关岭生物群的生活环境

产于贵州省关岭县新铺乡附近晚三叠世早期地层瓦窑组下部的关岭生物群科学意义重大、观赏性极好、生活环境独特。岩相古地理分析其生活环境为海湾。沉积和古生态特征显示生活环境水体平静。

恩施鱼塘坝自然硒的发现及其初步研究

在湖北恩施渔塘坝发现了罕见的自然硒矿物，同一地域内产出自然硒矿物的规模和多种成因类型并存的现象为首次报道。按自然硒的形成环境和赋存条件将其分为三种，分别是碳质硅质岩和硅质碳质页岩中的原生自然硒，表生环境氧化还原作用形成的自然硒和“石煤”自燃形成的自然硒晶体。自然硒矿物的发现将为硒的矿物学、矿床地球化学、环境地球化学提供新的认识和研究空间。

赣南大吉山钨矿岩体、矿脉白云母地球化学及成岩成矿意义

大吉山钨矿床是一个石英脉型钨矿床,同时伴有铌、钽、铍、钼等矿化,是南岭成矿带典型的钨多金属矿床.隐伏于大吉山钨矿深部的白云母花岗,具有钠长石化和云英岩化,是钨、铌、钽等稀有元素矿化花岗岩.白云母是一个含矿化剂(F、Cl等)的矿物,矿物中矿化剂的多寡可以反映岩浆体系矿化剂的含量.因此通过对花岗岩和矿脉中自云母成分分析研究可以了解岩石成因、岩石形成的构造背景以及体系挥发分或矿化剂的地球化学特性.

Cd的分析测试方法综述

通过对近10年来Cd的分析方法的归纳总结,分别讨论了容量法、原子吸收法、分光光度法及原子荧光法……等方法测定Cd的灵敏度、准确度、精密度以及适用范围,建议在实际工作中根据样品的数量和性质、含Cd量的高低以及其他测定的特殊要求,选择合适的分析方法.

Photodissociation of 1-bromo-2-chloroethane at 266 nm

The photodissociation of CH2BrCH2Cl at 266 nm has been investigated on the universal crossed molecular beam machine. The primary dissociation step leads exclusively to the formation of CH2CH2Cl radicals and Br atoms in the electronic ground state as well as in the spin-orbit excited state, with a branching ratio 2 +/- 1:8 +/- 1. Photofragment total c.m. translational energy distribution P(E-t) has been obtained and about 64% of the available energy is partitioned into translational energy for Br channel and about 28.5% of the available energy is partitioned into translational energy for Br* channel. The anisotropy parameters are determined to be beta(Br*) = 0.8 +/- 0.2 and beta(Br) = -0.6 +/- 0.2, respectively. Some CH2CH2Cl radicals with large internal excitation (corresponding to formation of ground state Br channel) may undergo secondary dissociation to form CH2CH2 +/- Cl. The experimental results are discussed in terms of a model that involves the initial excitation of two repulsive electronic states: one from an parallel transition to the (3)Q(0) state, and the other from a perpendicular transition to the (3)Q(1), (1)Q states. (C) 1999 Elsevier Science B.V. All rights reserved.

Synthesis of NaA zeolite membrane by microwave heating

The synthesis of NaA zeolite membrane on a porous alpha -Al2O3 support by microwave heating (MH) was investigated. The formation of a NaA zeolite membrane was drastically promoted by MH. The synthesis time was reduced from 3 h for conventional heating (CH) to 15 min for MH. Surface seeding cannot only promote the formation of NaA zeolite on the support, but also inhibit the transformation of NaA zeolite into other types of zeolites. The thickness of the NaA zeolite membrane synthesized by MH was about 4 mum, thinner than that of NaA zeolite membrane synthesized by CH. The permeance of NaA zeolite membrane synthesized by MH was four times higher than that of the NaA zeolite membrane synthesized by CH, while their permselectivities were comparable. Multi-stage synthesis resulted in the transformation of NaA zeolite into other types of zeolites, and the perfection of the as-synthesized membrane decreased.

The effect of tungsten additive on the surface characteristics of amorphous Ni-P alloy

The variation of surface compositions on amorphous Ni80.4W1.5P18.1 alloy by O-2 oxidation and H-2 reduction treatments have been studied by XPS, UPS and ISS. It shows that addition of tungsten in the amorphous Ni-P alloy leads to dramatic changes of the relating component distributions in the surface layers before and after these treatments. Oxidation of a Ni80.4W1.5P18.1 amorphous alloy in 1 bar of oxygen at 513 K caused a significant segregation of nickel in different oxide states at the surface. The subsequent reduction of the oxidized surface with I bar hydrogen at 553 K resulted in only a small portion of Ni and P being reduced into elemental states, while most of them was found to combine to form a kind of nickel phosphate compound. On the other hand, under the same conditions, the oxidation and reduction of a Ni80P20 alloy gave rise to metallic Ni and elemental P as the predominate species on the alloy surface. The addition of W in the amorphous alloy might act as nuclei for a favorable formation of the phosphate structure which was proposed to be an active species for hydrogen-relating catalytic reactions. (C) 1999 Elsevier Science B.V. All rights reserved.

中老年危机热线来电者的应激源与自杀危险性

Objective: Psychosocial crisis and psychiatric disorders are two stressors for suicide action. This study will explore the differences on demographic characteristics, severity of depression, and suicidality of middle-aged and elder crisis line callers under the influences of psychosocial crisis or psychiatric disorders or two simultaneously-mixed stressors, in order to develop effective intervention strategies for crisis line. Methods: Analysis data of 1,092 cases selected from national crisis line callers aged 45 and over who were assessed with “Suicide risk assessment” during the period from December, 2002 to December, 2008. The sample were divided into three groups of psychosocial crisis, mental health problems, and mixed-stressors of three types of general callers (48.2%, 32.3%, 19.5%), callers with current suicide ideation (43.7%, 33.0%, 23.3%) and callers attempted suicide 2 weeks prior to the call (33.6%, 42.3%, 24.1%) respectively according to the operators’ judgments of the callers’ claimed difficult situations and classification system of crisis line database. X2 test and Tukey-type and Multinomial Logistic Regression multiple comparison methods are applied to analysis the differences of the three groups. Results: In agreement with previous studies, more females (71.3%, X2=13.45, P<0.001), especially females influenced by relationship stressors (76.8%, X2=25.12, P<0.001) made the call for crisis. Among general callers, the check-out rates of Major Depression Episode of mixed-stressor callers (78.5%, P<0.001) and problem callers (68.7%, P<0.05) were significantly higher than that of crisis callers (57.1%). The check-out rates of suicide ideation of mixed-stressor callers (71.4%) were significantly higher than that in crisis callers (53.8%, P<0.001) and problem callers (60.9%, P<0.05). The check-out rates of prior suicide attempts of mixed-stressor (16.6%, P<0.05) and problem callers (18.5%, P<0.01) were significantly higher than that of crisis callers (9.8%). More than half of the mixed-stressor callers (51.8%) reported over 50% degree of hopelessness, which was significantly higher than that of crisis callers (35.6%, P<0.01) and problem callers (38.2%, P<0.05). Fewer crisis callers sought medical help than problem and mixed-stressor callers among three types of callers (X2=241.35, 146.56, 50.87; P<0.001). Compare to non-compound crisis callers, the proportion of minor, severe depression and prior depression diagnosis (14.0% vs. 17.4%; 54.9% vs. 65.2%; 0 vs. 2.2%; X2=14.35，P<0.01), suicide ideation (51.1% vs. 64.0%, P<0.05) and prior suicide attempts (8.4% vs. 15.0%, P<0.05) in compound crisis callers were significantly higher. There were more compound crisis callers with over 50% hopelessness (51.9% vs. 31.0%，X2=11.96，P<0.01). Conclusion: As predicted, among middle-aged and elderly participants, mixed-stressor and compound crisis callers were higher in degree of severity of depression and suicidality. Intervention strategies should be developed addressing to specific stressor or stressors. The promotions of crisis callers’ medical help seeking behavior need to be emphasized.