非线性减振结构等效动弹性亚超谐共振拟合法研究术(Ⅰ)

提出了利用亚超谐共振响应傅氏谱拟合非线性弹性结构等效参数的两种基本方法,得到了以三次多项式描述非线性弹性的亚超谐共振约束方程,研究了稳态响应或周期响应存在条件,从理论上分析了两种拟合方法的特点     

The NMFECC cray time-sharing system

The National Magnetic Fusion Energy Computer Center (NMFECC) at the Lawrence Livermore National Laboratory (LLNL) has implemented a simple, yet powerful interactive operating system, the Cray Time-Sharing System (CTSS), on a Cray-1 supercomputer. CTSS augments the multi-programming batch facilities normally found in supercomputer systems with many of the interactive services typical of interactive minicomputer systems. This paper gives some of the historical background leading to CTSS and gives an overview of the system that emphasizes the strong points or unusual features such as multiple channels, decentralized control of resources, priorities and program scheduling, system recovery, and on-line documentation.     

Extracorporeal membrane oxygenator support for cardiopulmonary failure. Experience in 28 cases

We have used extracorporeal membrane oxygenation (ECMO) for 28 patients (14 children and 14 adults) over a 5 year period. Nine patients improved on ECMO and 5 were long-term survivors. ECMO was used for pulmonary insufficiency in 24 patients. Initially, only moribund patients were treated, but recently the combination of open lung biopsy and pulmonary insufficiency index (PII) has been used to select patients. The best results have been obtained in newborn cases and the adult capillary leak syndromes; the major problem has been progression to fibrosis despite ECMO support. ECMO was used for cardiac failure in 4 patients. Children with postoperative cardiac failure did the best; profound shock was not reversed with venoarterial bypass. ECMO support is lifesaving in selected cases of pulmonary insufficiency. Initial trials in cardiac failure and the infant age group in this series suggest that ECMO will have an even greater role in those applications.     

Structure and stability of an immunoglobulin superfamily domain from twitchin, a muscle protein of the nematode Caenorhabditis elegans

The NMR solution structure of an immunoglobulin superfamily module of twitchin (Ig 18') has been determined and the kinetic and equilibrium folding behaviour characterised. Thirty molecular coordinates were calculated using a hybrid distance geometry-simulated annealing protocol based on 1207 distance and 48 dihedral restraints. The atomic rms distributions about the mean coordinate for the ensemble of structures is 0.55( +/- 0.09) A for backbone atoms and 1.10( +/- 0.08) A for all heavy atoms. The protein has a topology very similar to that of telokin and the titin Ig domains and thus it falls into the I set of the immunoglobulin superfamily. The close agreement between the predicted and observed structures of Ig 18' demonstrates clearly that the I set profile can be applied in the structure prediction of immunoglobulin-like domains of diverse modular proteins. Folding studies reveal that the protein has relatively low thermodynamic stability, deltaG(H2O)U-F = 4.0 kcal mol(-1) at physiological pH. Unfolding studies suggest that the protein has considerable kinetic stability, the half life of the unfolding is greater than 40 minutes in the absence of denaturant.     

中国废弃煤矿压气蓄能潜力与初步可行性研究

随着中国化石能源比重下降、无碳能源比重上升的能源清洁化的结构转型,井下废弃矿井数量增多,同时风能和太阳能（WS）得到迅速发展,但资源利用率却很低。为了提高资源化利用率和加快转型升级,提出了一种结合风能和太阳能的混合压缩空气蓄能（CAES）系统,并将井下废弃矿井作为压缩空气的储能空间。首先,根据太阳能、风能、毁弃煤矿地下空间资源及电网分布特征确定了WS-CAES混合系统的潜在区域,主要分布在三北（东北、华北北部和西北）地区,具备了发展该系统的巨大潜力。然后,基于系统压缩机、膨胀机、热换器和储气室等各参数数学模型,研究了换热器效能、环境温度、质量流量、总压比和压缩/膨胀级数运行变量对系统输出功率和总效率的性能影响,压缩机/涡轮机级数对总效率（η）具有显着影响,级数2增至级数5时,η增幅为7.31％。最后,针对毁弃煤矿巷道储存高压气体的可行性,从巷道深度、内衬及围岩渗透性方面进行Comsol软件数值计算和分析,结果表明：巷道深度对系统储存气体的泄漏无明显影响;巷道内衬对系统稳定性具有重要作用;围岩渗透率则是决定系统气密性的关键因素,其围岩渗透率越小,储气库气体泄露量越小,气密性则越好;同时,煤矿井下主通风巷和运输巷具有储存压缩空气能力。     

The anthropogenic nitrogen cycle in the Netherlands

Results of a study on the nitrogen flows in the Netherlands are presented for three different years. The details given for 1995 are preliminary. The data are derived from a material balance sheet investigation. The objective of the study is to present a complete, integrated and accurate overview of nitrogen losses from the anthropogenic nitrogen cycle in the country with respect to present and possible future nitrous oxide emissions. Losses are analyzed in terms of economic sources and the recipient environmental compartments. The nitrogen losses account for about 25% of the total nitrogen input in the anthropogenic nitrogen cycle. Most of the losses occur in agriculture (67%), whereas industry, traffic and households each contribute about 10% to the total nitrogen loss. About 15% of the total nitrogen input in the national economy ends up in the environment, where it gives rise to adverse effects as the eutrophication of fresh surface water and the contamination of ground water with nitrate. A comparison of the results for different years shows that little progress has been made in emission reductions so far. Ammonia emissions have been reduced, but at the expense of an increase of the nitrogen input to agricultural soils.