Effect of Laser Annealing on Permeability Spectra in Co-based Amorphous Ribbon

We investigated the variation of permeability spectra and relaxation frequency in Co-based amorphous ribbon annealed by pulsed Nd:YAG laser at various annealing energy Ea. The complex permeability spectra varies sensitively with the annealing energy, where the spectra could be decomposed into two contributions from domain wall motion,μdw(f) and rotational magnetization μrot(f) by analyzing the measured spectra as a function of driving ac field amplitude. The magnitude of μdw(f) and μrot(f) in dc limit shows maximum at Ea = 176 mJ. The maximum relaxation frequency for rotational magnetization, determined by μ'(f) curve, is about 700 kHz at Ea=62 mJ but that for wall motion is about 26 kHz at 230 mJ. These variations reflect the increase of magnetic softness and microstructural change by the annealing.

Modeling flow in naturally fractured reservoirs： effect of fracture aperture distribution on dominant sub-network for flow

Fracture network connectivity and aperture （or conductivity） distribution are two crucial features controlling flow behavior of naturally fractured reservoirs. The effect of connectivity on flow properties is well documented. In this paper, however, we focus here on the influence of fracture aperture distribution. We model a two dimensional fractured reservoir in which the matrix is impermeable and the fractures are well connected. The fractures obey a power-law length distribution, as observed in natural fracture networks. For the aperture distribution, since the information from subsurface fracture networks is limited, we test a number of cases： log-normal distributions （from narrow to broad）, power-law distributions （from narrow to broad）, and one case where the aperture is pro- portional to the fracture length. We find that even a well- connected fracture network can behave like a much sparser network when the aperture distribution is broad enough （c~ 〈 2 for power-law aperture distributions and σ ≥ 0.4 for log-normal aperture distributions）. Specifically, most fractures can be eliminated leaving the remaining dominant sub-network with 90% of the permeability of the original fracture network. We determine how broad the aperture distribution must be to approach this behavior and the dependence of the dominant sub-network on the parameters of the aperture distribution. We also explore whether one can identify the dominant sub-network without doing flow calculations.

THREE NEW Fe-BASED MICROCRYSTALLINE ALLOYS WITH SUPERIOR MAGNETIC PROPERTIES

Three new Fe-based microcrystalline alloys,i.e.,Fe_(73.1)Cu_(1.2)Nb_(3.2)Si_(12 5)B_(10), Fe_(73)Cu_1Nb_(1.5)Mo_2Si_(12.5)B_(10) and Fe_(73)Cu_1Zr_3C_(0.5)Mo_Si_(12.5)B_(10),were developed with su- perior magnetic properties.e.g.,high relative initial permeability of μ_i^15×10~4,low coercivity of H_c1.0A/m,high effective permeability and low core losses in a consid- crable wide frequency range and high pulse-magnetic permeability under narrow pulse. The optimum value of relative effective permeability,μ_5~1 is 16×10~4 under condition of f=1 kHz and H_m=0.4 A/m.The optimum values of core loss reach 57.9 30.2 and 68 W/kg under condition of f=50.100.100 KHz and B_m=0.5,0.2,0.3 T,respectively. These three alloys have superior stability of magnetic properties.Initial permeability may be not changed during heating at 130℃ up to 216 h.The main crystalline phase is ordered phase Fe_((75)+y)Si_((25)-y) which is ultrafine particles of average size 10—20 nm.

EPR Effect of Amphiphilic Copolymer Micelles Observed by Fluorescent Imaging

Enhanced permeation and retention（EPR） targeting effect of rhodamine B labeled PEG-b-P（LA-co-DHP） [PEG：poly（ethylene glycol）;LA：L-lactide;DHP：2,2-dihydroxylmethyl-propylene carbonate] micelles（RhB-micelles） was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P（LA-co-DHP） followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P（LA-co-DHP） was synthesized by ring-opening copolymerization of LA and DHP with PEG as macroinitiator and diethyl zinc（ZnEt2） as catalyst.The micelles have a spherical shape and the average diameter is ca.50 nm by TEM（transmission electron microscope） or 80 nm by DLS（dynamic light scattering）.Their in vitro cell uptake experiment by CLSM（confocal laser scanning microscopy） and flow cytometry showed preferential internalization of micelles by MCF-7 human breast cancer cells to free RhB.The in vivo tests by live animal imaging and ex vivo excised organ imaging showed that after vena tail injection,free RhB molecules were distributed in the whole body through the circulation system and then gradually metabolized and excreted and there was no preferential partition in tumor bed from the beginning to the end.But the RhB-micelles were preferentially distributed to the tumor bed so that their concentration（fluorescent intensity） in tumor bed got the level of the liver at a certain time point between 1 and 6 h and reached a maximum relative intensity at around 12 h,indicating an obvious EPR effect of RhB-micelles in H22 liver cancer.

The enhanced permeability and retention effect based nanomedicine at the site of injury

The enhanced permeability retention(EPR)effect based nanomedicine has been widely used for tumor targeting during the past decades.Here we unexpectedly observed the similar"EPR effect"at the site of iniury.We found that the temporary dilated and leaky blood vessels caused by the potent vasodilator histamine in response to injury allowed the injected nanoparticles to pass through the vasculature and reached the injured tissue.Our finding shows the potential underline mechanism of"EPR effect"at the injured site.By loading with antibiotics,we further demonstrated a new strategy for prevention of infection at the site of injury.

An Efficient Numerical Model for Immiscible Two-Phase Flow in Fractured Karst Reservoirs

Numerical simulation of two-phase flow in fractured karst reservoirs is still a challenging issue.The triple-porosity model is the major approach up to now.However,the triple-continuum assumption in this model is unacceptable for many cases.In the present work,an efficient numerical model has been developed for immiscible two-phase flowin fractured karst reservoirs based on the idea of equivalent continuum representation.First,based on the discrete fracture-vug model and homogenization theory,the effective absolute permeability tensors for each grid blocks are calculated.And then an analytical procedure to obtain a pseudo relative permeability curves for a grid block containing fractures and cavities has been successfully implemented.Next,a full-tensor simulator has been designed based on a hybrid numerical method(combining mixed finite element method and finite volume method).A simple fracture system has been used to demonstrate the validity of our method.At last,we have used the fracture and cavity statistics data fromTAHE outcrops in west China,effective permeability values and other parameters from our code,and an equivalent continuum simulator to calculate the water flooding profiles for more realistic systems.

A modified gas flow model in the near wellbore region below dew point pressure

When pressure in gas reservoirs fall below the dew point,condensate banking occurs around the wellbore which alters the fluid flow behavior.The state of the knowledge on this flow behavior is yet not fully-developed;which leads to severe problems in field.In this study,the Al-Hussainy,Ramey,and Crawford Solution Technique has been modified to accurately resemble the real gas flow behavior for this condition.First,a primary investigation was conducted to observe the severity of the problem in three condensate banked reservoirs.Then this study involved Constant Composition Expansion tests for determining the dew point,Prode Properties software for modeling the reservoir fluid properties,Flowing Material Balance(or Dynamic P/Z Material Balance)for identifying the pressure distribution of the selected reservoirs.The real field data along with the determined(analytical,computational,and experimental)data were incorporated to check the validity of the models.The modification proposes a Dimensionless Correction Factor(CD)for any condensate banked reservoir and identifies parameters such as the Perforation Factor(Pf)and Heterogeneity Factor(n).It is found that the Modified Al-Hussainy,Ramey,and Crawford Solution Technique successfully models the actual flow characteristics of the stated condition.

Nano-bio interactions: the implication of size-dependent biological effects of nanomaterials

Due to their many advantageous properties,nanomaterials(NMs)have been utilized in diverse consumer goods,industrial products,and for therapeutic purposes.This situation leads to a constant risk of exposure and uptake by the human body,which are highly dependent on nanomaterial size.Consequently,an improved understanding of the interactions between different sizes of nanomaterials and biological systems is needed to design safer and more clinically relevant nano systems.We discuss the sizedependent effects of nanomaterials in living organisms.Upon entry into biological systems,nanomaterials can translocate biological barriers,distribute to various tissues and elicit different toxic effects on organs,based on their size and location.The association of nanomaterial size with physiological structures within organs determines the site of accumulation of nanoparticles.In general,nanomaterials smaller than 20 nm tend to accumulate in the kidney while nanomaterials between 20 and 100 nm preferentially deposit in the liver.After accumulating in organs,nanomaterials can induce inflammation,damage structural integrity and ultimately result in organ dysfunction,which helps better understand the size-dependent dynamic processes and toxicity of nanomaterials in organisms.The enhanced permeability and retention effect of nanomaterials and the utility of this phenomenon in tumor therapy are also highlighted.

Nanocarrier drugs in the treatment of brain tumors

Nanoparticle-mediated targeted delivery of drugs might significantly reduce the dosage and optimize their release properties,increase specificity and bioavailability,improve shelf life,and reduce toxicity.Some nanodrugs are able to overcome the blood-brain barrier that is an obstacle to treatment of brain tumors.Vessels in tumors have abnormal architecture and are highly permeable;moreover,tumors also have poor lymphatic drainage,allowing for accumulation of macromolecules greater than approximately 40 kDa within the tumor microenvironment.Nanoparticles exploit this feature,known as the enhanced permeability and retention effect,to target solid tumors.Active targeting,i.e.surface modification of nanoparticles,is a way to decrease uptake in normal tissue and increase accumulation in a tumor,and it usually involves targeting surface membrane proteins that are upregulated in cancer cells.The targeting molecules are typically antibodies or their fragments;aptamers;oligopeptides or small molecules.There are currently several FDA-approved nanomedicines,but none approved for brain tumor therapy.This review,based both on the study of literature and on the authors own experimental work describes a comprehensive overview of preclinical and clinical research of nanodrugs in therapy of brain tumors.