Properties and behaviour of Pb-free solders in flip-chip scale solder interconnections

Due to pending legislations and market pressure, lead-free solders will replace Sn–Pb solders in 2006. Among the lead-free solders being studied, eutectic Sn–Ag, Sn–Cu and Sn–Ag–Cu are promising candidates and Sn–3.8Ag–0.7Cu could be the most appropriate replacement due to its overall balance of properties. In order to garner more understanding of lead-free solders and their application in flip-chip scale packages, the properties of lead free solders, including the wettability, intermetallic compound (IMC) growth and distribution, mechanical properties, reliability and corrosion resistance, were studied and are presented in this thesis. [Continues.

How to peak carbon emissions of provincial construction industry? Scenario analysis of Jiangsu Province

China has become the world's largest carbon emitter, and its commitment to peak carbon emissions by 2030 is important for global development. The construction industry is one of China's biggest carbon emitters, and its peak has a direct impact on China's carbon commitment. Due to the regional heterogeneity of different provinces, the carbon emission of construction industry (CECI) at provincial level is of unique significance. To accurately predict the peak of provincial CECI, a prediction model was established by system dynamics, including direct CECI, indirect CECI and operational CECI. Taking Jiangsu province as an example, the single and multiple scenario settings with increasing R&D investment, promoting energy-saving buildings and implementing carbon trading from 2016 to 2030 was carried out, indicating that: 1) Without any carbon emission reduction measures, the CECI would maintain an annual growth rate of 5.58% to reach 530.61 million tons by 2030, and the indirect and operational CECI account for the majority of total with an average annual growth rate of 8.02% and 2.79% respectively. 2) All three measures had good carbon reduction effects, which would reduce the total CECI by 26.46% 21.68% and 10.68% respectively by 2030, but only when implemented simultaneously can CECI peak before 2030, 308.77 million tons at 2029. In the end, three policy implications was put forward. The framework presented in this paper provided a basis for the prediction of peak CECI in a province or state, which can help policy makers plan a more reasonable low-carbon development roadmap

A Two-Step, One-Pot, and Multigram-Scale Synthesis of <i>N</i>‑Difluoromethylthiophthalimide

A new method for the 100 g scale synthesis of <i>N</i>-difluoro­methyl­thiophthalimide <b>1</b> from cheap commodity chemical benzyl mercaptan and HCF₂Cl or other difluorocarbene precursors was described. Reagent <b>1</b> is an excellent electrophilic difluoromethyl­thiolating reagent as demonstrated by the gram-scale synthesis of five difluoro­methyl­thiolated derivatives of structurally complicated drug-like molecules and natural products

Solar Light Driven Pure Water Splitting on Quantum Sized BiVO₄ without any Cocatalyst

Photocatalytic water splitting is the most promising process to convert solar energy into high purity chemical fuel (hydrogen), which has received significant attention in recent years. Only several photocatalysts have been reported in the literature for pure water splitting under visible light. Herein we report for the first time quantum sized BiVO₄ can decompose pure water into H₂ and O₂ simultaneously under simulated solar light irradiation without any cocatalysts or sacrificial reagents. By electrochemical measurement, we demonstrate that the significantly different photocatalytic activity of the quantum sized BiVO₄ arises from the negative shift of conduction band edge by a quantum confinement effect and a decreased overpotential for water reduction. Although the generated H₂ and O₂ are nonstoichiometric in the present study, these findings establish the great potential of using quantum sized BiVO₄ photocatalyst and solar energy for overall water splitting

Data_Sheet_1_The gut microbiome in human health and disease—Where are we and where are we going? A bibliometric analysis.docx

BackgroundThere are trillions of microbiota in our intestinal tract, and they play a significant role in health and disease via interacting with the host in metabolic, immune, neural, and endocrine pathways. Over the past decades, numerous studies have been published in the field of gut microbiome and disease. Although there are narrative reviews of gut microbiome and certain diseases, the whole field is lack of systematic and quantitative analysis. Therefore, we outline research status of the gut microbiome and disease, and present insights into developments and characteristics of this field to provide a holistic grasp and future research directions.MethodsAn advanced search was carried out in the Web of Science Core Collection (WoSCC), basing on the term “gut microbiome” and its synonyms. The current status and developing trends of this scientific domain were evaluated by bibliometric methodology. CiteSpace was used to perform collaboration network analysis, co-citation analysis and citation burst detection.ResultsA total of 29,870 articles and 13,311 reviews were retrieved from the database, which involve 42,900 keywords, 176 countries/regions, 19,065 institutions, 147,225 authors and 4,251 journals. The gut microbiome and disease research is active and has received increasing attention. Co-cited reference analysis revealed the landmark articles in the field. The United States had the largest number of publications and close cooperation with other countries. The current research mainly focuses on gastrointestinal diseases, such as inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn’s disease (CD), while extra-intestinal diseases are also rising, such as obesity, diabetes, cardiovascular disease, Alzheimer’s disease, Parkinson’s disease. Omics technologies, fecal microbiota transplantation (FMT) and metabolites linked to mechanism would be more concerned in the future.ConclusionThe gut microbiome and disease has been a booming field of research, and the trend is expected to continue. Overall, this research field shows a multitude of challenges and great opportunities.</p

Population characteristics in the study area (n = 50 plots) (mean±SE).

<p>Population characteristics in the study area (n = 50 plots) (mean±SE).</p

Physical characteristics in the different tidal zones (n = 30 plots) (mean±SE).

<p>Physical characteristics in the different tidal zones (n = 30 plots) (mean±SE).</p

The interaction strength (I) of <i>P. australis</i> and <i>S. alterniflora</i> along the tidal gradient.

<p>The performance of targets was measured by the relative growth rate per day (RGR).</p

The interaction strength (I) of <i>P. australis</i> and <i>S. alterniflora</i> along the tidal gradient.

<p>The performance of targets was measured by the number of newly produced tillers per day (TNT).</p

The distribution of <i>P. australis</i> and <i>S. alterniflora</i> in the research area along the environmental gradient.

<p>The distribution of <i>P. australis</i> and <i>S. alterniflora</i> in the research area along the environmental gradient.</p