Spatial variation in aragonite saturation state and the influencing factors in Jiaozhou Bay, China

Both natural processes and human activities affect seawater calcium carbonate saturation state (Ωarag), while the mechanisms are still far from being clearly understood. This study analysed the seawater surface Ωarag during summer and winter in Jiaozhou Bay (JZB), China, based on two cruises observations performed in January and June 2017. The ranges of Ωarag values were 1.55~2.92 in summer and 1.62~2.15 in winter. Regression analyses were conducted to identify the drivers of the change of Ωarag distribution, and then the relative contributions of temperature, mixing processes and biological processes to the spatial differences in Ωarag were evaluated by introducing the difference between total alkalinity (TA) and dissolved inorganic carbon (DIC) as a proxy for Ωarag. The results showed that biological processes were the main factor affecting the spatial differences in Ωarag, with relative contributions of 70% in summer and 50% in winter. The contributions of temperature (25% in summer and 20% in winter) and the mixing processes (5% in summer and 30% in winter) were lower. The increasing urbanization in offshore areas can further worsen acidification, therefore environmental protection in both offshore and onshore is needed

Modeling Paying Behavior in Game Social Networks

Online gaming is one of the largest industries on the Internet, generating tens of billions of dollars in revenues annually. One core problem in online game is to find and convert free users into paying customers, which is of great importance for the sustainable development of almost all online games. Although much research has been conducted, there are still several challenges that remain largely unsolved: What are the fundamental factors that trigger the users to pay? How does users? paying behavior influence each other in the game social network? How to design a prediction model to recognize those potential users who are likely to pay? In this paper, employing two large online games as the basis, we study how a user becomes a new paying user in the games. In particular, we examine how users' paying behavior influences each other in the game social network. We study this problem from various sociological perspectives including strong/weak ties, social structural diversity and social influence. Based on the discovered patterns, we propose a learning framework to predict potential new payers. The framework can learn a model using features associated with users and then use the social relationships between users to refine the learned model. We test the proposed framework using nearly 50 billion user activities from two real games. Our experiments show that the proposed framework significantly improves the prediction accuracy by up to 3-11% compared to several alternative methods. The study also unveils several intriguing social phenomena from the data. For example, influence indeed exists among users for the paying behavior. The likelihood of a user becoming a new paying user is 5 times higher than chance when he has 5 paying neighbors of strong tie. We have deployed the proposed algorithm into the game, and the Lift_Ratio has been improved up to 196% compared to the prior strategy

Electrochemical migration of Sn and Sn solder alloys: a review

Sn and Sn solder alloys in microelectronics are the most susceptible to suffer from electrochemical migration (ECM) which significantly compromises the reliability of electronics. This topic has attracted more and more attention from researchers since the miniaturization of electronics and the explosive increase in their usage have largely increased the risk of ECM. This article first presents an introductory overview of the ECM basic processes including electrolyte layer formation, dissolution of metal, ion transport and deposition of metal ions. Then, the article provides the major development in the field of ECM of Sn and Sn solder alloys in recent decades, including the recent advances and discoveries, current debates and significant gaps. The reactions at the anode and cathode, the mechanisms of precipitates formation and dendrites growth are summarized. The influencing factors including alloy elements (Pb, Ag, Cu, Zn, etc.), contaminants (chlorides, sulfates, flux residues, etc.) and electric field (bias voltage and spacing) on the ECM of Sn and Sn alloys are highlighted. In addition, the possible strategies such as alloy elements, inhibitor and pulsed or AC voltage for the inhibition of the ECM of Sn and Sn solder alloys have also been reviewed

Orthogonal Polynomials, Asymptotics and Heun Equations

The Painlev\'{e} equations arise from the study of Hankel determinants generated by moment matrices, whose weights are expressed as the product of ``classical" weights multiplied by suitable ``deformation factors", usually dependent on a ``time variable'' $t$. From ladder operators one finds second order linear ordinary differential equations for associated orthogonal polynomials with coefficients being rational functions. The Painlev\'e and related functions appear as the residues of these rational functions. We will be interested in the situation when $n$, the order of the Hankel matrix and also the degree of the polynomials $P_n(x)$ orthogonal with respect to the deformed weights, gets large. We show that the second order linear differential equations satisfied by $P_n(x)$ are particular cases of Heun equations when $n$ is large. In some sense, monic orthogonal polynomials generated by deformed weights mentioned below are solutions of a variety of Heun equa\-tions. Heun equations are of considerable importance in mathematical physics and in the special cases they degenerate to the hypergeometric and confluent hypergeometric equations. In this paper we look at three type of weights: the Jacobi type, which are are supported $(0,1]$ the Laguerre type and the weights deformed by the indicator function of $(a,b)$ $\chi_{(a,b)}$ and the step function $\theta(x)$

A Historical Overview of Artificial Intelligence in China

Artificial intelligence (AI) refers to the interdisciplinary field of study that involves the development of computer systems and machines capable of performing tasks that typically require human intelligence, such as learning, problem-solving, and decision-making. AI has undergone a tumultuous developmental trajectory since its inception as a distinct field of study in 1956. This paper provides a concise review of the historical development of AI in China, with a particular focus on the country’s recent advancements in AI research, innovation, and application

Teaching Research under the “Internet plus” Initiative: Driving Teacher Professional Development in the Digital Era

Information technology permeates every facet of human society in the internet age. The internet has fundamentally transformed human interactions by providing unprecedented support for interpersonal and inter-organizational communication and information sharing. As the paramount technological tool in the contemporary world, it is instigating social reconstruction (Li, 2017). Currently, the comprehensive impact of the internet on education is intensifying, bringing about digital transformation of education across the globe (Zhong, 2019)

The Smart Classroom Grows Ever Smarter amid Technological Advances

The classroom is the most vital component of any educational setting, providing the venue for teaching and learning. Amid the rapid development of information technology, the evolution of its functioning is also being expedited

Qualitative Comparative Analysis (QCA): An Innovative Approach for Integrating Qualitative and Quantitative Analysis

Educational research has long used quantitative and qualitative analysis. Quantitative analysis is the process of quantifying things through the use of numbers, which represent quantifiable characteristics of things such as scale, speed, and degree, as well as the spatial arrangement of their constituents (Yang, 1995). Qualitative analysis is the polar opposite, i.e., evaluating things on the basis of their quality rather than their quantity. A thing's quality refers to its normative nature, which distinguishes it from other things (Li, 1997). Simply put, quantitative analysis focuses on the "what" and employs numerical expressions to depict a given reality, whereas qualitative analysis aims to comprehend the "why" and investigates how we describe something

Cross-Border E-Commerce: Opportunities versus Challenges

The fast expansion of cross-border e-commerce places new expectations not just on practitioners and platforms, but also on customers themselves. Personal information should be protected with care in order to prevent leakage or fraudulent use of the information. It is possible to lower transaction costs by complying with the World Trade Organization’s trade regulations for each member country. It is full of tremendous opportunities, but it also presents big challenges