Structural optimization of Fe-n-Pt-m ( 5 <= n + m <= 24) alloy clusters based on an improved Basin-Hopping Monte Carlo algorithm

合金纳米团簇可以充分利用多种金属的协同效应来实现材料的多功能特性,因而备受关注.本文利用改进的Basin-Hopping Monte; Carlo算法研究了不同尺寸和不同比例下的Fe-Pt二元合金团簇的结构稳定性.为证明初始结构相关性,引入了相似函数来分析合金团簇稳定结构与其对应; 的单金属团簇结构之间的相似性,并分析了Fe-Pt合金团簇在稳定结构下的元素分布.研究结果表明:对于N ≤; 24的Fe-Pt合金团簇,其结构并没有随原子数的增长呈现出明显的形状变化.但是就原子分布而言,对于相同尺寸下不同比例的原子结构,Fe元素趋向于分; 布在外层,而Pt元素更趋向于分布在内层;对于相同比例不同尺寸的原子结构也得到了同样的结论,并且在Fe原子比例越大的情况下,这种趋向的分布越明显.; 此外,通过计算合金团簇与单一金属团簇的结构相似函数,发现N≤; 24的Fe-Pt合金团簇在吸收Fe单金属和Pt单金属基态结构的基础上,随着元素比例的变化,发生了不同于单金属基态结构的变化,并且不同比例结构差异; 较大.最后,通过计算Fe-Pt合金团簇能量的二阶有限差分值,在Fe-Pt表现出分离结构状态时找到了相对稳定度最好的稳定结构.Alloy nanoclusters have received extensive attention because they can achieve bifunctional properties by making good use of the cooperative effect of two metals. In this paper, an improved Basin-Hopping Monte Carlo (BHMC) algorithm is proposed to investigate the structural stabilities of Fe-Pt alloy nanoclusters. Different cluster sizes and chemical compositions are considered. Moreover, a similarity function is introduced to analyze the structural similarity between the stable structures of alloy clusters and those of their monometallic clusters. Meanwhile, the atomic distributions of Fe-Pt alloy clusters are considered for their stable structures. The results indicate that for Fe-Pt alloy clusters with the size N <= 24, there is no significant structural evolution with the increase of cluster size. Fe atoms prefer to segregate at the peripheral positions of the clusters, while Pt atoms tend to occupy the interior. The same distribution result can be obtained for the structures of clusters with different compositions. With Fe composition increasing, this distribution trend is more pronounced for the Fe-Pt alloy clusters.; In addition, by calculating the structural similarity function between alloy and monometallic clusters, we find that the stable structures of Fe-Pt alloy clusters gradually vary with composition ratio. Moreover, when the Fe atoms or Pt atoms are added into the Fe-Pt alloy system, they change the stable structures of Fe-Pt alloy clusters, resulting in a different structure from Fe and Pt monometallic ones. Also, the structural similarity is different when the Fe composition varies. Furthermore, the best stable structures of Fe-Pt clusters with different compositions and sizes are obtained by calculating the second-order finite difference in energy of Fe-Pt alloy clusters.National Natural Science Foundation of China [11474234, 51271156,; 61403318]; Fundamental Research Fund for the Central Universities, China; [20720160085

synthesis of supported single-layer MoS2/TiO2 nanocatalyst with enhanced catalytic activity of anthracene hydrogenation by hydrothermal method

synthesis of supported single-layer MoS2/TiO2 nanocatalyst with enhanced catalytic activity of anthracene hydrogenation by hydrothermal metho

Electrochemical Studies of Spinel LiMn 2O 4 Rechargeable Lithium Battery

本文报导尖晶石型ＬｉＭｎ２Ｏ４化合物的制备方法，用循环伏安法和交流阻抗技术研究了Ｌｉ／有机电解液／ＬｉＭｎ２Ｏ４电池的电化学行为，用分形理论首次考察和进一步讨论电极材料的阻抗行为随锂离子嵌入或脱嵌电极时的变化The spinel Li intercalation compound LiMn 2O 4 was prepared and studied using ac impedance and cyclic voltammogram techniques. It was first discussed that the impedance behaviors of LiMn 2O 4 electrode varied as lithium ion was intercalated in or out the electrode with the help of fractal theory. The Li reversible behaviors in LiMn 2O 4 electrode were shown by the cyclic voltammogram results.作者联系地址：中国科学院长春应用化学研究所Author's Address: Changchun Inst. of Applied Chem., Chinses Academy of Sciences, Changchun 13001

气候变化国家评估报告(Ⅱ):气候变化的影响与适应

已经观测到的气候变化影响是显著的、多方面的。各个领域和地区都存在有利和不利影响,但以不利影响为主,未来的气候变暖将会对中国的生态系统、农业以及水资源等部门和沿海地区产生重大的不利影响。采取适应措施可以减轻气候变化的不利影响,应将适应气候变化的行动逐步纳入国民经济和社会发展的中长期规划中。由于我国科学研究的相对不足和科学认识能力的局限,目前的气候变化影响评估方法和结果还存在很大的不确定性。应当加强区域适应气候变化的案例研究、扩大研究领域、加强极端天气、气候事件影响的研究,以降低影响评估的不确定性,并提出切实可行的适应对策

艾比湖地区植被分布及物种多样性研究/Study on Vegetation Distribution and Species Diversity in the Ebinur Lake Basin[J]

应用重要值计算多样性指数、均匀度指数、优势度指数,对艾比湖流域植被分布及物种多样性进行分析。结果表明：①研究区域内可划分出10个群落,其中多枝柽柳群落（Form.Tamarix ramosissima）分布最为广泛。②湖岸植被表现出明显的带状分布特点,并且群落物种多样性随地势发生变化,地势高的地方,物种多样性较高,均匀度较好。③在南北断面内,影响植物生长的主要因素为土壤含盐量。随着土壤盐分的增加,物种种类趋向单一,群落结构趋向简单。相反物种多样性随着土壤盐分的减少而增大。④受风况和土壤含盐量的影响,南北断面植被组成差异较大,且在近湖岸范围内,南断面植物群落物种多样性和植物生长状态明显优于北断面

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND: In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first line drug treatments for people with schizophrenia. In this review we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics. OBJECTIVES: To evaluate the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Trials Register (November 2011), inspected references of all identified studies for further trials, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA: We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses. DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study. MAIN RESULTS: We included 12 trials involving 6389 patients. Aripiprazole was compared to olanzapine, risperidone and ziprasidone. All trials were sponsored by an interested drug manufacturer. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with olanzapine no differences were apparent for global state (no clinically important change: n = 703, 1 RCT, RR short-term 1.00 95% CI 0.81 to 1.22; n = 317, 1 RCT, RR medium-term 1.08 95% CI 0.95 to 1.22) but mental state tended to favour olanzapine (n = 1360, 3 RCTs, MD total Positive and Negative Syndrome Scale (PANSS) 4.68 95% CI 2.21 to 7.16). There was no significant difference in extrapyramidal symptoms (n = 529, 2 RCTs, RR 0.99 95% CI 0.62 to 1.59) but fewer in the aripiprazole group had increased cholesterol levels (n = 223, 1 RCT, RR 0.32 95% CI 0.19 to 0.54) or weight gain of 7% or more of total body weight (n = 1095, 3 RCTs, RR 0.39 95% CI 0.28 to 0.54).When compared with risperidone, aripiprazole showed no advantage in terms of global state (n = 384, 2 RCTs, RR no important improvement 1.14 95% CI 0.81 to 1.60) or mental state (n = 372, 2 RCTs, MD total PANSS 1.50 95% CI -2.96 to 5.96).One study compared aripiprazole with ziprasidone (n = 247) and both the groups reported similar change in the global state (n = 247, 1 RCT, MD average change in Clinical Global Impression-Severity (CGI-S) score -0.03 95% CI -0.28 to 0.22) and mental state (n = 247, 1 RCT, MD change PANSS -3.00 95% CI -7.29 to 1.29).When compared with any one of several new generation antipsychotic drugs the aripiprazole group showed improvement in global state in energy (n = 523, 1 RCT, RR 0.69 95% CI 0.56 to 0.84), mood (n = 523, 1 RCT, RR 0.77 95% CI 0.65 to 0.92), negative symptoms (n = 523, 1 RCT, RR 0.82 95% CI 0.68 to 0.99), somnolence (n = 523, 1 RCT, RR 0.80 95% CI 0.69 to 0.93) and weight gain (n = 523, 1 RCT, RR 0.84 95% CI 0.76 to 0.94). Significantly more people given aripiprazole reported symptoms of nausea (n = 2881, 3 RCTs, RR 3.13 95% CI 2.12 to 4.61) but weight gain (7% or more of total body weight) was less common in people allocated aripiprazole (n = 330, 1 RCT, RR 0.35 95% CI 0.19 to 0.64). Aripiprazole may have value in aggression but data are limited. This will be the focus of another review. AUTHORS' CONCLUSIONS: Information on all comparisons are of limited quality, are incomplete and problematic to apply clinically. Aripiprazole is an antipsychotic drug with a variant but not absent adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerges from the many Chinese studies as well as from ongoing larger, independent pragmatic trials