Testing the CAPM and Three Factors Model in China: Evidence from the Shanghai Stock Exchange

Since inception, China’s stock market has grown rapidly and has become one of the most important emerging markets in the world. However, many popular financial media depicts China’s stock market as irrational. Besides, empirical studies on asset pricing in China’s stock market do not provide a consistent conclusion for different periods. This study tests the Capital Asset Pricing Model (CAPM) and Fama-French Three Factors Model in Shanghai Stock Exchange, China. For validity test of the CAPM, I follow the Fama-MacBeth (1973) procedure on a data set consisting of 180 A-shares with daily frequencies. Considerable evidence is obtained to conclude that the CAPM is not suitable to predict stock returns in China’s stock market. Beta alone cannot solely measure the risk and the stock return is not linear related to it. For validity test of Three Factors Model, I employ the Fama-French (1993) procedure to examine whether the size and book-to-market effect exists in China. Empirical results confirm the “small firm effect” but challenge Fama and French (1996) who states value firm outperform the growth firm. Besides, the results provide evidence that Three Factors Model have a better explanatory power than the CAPM. The findings suggest that mean-variance efficient investors can form their portfolio with small and low book-to-market equity firms to achieve higher risk-adjusted returns

Fabrication of imitative cracks by 3D printing for electromagnetic nondestructive testing and evaluations

AbstractThis study demonstrates that 3D printing technology offers a simple, easy, and cost-effective method to fabricate artificial flaws simulating real cracks from the viewpoint of eddy current testing. The method does not attempt to produce a flaw whose morphology mirrors that of a real crack but instead produces a relatively simple artificial flaw. The parameters of this flaw that have dominant effects on eddy current signals can be quantitatively controlled. Three artificial flaws in type 316L austenitic stainless steel plates were fabricated using a powderbed-based laser metal additive manufacturing machine. The three artificial flaws were designed to have the same length, depth, and opening but different branching and electrical contacts between flaw surfaces. The flaws were measured by eddy current testing using an absolute type pancake probe. The signals due to the three flaws clearly differed from each other although the flaws had the same length and depth. These results were supported by subsequent destructive tests and finite element analyses

EDIS: Entity-Driven Image Search over Multimodal Web Content

Making image retrieval methods practical for real-world search applications requires significant progress in dataset scales, entity comprehension, and multimodal information fusion. In this work, we introduce \textbf{E}ntity-\textbf{D}riven \textbf{I}mage \textbf{S}earch (EDIS), a challenging dataset for cross-modal image search in the news domain. EDIS consists of 1 million web images from actual search engine results and curated datasets, with each image paired with a textual description. Unlike datasets that assume a small set of single-modality candidates, EDIS reflects real-world web image search scenarios by including a million multimodal image-text pairs as candidates. EDIS encourages the development of retrieval models that simultaneously address cross-modal information fusion and matching. To achieve accurate ranking results, a model must: 1) understand named entities and events from text queries, 2) ground entities onto images or text descriptions, and 3) effectively fuse textual and visual representations. Our experimental results show that EDIS challenges state-of-the-art methods with dense entities and a large-scale candidate set. The ablation study also proves that fusing textual features with visual features is critical in improving retrieval results

Quantum Well Laser Diodes With Slightly-Doped Tunnel Junction

We experimentally investigate the electrical and optical characteristics of conventional quantum well laser diodes and the quantum well laser diodes with slightly-doped tunnel junction N++GaAs/undoped-GaAs. The results show that the slightly-doped tunnel junction give significant role on the laser diodes performances in the InGaAs/GaAs quantum well material system. The TJ LD has a internal quantum efficiency of 21% and the loss is 6.9 em -1 , the current threshold is 35 mA, both the lasers are operating at 1.06 μm, but the slightly-doped tunnel junction diode show nonlinear S-shaped current-voltage and broadband lasing characteristics. The results may also lead to the realization of more applications

Asymmetric quantum well broadband thyristor laser

A broadband thyristor laser based on InGaAs/GaAs asymmetric quantum well (AQW) is fabricated by metal organic chemical vapor deposition (MOCVD). The 3-μm-wide Fabry–Perot (FP) ridge-waveguide laser shows an S-shape I−V characteristic and exhibits a flat-topped broadband optical spectrum coverage of ~27 nm (Δ−10 dB) at a center wavelength of ~1090 nm with a total output power of 137 mW under pulsed operation. The AQW structure was carefully designed to establish multiple energy states within, in order to broaden the gain spectrum. An obvious blue shift emission, which is not generally acquired in QW laser diodes, is observed in the broadening process of the optical spectrum as the injection current increases. This blue shift spectrum broadening is considered to result from the prominent band-filling effect enhanced by the multiple energy states of the AQW structure, as well as the optical feedback effect contributed by the thyristor laser structure