Injection Molding Shrinkage and Mechanical Properties of Polypropylene Blends

Polypropylene (PP) blends based on isotactic polypropylene (iPP), propylene-ethylene block copolymer (bPP), and propylene–ethylene random copolymer (rPP) were prepared by melt blending and the effects of content of bPP and rPP on the shrinkage during solidification and storage and mechanical properties of the blends were studied. It was found that the addition of polypropylene copolymer could effectively reduce the processing shrinkage of iPP and the lowest shrinkage of the blends was achieved at a loading of 2 wt% bPP or rPP. The flexural modulus and tensile strength of the blends decreased a little while the impact strength and elongation at break were improved greatly compared with those of iPP.     

Microstructure,Rheology, and Potential Oil Absorbency of Poly(Butyl Methacrylate) and Poly(Hydroxyethyl Methacrylate) Blends

To prepare oil-absorptive polymers with moderate cross-linking structure, poly(butyl methacrylate) (PBMA) was synthesized as a linear hydrophobic polymer by suspension polymerization. In addition, hydroxyethyl methacrylate (HEMA), as a monomer, which could construct a network structure among the macromolecules via hydrogen bond interactions, was solution polymerized in dimethylacetamide (DMAc) with PBMA, yielding a polymer blend of PBMA and PHEMA. The solution of the polymer blend was investigated by rotational viscometry and extended rheometry. The results showed that the viscosity varied greatly with the temperature and shear rate for three different compositions. Fourier transform infrared (FTIR) spectra indicated that an entanglement or interlocking cross-linking structure of molecular chains was constructed by hydrogen bonds. The results from nuclear magnetic resonance (NMR) spectra exhibited a downfield movement of the proton peak as influenced by end groups or hydroxyls in the polymer chains. The rheological measurements demonstrated that the cross-linking structure greatly affected the rheological behavior of the blend solution. In addition, the cross-linking structure was also evaluated by oil absorbency of films.     

Ab initio MRCI＋Q study on potential energy curves and spectroscopic parameters of low-lying electronic states of CS＋

Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV~0.2 eV.     

Molecular dynamics study of thermal stress and heat propagation in tungsten under thermal shock

Using molecular dynamics （MD） simulation, we study the thermal shock behavior of tungsten （W）, which has been used for the plasma facing material （PFM） of tokamaks. The thermo-elastic stress wave, corresponding to the collective displacement of atoms, is analyzed with the Lagrangian atomic stress method, of which the reliability is also analyzed. The stress wave velocity corresponds to the speed of sound in the material, which is not dependent on the thermal shock energy. The peak pressure of a normal stress wave increases with the increase of thermal shock energy. We analyze the temperature evolution of the thermal shock region according to the Fourier transformation. It can be seen that the “obvious” velocity of heat propagation is less than the velocity of the stress wave; further, that the thermo-elastic stress wave may contribute little to the transport of kinetic energy. The heat propagation can be described properly by the heat conduction equation. These results may be useful for understanding the process of the thermal shock of tungsten.     

Open critical area model and extraction algorithm based on the net flow-axis

In the integrated circuit manufacturing process, the critical area extraction is a bottleneck to the layout optimization and the integrated circuit yield estimation. In this paper, we study the problem that the missing material defects may result in the open circuit fault. Combining the mathematical morphology theory, we present a new computation model and a novel extraction algorithm for the open critical area based on the net flow-axis. Firstly, we find the net flow-axis for different nets. Then, the net flow-edges based on the net flow-axis are obtained. Finally, we can extract the open critical area by the mathematical morphology. Compared with the existing methods, the nets need not to divide into the horizontal nets and the vertical nets, and the experimental results show that our model and algorithm can accurately extract the size of the open critical area and obtain the location information of the open circuit critical area.     

Consistency proof of two denoising methods and the parameter selection of PDE filtering method for ESPI

Electronic speckle pattern interferometry （ESPI） is a nondestructive, whole-field optical measurement technique. The removal of speckle noise is fundamental to extract measurement information accurately. In this letter, two filtering methods based on the oriented feature of ESPI fringes, i.e., the second-order oriented partial differential equation （SOOPDE） and oriented, regularized quadratic-cost function filtering methods, are first proven to be consistent. An important question in solving partial differential equation, i.e., how to select suitable parameters in an adaptive manner, is then discussed. The computer-simulated and experimentally obtained ESPI fringe patterns and phase map are processed by the SOOPDE filtering model with adaptive selective parameters. The qualitative and quantitative analyses demonstrate that the parameters selected by the adaptive method are effective and suitable for the SOOPDE filtering model.     

环式M(SO2)(M=Zn, Cd)分子及其阴离子的基质隔离红外光谱和密度泛函理论计算

激光溅射锌和镉原子与SO₂分子反应的低温基质隔离红外光谱实验表明,在氩和氖的惰性基质中,形成了环式M(SO₂)分子及其阴离子M(SO₂)^- (M=Zn, Cd)．相关同位素(³⁴SO₂和S¹⁸O₂)替代实验及密度泛函理论计算均证实了这一结果．此外,自然电荷布居分析表明电子从金属锌和镉的s轨道转移到了SO₂配体上形成了M⁺(SO₂)^-“离子对”复合物,且该分子中的Zn-O键以及Cd-O键均表现出强的极化共价性．而Hg原子在与SO₂反应中所表现出来的惰性可由其较强的相对论效应所致的6s价电子层收缩与高电离电位得以解     

Semiclassical approximation for transmission through open Sinai billiards

We use a semiclassical approximation to study the transport through the weakly open chaotic Sinai quantum billiards which can be considered as the schematic of a Sinai mesoscopic device,with the diffractive scatterings at the lead openings taken into account.The conductance of the ballistic microstructure which displays universal fluctuations due to quantum interference of electrons can be calculated by Landauer formula as a function of the electron Fermi wave number,and the transmission amplitude can be expressed as the sum over all classical paths connecting the entrance and the exit leads.For the Sinai billiards,the path sum leads to an excellent numerical agreement between the peak positions of power spectrum of the transmission amplitude and the corresponding lengths of the classical trajectories,which demonstrates a good agreement between the quantum theory and the semiclassical theory.     

ICF靶丸装配误差检测

针对激光惯性约束聚变装置中靶丸装配误差检测困难、要求精度高的特点,研制了一套用于微靶装配参数检测的测量系统。提出了一种基于激光与CCD的复合式测量方法,建立了二者数据融合的数学模型,通过标定空间位置关系有效地把二者的测量数据融合到同一个坐标系中,从而实现了高精度三维测量。分两种情况讨论了靶丸装配误差的检测方法。实验结果验证了这两种方法的可行性,并比较了两种方法的测量精度,其极限测量误差均不超过3 m。     

Calibrating an optical fiber humidity sensor and applying it in real-time monitoring of relative humidity in fresh concrete

A doubly cladding single-mode fiber humidity sensor is fabricated by agarose. The sensor has an insertion loss of -0.08 dB and a power change of -17.83 dB. The responses of the sensor to a relative humidity （RH） range form 30% to 100% at a temperature range form 25 to 34 ~C are validated. The experiments demonstrate that the absorbability of agarose gel to moisture decreases with increasing RH in measured gas. We propose a calibration method that uses lookup tables and construct a corresponding calibration matrix. Using the sensor, we conduct real-time monitoring of RH in fresh concrete during its hardening nrocess.