野战防空导弹武器系统综合机动性灰色关联度分析

本文应用灰色系统理论中关联度分析和模糊数学中隶属函数方法,对当前外军装备的九种主要低空近程野战防空导弹武器系统机动性进行分析、评判。其结果对野战防空导弹的论证、研制和使用均具有一定的参考价值。     

试论元认知、数学学习策略及其关系

首先阐述了对元认知和数学学习策略两个概念的理解,然后探讨了两者之间的关系。数学学习策略是元认知的重要组成部分,两者相互影响、彼此促进、协调发展。     

基于TCP/IP的局域安保监视系统

实现一个由ZR36060完成图像编解码，CS8900芯片实现TCP／IP协议，完成数据传榆，单片机则完成数据的调度、管理，对各部件的初始化和控制，完全不依赖复杂的实时操作系统，仅依靠单片机自身的监控系统和部分自主开发的应用软件，即可实现一个瘦客户型的局域安保监视系统。     

Dendritic spikes as a mechanism for cooperative long-term potentiation

Strengthening of synaptic connections following coincident pre- and postsynaptic activity was proposed by Hebb as a cellular mechanism for learning. Contemporary models assume that multiple synapses must act cooperatively to induce the postsynaptic activity required for hebbian synaptic plasticity. One mechanism for the implementation of this cooperation is action potential firing, which begins in the axon, but which can influence synaptic potentiation following active backpropagation into dendrites. Backpropagation is limited, however, and action potentials often fail to invade the most distal dendrites. Here we show that long-term potentiation of synapses on the distal dendrites of hippocampal CA1 pyramidal neurons does require cooperative synaptic inputs, but does not require axonal action potential firing and backpropagation. Rather, locally generated and spatially restricted regenerative potentials (dendritic spikes) contribute to the postsynaptic depolarization and calcium entry necessary to trigger potentiation of distal synapses. We find that this mechanism can also function at proximal synapses, suggesting that dendritic spikes participate generally in a form of synaptic potentiation that does not require postsynaptic action potential firing in the axon.     

化学发光法确定库仑滴定终点的研究

利用鲁米诺－Ｉ＿２的化学发光体系与Ａｓ（Ⅲ）的无机偶和反应，确定Ｉ＿２库仑滴定法的终点，实验证明，此法测砷的灵敏度高（检测限３．０×１０￣（－８）ｇ／Ｌ），线性范围１．０×１０￣（－６）ｇ／Ｌ～３．５×１０（－８）ｇ／Ｌ，且选择性好，仪器装置简单，操作方便．     

动态信道分配在TD-SCDMA系统中的应用研究

针对TD-SCDMA系统,充分结合TD-SCDMA系统的关键技术、资源特点、业务特点和干扰特点,寻求适用于该系统(包括频域载频、时域时隙、码域码道和空域位置)的最优组合动态信道分配策略,为了比较该策略下不同动态信道分配(DCA)算法性能,提出了4种DCA算法,并结合实际情况建立仿真模型,通过正确设置仿真参数,进行系统级仿真,以确定各种动态信道分配算法,各种仿真参数设置对系统呼阻率的影响。仿真结果表明,TD-SC- DMA系统是下行受限的系统,其上、下行干扰门限理想值分别为1.5和3.1左右。     

林文漪副市长畅谈首都农业科技革命

今年年初,北京市科委与市农委联合召开了全市农村科技工作会议.副市长林文漪出席大会并作了重要讲话.     

车削时切削用量的优化设计

较详细地介绍了车削时切削用量合理选择、优化设计对目标函数的确定，约束条件的建立，并以切削速度为例，介绍最优切削速度确定。     

Mutations in BRIP1 confer high risk of ovarian cancer

Ovarian cancer causes more deaths than any other gynecologic malignancy in developed countries. Sixteen million sequence variants, identified through whole-genome sequencing of 457 Icelanders, were imputed to 41,675 Icelanders genotyped using SNP chips, as well as to their relatives. Sequence variants were tested for association with ovarian cancer (N of affected individuals = 656). We discovered a rare (0.41% allelic frequency) frameshift mutation, c.2040_2041insTT, in the BRIP1 (FANCJ) gene that confers an increase in ovarian cancer risk (odds ratio (OR) = 8.13, P = 2.8 × 10(-14)). The mutation was also associated with increased risk of cancer in general and reduced lifespan by 3.6 years. In a Spanish population, another frameshift mutation in BRIP1, c.1702_1703del, was seen in 2 out of 144 subjects with ovarian cancer and 1 out of 1,780 control subjects (P = 0.016). This allele was also associated with breast cancer (seen in 6/927 cases; P = 0.0079). Ovarian tumors from heterozygous carriers of the Icelandic mutation show loss of the wild-type allele, indicating that BRIP1 behaves like a classical tumor suppressor gene in ovarian cancer.