Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning, China: New 40Ar/39Ar dating of the Yixian and Tuchengzi

We report new ⁴⁰Ar/³⁹Ar dating results obtained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby basaltic sill. The second is the Yixian Bed 9 tuff from Hengdaozi considered by Lo et al. to be unaffected by metamorphism and whose age, based on total fusion ⁴⁰Ar/³⁹Ar dating of biotite, argues for a Jurassic age for the Yixian Formation. The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion ⁴⁰Ar/³⁹Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ± 0.04 (SE) Ma. Single sanidine crystal total fusion ⁴⁰Ar/³⁹Ar analyses of the Hengdaozi tuff gave a mean age of 125.0 ± 0.19 (1SD) ± 0.04 (SE) Ma, which is indistinguishable from the Sihetun tuff. The Tuchengzi Formation tuff gave a mean age of 139.4 ± 0.19 (1SD) ± 0.05 (SE) Ma. Detailed laser incremental-heating analyses of biotite from Sihetun, Hengdaozi, and Tuchengzi tuffs show disturbed Ar release patterns and evidence of trapped argon components. We conclude from these analyses that the total fusion dates on biotite by Lo et al. are erroneously old and isotopic dating of both biotite and sanidine from tuffs of the Yixian Formation point to a middle Early Cretaceous age. The upper part of the Tuchengzi Formation can be referred to the Early Cretaceous.     

Discovery of mitochondrial chimeric-gene associated with cytoplasmic male sterility of HL-rice

The mitochondrial genome libraries of HL-type sterile line (A) and maintainer line (B) have been constructed. Mitochondrial gene, atp6 , was used to screen libraries, due to the different Southern and Northern blot results between sterile and maintainer line. Sequencing analysis of positive clones proved that there were two copies of atp6 gene in sterile line and only one in maintainer line. One copy of atp6in sterile line was same to that in maintainer line; the other showed different flanking sequence from the 49th nucleotide downstream of the termination codon of atp6 gene. A new chimeric gene, orfH79 , was found in the region. orfH79 had homology to mitochondrial gene coxⅡ and orfH79, and was special to HL-sterile cytoplasm.     

新型薄壁空腹异形材轧机切割小车控制系统研制

由于薄壁空腹异形材采用新的轧制工艺，节省了金属材料，提高了使用寿命，且外形美观，这种型材在国外早已赢得很大发展，文中重点介绍轧机对切割小车控制系统的要求，切割小车伺服控制的原理，数字控制器的构成，现场调试结果表明，系统工作令人满意，定尺长度误差小于１／１０００。     

家兔子宫血管的铸型观察

用血管铸型方法观察研究了家兔子宫动脉血管的构筑情况，结果表明，家兔子宫内膜动脉呈树杆状或有轻度弯曲，其形态与有月经的人子官内膜螺旋动脉的螺旋状形态有明显差异。     

图象显示与处理方法在纽约州Medina组Grimsby层区域地质研究中的应用

用图象显示和处理方法代替传统的计算机制图法,成功地对美国纽约州下志留统Medina组的Grimsby层进行了区域地质研究.揭示了该层的区域古沉积环境,划出了该层进一步勘探和开发的有利相带.研究结果表明,本文所采用的图象显示和处理技术具有直观、形象、快速和准确的优点.     

湖北省的驼舞虻及新种记述（双翅目：舞虻科）

本文根据作者1984年在神农架、武当山及九宫山采集的标本,报道了湖北省的双翅目舞虻科驼舞虻属9个种,其中包括7个新种和1个中国新记录种,附有雄外生殖器图,与近缘种作了比较。     

崖城地区汕优6号制种播种期的调查研究

笔者通过调查研究认为:崖城地区杂交水稻制种适宜扬花期是3月中旬至5月上旬,最佳扬花期是4月5日至5月上旬。汕优6号制种中 IR26(父本)适宜播种期是11月12日至翌年1月30日,它的最佳播种期是12月7日至翌年1月—5日,在 IR26秧苗8.5片叶左右时播种珍汕97A(母本)为宜。但是,确定播种期除了根据最佳扬花期之外,还必须注意四个问题:(1)制种田的水利条件;(2)制种田与周围稻田不同品种之间的花期应错开;(3)亲本种子贮存的时间长短;(4)病虫发生为害的规律。