关于隐式LU分解算法分解算法求矩阵主子阵逆的注记（英）

ＡＲｅｍａｒｋｏｎｔｈｅＩｎｖｅｒｓｅｏｆＰｒｉｎｃｉｐａｌＭａｔｒｉｃｅｓｂｙＩｍｐｌｉｃｉｔＬＵＦａｃｔｏｒｉｚａｔｉｏｎＨｕａｎｇＫａｉｂｉｎＷｕＨｅｂｉｎ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＮａｎｊｉｎｇＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｎａｎｊｉ...     

Synthesis and characterization of a new kind of immobilized Mn(salen) and catalytic epoxidation of styrene on the catalyst

A linear polystyrene‐isopropenyl phosphonic acid (PS‐IPPA) copolymer was newly synthesized by free radical reaction in solution with isopropenyl phosphonic acid (IPPA) and styrene. Zirconium poly(styrene‐isopropenyl phosphonate)‐phosphate acid (ZPS‐IPPA) was also synthesized. The benzene rings of ZPS‐IPPA were hydroxylated and then further reacted with Mn(salen)Cl. Thus the heterogeneous catalyst, Mn(salen) axially immobilized onto ZPS‐IPPA was synthesized. These substances were characterized by IR spectra, X‐ray diffraction (XRD), SEM, TEM, NMR, thermogravimetric analysis, and AAS. The catalyst showed good activity to epoxidation of styrene, which is close to that of the corresponding homogeneous catalyst. Copyright © 2008 John Wiley & Sons, Ltd.     

碳纳米管/炭黑混杂填充聚甲醛复合材料导电性能研究

采用在转矩流变仪中熔融混合的方法制备了多壁碳纳米管(MWCNTs)和导电炭黑(CB)共同填充的聚甲醛(POM)导电复合材料,研究了材料的体积电阻率和导电填料用量之间的关系.用该体系的实验数据点对已发表的混合导电填料体系的定量关系式进行了验证,结果表明实验数据点和理论预测略有偏差.为方便实际应用,把混合导电填料体系的定量关系式加以发展,推导出逾渗值和两种导电填料质量比之间的关系式,并绘出了工作曲线.设计实验对工作曲线进行了验证,结果表明工作曲线对实践具有指导意义.     

Phase dependent interference effects on atomic excitation

We present an experimental and theoretical study of phase-dependent interference effects in multi-photon excitation under bichromatic radio-frequency (rf) field. Using an intense rf pulse, we study the interference between the three-photon and one-photon transition between the Zeeman sub-levels of the ground state of ⁸⁷Rb that allows us to determine the carrier-envelope phase of the fields even for long pulses.     

Extraterrestrial3 He in marine polymetallic nodules: A potential method for measuring growth rate of nodules

The comparative measurements of helium isotope compositions between marine polymetallic nodules and their surrounding sediments, their magnetic fractions and bulk from C-C Zone of the East Pacific Basin are reported. The⁴He content and³He/⁴He ratio of polymetallic nodules and their surrounding sediments are extremely high; the³He,⁴ He concentrations and most³He/⁴He ratios of magnetic fractions in nodules and sediments are apparently higher than those in bulk. The helium isotope data points of nodules and sediments are all distributed along or closely to the mixing curve of the interplanetary dust particles (IDPs) and the terrigenous sediments in the chart of³He-³He/⁴He. In the same sampling site, the³He/⁴He ratios of nodules and their surrounding sediments are very similar, and the changes of both ratios are synchronous. It shows that the high³He/⁴He ratios in nodules and sediments may all result from IDPs. So, if the flux of extraterrestrial³He into the nodules and sediments is constant, the growth rate of polymetallic nodules and the sedimentation rate of sediments can be independently calculated according to the concentra-tion of extraterrestrial³He in nodules and sediments.

     

Chiral Hybrid Germanium(II) Halide with Strong Nonlinear Chiroptical Properties

Due to the pronounced anisotropic response to circularly polarized light, chiral hybrid organic–inorganic metal halides have been regarded as promising candidates for the application in nonlinear chiroptics, especially for the second-harmonic generation circular dichroism (SHG-CD) effect. However, designing novel lead-free chiral hybrid metal halides with large anisotropy factors and high laser-induced damage thresholds (LDT) of SHG-CD remains challenging. Herein, we develop the first chiral hybrid germanium halide, (R/S-NEA)₃Ge₂I₇⋅H₂O (R/S-NGI), and systematically investigated its linear and nonlinear chiroptical properties. S-NGI and R-NGI exhibit large anisotropy factors (g_SHG-CD) of 0.45 and 0.48, respectively, along with a high LDT of 38.46 GW/cm²; these anisotropy factors were the highest values among the reported lead-free chiral hybrid metal halides. Moreover, the effective second-order nonlinear optical coefficient of S-NGI could reach up to 0.86 pm/V, which was 2.9 times higher than that of commercial Y-cut quartz. Our findings facilitate a new avenue toward lead-free chiral hybrid metal halides, and their implementation in nonlinear chiroptical applications.     

Intensity correlations in a coherently prepared Rb vapor in a magnetic field

We have studied the intensity correlations between two orthogonally linearly polarized components of a laser field propagating through a resonant atomic medium. These experiments have been performed in a rubidium atomic vapor. We observe that the correlations between the orthogonally polarized components of the laser beam are maximal in the absence of a magnetic field. The magnitude of the correlations depends on the applied magnetic field, and the magnitude first decreases and then increases with increasing magnetic field. Minimal correlations and maximal rotation angles are observed at the same magnetic fields. The width of the correlation function is directly proportional to the excited state lifetime and inversely proportional to the Rabi frequency of laser field.     

Extraterrestrial ~3He in marine polymetallic nodules: a potential method for measuring growth rate of nodules

The comparative measurements of helium isotope compositions between marine poly-metallic nodules and their surrounding sediments, their magnetic fractions and bulk from C-C Zoneof the East Pacific Basin are reported. The ~4He content and ~3He/~4He ratio of polymetallic nodulesand their surrounding sediments are extremely high; the ~3He, ~4He concentrations and most~3He/~4He ratios of magnetic fractions in nodules and sediments are apparently higher than those inbulk. The helium isotope data points of nodules and sediments are all distributed along or closelyto the mixing curve of the interplanetary dust particles (IDPs) and the terrigenous sediments in thechart of ~3He-~3He/~4He. In the same sampling site, the ~3He/~4He ratios of nodules and their surround-ing sediments are very similar, and the changes of both ratios are synchronous. It shows that thehigh ~3He/~4He ratios in nodules and sediments may all result from IDPs. So, if the flux of extrater-restrial ~3He into the nodules and sediments is constant, the growth rate of polymetallic nodules andthe sedimentation rate of sediments can be independently calculated according to the concentra-tion of extraterrestrial ~3He in nodules and sediments.     

声速匹配组织量化技术对非酒精性脂肪性肝炎定量评价的初步应用研究

目的探讨声速匹配组织量化（SVQ）技术定量评价非酒精性脂肪性肝炎（NASH）的可行性和临床应用价值。方法选取经肝穿刺或临床资料证实的非酒精性单纯性脂肪肝（NAFL）及NASH患者各20例,并选取健康体检者20例作为对照组,分别采集3组受试者临床相关资料,进行SVQ检测,采集声速匹配值（ZSI）和组织声速（SV）。结果3组受试者在年龄、身高、体重方面均无统计学差异（均P＞0.05）,BMI、ZSI和SV均存在统计学差异（均P＜0.01）。SVQ技术诊断NASH的AUC为0.801。以SV=1527m/s作为临界点,判断NASH的灵敏度、特异度分别为95.20%、70.60%。结论SVQ技术定量评价NASH是可行的,具有很好的临床应用价值。     

Selective reflection of a laser beam from a dilute rubidium vapor

We study the selective reflection of the laser beam from rubidium atomic vapor at the D₂ line (wavelength λ = 780 nm) at different atomic densities. We use a tunable free-running diode laser. We observed a measurable signal at a low atomic density N when the mean distance between resonance atoms reached two wavelengths. In our experiment, the dimensionless parameter N ^1/3 λ varied from 0.5 to 2.8. The reflectivity increased with density monotonically. It is interesting to perform experiments when the parameter N ^1/3 λ ≪ 1.