Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today’s manufacturing industry.In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were Measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger,and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified,when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior

Ginzburg-Landau-type theory of non-polarized spin superconductivity

Since the concept of spin superconductor was proposed, all the related studies concentrate on spin-polarized case. Here, we generalize the study to spin-non-polarized case. The free energy of non-polarized spin superconductor is obtained, and the Ginzburg-Landau-type equations are derived by using the variational method. These Ginzburg-Landau-type equations can be reduced to the spin-polarized case when the spin direction is fixed. Moreover, the expressions of super linear and angular spin currents inside the superconductor are derived. We demonstrate that the electric field induced by super spin current is equal to the one induced by equivalent charge obtained from the second Ginzburg-Landau-type equation, which shows self-consistency of our theory. By applying these Ginzburg-Landau-type equations, the effect of electric field on the superconductor is also studied. These results will help us get a better understanding of the spin superconductor and the related topics such as Bose-Einstein condensate of magnons and spin superfluidity.Comment: 9 pages, 5 figure

Inclusive χcJ\chi_{cJ} production in Υ\Upsilon decay at O(αs5)\mathcal{O}(\alpha_s^5) in NRQCD factorization

Inclusive $\chi_{cJ}$ $(J=0,1,2)$ production from $\Upsilon(1S)$ decay is studied within the framework of nonrelativistic QCD (NRQCD) factorization at leading order in $v_Q^2$, which includes the contributions of $b\bar{b}({}^3S_1^{[1]})\to c\bar{c}(^3P_J^{[1]})+X$ and $b\bar{b}({}^3S_1^{[1]})\to c\bar{c}(^3S_1^{[8]})+X$. For both channels, the short-distance coefficients are calculated through ${\cal O}(\alpha_s^5)$, which is next-to-leading order for the second one. By fitting to the measured $\Upsilon(1S)$ branching fractions to $\chi_{c1}$ and $\chi_{c2}$, we obtain the color-octet long-distance matrix element (LDME) $\langle\mathcal{O}^{\chi_{c0}}({}^3S_1^{[8]})\rangle =(4.04\pm0.47_{-0.34}^{+0.67})\times10^{-3}$ GeV$^3$, where the first error is experimental and the second one due to the renormalization scale dependence, if we use as input $\langle\mathcal{O}^{\chi_{c0}}({}^3P_0^{[1]})\rangle=0.107$ GeV$^5$ as obtained via potential-model analysis. Previous LDME sets, extracted from data of prompt $\chi_{cJ}$ hadroproduction, yield theoretical predictions that systematically undershoot or mildly overshoot the experimental values of $\mathcal{B}(\Upsilon\to \chi_{cJ}+X)$.Comment: 10 pages, 8 figures, minor changes, matches journal versio

高血压合并主动脉夹层患者高血压特征及院前降压治疗

Objective: To summarize hypertension characteristics and pre hospital antihypertensive therapy in patients with hypertension and aortic dissection, to explore the measures of prevention and control. Methods:  683 patients with hypertension complicated with aortic dissection patients (AD group), 8974 patients with hypertension (hypertension group), during the five years from October 2009 to October 2014, were analyzed retrospectively according to the hospital medical records data combined with outpatient clinical data.Retrospective analysis of hypertension characteristics and pre hospital antihypertensive therapy from the two groups of patients when first diagnosed was conducted. Results: The two groups ratio of diabetes, coronary heart disease, hyperlipidemia, renal insufficiency, have no statistical difference. Most patients in AD group have over 10 years’ history of hypertension (P <0.05).The incidence of aortic dissection in men of AD group is higher than the hypertensive group（P <0.05）. The ratio of 40～60 years in AD group is more than that in hypertensive group (P <0.05). The ratio of stage 3 hypertension in AD group is more than that in hypertension group (P < 0.05).The ratio of no antihypertensive treatment in patients in the AD group is more than that in hypertension group (P < 0.05).The average age of onset in AD group was lower than that in hypertension group (P<0.05). The ratio of patients in the AD group treated with ARB or ACEI antihypertensive was lower than that in hypertension group (P<0.05). Conclusion:  Hypertension complicated with aortic dissection is mostly accompanied by more than 10 years’ history of hypertension in most male patients of 40～60 age group, with grade 3 hypertension. Most did not receive antihypertensive treatment, the average age of onset is low, using ARB or ACEI for the treatment of patients is less.目的： 总结高血压合并主动脉夹层（aortic dissection,AD）患者入院时高血压特征及院前降压治疗，探讨防治措施。方法：根据住院病历资料结合门诊高血压微机管理病例资料分析2009年10月至２014年10月5年期间存活的683例高血压合并主动脉夹层患者（AD组），高血压病患者8974例（高血压组），对二组患者首诊时的高血压特征及院前降压治疗情况进行回顾性分析。结果：两组糖尿病、冠心病、高脂血症、肾功能不全比例无统计学差异。AD组多有10年以上的高血压病史（Ｐ＜0.0５）。AD组男性主动脉夹层发生率多于高血压组（Ｐ＜0.0５）。AD组40-60岁比例多于高血压组（Ｐ＜0.0５）。AD组高血压3级多于高血压组（Ｐ＜0.0５）。AD组未降压治疗者比例多于高血压组（Ｐ＜0.0５）。AD组发病平均年龄低于高血压病组（Ｐ＜0.0５）。AD组采用ARB或ACEI降压治疗者少于高血压组（Ｐ＜0.0５）。结论：高血压合并主动脉夹层多有10年以上高血压病史，男性患者多，在40-60岁年龄段多，3级高血压多，未接受降压治疗者多，发病平均年龄低，采用ARB或ACEI治疗者少

Role of extracellular signal-regulated kinase 1/2 signaling underlying cardiac hypertrophy

Cardiac hypertrophy is the result of increased myocardial cell size responding to an increased workload and developmental signals. These extrinsic and intrinsic stimuli as key drivers of cardiac hypertrophy have spurred efforts to target their associated signaling pathways. The extracellular signal-regulated kinases 1/2 (ERK1/2), as an essential member of mitogen-activated protein kinases (MAPKs), has been widely recognized for promoting cardiac growth. Several modified transgenic mouse models have been generated through either affecting the upstream kinase to change ERK1/2 activity, manipulating the direct role of ERK1/2 in the heart, or targeting phosphatases or MAPK scaffold proteins to alter total ERK1/2 activity in response to an increased workload. Using these models, both regulation of the upstream events and modulation of each isoform and indirect effector could provide important insights into how ERK1/2 modulates cardiomyocyte biology. Furthermore, a plethora of compounds, inhibitors, and regulators have emerged in consideration of ERK, or its MAPK kinases, are possible therapeutic targets against cardiac hypertrophic diseases. Herein, is a review of the available evidence regarding the exact role of ERK1/2 in regulating cardiac hypertrophy and a discussion of pharmacological strategy for treatment of cardiac hypertrophy