加拿大落基山脉野生动物拾零

<正>纵贯加拿大和美国的落基山脉是野生动物的王国,悠闲的黑熊,面相温和的郊狼,不怕人的大角羊,奔跑迅速的骡鹿,打洞高手哥伦比亚黄鼠,既能飞又善走的旅鸫……落基山脉自北向南纵贯加拿大和美国,延绵数千千米,在加拿大境内有4个世界遗产级的国家公园,那里有高山、森林、冰川、瀑布、河流、湖泊和温泉。十几年前我就领略过加拿大落基山脉迷人的风采,这次故地重游,又有了新的感受和体验。素食为主的美洲黑熊熊是大多数游客都害怕遇到的动物,有关"黑瞎子"伤人的传说与故事实在太多了,以至于人们谈熊色变,谁又愿意在荒山野岭与它狭路相逢呢?其实,美洲黑熊并非人们想象的那么凶残。它们     

反思在服务学习中的作用研究

反思是服务学习的一个重要特质,也是实施过程中一个重要的阶段,是保证服务学习质量,提升服务效果的重要组成部分。本文主要从反思的理论基础,反思的特质以及反思的作用等方面阐述反思在服务学习中的地位和价值,有助于更好地开展服务学习,提升服务学习效果。     

我国铁矿消费强度与钢铁冶炼及加工业的关系

简要分析了我国改革开放以来铁矿消费强度的阶段性变化特征,建立了铁矿消费强度的增量分解模型,应用国民经济投入产出表中数据,分时段对铁矿消费强度进行了增量分解计算和分析.结果表明,2002年前,资本形成以低于或基本等于GDP的增速增长,钢铁冶炼及加工业的铁矿消耗系数下降,致使铁矿消费强度降低;2002~2010年间,资本形成增速高于GDP增速,钢铁冶炼及加工业产出效益下降、铁矿消耗系数升高,致使铁矿消费强度大幅上升.因此,钢铁冶炼及加工业需要解决的主要矛盾是淘汰过剩的低端产能和推动产品结构升级,降低整个经济的铁矿消费强度,达到产业健康稳定发展的目的.     

Template/surfactant free and UV light irradiation assisted fabrication of Mn-Co oxides composite nanorings: Structure and synthesis mechanism

A facile, green, cost effective, and template or surfactant free strategy via a two-step route i.e. UV irradiation followed by dissolution-growth for the controlled synthesis of Mn-Co composite nanorings at room temperature was proposed. The nanorings structures and the process were systematically studied via TEM, HRTEM, EDX and XRD. Bir-MnO_2 nanosheets first formed through the direct photolysis of KMnO_4 under UV light irradiation. This was followed by a dissolution-growth process via the dissolution of Bir-MnO_2 nanosheets by the generated H~+ from the redox reaction between the added Co(NO_3)_2 and residual KMnO_4, as well as the accompanied formation of CoOOH, and Mn-Co composite nanorings. It was found that a balance between the dissolution and growth rate was needed. Suitable pH, KMnO_4 presence and the starting nanosheets like Bir-MnO_2 were the key factors for the formation of nanorings. The obtained Mn-Co nanorings/TiO_2 showed enhanced efficiency for the catalytic oxidation of HCHO. Based on the above understandings, it is believed that the developed dissolution-growth method can be adopted for the designing and preparation of other Mn-Co composite nanostructures which can be further applied for environmental pollution remediation.     

碱性与中基性粗集料影响混凝土抗冻性能对比

粗集料作为混凝土的重要组成材料,其品质直接关系到混凝土的各项性能.通过试验对比研究了碱性矿料石灰岩(ω(SiO_2)为1.01%)和中基性矿料玄武岩(ω(SiO_2)为53.5%)混凝土的抗冻性能,分析了两类试件的质量损失率和相对动弹性模量.结果表明:碱性矿料能够提高混凝土的抗冻性能,这对解决混凝土抗冻性能具有重要意义.     

肝动脉化疗栓塞术治疗肝恶性肿瘤对肝功能的影响

目的探讨肝动脉化疗栓塞术(TACE)治疗肝恶性肿瘤患者对肝功能的影响.方法选取60例肝恶性肿瘤患者作为本组观察病例,分别在术前、术后1d、7d、3周及6周时对患者进行肝功能检测,并对结果进行对比分析.结果术后1d及术后7d的ALT,TBIL,DBIL均明显高于术前,差异具有统计学意义(P0.05);术后其余各项指标与术前相比均无明显差异,无统计学意义(P0.05).结论 TACE治疗后短期内对肝恶性肿瘤患者的肝功能有较大影响,在治疗后要注意加强对患者肝功能的保护.     

概念精准与逻辑严密视角下对"密度"概念教学思路的再认识

"密度"作为初中物理引入最早、抽象程度最高的概念,历来都是教学的重点和难点,针对"密度"在日常教学中存在的症结,联系学生朴素认识,导入密度物理意义;直接比较物体质量,成功引发认知冲突;找出谬误产生根源,合理修正先前假设;结合具体实验数据,尝试诠释比值内涵;巧妙安排问题顺序,完成密度学习进阶4个环节,并对教学效果进行了相关的实证分析,教学效果很好.     

民办高校党组织与董事会关系探究

随着民办高校的发展,民办高校党建工作在逐渐步入正轨的同时面临许多发展难题,其中最核心的是民办高校党组织与董事会的关系问题。从理论来看,二者之间的关系为决策与参与决策、监督与被监督、引导与被引导、分工协作,但在实践中却出现分权不清、失衡、权力运作失范、制度缺失严重、机制运作失调等问题,因此,只有转变观念,准确定位,建立框架科学、细节完备的制度体系,打造良性互动的科学机制,夯实基础、循序渐进才能处理好二者的关系,推进民办高校健康发展。     

整合多功能景观和生态系统服务的景观服务制图研究框架

生态系统和景观是地球表层系统的基本功能单元,其变化影响着景观和生态系统服务的供给.从当前国内外研究进展上看,结合多功能景观和生态系统服务的景观服务定量化研究还比较薄弱.本文从结合多功能景观和生态系统服务以及景观服务研究的角度出发,以景观服务制图作为切入点,通过对景观服务和生态系统服务以及多功能景观的综述,提出了一种景观服务制图的研究框架,旨在为区域景观服务评价以及可持续性科学研究提供参考和借鉴.     

Mechanical behavior of a near α titanium alloy under dynamic compression: Characterization and modeling

Dynamic compression tests under strain rates from 870 s^?1 to 2100 s^?1 were conducted for a near α Ti–8Al–1Mo–1V titanium alloy with equiaxed microstructure. Compression behavior, adiabatic shearing and band microstructure were investigated via characterization and calculation. The results demonstrate that all dynamic constitutive curves exhibited obvious stress fluctuation phenomenon with double increase-decrease changing stages at the primary stage of compression. The dislocation multiplication theory can be used to explain this phenomenon. After the stress fluctuation period, work hardening coexisted with the thermal softening, resulting in the slow hardening tendency in constitutive curves. J-C model was utilized to quantify the dynamic constitutive curves. The deviations between the predicted and experimental curves under high strain rates may be attributed to the over-consideration of thermal softening effect in J-C model. Adiabatic shearing band (ASB) began to form under the strain rate of 2100 s^?1. A total shearing strain of 8.1 within ASB achieved in 8.9 μs, corresponding to a local strain rate of about 9.1 × 10⁵ s^?1 and is over 430 times of the macro strain rate. Post annealing was conducted on ASB before EBSD characterization. Due to the static recrystallization during annealing, the α phase within ASB generally presented as ultra-fine grains less than 1 μm in diameter.