P-wave attenuation anisotropy in TI media and its application in fracture parameters inversion

The existence of aligned fractures in fluid-saturated rocks leads to obvious attenuation anisotropy and velocity anisotropy. Attenuation anisotropy analysis can be applied to estimate fracture density and scale, which provide important information for reservoir identification. This paper derives P-wave attenuation anisotropy in the ATI media where the symmetry axis is in the arbitrary direction theoretically and modifies the spectral ratio method to measure attenuation anisotropy in the ATI media, thus avoiding a large measurement error when applied to wide azimuth or full azimuth data. Fracture dip and azimuth can be estimated through attenuation anisotropy analysis. For small-scale fractures, fracture scale and fracture density can be determined with enhanced convergence if velocity and attenuation information are both used. We also apply the modified spectralratio method to microseismic field data from an oilfield in East China and extract the fracture dip through attenuation anisotropy analysis. The result agrees with the microseismic monitoring.     

Correction of the temperature effect in calibration of a solar radio telescope

This work analyzes the annual fluctuation of the observation data of the Mingantu Solar radio Telescope(MST) in S, C and X bands. It is found that the data vary with local air temperature as the logarithmic attenuation of equipment increases with temperature and frequency. A simplified and effective calibration method is proposed, which is used to calibrate the MST data in 2018–2020, while the correction coefficients are calculated from data in 2018–2019. For S, C and X bands, the root mean square errors of one polarization are 2.7, 5.7 and 20 sfu, and the relative errors are 4%, 6% and 8% respectively. The calibration of MUSER and SBRS spectra is also performed. The relative errors of MUSER at 1700 MHz,SBRS at 2800 MHz, 3050 MHz and 3350 MHz are 8%, 8%, 11% and 10% respectively. We found that several factors may affect the calibration accuracy, especially at X-band. The method is expected to work for other radio telescopes with similar design.     

洪湖日本沼虾的种群繁殖生物学

1994年5月至1995年6月对洪湖日本沼虾的种群繁殖生物学进行了研究．洪湖日本沼虾的繁殖期为4月中旬至10月上旬,5月中旬至8月中旬为日本沼虾的繁殖高峰期,其中6月、8月雌虾抱卵率均在70％以上;日本沼虾群体中雄性总是少于雌性,月性比（♀／♂）变化于1．104－5．780之间,3—6月性比逐渐增高,7─10月性比则逐渐降低;在整个繁殖期．4─7月的抱卵虾均为前一年出生的大、中规格的个体,之后当年出生的个体在繁殖群体中逐渐占据优势;春季抱卵虾的绝对繁殖力和相对繁殖力都大于秋季抱卵虾,分别计算了绝对繁殖力、相对繁殖力与体长、体重的函数关系．本文还对日本沼虾群体性比的周年变化及其产卵次数进行了讨论．     

Compact and tunable mid-infrared source based on a 2 μm dual-wavelength KTiOPO4 intracavity optical parametric oscillator

Using a double resonant KTiOPO₄ (KTP) intracavity optical parametric oscillator operating at degenerated point of 2 μm, we demonstrate a unique mid-infrared source based on difference frequency generation in GaSe crystal. The output tuning range is 8.42-19.52 μm, and a peak power of 834 W for type-I phase matching scheme and 730 W for type-II phase matching scheme are achieved. Experimental results show that this oscillator is a good alternative to the generator of a compact and tabletop mid-infrared radiation with a widely tunable range.     

正韵律厚油层剩余油的水平井开发技术研究

与直井相比,水平井开发具有缩短油井井距,扩大泄油面积,提高临界锥流量,更好地控制注入流体、改善波及效率等优势。在相同采液量的情况下,水平井可以降低采液强度,减缓含水上升速度。特高含水期河流相储集层的顶部是剩余油富集区,利用水平井技术挖掘正韵律厚油层顶部剩余油,取得了很好的开发效果,最终采收率较直井开发提高了14个百分点。     

莱州湾东部滨海水域砂金分布特征

通过对莱州湾东部滨海水域地球物理和地质钻综合调查，业已查明该海区地质的构造和古地理环境特征，并发现区内砂金分布较普遍，本文从砂金分布的地貌单元，沉积物类型，砂金成因类型，物质来源，古气候，构造作用，砂金成因等诸方面，研究了该海域内砂金特征。     

The myth of community and sustainable grassland management in China

Within national and international domestic academic circles, there are increasing calls for enhanced involvement of communities in formulating and implementing grassland management arrangements. In contrast to the current national policy of contracting grasslands to households, many scholars call for support for collective grassland use arrangements. Several reasons are given for increased recognition and support for community-based management of grasslands, including lower costs of exclusion and dispute resolution, economies of scale in herding and marketing, mitigation of environmental risk, and ensuring equitable access to grassland resources. One conclusion from this literature is that devolving authority for designing and implementing grassland management systems to communities would lead to more sustainable grassland use, a position that I term as the ‘myth of community.’ This paper presents the results of a study of grazing systems in two communities in Hongyuan County, Sichuan Province. Each community uses its grasslands collectively. However, the study found evidence of severe overgrazing, especially in winter pastures, suggesting that community-based management of grasslands is not necessarily sustainable. The paper discusses three potential policy innovations required to support sustainable grazing systems in China’s grassland areas: overcoming constraints in labor and land markets, and payments for environmental services that reward sustainable stocking levels.     

气候分析应用聚类方法的评价

对聚类分析的华德法、重心法和平均联系法的理论分析指出:在组间距离相同的条件下,华德法优先合并小的组,最终产生大小较为均匀的组,这不能准确地反映气候的现实。在组内平方和增量相同的条件下,重心法优先合并大的组,最终产生一个很大的组和很多极小的组,背离气候的现实。平均联系法基本上避免了上述偏歧,产生凝聚、方差均匀的组,较好地反映气候现实。中国东部大陆夏季降水的分区证实了以上结论。     

云南地区房屋建筑的震害矩阵

自1992年4月23日云南孟连西中缅交界6.7、6.9级地震始,地震部门对云南地区的破坏性地震进行了现场灾害调查和经济损失评估。1992~2003年,云南地区共发生50次破坏性地震,积累了丰富的震害资料。本文根据云南地区的主要建筑结构,统计分析了50次地震不同烈度区的破坏比、损失比和震害指数,给出了房屋建筑的震害矩阵。     

Loss of preferred habitat and pollen limitation threatens reproduction in a rare mountain <Emphasis Type="Italic">Paeonia delavayi</Emphasis>

Paeonia delavayi is a wild tree peony species endemic to high-altitude regions in southwestern China. Recent agricultural land expansion, however, not only causes its dwindling population size, but also poses a severe threat to its long-term persistence. Since our knowledge of the reproductive biology of P. delavayi is very limited, and some management misconceptions have further exacerbated the already worrisome situation, the aim of the present study is to provide some scientific evidence regarding habitat preference and breeding system of P. delavayi, and to help correct some management misconceptions. Specifically, morphological traits of P. delavayi populations growing in two different habitats (i.e., the open area versus forest understory), including basal stem diameter, plant height and flower numbers per plant, were measured and compared with each other. A range of floral manipulation experiments was further conducted to study the extent of self-compatibility and pollen limitation. The results showed that P. delavayi preferred the open habitat over forest understory as it generally grew bigger with thicker stems, and produced a higher number of flowers in the former habitat. Therefore, the open habitat should receive immediate priority for conservation action instead of being converted to agricultural land; also, P. delavayi is pollen limited, as evidenced by the fact that experimental flowers receiving supplemental non-self pollen generally displayed elevated seed production than flowers subjected to other treatments (e.g., non-supplemental self pollen, non-supplemental non-self pollen and supplemental self pollen), which is consistent with reported observations that alpine plants are more likely to be pollen-limited than lowland plants. We suggest that human intervention might be necessary to guarantee the long-term persistence of P. delavayi as harsh alpine environment, intense competition for pollinators and different anthropogenic perturbations co-limit its reproductive success.