锌粉含量对汽车制动摩擦材料摩擦学性能的影响

采用粉末冶金法制备具有不同锌粉含量(0,2%,4%,6%,8%,质量分数)的汽车制动摩擦材料。结果表明,随着锌粉含量的增加,材料的密度和导热系数逐渐增加,而硬度呈单调下降趋势。随着锌粉含量的增加,标称摩擦因数曲线呈波动趋势,但最低摩擦因数呈现增加趋势。然而,随着锌含量的增加,摩擦材料的磨损率和制动噪声单调递减,这是因为摩擦机理从粘着磨损和磨粒磨损转变为粘着磨损。含4%(质量分数)锌粉的制动摩擦材料表现出最佳的摩擦学和抗噪声性能.

A review of physical supply and EROI of fossil fuels in China

This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year(or 9.6 EJ/year),in 2018; its total gas production will peak at around350 Bcm/year(or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year(or 91.9 EJ/year)around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI(energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found.

环境因素所致印迹基因改变与子代器官发育

印迹基因是由大约100个基因组成的一类特殊子集,主要以亲本单等位基因的方式表达,对胚胎的生长发育具有重要作用。近年来发现,环境因素所引起的印迹基因表观遗传修饰改变可造成胎儿多脏器发育不良甚至成年后多疾病易感,且存在多代遗传效应。本文基于国内外最新研究进展,总结了印迹基因表达改变对个体发育阶段以及生命后期器官功能的影响,提出环境有害因素所致印迹基因表观遗传修饰及表达异常是子代多器官发育不良的重要发生机制,这对于理解个体发育过程中印迹基因表达改变所引起的表型改变及探寻疾病早期防治策略具有重要意义。

HC2nO+（n=3-6）正离子的红外光解离光谱以及理论计算研究（英文）

本文利用脉冲激光溅射-超声分子束载带离子源在气相中产生了HC2nO+(n=3-6)正离子.通过对贴附CO的络合物离子的红外光解离光谱实验获得了HC2nO+正离子在1600∽3500 cm-1范围内的红外光谱.通过比较实验光谱和理论模拟光谱确定了HC2nO+正离子具有端接氢和氧的直线型碳链衍生物结构,基态为三重态,单重态比三重基态能量高10∽15 kcal/mol.成键分析表明HC2nO+中的碳链具有连烯的结构特征.

HAND2-AS1,PRKAA2 and VLDLR predict the risk of peritoneal metastasis in gastric cancer of different Lauren types based on STEPP analysis

The peritoneum is the most common site of recurrence of gastric cancer(GC).Early occult peritoneal metastasis is difficult to detect by imaging examination.Stratifying the risk of peritoneal metastasis in patients with different Lauren subtypes is of great clinical value.We performed a univariate Cox regression to identify those genes with prognostic value of overall survival(OS)and peritoneal-specified disease-free survival(psDFS)from the Gene Expression Omnibus database.The candidate genes were screened by the Subpopulation Treatment Effect Pattern Plot(STEPP)method.Propensity score matching(PSM)analysis was used to reduce the interference of confounders on the results.Based on the optimal cut-off values determined by the STEPP method,we found overexpression of three genes(HAND2-AS1,PRKAA2,and VLDLR)was correlated with shorter 1-year psDFS among patients with diffuse-type than that of patients with intestinal-type GC,and it is highly significant.Gene Set Enrichment Analysis(GSEA)potentially suggested that the three genes promote the early occurrence of peritoneal metastasis in patients with diffuse-type GC through glucose metabolism-related pathways.These three genes may be potential biomarkers.They can be used to assess the risk of peritoneal metastases to guide treatment decisions and follow-up strategies.

Change of ancient hydrology net in Northeast China Plain

Comparing with lithofacies palaeogeography of several great plains,the authors analyzed four great plains in Quaternary diastrophism,the sedimentary facies,sedimentary environment and their evolution from the independent embryonic and river system of ancient Heilongjiang finally to the Halar highland,Songnen Plain,Sanjiang Plain,the Xingkai Lake Plain and various river systems,collected the unification outside the system of Heilongjiang River to release into the sea,south ancient Xialiao River finally piracy Dongliao River,Xialiao River had released into the sea the ancient water law vicissitude and the evolved rule.

Tirofiban combined with Aspirin in the Treatment of Acute Penetrating Artery Territory Infarction (STRATEGY): protocol for a multicentre, randomised controlled trial

Background Perforating artery territorial infarction(PAI)caused by branch atheromatous disease(BAD)is prone to recurrence and early progression without an effective and well-documented antiplatelet treatment regimen.Tirofiban,an adjunctive antiplatelet agent,has shown great potential to treat acute ischaemic stroke.However,whether the combination of tirofiban and aspirin can improve the prognosis of PAI remains unclear.Aim To explore an effective and safe antiplatelet regimen for reducing the risk of recurrence and early neurological deterioration(END)in PAI caused by BAD by comparing the tirofiban and aspirin combination with placebo and aspirin combination.Methods Tirofiban combined with Aspirin in the Treatment of Acute Penetrating Artery Territory Infarction(STRATEGY)trial is an ongoing multicentre,randomised,placebo-controlled trial in China.Eligible patients shall be randomly assigned to receive standard aspirin with tirofiban or placebo on the first day and standard aspirin from days 2 to 90.The primary endpoint is a new stroke or END within 90 days.The primary safety endpoint is severe or moderate bleeding within 90 days.Discussion The STRATEGY trial will assess whether tirofiban combined with aspirin is effective and safe in preventing recurrence and END in patients with PAI.Trial registration number NCT05310968.