the compressive strength (fcc), splitting tensile strength (fts), compression energy (W1.0), and shrinkage properties of concrete. It also establishes a multi-factor crack resistance index evaluation model based on the Analytic Hierarchy Process (AHP) to comprehensively evaluate the crack resistance of concrete.

Experimental Study on the Flexural Performance of Steel-Polyvinyl Alcohol Hybrid Fiber-Reinforced Concrete.

This paper explores the impact of steel-PVA hybrid fibers (S-PVA HF) on the flexural performance of panel concrete via three-point bending tests. Crack development in the concrete is analyzed through Digital Image Correlation (DIC) and Scanning Electron Microscope (SEM) experiments, unveiling the underlying mechanisms. The evolution of cracks in concrete is quantitatively analyzed based on fractal theory, and a predictive model for flexural strength (PMFS) is established.

Temporally modulated laser with an alkali vapor amplifier.

A diode-pumped alkali laser has gained rapid development in recent years. In this study, we take the advantages of high-gain cross section and low upper energy lifetime of an alkali laser to propose, to the best of our knowledge, a novel type of time-domain-modulated alkali vapor amplifier. By using the amplifier, we experimentally demonstrate the power scaling of a modulated seed laser.

Dual-wavelength end-pumped Rb-Cs vapor lasers.

Diode-pumped alkali vapor lasers (DPALs) have been rapidly developed because of their excellent performances. However, there have been few reports about DPALs with multiple wavelengths until now. The effects of the output features on the waist size and position of both Rb and Cs pump beams were first theoretically investigated using a kinetic model for an end-pumped dual-wavelength Rb-Cs laser.

Theoretical analyses of an injection-locked diode-pumped rubidium vapor laser.

Diode-pumped alkali lasers (DPALs) have drawn much attention since they were proposed in 2001. The narrow-linewidth DPAL can be potentially applied in the fields of coherent communication, laser radar, and atomic spectroscopy. In this study, we propose a novel protocol to narrow the width of one kind of DPAL, diode-pumped rubidium vapor laser (DPRVL), by use of an injection locking technique.

Optimization of physical conditions for a diode-pumped cesium vapor laser.

A diode-pumped alkali laser (DPAL) is thought to provide the significant promise for construction of high-powered lasers in the future. To examine the kinetic processes of the gas-state media (cesium vapor in this study), a mathematical model is developed while the processes including normal 3-enegry-level transition, energy pooling, and ionization are taken into account in this report. The procedures of heat transfer and laser kinetics are combined together in creating the model.

Influence of energy pooling and ionization on physical features of a diode-pumped alkali laser.

In recent years, a diode-pumped alkali laser (DPAL) has become one of the most hopeful candidates to achieve the high power performance. A series of models have been established to analyze the DPAL's kinetic process and most of them were based on the algorithms in which only the ideal 3-level system was considered. In this paper, we developed a systematic model by taking into account the influence of excitation of neutral alkali atoms to even-higher levels and their ionization on the physical features of a static DPAL.

Algorithm for evaluation of temperature distribution of a vapor cell in a diode-pumped alkali laser system (part II).

With high efficiency and small thermally-induced effects in the near-infrared wavelength region, a diode-pumped alkali laser (DPAL) is regarded as combining the major advantages of solid-state lasers and gas-state lasers and obviating their main disadvantages at the same time. Studying the temperature distribution in the cross-section of an alkali-vapor cell is critical to realize high-powered DPAL systems for both static and flowing states. In this report, a theoretical algorithm has been built to investigate the features of a flowing-gas DPAL system by uniting procedures in kinetics, heat transfer, and fluid dynamic together.

Theoretical study on temperature features of a sealed cesium vapor cell pumped by laser diodes.

The diode-pumped alkali laser (DPAL) is a new type of laser source which has been widely studied in the recent years. The temperature distribution of a sealed vapor cell, which is the crucial component in a DPAL system, produces an important effect on the output performance of a DPAL. In this paper, the strict solution of the heat conduction equation for a cesium vapor cell is obtained by using a finite difference procedure.

Algorithm for evaluation of temperature distribution of a vapor cell in a diode-pumped alkali laser system: part I.

A diode-pumped alkali laser (DPAL) is one of the most hopeful candidates to achieve high power performances. As the laser medium is in a gas-state, populations of energy-levels of a DPAL are strongly dependent on the vapor temperature. Thus, the temperature distribution directly determines the output characteristics of a DPAL.