青藏铁路的国民经济后评价体系及方法

文章对即将运营的青藏铁路工程建立了一个以成本一效能评价为总体评价法的国民经济综合后评价体系，其中又以模糊综合评价法对各效能因素进行了模拟评价。     

Novel evaluation method of TCP performance over satellite links

1 .INTRODUCTIONIn recent years , much attention has been paid tothe efficient application of transmission control pro-tocol ( TCP) to satellite environments[1 ~3]. TCPhas been developed for wired networks that have alower delay and a very low bit error rate .It is themost commonly usedtransport layer protocol intheInternet and provides reliable and end-to-end com-munication services for applications . TCP conges-tion control and error control mechanisms will besignificantly influenced …     

在半适应多孔网状网络系统中解除死锁的多址发送机制

描述在多孔网状网络上解除多址发送中死锁问题的一种方法，这种方法将多址发送的目标组织成一棵分配树，树的分枝由一些消息链接而成，这些消息能够按照半适应回转路由选择策略沿着不会造成死锁的路线传送。     

一类离散事件动态系统及其应用

从实际生产过程中抽象出一类特殊的离散事件动态系统,对该系统进行数学描述,构造仿真策略。将其用于某啤酒厂的生产决策,获得了满意的结果。     

电流模式MOS A／D转换神经网络的研究

从Ａ／Ｄ转换基本规则出发，提出了一种电流模式ＭＯＳＡ／Ｄ转换神经网络，并对该网络进行了分析研究，导出确定权值的公式。网络权值易存贮且调节简单。用ＰＳＰＩＣＥ对４－ｂｉｔＡ／Ｄ转换网络进行仿真，并对采用分立元件的构成的３－ｂｉｔＡ／’Ｄ转换网络进行了实验。     

Permutation Code Encryption-New Achievement Based on Path Encryption

0 IntroductionThere are two main methods to attack block cipher :dif-ferential cryptanalysis[1]and linear cryptanalysis[2 ,3].Differential cryptanalysis can successfully attack 8-round,10-round,14-round,16-round data encryption standard (DES)using respectively 224,231,239,247plaintext-cipher text cou-ples , while linear cryptanalysis needs 221,233,247plaintext-cipher text couples to attack respectively 8-round,12-round,16-round DES successfully,the process may cost 40 secondsfifty hours and …     

On the use of ordered sets in problems of comparison and consensus of classifications

Ordered set theory provides efficient tools for the problems of comparison and consensus of classifications Here, an overview of results obtained by the ordinal approach is presented Latticial or semilatticial structures of the main sets of classification models are described Many results on partitions are adaptable to dendrograms; many results on n-trees hold in any median semilattice and thus have counterparts on ordered trees and Buneman (phylogenetic) trees For the comparison of classifications, the semimodularity of the ordinal structures involved yields computable least-move metrics based on weighted or unweighted elementary transformations In the unweighted case, these metrics have simple characteristic properties For the consensus of classifications, the constructive, axiomatic, and optimization approaches are considered Natural consensus rules (majoritary, oligarchic, ) have adequate ordinal formalizations A unified presentation of Arrow-like characterization results is given In the cases of n-trees, ordered trees and Buneman trees, the majority rule is a significant example where the three approaches convergeThe authors would like to thank the anonymous referees for helpful suggestions on the first draft of this paper, and W H E Day for his comments and his significant improvements of style     

Ricerche fisiologiche sulla distribuzione periferica del nervo depressore aortico destro nel cane

Summary The periferal distribution of the right aortic nerve has been studied in physiological experiments on the dog. It has been found that after section of both Hering's nerves and left vago-depressor trunk and after denervation of the baroceptor area ofMuratori-Nonidez lying at the root of the right subclavian artery, the electrical stimulation of one splancnic nerve or the intravenous injection of adrenaline still produces a reflex bradycardia; moreover the cooling of the vagus nerve still results in a rise of the blood pressure. It is inferred that a group of baroceptor fibres of the right aortic nerve originate from areas situated in the aortic region.     

Molecular basis of photoprotection and control of photosynthetic light-harvesting

In order to maximize their use of light energy in photosynthesis, plants have molecules that act as light-harvesting antennae, which collect light quanta and deliver them to the reaction centres, where energy conversion into a chemical form takes place. The functioning of the antenna responds to the extreme changes in the intensity of sunlight encountered in nature. In shade, light is efficiently harvested in photosynthesis. However, in full sunlight, much of the energy absorbed is not needed and there are vitally important switches to specific antenna states, which safely dissipate the excess energy as heat. This is essential for plant survival, because it provides protection against the potential photo-damage of the photosynthetic membrane. But whereas the features that establish high photosynthetic efficiency have been highlighted, almost nothing is known about the molecular nature of the dissipative states. Recently, the atomic structure of the major plant light-harvesting antenna protein, LHCII, has been determined by X-ray crystallography. Here we demonstrate that this is the structure of a dissipative state of LHCII. We present a spectroscopic analysis of this crystal form, and identify the specific changes in configuration of its pigment population that give LHCII the intrinsic capability to regulate energy flow. This provides a molecular basis for understanding the control of photosynthetic light-harvesting.     

Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago

Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20?metres, in less than 500?years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the B?lling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A.