用VHDL实现的23位快速浮点数加减法器

With the development of LSI, FPGA/CPLD has been used more and more in the fields of digital signal processing and au-tocontrol and so on. And with the development of the techniques of digital processing, for fitting the system’s function, it should be a higher requirement to speed and used-resource to compute the floating point numbers. The author introduces a high speed adder-subtracter of the 23 bit’s floating point numbers, which is carried out with the parallel arithmetic and the computational speed cou...中文文摘：随着大规模集成电路的不断发展,FPGA/CPLD在数字信号处理、自动控制等方面得到了越来越多的应用。并且伴随着数字化处理技术的不断发展,为满足系统功能的要求,对浮点数运算的速度以及相应占用的资源也就提出了更高的要求。笔者即介绍了以VHDL语言为基础,采用并行算法且计算速度达到33MHz的,对23位标准浮点数实现的高速浮点加减法运算器,并以Cyclone II芯片EP2C20F484为硬件环境,最终进行时序模拟仿真,从而验证该浮点加减法器的正确性和快速特性。

Xe~(23+)离子辐照Al_2O_3的光谱特性

本工作研究460 keV、3 MeV和308 MeV Xe23+辐照Al2O3单晶样品的光致发光特性。从经过460 keV Xe23+辐照后样品的光致发光测试结果可看到,波长为380、413和450 nm的发光峰明显增强,在390和564 nm处出现了新的发光峰。从3 MeV的Xe23+辐照后样品谱的变化可看到,在较低剂量条件下,516 nm(2.4 eV)和564 nm(2.2 eV)处的发光峰随辐照剂量增加而增强,且当剂量增到1×1016cm-2时,564 nm处的发光峰消失,只有516 nm(2.4 eV)处的发光峰较强。从308 MeV Xe23+辐照后样品的光致发光谱中可看到,357 nm(3.47 eV)和516 nm(2.4 eV)处的发光峰随着剂量增加明显增强。辐照后样品的FTIR谱显示:波数在460~510 cm-1和630 cm-1附近的吸收是Al2O3振动模式,经离子辐照后,吸收带展宽;1 000~1 300 cm-1间为Al—O—Al桥氧键的伸缩振动模式,高能辐照后的吸收带向低波数方向移动。

~(22)Na(p,γ)~(23)Mg反应的实验研究

讨论了目前有关2 2 Na(p ,γ) 2 3Mg反应的实验研究工作 ,结合兰州放射性束流线上的放射性束流2 3Al的β+延发质子衰变实验的测量结果 ,给出了2 3Al延发衰变的质子能谱 ,并比较了近期实验给出的相关能级的自旋、宇称值 ,正是由于这种自旋、宇称和能级部分宽度的不确定性 ,导致了反应率计算的不确定性 .计算了同位旋相似态的共振强度 .对于测量到的新的延发衰变能级Ed =8.91 6MeV ,由于没有相应的能级宽度值 ,实验仅给出其相对共振强度值

~(23)Al 的β~+延发质子测量

利用ＴＯＦ－ Ｅ和０°注入探测器的方法，鉴别并测量了２３Ａｌβ＋延发质子衰变能谱，通过精密脉冲发生器和计数器测得２３Ａｌ的半衰期 Ｔ１／２＝（４７６±４５）ｍｓ．实验中重现了能量为０．２１６，０．２７８，０．４３８，０．４７９ＭｅＶ的低能衰变质子．另外，还观察到了一个新的β＋延发衰变能级 Ｅｘ＝ ８．９１６ＭｅＶ，并给出了它们的相对强度．

Studies on the exotic structure of Al-23

The longitudinal momentum distribution (P-//) of fragments after one-proton removal from Al-23 and reaction cross sections (sigma(R)) for Al-23,Al-24 on carbon target at 74A MeV have been measured simultaneously. An enhancement in sigma(R) is observed for Al-23 compaxed with Al-24. The full width at half maximum of the P-// distribution for Mg-22 fragments has been determined to be 232 +/- 28 MeV/c. Analysis of P-// using the Few-Body Glauber Model indicates a dominant d-wave configuration for the valence proton in the ground state of Al-23. The exotic structure in Al-23 is discussed.

MEASUREMENT OF TWO-PROTON CORRELATION FROM THE BREAK-UP OF Al-23

Experiments of Al-23 and Mg-22 radioactive beams bombarding a C-12 target at an energy of 60 similar to 70 A MeV have been performed at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility to study the two-proton emission from Al-23 and Mg-22 excited states, respectively. The trajectorie of the decay products, namely Na-21 + p + p from Al-23 and Ne-20 + p + p from Mg-22, are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels are obtained by relativistic-kinematics reconstruction. The results demonstrate that there are some di-proton emission components from He-2 cluster for the excited Al-23 and Mg-22.

~(23)Si + ~(238)U非完全熔合裂变与跟随裂变测量

用~(28)Si束流在15.0 Mev/A和21.7 Mev/A两个能量轰击~(238)U靶，裂变碎片由六片PSAD来探测，六片PSAD分为两组，前角组覆盖角度为5°～ 74 °，后角组覆盖角度为-60 °～ -168。在这能区出现了非完全线性动量转移现象，线性动量转移分布是双峰结构，小线性动量转移部分对应于跟随裂变，大线性动量转移部分对应于非完全熔合裂变。用线性动量转移将它们区分开来，得到了跟随裂变截应的相对激发函数。用简单的引导粒子模型对非完全熔合裂变线性动量转移最可几值进行了估算，并与21.7Mev/A的实验进行了比较。用跟随裂变线性动量转移最可几值修正后对其类靶核激发能进行了估算，用单体耗散能对其进行了解释。在这能区，考虑了线性动量转移修正后，总动能仍符合Vio/a系统化公式。由于轻粒子蒸发使裂变碎片产生出反应平面角，得到出反应平面角分布的标准偏差与激发能的关系。发现对Zcn> 100的重系统，有额列轻粒子发射现象

基于QuickBird和GIS的沈阳市城市景观格局

利用高分辨率遥感影像QuickBird和GIS研究沈阳市三环内景观的空间格局及其属性特征。结果表明:(1)研究区域内农村和城市景观并存,斑块数量集中在城市中,在建街区无论是面积还是斑块数量均占有可观的比重,说明城市处于快速扩张时期;(2)研究区域可以划分成以市中心为圆心2km为半径间隔的5个同心圆,各地类的重心近似分布于圆上,由内而外的顺序是道路<老式居住<公共绿地及广场=公共设施=铁路<工业用地=在建用地=水体<农村各地类=防护林。居住用地距离市中心距离的规律为高层≤多层老式≤混合≤多层≤别墅;(3)道路面积>防护林面积,但是防护林植被>道路植被,防护林能够有效提高交通及附属用地的绿化率;(4)农村面积<城市面积,阴影绝大多数集中在城市,农村植被>城市植被,农田的高绿化率对研究区域的绿化率影响很大;城市4类主要用地中,居住区的绿化率(23.3%)<工业用地(28.92%)<公共设施用地(32.32%)<公共绿地及广场(73.83%);居住用地阴影率(26.22%)>公共绿地及广场(16.33%)>公共设施用地(13.41%)>工业用地(8.73%);(5)就居住用地而言,多层老式居住用地的绿化率(19.76%)>高层新式居住用地(10.31%),而小于其余7类居住用地。高度类型相同的情况下绿化率均是花园式>片块式,阴影率差异不大;花园式4类间,绿化率顺序是高层<混合<多层<别墅,阴影率顺序恰好相反;片块式4类间,绿化率顺序是高层<多层<混合<别墅,阴影率顺序恰好相反。

Polymerization of 1,3-butadiene with VO(P-204)(2) and VO(P-507)(2) activated by alkylaluminum

The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.

水溶性聚合物和两亲聚合物23.两亲聚合物PAMC_(16)S对螺口恶嗪化学和物理行为的影响

研究了两亲聚合物聚 (2 -丙烯酰胺基十六烷磺酸 ) (PAMC16S)存在下 1 -乙基 -3 ,3 -二甲基螺 [吲哚啉 -萘并口恶嗪 ](SO -E)在水溶液中的增溶作用及PAMC16S对SO -E化学和光化学性质的影响。PAMC16S明显增加了SO -E在水相的溶解性 ,SO -E的最大增溶浓度随PAMC16S浓度增加呈线性增加规律。在PAMC16S存在下 ,新配制的SO -E溶液显示可逆的光致变色性 ,显色体呈红色 ,最大吸收峰位于 5 2 0nm ,在室温下的消色反应速度明显慢于无PAMC16S存在下的兰色显色体。SO -E/PAMC16S溶液是不稳定的 ,配制后较长时间即失去SO -E的正常光致变色性质。盐酸具有与PAMC16S相似的作用 ,SO -E/PAMC16S体系的不稳定性可用氨水中和的方法解决。1H -NMR结果表明SO -E在酸性介质中发生了不可逆的化学反应。

The effect of preparation conditions on the catalyst Nd(P-507)(3)/H2O/Al(i-Bu)(3) for the polymerization of styrene

The catalyst system neodymium phosphonate Nd(P-507)(3)/H2O/Al(i-Bu)(3) for the polymerization of styrene was examined. Effects of the addition order of the catalyst components, catalyst aging time and aging temperature on the catalyst activity and the polymer characteristics were investigated. The catalyst activity for isospecific polymerization of styrene increases with aging time and reaches the maximum with a catalyst aged for 45 min at 70 degrees C. The aging time that the catalyst needs to reach the highest activity for isospecific polymerization decreases with increasing aging temperature. The preformed catalyst and the in situ catalyst were compared with respect to the kinetic behavior of the styrene polymerization and the polymer characteristics.