半干旱区全膜玉米集雨补灌水分利用效率研究

会宁县属陇中半干旱黄土丘陵区,水资源严重缺乏,6月下旬至7月上旬正值玉米需水关键期的短期干旱,是玉米生产的主要不利气候因素,集雨补灌是应对短期干旱,保证玉米稳产高产的必要条件。玉米拔节与大喇叭口2个关键期补水与补水量试验表明:集雨补灌后较对照增产1791.36～4086.33kg/hm2,增产率34.3%～78.3%;补水时期以大喇叭口期最佳,产量可达8201.44～9316.55kg/hm2,较拔节期同水量增产19.6%～22.7%;增产率、水分生产效率随着补水量的增加而增加,补水生产效率随着补水量的增加而降低,补水量以225m3/hm2为好,大喇叭口期补水225m3/hm2较补灌112.5m3/hm2增产率提高21.4个百分点、水分生产效率提高0.31kg/m3、补水生产效率下降8.27kg/m3。     

旱地玉米双垄全膜覆盖集雨沟播补灌试验初报

利用集雨窖集蓄水进行玉米补灌试验结果表明,在灌水定额为225 m3/hm2时,以大喇叭期灌水处理的效果最好,玉米产量为8 689.53 kg/hm2,较不灌水对照增加16.4%.     

旱地玉米覆膜保墒集雨补灌量试验初报

在西吉县黄土丘陵缓坡地上对旱地玉米覆膜保墒集雨补灌进行了试验研究。结果表明:玉米覆膜栽培条件下补灌量不同表现差异较大,集水补灌效应最明显的最佳补灌量为362.8 m3/hm2,产量可达5938.4kg/hm2,对提高水土资源利用效率和经济效益最有效,能达到充分挖掘旱作区增产潜力的目的,是提高旱地玉米产量和经济效益的有效途径之一。     

陇中半干旱区梯田地膜冬小麦集雨补灌水肥效应研究

在静宁县山地梯田地膜冬小麦上进行集雨补灌试验的初步结果表明,在生育期降水≤180 m m 的条件下,地膜冬小麦较露地冬小麦增产991.00 kg/hm 2,氮肥基施时于拔节期补充灌水100 m 3/hm 2 可增产381.00kg/hm 2,拔节期和孕穗期分别补充灌水100 m 3/hm 2 时增产量可达876.00 kg/hm 2,以孕穗期补灌的增产作用优于拔节期补灌。在陇中半干旱区,有限的集蓄降水必须在冬小麦生育期最关键时期补灌,同时结合地膜的保水抑蒸作用,才能发挥最大的增产效率。     

干旱半干旱区全膜双垄沟播玉米最佳注水补灌时期试验研究

干旱半干旱区全膜双垄沟播玉米最佳注水补灌时期试验结果表明,在干旱半干旱区,对全膜双垄沟播玉米进行适期补灌,可显著增加玉米产量,提高经济效益。以全膜双垄沟播玉米开花期注水为最适宜注水时期,其产量为8 125 kg/hm2,比对照增产2 100 kg/hm2,增幅34.85%,比对照净增加收益2 200元/hm2,增收效益最为明显。     

宁夏彭阳县玉米集雨补灌节水增产技术研究

机修水平梯田种植地膜玉米．在生育关键期利用水窖集雨补充灌溉试验结果表明：在春季严重干旱少雨的气候年份，两年机修水平梯田种植地膜玉米（垄上种植），以补灌标准为15m3／667m^2．30m^3/667m^2、45m^3／667m^2,玉米产量达到346．3-389．1kg／667m^2，较不补灌产量326．9kg／667m^2．增产幅度5．94％-19．03％。其中以补灌标准为45m3／667m^2增产效益较好，生育期水分利用效率（WUE）为2．08kg／m^3，较对照处理区净增加0．45kg／m^3，提高27．61％。     

河西绿洲灌区带田微垄沟灌节水技术研究

采用随机区组设计对河西灌区小麦/玉米带田微垄沟灌技术的研究结果表明,微垄沟灌处理的产量最高可达12 819.0 kg/hm2,较平作对照增产744.0 kg/hm2以上.微垄沟灌种植方式的节水效果显著,可节水1 500 m3/hm2,水分利用效率比平作提高1.35～3.15 kg/(mm*hm2).     

马铃薯垄膜微集雨根际补灌适宜补灌量研究

在宁夏中卫市海原县进行的地膜马铃薯垄膜微集雨注射补灌量的研究,结果表明：地膜马铃薯适宜补灌水量为375～450 m 3/hm 2,全生育期补灌3次,薯块产量及商品率明显提高。     

旱地地膜玉米补水补肥效应研究

在甘肃中部会宁县旱地地膜玉米上进行的不同生育期补肥、大喇叭口期补水和补肥对玉米籽粒产量和水分利用效率影响的研究结果表明 :大喇叭口期补水的效果最好 ,籽粒产量比对照增加 14 .1%、水分利用率提高6 .333kg/ (m m· hm2 ) ;大喇叭口期补水量 2 .5 kg/株的玉米籽粒产量和水分利用效率最高 ,2 a平均籽粒产量较不补灌对照增加 2 9.5 % ,水分利用效率增加 9.6 2 6 kg/ (mm· hm2 ) ;大喇叭口期补施尿素 2 .5 0～ 3.33g/株的效益最好 ,产投比为 6 .5 9。     

秦安县玉米全膜双垄集雨富水储存补灌效应

严酷的农业生产条件严重制约着区域内农村经济的发展,是典型的旱作雨养农业区。玉米是秦安县的主要粮食作物,年播种面积稳定在1.33万hm2左右,产量的高低直接决定着当地的粮食安全。为了研究和探索全膜双垄集雨沟播玉米,在不同生育期利用集雨水窖实施补灌,比较其对玉米产量的影响,作者在千户乡千户村设立了玉米全膜双垄集雨富水储存补灌试验。现将试验结果报告如下。     

Carbonic anhydrase interaction with DDT, DDE, and dieldrin

The active site of various carbonic anhydrases is not blocked by DDT. DDE, or dieldrin. Impairment of catalytic efficiency can only be documented in opalescent test solutions in which the insecticides are present in excess of their solubility limit. These slowly forming precipitates occlude enzyme from solution and furnish a physical explanation of the supposed inhibition. The amounts occluded depend, among other things, on the conformational and topographical characteristics of the particular carbonic anhydrase molecules.     

Capturing sound, light, and strength with new materials

Physicists, chemists, and other scientists gathered in Boston from 28 November to 2 December for the fall meeting of the Materials Research Society (MRS) to explore everything from the behavior of single atoms to bulk structures. Among the more than 4000 papers and posters presented, attendees learned about novel devices that convert light directly to sound, new techniques for studying minuscule structures called quantum dots, and organic-inorganic hybrid materials.     

Cooling, heating, generating power, and recovering waste heat with thermoelectric systems

Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconducting properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating. These materials can be competitive with fluid-based systems, such as two-phase air-conditioning compressors or heat pumps, or used in smaller-scale applications such as in automobile seats, night-vision systems, and electrical-enclosure cooling. More widespread use of thermoelectrics requires not only improving the intrinsic energy-conversion efficiency of the materials but also implementing recent advancements in system architecture. These principles are illustrated with several proven and potential applications of thermoelectrics.     

榆中县半干旱山地地膜玉米集雨补灌高产栽培技术

在总结榆中县半干旱山地雨养农业抗旱生产实践的基础上 ,从选地及播前准备、种植方式、施肥、补灌和田间管理等方面提出了适宜当地半干旱山地推广的地膜玉米高产栽培技术     

Magma generation on Mars: amounts, rates, and comparisons with Earth, moon, and venus

Total extrusive and intrusive magma generated on Mars over the last approximately 3.8 billion years is estimated at 654 x 10(6) cubic kilometers, or 0.17 cubic kilometers per year (km(3)/yr), substantially less than rates for Earth (26 to 34 km(3)/yr) and Venus (less than 20 km(3)/yr) but much more than for the Moon (0.025 km(3)/yr). When scaled to Earth's mass the martian rate is much smaller than that for Earth or Venus and slightly smaller than for the Moon.     

Label-free, single-molecule detection with optical microcavities

Current single-molecule detection techniques require labeling the target molecule. We report a highly specific and sensitive optical sensor based on an ultrahigh quality (Q) factor (Q > 10(8)) whispering-gallery microcavity. The silica surface is functionalized to bind the target molecule; binding is detected by a resonant wavelength shift. Single-molecule detection is confirmed by observation of single-molecule binding events that shift the resonant frequency, as well as by the statistics for these shifts over many binding events. These shifts result from a thermo-optic mechanism. Additionally, label-free, single-molecule detection of interleukin-2 was demonstrated in serum. These experiments demonstrate a dynamic range of 10(12) in concentration, establishing the microcavity as a sensitive and versatile detector.     

Iron ore: energy, labor, and capital changes with technology

Resource gathering is depending on leaner crude ores. Iron ore mining typifies this trend. To make lean taconite iron ores useful required a technologic breakthrough-pelletization. The shift to iron ore pellets has the advantage that they require less energy and labor per ton of molten iron than high-grade naturally concentrated ores. Increased reliance on pellets causes a geographic shift of some jobs and environmental effects from blast furnaces to iron ore mines.