Mixing the transition metals in transition metal carbides

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Simultaneous strength and ductility enhancements of high thermal conductive Ag7.5Cu alloy by selective laser melting

High electrical and thermal conductive metals (HETCM) play a key role in smart electronics, green energy, modern communications and healthcare, however, typical HETCM (e.g., Ag, Au, Cu) usually have relatively low mechanical strength, hindering further applications. Selective laser melting (SLM) is a potentially transformative manufacturing technology that is expected to address the issue. Ag is the metal with the highest thermal conductivity, which induces microscale grain refinement, but also leads to high internal stresses by SLM. Here, we select Ag7.5Cu alloy as an example to demonstrate that multi-scale (micro/meso/macro) synergies can take advantage of high thermal conductivity and internal stresses to effectively strengthen Ag alloy. The mimicry of metal-hardened structures (e.g., large-angle boundary) is extended to the mesoscale by controlling the laser energy density and laser scanning strategy to manipulate the macroscale internal stress intensity and mesoscale internal stress direction, respectively, to form mesoscale large-angle "grains", resulting in multiple mutual perpendicular shear bands during fracture. The presented approach achieved a significant enhancement of yield strength (+ 145%) and ductility (+ 28%) without post-treatment. The results not only break the strength-ductility trade-off of conventional SLM alloys, but also demonstrate a multi-scale synergistic enhancement strategy that exploits high thermal conductivity and internal stresses

Associations of green tea and rock tea consumption with risk of impaired fasting glucose and impaired glucose tolerance in Chinese men and women.

OBJECTIVE: To explore the associations of green tea and rock tea consumption with risk of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). METHODS: A multistage, stratified, cluster, random-sampling method was used to select a representative sample from Fujian Province in China. In total, 4808 subjects without cardiovascular disease, hypertension, cancer, or pancreatic, liver, kidney, or gastrointestinal diseases were enrolled in the study. A standard questionnaire was used to gather data on tea (green, rock, and black) consumption and other relevant factors. The assessment of impaired glucose regulation (IGR) was using 75-g oral glucose tolerance test (OGTT), the diagnostic criteria of normal glucose tolerance was according to American Diabetes Association. RESULTS: Green tea consumption was associated with a lower risk of IFG, while rock tea consumption was associated with a lower risk of IGT. The adjusted odds ratios for IFG for green tea consumption of <1, 1-15, 16-30, and >30 cups per week were 1.0 (reference), 0.42 (95% confidence intervals (CI) 0.27-0.65), 0.23 (95% CI, 0.12-0.46), and 0.41 (95% CI, 0.17-0.93), respectively. The adjusted odds ratios for IGT for rock tea consumption of <1, 1-15, 16-30, and >30 cups per week were 1.0 (reference), 0.69 (95% CI, 0.48-0.98), 0.59 (95% CI, 0.39-0.90), and 0.64 (95% CI, 0.43-0.97), respectively. A U-shaped association was observed, subjects who consumed 16-30 cups of green or rock tea per week having the lowest odds ratios for IFG or IGT. CONCLUSIONS: Consumption of green or rock tea may protect against the development of type 2 diabetes mellitus in Chinese men and women, particularly in those who drink 16-30 cups per week

Plasma glucose concentrations grouped according to weekly consumption of green tea or rock tea.

<p>Subjects with normal glucose tolerance were included in the analysis. Data are expressed as mean (SD). Model 1 was adjusted for age and gender. Model 2 was adjusted for age, gender, HDL-C, LDL-C, TC, TG, family history of diabetes, consumption of milk, consumption of soybean milk, smoking, consumption of alcohol, sleep, physical activity, BMI, and waist to hip ratio. *Compared with drinking <1 cup per week, <i>p</i><0.05.</p

Baseline characteristics grouped according to weekly consumption of green tea.

<p>Data are expressed as mean (SD), median (interquartile ranges), or percentages. HDL-C, high-density lipoprotein-cholesterol; LDL-C, low-density lipoprotein-cholesterol; TC, total cholesterol; TG, triglycerides; BMI, body mass index; WHR, waist to hip ratio.</p

Baseline characteristics grouped according to weekly consumption of rock tea.

<p>Data are expressed as mean (SD), median (interquartile ranges), or percentages. HDL-C, high-density lipoprotein-cholesterol; LDL-C, low-density lipoprotein-cholesterol; TC, total cholesterol; TG, triglycerides; BMI, body mass index; WHR, waist to hip ratio.</p

Odds ratio for glucose tolerance status grouped according to the level of rock tea consumption.

<p>Abbreviations: CI, confidence interval; IFG, impaired fasting glucose; IGT, impaired glucose tolerance.</p><p>Model1: Adjusted for age, gender, and level of rock tea consumption.</p><p>Model2: Adjusted for age, gender, level of rock tea consumption, dyslipidemia, family history of diabetes, consumption of milk, consumption of soybean milk, smoking status, consumption of alcohol, physical activity, sleep status, BMI, and waist to hip ratio.</p

Odds ratio for glucose tolerance status grouped according to the level of green tea consumption.

<p>Abbreviations: CI, confidence interval; IFG, impaired fasting glucose; IGT, impaired glucose tolerance.</p><p>Model1: Adjusted for age, gender, and level of green tea consumption.</p><p>Model2: Adjusted for age, gender, level of green tea consumption, dyslipidemia, family history of diabetes, consumption of milk, consumption of soybean milk, smoking status, consumption of alcohol, physical activity, sleep status, BMI, and waist to hip ratio.</p