阜新煤矿区次生裸坡土壤抗冲性动态变化

为探讨煤矿区次生裸坡的稳定性,采用径流含沙量和土壤抗冲系数分析方法,对阜新孙家湾煤矸石山的6个典型坡面的表层土壤进行了抗冲性试验。结果表明,矿区次生裸坡不同坡向、不同坡位的径流含沙量和土壤抗冲系数存在较大差异,且均存在一定的动态变化规律。在土壤冲刷过程中,初始径流含沙量均较大,之后呈规律性骤减,并逐渐趋于稳定。与对照样地相比,矿区次生裸坡的总径流含沙量虽少,但衰减速度较快,至冲刷第2min后基本趋于稳定。不同样地径流含沙量与时间之间显著服从于幂函数关系土壤抗冲系数的变化是随着冲刷时间的延长呈现出先缓慢后快速增大趋势,且前10min的抗冲系数表现为:矿区次生裸坡>对照样地。不同样地的土壤抗冲系数与时间之间显著服从于指数函数关系。     

木麻黄苗期生长特性和生物产量的研究

通过木麻黄实生苗年生长节律的研究，划分了苗木的生长时期，确定了影响苗木高、径生长的主导因子。同时探讨了木麻黄１年生苗的生物产量积累和分配特点，查明了密度对苗木生物产量的影响，提出了木麻黄适宜的育苗密度和苗木生物量估测模型。     

The Effect of Angiotensin‐Converting Enzyme Inhibitors of Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

Background: Despite many epidemiological reports concerning the efficacy of angiotensin‐converting enzyme (ACE) inhibitors in dogs with mitral regurgitation (MR), the hemodynamic effects of ACE inhibitor administration have not been fully evaluated. Objectives: To document left atrial pressure (LAP) in dogs with MR administered ACE inhibitors, in order to obtain interesting information about daily LAP changes with administration of ACE inhibitors. Animals: Five healthy Beagle dogs weighing 9.8 to 14.2 kg (2 males and 3 females; aged 2 years). Methods: Experimental, crossover, and interventional study. Chordae tendineae rupture was induced, and a radiotelemetry transmitter catheter was inserted into the left atrium. LAP was recorded for 72 consecutive hours during which each of 3 ACE inhibitors—enalapril (0.5 mg/kg/d), temocapril (0.1 mg/kg/d), and alacepril (3.0 mg/kg/d)—were administered in a crossover study. Results: Averaged diurnal LAP was significantly, but slightly reduced by alacepril (P= .03, 19.03 ± 3.01–18.24 ± 3.07 mmHg). The nightly drops in LAP caused by alacepril and enalapril were significantly higher than the daily drops (P= .03, ?0.98 ± 0.19 to ?0.07 ± 0.25 mmHg, and P= .03, ?0.54 ± 0.21–0.02 ± 0.17 mmHg, respectively), despite the fact that the oral administrations were given in the morning. Systolic blood pressure (122.7 ± 14.4–117.4 ± 13.1 mmHg, P= .04) and systemic vascular resistance (5800 ± 2685–5144 ± 2077 dyne × s/cm⁵, P= .03) were decreased by ACE inhibitors. Conclusions and Clinical Importance: ACE inhibitors decrease LAP minimally, despite reductions in left ventricular afterload. ACE inhibitors should not be used to decrease LAP.     

农户改厕与其使用行为悖离现象探究——基于宁夏微观调研数据

人居环境整治是乡村振兴的必然要求,“厕所革命”则是其中的关键环节,而提升农户对卫生厕所的使用率无疑是当前“厕所革命”中亟待解决的重大现实问题。为此,基于技术接受模型,利用宁夏微观农户调研数据,采用二元Logit模型,阐明农户改厕与其使用行为悖离之因,探究其影响因素和内在逻辑。结果表明：样本中89.14%的农户完成了户厕改造,但其中有39.69%的卫生厕所却长期处于闲置状态,农户改厕与其使用行为发生显著悖离。究其故,改厕方式和农户使用条件的差异及其从众意识的影响,导致卫生厕所使用率在村级层面呈两极分化,这看似农户生活成本提高所致,实则是其思想消极、条件限制而为。而且,受农户感知有用性结构性的偏差、设施便利条件不高和农户感知易用性不强等因素限制,使得农户对卫生厕所需求和参与意愿仍处于较低水平。据此,提出整改完善现有存量、科学谋划未来增量,充分发挥农户主体作用,提高农户参与意愿和责任担当等政策建议。     

浇筑温度对碾压混凝土重力坝温度应力的影响

采用三维有限元浮动网格法模拟碾压混凝土重力坝薄层施工过程，对百色碾压混凝土重力坝施工期和运行期的温度场、温度徐变应力场进行了全过程仿真计算，分析了按旬平均气温浇筑和设计浇筑温度浇筑两种不同浇筑温度对坝体温度应力分布的影响．     

尖峰岭绿楠树生长过程的研究

对海南尖峰岭地区３０年生的热带乡土树种———绿楠人工林进行了样地调查,并进行了样木横剖树干解析,研究其生长规律及与环境的关系。研究结果表明：（１）绿楠是比较速生的树种,地径、胸径、树高和材积的年生长都呈多峰态曲线;（２）胸径年生长高峰值出现在第１１年,而树高年生长量高峰期晚于地径和胸径生长高峰值出现的年份;（３）在生长初期（８ａ前）,材积生长极缓慢,年生长量＜００００９ｍ３,其后开始较快增长,到第１７年出现最大值０００８６８ｍ３;（４）从平均生长量看,地径变化比较平缓;胸径在１４ａ前呈稳态上升趋势,１４ａ后呈平稳发展状态并略有下降;树高在１９ａ前基本呈稳态上升趋势,１９ａ后保持在０５０ｍ／ａ左右,并呈缓慢地下降趋势;材积一直是随着年龄的增加而增加;（５）不同坡位的水肥等条件不同,因而影响了绿楠树的生长,离水沟最近的下坡地的树高和胸径比上坡分别大３７５％和２９１％;（６）绿楠树地径、胸径和树高的连年生长变化趋势基本上与降雨蒸发比（Ｒ／Ｅ）变化趋势相一致,说明水分状况是影响绿楠生长的一个重要环境因子。     

西洋参叶片光合日变化与内生节奏的关系

以人工气候箱内培养的西洋参为材料，研究了西洋参光合日变化及其与内生节奏的关系。结果表明，在相对恒定的光、温、湿条件下，各生育期西洋参叶片的光合日变化表现出下午(13：30-17：30)低于上午(7：30～11：30)的规律，即呈日下降变化。长时间(36h)连续光照下叶片光合速率(Pn)、气孔导度(gs)和蒸腾速率(Tr)也表现日高夜低的规律，光照后Pn、gs和Tr逐渐增加，约10：00达到高峰，下午逐渐下降，午夜最低，翌日又开始上升，说明西洋参光合日变化与植株内生节奏调节有关。     

Rejuvenation of juvenile growth characters in picea abies

Cuttings were made from six‐year‐old seedlings of Picea abies L. (Karst.) that had been studied in the Stockholm phytotron. The seedlings belonged to four full‐sib families, one being of French origin, one of North‐Swedish origin and two being hybrids between parents of North‐Swedish and French origin. Nine clones from each family were included. After the rooting phase, the cuttings were exposed to the same cultivation regimes as the seedling ortets. Characteristics of growth rhythm, percentage free growth and leader length were recorded during the 2nd to the 5th growth period (GP). Plagiotropic growth habit was recorded in the 3rd to the 5th growth period, and, characteristics of the rooting phase were studied. A juvenile behaviour very similar to that characterizing growth periods 2–3 of the seedlings was observed for growth rhythm characteristics and for free growth capacity during GP2 of the cuttings. The absolute value of the differences between each observation of the seedling ortets in GP6 and the means of the cuttings in GP2 produced a new variable that quantified the degree of rejuvenation. This new variable was meaningfully calculated only for growth rhythm and growth pattern variables. A gradual reversion of the growth rhythm occurred for the cuttings, which corresponded to the change with increasing age for the seedlings. The capacity for free growth, on the contrary, disappeared already in GP3 for the cuttings, except for the French family. A large variation in the rejuvenation ability between families was observed. Furthermore, the rejuvenation ability was negatively correlated with the ability to grow plagiotropically.     

黄河羊曲水电站库区乔木状甘蒙柽柳种群特征分析

在全面调查资源分布的基础上,对基径≥30cm的树木进行每木检尺,分析库区甘蒙柽柳的资源分布、种群结构和生长规律。结果表明:库区甘蒙柽柳分布范围51.3hm2,占库区总面积的0.88%。基径30~49cm的植株占总株数的64.7%,种群结构增长型。年均生长量在0.3~1.25cm之间,基径和年轮之间存在较大的相关性,符合y=0.9721x+13.027。年均生长量单样本T检验结果显示差异极显著。     

气候变暖对葫芦岛地区气候的影响

对葫芦岛地区1959～2005年所辖4个气象站（绥中站、连山站、兴城站和建昌站）的温度、降水资料进行了分析。结果表明：气候变暖导致葫芦岛地区气温上升趋势和降水下降趋势比较明显;进入20世纪80年代以后,葫芦岛地区干旱频率增加,严重干旱次数明显高于1980年以前。同时,通过计算不同农业生产季节的干旱指数（Ik）,分析其变化趋势,指出进入20世纪80年代以后夏季、秋季及夏秋连季干旱频发,应予以高度关注。