长期开垦与放牧对内蒙古典型草原地下碳截存的影响

以围封26 a草地(E26)为对照,研究了内蒙古典型草原区长期开垦与放牧对土壤-植物根系系统碳截存的影响.结果表明,0～40 cm土壤和根系中的C贮量, E26(7 307.59和950.32 g·m-2)≈连续放牧草地(LG)(7834.01和843.43 g·m-2)>开垦35 a耕地(LC)(4537.04和277.35 g·m-2). E26、LG和LC中,0～40 cm土壤贮存的C分别占各自土壤-根系系统C总贮量的88.49%、90.28%和94.24%.长期开垦完全破坏了草地原生的植被-土壤系统,造成严重的土壤风蚀:相对于E26,比中O～10 cm和10～20 cm砂粒含量分别增加了81%和39%,0～40 cm土层中根系生物量减少了71%;长期开垦导致草地土壤及根系碳截存分别降低了37.9%和70.8%.因此,在草原地区,若将长期开垦的耕地恢复为天然草地,土壤和植物根系将会有较大的固碳潜力.放牧对该区土壤有机碳含量及根系生长的影响较小;但长期放牧样地土壤表层容重显著增加,预示目前放牧压力已达到或接近草地的承载阈值,应及时减小放牧压力以避免草地的进一步退化.     

苍山4.4级地震与相公庄水准短临前兆异常

摘要本文采用逐步回归等方法处理了山东相公庄水准 EW、SN 向1989年1月1日至1990年9月30日的五日均值观测资料。回归分析结果表明:苍山4.4(M_L)级地震前相公庄水准 EW、SN 向均有10天左右的短临前兆异常,异常最大幅值分别为0.84mm和0.42mm,地震发生在异常达最大值的前一天,回归剩余标准差分别为±0.17mm和±0.12mm。据动态灰箱法处理的结果说明:短临异常在月均值上也有一定显示,只是幅度小些。作者认为:距震中50km左右的定点形变台,在一定条件下有可能监测到4级以上地震的短临前兆异常。     

保护北疆铁路,建设良好的生态环境,促进博州经济发展

保护和改善生态环境,是确保北疆铁路畅通无阻与发展博尔塔拉州国民经济的重要环节,就此,本文根据资料进行了讨论并提出了相应措施。     

Model Computations on Sequestration of Carbon in Managed Forests and Wood Products under Changing Climatic Conditions in Finland

The aim of this study was to assess the effects of forest management on carbon sequestration in forests and wood products by using a gap-type forest model interfaced with a wood product model. The assessment is based on total carbon sequestration, i.e. the amount of carbon left in vegetation, litter, soil organic matter and products when the flows of carbon back to the atmosphere have been subtracted. Thirty mixed-species stands, representing medium fertility sites in southern Finland, were included in each simulation for 300 years under current climatic conditions and predicted conditions of changing climate. The average total balance for the first 100 years was higher in the unmanaged system than in the managed system, but for the second and third 100-year periods the results were clearly opposite. Differences in the total balance between the treatments were larger during the first 100 years than over the whole 300-year period. Under conditions of changing climate, differences in carbon sequestration between management options were more pronounced than under current climatic conditions. Under current climatic conditions with the 100-year time frame, the ratio between the total annual balance and annual gross production was 0·208–0·289. Over the whole 300 years, however, efficiency was much lower, 0·088–0·121. Under changing climatic conditions, efficiency was also lower, 0·182–0·252 and 0·081–0·096, respectively. Different management alternatives clearly produced different amounts of timber for the production process; under conditions of changing climate, timber production was substantially enhanced. However, total carbon storages at the end of the simulation varied less than timber production. In the managed system, the flow back into the atmosphere was largest from litter, 41–51% of the total outflow, the flow from vegetation was 23–28%, from soil organic matter 22–25%, emissions from products 1–7%, and emissions from landfills 0–3%. If emissions due to the use of machinery in timber harvesting and transportation were included, they made up only 0·03–0·33% of the total outflow.     

Joint implementation: Biodiversity and greenhouse gas offsets

One of the most pressing environmental issues today is the possibility that projected increases in global emissions of greenhouse gases from increased deforestation, development, and fossil-fuel combustion could significantly alter global climate patterns. Under the terms of the United Nations Framework Convention on Climate Change, signed in Rio de Janeiro during the June 1992 Earth Summit, the United States and other industrialized countries committed to balancing greenhouse gas emissions at 1990 levels in the year 2000. Included in the treaty is a provision titled Joint Implementation, whereby industrialized countries assist developing countries in jointly modifying long-term emission trends, either through emission reductions or by protecting and enhancing greenhouse gas sinks (carbon sequestration). The US Climate Action Plan, signed by President Clinton in 1993, calls for voluntary climate change mitigation measures by various sectors, and the action plan included a new program, the US Initiative on Joint Implementation. Wisconsin Electric decided to invest in a Jl project because its concept encourages creative, cost-effective solutions to environmental problems through partnering, international cooperation, and innovation. The project chosen, a forest preservation and management effort in Belize, will sequester more than five million tons of carbon dioxide over a 40-year period, will become economically selfsustaining after ten years, and will have substantial biodiversity benefits.     

昆钢滇中铁合金厂6000KVA电炉烟尘治理

昆钢滇中铁合金厂6000KVA电炉采用干法袋式除尘工艺处理烟气，通过改变滤袋材质、控制在线过滤风速、延长清灰静止沉降时间等措施，使整套装置除尘效率达到99．5％。     

Prenatal diagnosis of thalassemia major by fetal blood analysis: Experience with 1000 cases

In this report we have summarized our experience with the prenatal diagnosis of β-thalassemia in 1000 pregnancies followed at least until 12 months after birth. In the majority of these cases, the thalassemia lesion was the nonsense mutation at the codon corresponding to amino acid 39, which produces the hematological phenotype of β-thalassemia. Fetal blood sampling was carried out by placental aspiration, by which a sufficient amount of fetal blood for analysis was obtained in the majority of cases (99 per cent). The fetal mortality associated with fetal blood sampling was 6·3 per cent. Those placental samples contaminated by maternal cells were successfully purified by Ørskov lysis. Fetal blood was analysed by globin chain synthesis on CM–52 columns, which gave reliable results. Two misdiagnoses (0·2 per cent) have been made of which one was due to a non-globin protein co-migrating with the β-chains while the other resulted from a misclassification of the type of thalassemia segregating in the family.     

The prognostic factors in the prenatal diagnosis of the echogenic fetal lung

The prenatal diagnosis of an echogenic fetal lung (EFL) is now often made in the early second trimester using high-resolution ultrasound. This ultrasound appearance is usually caused by a congenital cystic adenomatoid lung malformation (CCAM), an intrapulmonary lung sequestration or obstruction of a major airway. In order to provide prognostic guidelines to parents who may be considering termination of a fetus with these findings, we have analysed a series of 11 cases diagnosed in our centre over the past 2 years in conjunction with 60 cases from major published series. The data suggest that in the absence of non-immune hydrops fetalis (NIHF) or other anomalies, the outcome for the fetuses is excellent, with over 90 per cent survival. Neither early diagnosis (24 weeks) nor the presence of mediastinal shift is a poor prognostic indicator. In addition, it appears that if NIHF is absent at diagnosis, the chance that it will develop as the pregnancy continues is small (6 per cent). Furthermore, there is a significant (up to 30 per cent) chance that this ultrasound finding will resolve in utero. The development of in utero fetal surgical techniques may be the only hope for those hydropic fetuses who appear to have a dismal prognosis.     

Electrochemical reduction characteristics and mechanism of nitrobenzene compounds in the catalyzed Fe-Cu process

The reduction of the nitrobenzene compounds （NBCs） by the catalyzed Fe-Cu process and the relationship between the electrochemical reduction characteristics of NBCs at copper electrode and reduction rate were studied in alkaline medium（pH=11）. The catalyzed Fe-Cu process was found more effective on degradation of NBCs compared to Master Builder＇s iron. The reduction rate by the catalyzed Fe-Cu process decreased in the following order： nitrobenzene 〉4-chloro-nitrobenzene ≥m-dinitrobenzene ：〉 4-nitrophenol ≥2,4-dinitrotoluene 〉2-nitrophenol. The reduction rate by Master Builder＇s iron decreased in the following order： m-dinitrobenzene ≥4-chloro-nitrobenzene 〉4-nitrophenol 〉2,4-dinitrotoluene ≈nitrobenzene 〉2-nitrophenol. NBCs were reduced directly on the surface of copper rather than by the hydrogen produced at cathode in the catalyzed Fe-Cu process. The reduction was realized by the hydrogen produced at cathode and Fe（OH）2 in Master Builder＇s iron, It is an essential difference in reaction mechanisms between these two technologies. For this reason, the reduction by the catalyzed Fe-Cu depended greatly on NBC＇s electron withdrawing ability.     

LS系列硫磺回收催化剂工业装置使用总结

对比总结了LS系列催化剂的使用情况，结果表明，在一级转化器均装填LS-931Al2O3基催化剂的前提下，二级转化器上部装填LS－971脱氧保护型催化剂，下部装填LS－811Al2O3催化剂后，与单纯使用LS－931催化剂相比，单器转化率由64．1％提高到70．1％，有机硫水解率由96％提高到接近100％，两项合计使装置总硫转化率由95．1％提高到96．2％，若与两个转化器全部使用LS－811催化剂相比，则装置总硫转化率可由94．49％提高到96．2％使用效果更加显著。