Around-the-World Relativistic Sagnac Experiment

In 1971 Hafele and Keating carried portable atomic clocks east and then west around the world and verified the Sagnac effect, a special relativity effect attributable to the earth's rotation. In the study reported here observations of the effect were made by using electromagnetic signals instead of portable clocks to make clock comparisons. Global Positioning System satellites transmit signals that can be viewed simultaneously from remote stations on the earth; thus an around-the-world Sagnac experiment can be performed with electromagnetic signals. The effect is larger than that occurring when portable clocks are used. The average error over a 3-month experiment was only 5 nanoseconds.     

麦田泽漆的发生为害与防治

盐城市稻茬麦田泽漆发生较 2 0世纪 80年代前大为严重 ,其发生高峰在小麦播种后 15～ 2 0d ,全生育期约 2 0 0d。泽漆发生密度和小麦产量损失及穗数减少均呈直线函数关系 ,其危害临界期在 2月 2 5日～ 3月 2 5日之间。化防试验结果表明 ,冬前应用 2甲 4氯 +使它隆或 2甲 4氯与巨星合剂均可有效地防除麦田泽漆     

红叶茎枯病对棉花产量性状及纤维品质的影响

为了明确红叶茎枯病对棉花产量性状及纤维品质的影响,以中棉41为材料,采用田间调查和室内分析相结合的方法,对产量结构和纤维品质相关性状进行了测定和分析。结果表明,不同红叶茎枯病发病级别之间产量性状有明显差异,其中,该病对单铃重影响最大,对株果枝数影响最小。同时,红叶茎枯病使纤维强度、断裂长度、成熟度及马克隆值降低,使纤维细度变细。在5个纤维性状,中纤维细度和马克隆值受到的影响最大,纤维断裂长度受到的影响不明显。     

Suppression of collisional shifts in a strongly interacting lattice clock

Optical lattice clocks with extremely stable frequency are possible when many atoms are interrogated simultaneously, but this precision may come at the cost of systematic inaccuracy resulting from atomic interactions. Density-dependent frequency shifts can occur even in a clock that uses fermionic atoms if they are subject to inhomogeneous optical excitation. However, sufficiently strong interactions can suppress collisional shifts in lattice sites containing more than one atom. We demonstrated the effectiveness of this approach with a strontium lattice clock by reducing both the collisional frequency shift and its uncertainty to the level of 10(-17). This result eliminates the compromise between precision and accuracy in a many-particle system; both will continue to improve as the number of particles increases.     

Doppler interpretation of quasar red shifts

The hypothesis that the quasistellar sources (quasars) are local objects moving with velocities close to the speed of light is examined. Provided there is no observational cutoff on apparent bolometric magnitude for the quasars, the transverse Doppler effect leads to the expectation of fewer blue shifts than red shifts for an isotropic distribution of velocities. Such a distribution also yields a function N(z), the number of objects with red shift less than z which is not inconsistent with the present data. On the basis of two extreme assumptions concerning the origin of such rapidly moving sources, we computed curves of red shift plotted against magnitude. In particular, the curve obtained on the assumption that the quasars originated from an explosion in or nearby our own galaxy is in as good agreement with the observations as the curve of cosmological red shift plotted against magnitude.     

The sun azimuth compass: one factor in the orientation of homing pigeons

In accordance with the theory of the sun azimuth compass (1), displaced homing pigeons are misled in a predictable way if their "internal clock" has been reset by exposure to a time-shifted sequence of day-night cycles.     

开心树形叶幕结构对苹果园地面太阳辐射的影响

以小冠开心形和小冠分层形苹果树为试材,进行了不同处理地面太阳辐射光谱变化以及对叶幕太阳辐射影响的研究。结果表明,(1)受树形处理的影响,地面太阳辐射光谱和强度均发生了明显变化。其中,紫外光(U,300～380 nm)、光合有效辐射(PAR,400～700 nm)和红外/远红外(R/FR,780～1 010 nm)到达果园地面的比率分别为35.73%,13.35%和28.88%。从果园地面外侧(0 cm)到主干(120 cm),太阳辐射光谱中PAR强度依次递减,而U,R/FR辐射的强度依次递增。(2)受果园地面太阳辐射变化的影响,果园地面辐射与叶幕辐射之间、地面辐射与叶幕反射辐射之间、叶幕辐射与叶幕反射辐射之间均呈显著相关关系,同时开心形处理地面全波辐射和PAR均提高,其迎光面地面平均太阳辐射和PAR分别达到了29.7%和25.3%,同时地面及叶幕反射光谱中PAR的平均比例分别比对照提高了74.9%和71.0%。     

Nondependence of frequency on mass: a differential experiment

A differential Loran C experiment, which is independent of variations in clock rates, shows that the frequency of a radio transmission is not affected by the mass of the earth.     

基于AT89S52的智能型双精度太阳自动跟踪系统设计

为提高太阳能的利用率,以AT89S52单片机为控制核心,采取极轴式跟踪方式,设计了一套以视日运动轨迹跟踪为主、光电跟踪进行跟踪校正的智能型双精度太阳跟踪系统,该系统通过采集时钟芯片信息计算当前太阳位置,实现视日运动轨迹跟踪;同时利用光电传感器采集的光强偏差控制步进电机,实现光电跟踪,校正轨迹偏差,保证聚光板与太阳光相垂直。试验表明,该太阳跟踪系统能在不同天气状况下对太阳进行较准确跟踪,能量接收效率提高20%以上,达到了充分利用太阳能的目的。     

薇菜机械化干制技术研究

为实现薇菜(Osmunda Japonica Thunb)规模化种植、机械化加工,采用自制网链式漂烫冷却机对鲜菜进行热水漂烫处理,经风扇冷却菜体,室外摊晾变红后装入揉捻机揉搓,交替使用热风干燥机或者日晒进行干制。通过生产试验找出了最佳机械化加工工艺参数:漂烫水温100℃,漂烫时间3～4 min,漂烫投菜量250 kg/h;揉捻机投菜量60%、压力大小控制分别是空压→20%→50%、转速35～38 r/min、揉搓7次,第一次15 min,以后每次30 min;第1次揉搓后采用85℃热风干燥0.5 h,第2次揉搓后75℃热风干燥0.5 h,第3次揉搓后75℃热风温度干燥0.5 h,取出再揉搓后进行日晒干燥,直到安全含水量为13%左右。     

Superior conjunction of pioneer 6

Spectrograms of the radio signals from Pioneer 6 were taken as the spacecraft was occulted by the sun. The spectral bandwidths increased slowly at first, then very rapidly at 1 degree from the sun. In addition, six solar "events" produced marked increases of bandwidth lasting for several hours. The received signal power seemed unaffected by the solar corona.     

甘肃历史地震与气象异常相关性研究之一——两汉三国魏晋南北朝时期

两汉至南北朝时期,气象灾异频次与地震频次之间存在着明显关联。从今甘肃地区发生的地震看,白虹贯日、雷发非时等异常气象与地震的关系最为密切,与地震关联的异常气象还有天雨血、黑气、青虹等,地震前后异常现象还具有多发特征。     

脲对麦芽酸性磷酸酶活力与构象的影响

应用荧光光谱、紫外差光谱等检测手段研究麦芽酸性磷酸酶经脲变性后的分子构象与活力的变化情况,结果表明,低浓度的脲(＜2 mol/L)微扰了酶的活性部位而使其局部构象发生变化,使酶的荧光强度略有下降,荧光发射峰位红移,酶活力下降.继续增大脲浓度,酶的整体构象被破坏,酶荧光强度增加,发射峰位红移,酶活力仍然呈下降趋势.荧光强度的增加和最大发射峰位的红移是酶变性失活的一个指标,酶活力的变化快于酶分子整体构象的变化,说明麦芽酸性磷酸酶的活性部位位于柔性较大的区域.     

西红柿成熟度与电特性关系的无损检测研究

本文利用LCR电棋逢对手测量仪和无损检测方法测定了不同成熟度（青、微红和红）西红柿的介电常数、等效阻抗、介质损耗因数等电特性。试验结果表明：在加载频率一定时，随着成熟度的提高，西红柿的相对介电常数增大，等效阻抗减小。在4KHz-150KHz的频段内，随着加载频率的增大，等效阻抗减小，相对介电常数略有减小，介质损耗因在4KHz-20KHz的频段内变化较小。     

Search for a Frequency Shift of the 21-Centimeter Line from Taurus A near Occultation by Sun

The 21-centimeter absorption line from the direction of Taurus A was used for detection of a shift in frequiency when the source passed near Sun. A possible decrease in frequency of 150 cycles per second was detected, which cannot be caused by general relativity or by the plasma around Sun.     

TKSS-C型信号与系统实验箱的带阻滤波器分析

分析了TKSS--C型信号与系统实验箱的带阻滤波器实验模块，用信号与系统中的S平面几何分析方法给出了幅频特性、相频特性，根据电路中通频带的定义给出了截止频率，并对RC参数相同的带阻有源和无源滤波器进行了比较。     

深冷速冻保鲜技术对舟山杨梅品质的影响

采用深冷（-60℃）速冻保鲜技术,以舟山杨梅为研究对象,在无太阳光照的条件下自然解冻,研究不同冷藏时间对杨梅果实的失重率、可溶性固形物含量、总酸含量、呼吸强度、果实硬度、腐败率及感观评定等理化指标的影响。结果表明：在-60℃的冷藏条件下,保藏6个月的杨梅的失重率较新鲜杨梅减少3．35％,较冷藏3个月后杨梅的呼吸强度降低51．5％,果实硬度降低7．1％,可溶性固形物的含量降低2％,总酸的含量降低0．19％,腐烂率增加5％。综合分析结果表明,采用深冷（-60℃）速冻保鲜技术保藏的杨梅,在3-6个月其营养品质变化较小。该研究将为杨梅的精深加工提供理论基础。     

Migration along orthodromic sun compass routes by arctic birds

Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.     

母羊3种应激行为下叫声信号的对比分析

为研究母羊在不同应激行为下叫声信号所具有的特征,选择体重相近、年龄在2~3岁的小尾寒羊母羊20只,分别录取其在3种应激行为(产羔、寻羔、饥饿)下的叫声信号。利用LabVIEW软件设计母羊发声信号特征提取与识别系统,对母羊发声信号进行时域分析、频域分析(Yule-Walker法估计功率谱、Welch法估计功率谱、线性坐标功率谱和倒谱分析)和时频域分析,提取发声信号的时间间隔、持续时间、主峰频率、能量集中范围和基音周期等特征参数。结果表明:母羊3种不同类型声音的持续时间以及主峰频率均存在显著差异(P0.05)。母羊在寻羔和饥饿时发声的持续时间是产羔时的1.93和1.82倍,饥饿叫声的主频分别为产羔和寻羔时的34.77和38.81倍,母羊叫声信号Yule-Walker法功率谱在饥饿出现1个峰值,寻羔时出现2个峰值,而产羔时无明显峰值。叫声信号能量在产羔时集中在400~600Hz,寻羔和饥饿时集中在0~900Hz,3种叫声基音周期接近为0.1ms。证明母羊叫声信号在3种应激行为下有明显的不同,因此可以作为评价其健康状况及福利化养殖水平的重要指标之一。     

H 2O和H 2 S与双卤分子形成的卤键的理论研究

用量子化学从头算方法对H2O和H2S与卤素分子(X—Y)形成的卤键O/S…X—Y进行了理论研究.计算结果表明,卤键的形成导致X—Y键长增大与伸缩振动频率红移;电子密度拓扑(AIM)分析表明,复合物中的卤键为闭壳层相互作用;自然键轨道(NBO)分析表明,卤键O/S…X—Y形成时,强的分子间超共轭n(O/S)→σ*(X—Y)引起的电荷转移是X—Y键伸缩振动频率红移的重要原因.