土壤可蚀性（K）值图编制方法的初步研究

利用土壤普查图件和剖面理化分析的成果资料编制了土壤可蚀性（Ｋ）值图，介绍了求取剖面点Ｋ值的查图表法、图斑分并与图斑Ｋ值的确定原则和编制程序等，应用上述方法，完成了我国第一张地区级Ｋ值图，经分析，与公式算法比，查图表法的Ｋ值精度为８５．４％，与径流小区实测值比，用Ｋ值图上相应Ｋ值监测的土壤年流失量的精度为８６．０％。     

废弃塑料热降解及燃烧动力学试验研究

通过塑料的热降解现象试验，观察出塑料的热降解温度特性；通过废塑料燃烧过程的燃烧失重试验，计算出其燃烧动力学参数，分析塑料燃烧特性。结果表明：在高炉炉缸高温，富氧的环境中，废塑料能够得到迅速、充分的燃烧，可以部分代替焦碳和煤粉。     

Chorionic mosaicism: Association with fetal loss but not with adverse perinatal outcome

Cytogenetic data from the United States NICHD collaborative study of chorionic villus sampling (CVS) were used to evaluate the clinical significance of chorionic mosaicism. The 10 754 patients with normal cytogenetic results were compared wtih 108 patients (1.0 per cent) with placental mosaicism and 181 patients (1.6 per cent) with pseudomosaicism. Of the pregnancies intended to continue, the pregnancy loss rate was significantly greater in patients with placental mosaicism than in the cytogenetically normal cohort (8.6 vs. 3.4 per cent, p <0.05). However, there was no difference in the frequencies of abruptio placenta, preterm labour or delivery, small-for-gestational-age newborns, pregnancy-induced hypertension, or neonates with Apgar scores less than 7.     

紫色土地区水文特征对硝态氮流失的影响研究

采用人工降雨模拟的方法,研究水文传输途径对紫色土中NO3--N流失的影响.研究结果表明,在所有雨强中均观察到壤中流的存在.在小雨强长历时的降雨中壤中流的径流量大于大雨强短历时降雨;随着雨强的增大,壤中流的径流系数下降.在紫色土地区,氮素的流失途径不仅包括地表径流而且包括壤中流,并且壤中流是NO3--N的主要水文传输途径.无论是否受到施肥措施的影响,壤中流中NO2--N浓度均高于地表径流.在对照小区,壤中流中NO3--N平均浓度是地表径流的7倍以上;施肥后壤中流NO3--N平均浓度为26.07mg·L-1,是地表径流的20倍以上.在对照小区,壤中流NO3--N的流失量占流失总量的30%以上;在施肥小区,壤中流NO3--N流失量占总流失量的90%以上.在紫色土地区,土壤特征和降雨特征决定了该地区壤中流形式的普遍存在,而NO3--N以壤中流流失的特点与当地施肥习惯的耦合效应增大了该地区的NO3--N流失风险.     

黄土高原南部土壤退化机理研究

黄土高原土壤侵蚀极其严重 ,这不仅导致了土壤生产力的降低 ,同时也导致了土壤的退化。本文在定位监测、室内分析及野外调查的基础上 ,研究了黄土高原南部土壤的退化机理。结果表明 :土壤中 <0 0 1mm颗粒和土壤养分流失是造成黄土高原土壤退化的主要原因 ,耕地土壤结构状况的恶化和土壤酶的流失使土壤退化程度进一步加剧 ,从而成为严重制约该区经济发展障碍。     

中国酸雨的生态影响和防治对策

我国是继欧洲、北美之后 ,在世界上出现的第三大酸雨区。长江以南各省是我国酸雨的主要分布区。酸雨对生态系统的危害日益严重。本文阐述了酸雨对农作物、森林和人体健康的影响。并根据可持续发展的战略思想 ,提出防治对策。     

Follow-up and pregnancy outcome after a diagnosis of mosaicism in CVS

In 2103 consecutive diagnostic chorionic villus samples, examined in a 4-year period in our clinical genetics unit, 26 samples (1.2 per cent) presented chromosomal mosaicism in the direct and/or long-term culture preparations. Only once (46,XX/47,XX,+9) was the mosaicism confirmed in the fetus. In the cytogenetic follow-up studies of the remaining 25 pregnancies, in no cases could the aberration be confirmed in amniotic fluid or fetal tissue. One patient requested a termination after the CVS result. Of the remaining 24 pregnancies, four (16.7 per cent) ended in a spontaneous abortion. These findings suggest an association between placental mosaicism and fetal loss.     

农田氮素流失对环境的污染现状及防治对策

从地表水、地下水、大气以及农产品等方面 ,概述了农田氮素流失对环境的污染现状 ,阐述了控制农田氮素流失的防治对策 ,指出实施生态农业政策、优化氮肥管理、选育氮高效品种以及控释 /缓释肥料的应用将是今后农业生产发展的方向     

Studies on the enzymatic and fungal degradation of cross-linked gelatin and its graft copolymers

Glutaraldehyde cross-linked gelatin was graft copolymerized with acrylic acid, acrylamide, vinyl acetate, methyl acrylate, and methyl methacrylate either individually or in combination. The enzymatic and fungal degradation of these graft copolymers with trypsin, pepsin, and mixed cultures ofAspergillus niger, Penicillium ochrochloron, Penicillium funiculosum, andTrichoderma viride was studied for short and extended periods. The weight loss suffered by the samples, the weight of biomass formed, the nitrogen content, and the pH of the culture medium were determined. With the help of these data, the extent of utilization of graft copolymers by fungi as a sole source of carbon was estimated. The samples with less than 100% grafting and with a ratio of polymethyl methacrylate content (L) to polyacrylic acid (H) content (L/H values) lower than 1.0 were readily and extensively degraded.IICT Communication No. 3375.     

世界职业灾害概述

本文讨论了我国和工业发达国家及世界范围的职业灾害问题，涉及事故伤亡数、重大恶性事故、职业危害、经济损失等四个方面．