生命中三分之一的幸福

如果我们愿意简单地看待生活,则无论凡夫俗子,还是富翁贵胄,其生命需求都不外“日求三餐,夜求一眠”。这显然不是生命的全部,但肯定是我们生存的基础。人的一生中,有三分之一的时间,是在床上度过的。因此,我以为,每天能否睡个好觉,也该是人生是否幸福的一个重要标准。西洋人塞万提斯曾有妙语:“睡眠是饿者之肉食,渴者之饮料,冻者之温暖,热者之凉快;

加拿大的地铁图书馆

加拿大蒙特利尔第一个地下铁路图书馆——梅特米基尔图书馆,于一九八一年十二月份正式开放。这个图书馆面积为二千平方英尺。有七千零八十个读者。其中三分之二的人是平生第一次到图书馆里来借书的。

电感耦合等离子体原子发射光谱法测定铈矿中微量的砷、锑

采用过氧化钠熔融试样 ,用盐酸调节试液酸度 ,对电感耦合等离子体原子发射光谱 (ICP AES)法同时测定铈矿中微量砷和锑进行了研究 ,考察了铈基体及共存元素 。

俄罗斯贸易和工业部门1994年的年度报告

俄罗斯新闻媒体最近报道了俄罗斯贸工局发布的1994年年度报告,主要内容如下: 中小规模经营:中小规模经营的生产组织仅仅在莫斯科就有25万个,从业人员150万。 金融业:在俄罗斯登记注册的银行有2500家。

第十三届国际档案大会之最

第十三届国际档案大会之最第一次在欧美之外的发展中国家召开。为历届国际档案大会参加国家和地区、人数最多的一次，共有１３０个国家的２６００名档案工作者参加。第一次召开了由中国倡议的档案期刊研讨会，来自１０个国家的近３０名代表出席会议。第一次发行纪念国际档...

“半阕”质疑

“半阕”质疑郑州市铁路五中雷劲生现行初中《语文》第五册１９３页“揣摩·运用”中有两道题目：“四阅读《沁园春·雪》上半阕，想像词的意境，回答问题。五阅读《沁园春·雪》下半阕，完成下边各题。”这里所谓“上半阕”“下半阕”的提法欠妥。词学专家夏承焘先生说：...

电视剧“套牢”太多亟需“缩水”

据了解,我国年产电视剧约1.25万部(集),其中三分之一左右因未能播出而被“套牢”。如果以每集20万元拍摄成本计算,则被搁置的资金就达8亿元之多。其原因一是供过于求,另一个则是质量低劣。与此同时,全国各地拍摄的电视剧总量还在不断增加,一年比一年多,使电视剧市场的形势更加恶化。

NUMERICAL SIMULATIONS OF EVOLUTIONS FROM WALL PULSE TO TURBULENT COHE RENT STRUCTURES

The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model.

Extraction and Crystal Structure of Karounidiol

The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2CH3OHH2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) , V = 3009.8(5) 3, Z = 4, Dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3,13,14, 20)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/D trans and D/E cis.

Impacts of mariculture practices on the temporal distribution of macrobenthos in Sandu Bay, South China

Sandu Bay is located in the East China Sea and is characterized by high-density fish farming and kelp culture. Despite this, little is known about the impacts of these different mariculture practices on the local environment. We investigated the temporal variation in macrobenthos and environmental conditions at three sites in the bay （fish farming site, kelp culture site, and a control site）. We collected water and sediment samples during nine cruises between May 2009 and February 2010. The density of macrobenthos peaked at the fish farming site in July （655 ind./mE） whereas density did not fluctuate as widely at the other two sites. Biomass varied significantly at both the control and kelp culture sites, but had only a single peak at the fish farming site in June （21.90 g/mE）. The dominant species varied throughout the study period at the control and kelp culture sites, whereas a single terebellid species （Lysilla pacifica） dominated the macrobenthos at the fish farming site. The diversity index H＇ increased at the control site beginning in February then decreased after May, whereas H＇ was low at the other sites in December. The mean dissolved oxygen level was highest at the control site （6.59 mg/L） and lowest at the fish farming site （5.54 mg/L）. DO levels were lowest at all sites in summer （July and August）. The sediment acid volatile sulfide content was higher at the fish farming site （1.46 mg/g dry weight） than those at the kelp culture and control sites （1.22 and 0.14 mg/g, respectively）. Our results suggest that mariculture practices have a clear impact on the benthic environment/ community in Sandu Bay.

Chemical fractions and potential mobility of lead in soils irrigated by sewage in Pearl River Delta,South China

The chemical fractions,i.e.,water soluble(WS),exchangeable(Ex),carbonate(Car),weakly organic(WO),Fe-Mn oxide(FMO),strongly organic(SO),residual(Res) fraction,of Pb in irrigated soils in South China were investigated by a modified Tessier sequential extraction technique.The results show that the chemical fraction of Pb in soil is mainly the Res fraction and followed by FMO fraction,and the WS,WO,FMO,and SO fractions in topsoils(0-10 cm) are higher than those in subsoils(30-40 cm).The sum of contents of WS and Ex fractions(SWE) in topsoils is significantly positively related with that in subsoils,indicating the strong mobility of Pb in WS and Ex fractions in soils,and the SWE in soils is higher than the German trigger value for the transfer path soil-plant,indicating the high bioavailability of Pb in soils of this area.Fortunately,SWE and the ratio of WS and Ex fractions(RWE) to the sum of all fractions generally decrease with the soil depth in soil profile and the RWE in soil profile is lower than 0.5%,indicating the low pollution risk for Pb in groundwater.In addition,soil particles,pH and Fe2O3 play an important role in the impact of mobility and chemical fractions of Pb in soils.

Competition between(18,18)and(18,16)Configurations in Ni2(CO)5:An Isomerization Energy Decomposition Analysis

The potential energy landscape of the neutral Ni_(2)(CO)_(5) complex was re-examined.A new C_(2v) structure with double bridging carbonyls is found to compete with the previously proposed triply carbonyl-bridged D_(3h) isomer for the global minimum of Ni_(2)(CO)_(5).Despite that the tri-bridged isomer possesses the more favored(18,18)configuration,where both metal centers satisfy the 18-electron rule,the neutral Ni_(2)(CO)_(5) complex prefers the di-bridged geometry with(18,16)configuration.The isomerization energy decomposition analysis reveals that the structural preference is a consequence of the maximization of electrostatic and orbital interactions.

THE REGIONAL DEVELOPMENT IN THE PEARL RIVER DELTA IN NEW TERM

Since China opening to outside world,the economy in the Pearl(Zhujiang)River Delta(PRD)has been dou-ble digit growth.It has been known as one of mature fast growth areas in the world and become the model and hope of Chi-nese reformand opening to outside wo rld.The regional development in PRD is the outcome of polarization effects .The polar-ization effects actually are extension of international regional divis ion and a combination of Hongkong’s i nfluence and re-form and open-door policies on the ma inland.Since the 1990s,driven by knowledge-based economy,the PRD has f urther adjusted the industrial structure a nd achieved good progress in upgradi ng industrial structure.Its high te chnology industry has developed quickly and the econom ic internationalization has deepen ed,meanwhile,the region is going th rough transforma-tion and some new trends have begun to appear,which include:university t owns springing up,industrial globalization and the construction of Hi-tech develop ment zones.The paper suggests that w ith the economic growth changing fro m relying on the low level production elements to relying on high level production ele ments,the regional policies in Guan gdong Province should develop correspondingly:1)make a plan to prohibite the blind con struction in innovative spatial con struc-tions;2)make measures to attract the overseas talents to establish a pool of talen t;3)work out the favorable policies for absorbing larger capital;4)formulate the policy of attracting a cluster of industries to speed up the upgrade of industrial development.

Mapping Soil Salinity Using a Similarity-based Prediction Approach:A Case Study in Huanghe River Delta,China

Spatial distribution of soil salinity can be estimated based on its environmental factors because soil salinity is strongly affected and indicated by environmental factors. Different with other properties such as soil texture, soil salinity varies with short-term time. Thus, how to choose powerful environmental predictors is especially important for soil salinity. This paper presents a similarity-based prediction approach to map soil salinity and detects powerful environmental predictors for the Huanghe(Yellow) River Delta area in China. The similarity-based approach predicts the soil salinities of unsampled locations based on the environmental similarity between unsampled and sampled locations. A dataset of 92 points with salt data at depth of 30–40 cm was divided into two subsets for prediction and validation. Topographical parameters, soil textures, distances to irrigation channels and to the coastline, land surface temperature from Moderate Resolution Imaging Spectroradiometer(MODIS), Normalized Difference Vegetation Indices(NDVIs) and land surface reflectance data from Landsat Thematic Mapper(TM) imagery were generated. The similarity-based prediction approach was applied on several combinations of different environmental factors. Based on three evaluation indices including the correlation coefficient(CC) between observed and predicted values, the mean absolute error and the root mean squared error we found that elevation, distance to irrigation channels, soil texture, night land surface temperature, NDVI, and land surface reflectance Band 5 are the optimal combination for mapping soil salinity at the 30–40 cm depth in the study area(with a CC value of 0.69 and a root mean squared error value of 0.38). Our results indicated that the similarity-based prediction approach could be a vital alternative to other methods for mapping soil salinity, especially for area with limited observation data and could be used to monitor soil salinity distributions in the future.

Empirical Analysis of City Contact in Zhujiang(Pearl) River Delta, China

In traditional urban geography, city contact research is a classic study element in city research. In general, researchers use the traditional gravity model to characterize the contacts that exist between two cities. The traditional gravity model assumes ideal conditions, but these preconditions and their results often do not exist in realistic conditions. Thus, we used a modified gravity model to characterize the city contacts within a specific region. This model considers factors such as intercity complementarities, government intervention, and the diversity of the transportation infrastructure which is characterized as the transportation distance instead of the traditional Euclidean distance. We applied this model to an empirical study of city contact in the Zhujiang(Pearl) River Delta(PRD) of China. The regression results indicated that the modified gravity model could measure city contact more accurately and comprehensively than the traditional gravity model, i.e., it yielded a higher adjusted R2 value(0.379) than the traditional gravity model result(0.259). Our study also suggests that, in addition to urban-regional and metropolitan development, the complementarities of the basic functions of cities at the administrative and market levels, as well as the corporeal and immaterial levels, play very significant roles in the characterization of city contact. Given the complexity of city contact, it will be necessary to consider more relevant influential factors in the modified gravity model to characterize the features of city contact in the future.

Investigation and Evaluation of Multilevel H-NPC Converter for Electrically Driven Trains

In this paper the operation of a three level H-bridge converter as well as its parallel operations is analyzed and simulated on the computer. Based on the simulation results the operating behavior between （a） a three level H-bridge neutral point clamped convener, （b） a three level back-to-back H-bridge neutral point clamped convener, （c） two three level H-bridge neutral point clamped converters parallel connected is being compared. From the simulation results it is obvious that in the first two cases the ripples, the distortion in primary and secondary winding currents, and the power factor are quite satisfactory and almost identical to each other. In the third case as compared with the first two, it is observed that current harmonics with higher amplitude appear in the primary winding of the transformer.

Dynamic Characteristic of the Medium Span Concrete Footbridges

Concrete footbridges, due to their mass, stiffness and damping, are perceived as strucaires more resistant to vibration caused by dynamic action of the users. In order to verify the dynamic behaviour of concrete footbridges, a series of field tests and numerical analyses have been carried out. In the paper, the results of the dynamic field tests of three medium span concrete footbridges with different structural systems （frame, beam and arch footbridges） and their dynamic characteristics （mass, stiffness and damping） are presented. The field tests were carried out for different types of vibration excitation caused by walking, running and jumping persons. Furthermore, the vibrational comfort criteria for footbridges are shortly described and verified for examined structures. The study were supplemented by numerical calculation of natural mode shapes and frequencies of the structures using the 3D FEA （finite element analysis） models with elastic supports elements in order to ensure the compatibility of the calculated and measured mode shapes of the footbridges.

马属动物春季放血好

马属动物春季放血好马属动物春季适当放血，能增强造血机能，促进血液新陈代谢等作用，可预防多种疾病。马属动物放血部位是颈静脉穴，该穴位于颈静脉沟内，于颈部上三分之一与中三分之一交界处的颈静脉血管上。放血时先压迫穴位后方，使血管怒张，然后用西医的１６号针头...

农村天地

长期以来,美国一直是我国农产品最大进口国,1995年我国从美国进口农产品34.7亿美元,约占我国农产品进口总值的30％。但是近几年,我国从美国进口的农产品比1995年减少了10多亿美元,从美国进口农产品总值的份额下降到22％—24％。1998年受国内需求不足的制约和亚洲金融危机的影响,我国农产品进口总值比1997年减少了16.3亿美元,其中三分之一是由于从美国进口的减少。