A Global Minimization Algorithm for Empirical Contact Potential Functions

Global minimization algorithm is indispensable for solving protein folding problems based on thermodynamic hypothesis. A contact difference （CD） based on pseudo potential function, for simulating empirical contact potential functions and testing global minimization algorithm was proposed. The present article describes a conformational sampiing and global minimization algorithm, which is called WL, based on Monte Carlo simulation and simulated annealing. It can be used to locate CD＇s globe minimum and refold extended protein structures, as small as 0. 03 nm, from the native structures, back to ones with root mean square distance（RMSD）. These results demonstrate that the global minimization problems for empirical contact potential functions may be solvable.

A Global Minimization Algorithm for Empirical Contact Potential Functions

Global minimization algorithm is indispensable to solving the protein folding problem based upon thermodynamic hypothesis. Here we propose a pseudo potential function, contact difference(CD), for simulating empirical contact potential functions and testing global minimization algorithm. The present paper covers conformational sampling and global minimization algorithm called BML03, based upon Monte Carlo and simulated annealing, which is able to locate CD′s global minimum and refold extended protein structures into ones with root mean square distance(RMSD) as small as 0.03 nm from the native structures. For empirical contact potential functions, these results demonstrate that their global minimization problems may be solvable.

A Continuous and Analytical Surface Potential Model for SOI LDMOS

A continuous and analytical surface potential model for SOI LDMOS, which accounts for automatic transitions between fully and partially-depleted statuses,is presented. The surface potential equation of the SOI de- vice is solved by using the PSP′s accurate algorithm of surface potential,and the front and back surface potentials are obtained analytically as a function of gate and drain voltage. The formulations of inversion charge and body charge under the fully-depleted state have been modified. The continuous and analytical DC model for SOl LD- MOS is given based on PSP. The comparisons between simulation and measurements indicate that this model can predict the DC characteristics of SOI LDMOS accurately.

成年小鼠触液神经元体外分离培养及自我更新能力的鉴定

背景:课题组前期成功在体外分离培养乳鼠触液神经元,尚无研究报道有效分离培养高纯度成年小鼠触液神经元的方法,且触液神经元的自我更新能力是否随着年龄发生变化尚无研究。目的:建立一种高纯度成年小鼠触液神经元体外分离培养的方法,并鉴定成年小鼠触液神经元与乳鼠触液神经元在体外的自我更新能力。方法:从成年3月龄小鼠颈髓分离含有触液神经元的原代细胞贴壁培养并利用融合多模态成像基因的慢病毒转染细胞,通过嘌呤霉素筛选得到高纯度成年小鼠触液神经元细胞,在完全培养基中悬浮培养。通过免疫荧光检测成年小鼠触液神经元表达神经干细胞标记物巢蛋白(Nestin)及SOX2情况,观察成年小鼠触液神经元体外成球与传代能力;将同等数量(5×10^(3))的第3代成年小鼠及乳鼠触液神经元在同等条件下分为2组,分别接种在含有完全培养基的超低黏附培养板中,在体积分数5%CO_(2),37℃恒温箱悬浮培养,通过体外成球、CCK8实验、qPCR和Western blot鉴定成年小鼠及乳鼠触液神经元的自我更新能力。结果与结论:①实验成功在成年小鼠体内分离出高纯度触液神经元,在体外表达Nestin及SOX2,能形成神经球并连续传代。②成年小鼠触液神经元体外自我更新能力较乳鼠相比明显减弱,细胞培养到第4天时乳鼠触液神经元已经形成直径约为150μm的神经球,而成年小鼠触液神经元所形成的神经球直径仅为40μm(P<0.0001)。③CCK8增殖实验结果表明,成年小鼠触液神经元的增殖活性在培养后各时间点显著弱于乳鼠(P<0.0001)。④qPCR和Western blot检测发现成年小鼠触液神经元Nestin及SOX2的mRNA(P<0.0001)和蛋白表达量(P<0.01)较乳鼠显著下降。⑤上述结果证实,成年小鼠触液神经元的体外自我更新能力显著弱于乳鼠。

Some recent advances in 3D crack and contact analysis of elastic solids with transverse isotropy and multifield coupling

Significant progress has been made in mixed boundary-value problems associated with three-dimensional（3D） crack and contact analyses of advanced materials featuring more complexities compared to the conventional isotropic elastic materials.These include material anisotropy and multifield coupling,two typical characteristics of most current multifunctional materials.In this paper we try to present a state-of-the-art description of 3D exact/analytical solutions derived for crack and contact problems of elastic solids with both transverse isotropy and multifield coupling in the latest decade by the potential theory method in the spirit of V.I.Fabrikant.whose ingenious breakthrough brings new vigor and vitality to the old research subject of classical potential theory.We are particularly interested in crack and contact problems with certain nonlinear features.Emphasis is also placed on the coupling between the temperature field（or the like） and other physical fields（e.g.,elastic,electric,and magnetic fields）.We further highlight the practical significance of 3D contact solutions,in particular in applications related to modern scanning probe microscopes.

Removal of disinfection by-products formation potential by biologically intensified process

The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon was evaluated. By IBAC removals of 31% and 68% for THMFP and HAAFP were obtained respectively. Under identical conditions, the removals of the same substances were 4% and 32% respectively only by the granular activated carbon(GAC) process. Compared with GAC, the high removal rates of the two formed potential substances were due to the increasing of bioactivity of the media and the synergistic capabilities of biological degradation cooperating with activated carbon adsorption of organic compounds. A clear linear correlation(R 2=0.9562 and R 2=0.9007) between DOC HAAFP removal rate and Empty Bed Contact Time(EBCT) of IBAC process was observed, while that between THMFP removal rate and EBCT of GAC was R 2=0.9782. In addition certain linear correlations between THMFP, HAAFP and UV 254 (R 2=0.855 and R 2=0.7702) were found for the treated water. For IBAC process there are also more advantages such as long backwashing cycle time, low backwashing intensity and prolonging activated carbon lifetime and so on.

Adhesive contact:from atomistic model to continuum model

Two types of Lennard-Jones potential are widely used in modeling adhesive contacts. However, the relationships between the parameters of the two types of Lennard-Jones potential are not well defined. This paper employs a self- consistent method to derive the Lennard-Jones surface force law from the interatomic Lennard-Jones potential with emphasis on the relationships between the parameters. The ei^ect of using correct parameters in the adhesion models is demonstrated in single sphere-flat contact via continuum models and an atomistic model. Furthermore, the adhesion hysteresis behaviour is investigated, and the S-shaped force-distance relation is revealed by the atomistic model. It shows that the adhesion hysteresis loop is generated by the jump-to-contact and jump-off-contact, which are illustrated by the S-shaped force-distance curve.

Potential Power of the Pyramidal Structure II

Research on “pyramid power” began in the late 1930s. To date, many documents on “pyramid power” have been published. We have been conducting scientific research on the unexplained “power” of a pyramidal structure (PS) since October 2007. The research focuses on the detection of a non-contact effect of the unexplained “power” of the PS on biosensors (i.e., edible cucumber sections of Cucumis sativus “white spine type”) placed at the top of the PS. In this paper, in particular, we compared the non-contact effect of upper and lower biosensors placed in two layers on the PS apex, and we analyzed the difference of the non-contact effect due to the difference in the layers. The magnitude of the non-contact effect was represented by the calibrated psi index Ψ(E-CAL) calculated from gas concentrations emitted from the biosensors. A method to determine the presence or absence of the non-contact effect by analyzing the gas concentrations was developed by the International Research Institute (IRI). Ψ(E-CAL), which represents the magnitude of the non-contact effect, was the average value of the respective non-contact effect of the upper and lower biosensors stacked in two layers on the PS apex. We conducted the analysis on the assumption that the non-contact effect on the upper and lower biosensors might be different. Therefore, we considered that upper and lower biosensor calibration was required for Ψ(E-CAL), and we introduced a new calibrated psi index Ψ(E-CAL)Layer. Scientifically rigorous experiments to date have detected Ψ(E-CAL) with statistical significance and have demonstrated potential power of the PS (p = 6.0 × 10-3;Welch’s t-test, two-tails, the following p values are also the Welch’s t-test values). Based on data demonstrating the potential power of the PS, we analyzed the non-contact effects on the upper and lower biosensors of the PS apex. We obtained a surprising result that the non-contact effect on the upper biosensors (farther from the PS) was larger than that on the lower biosensors (closer to the PS) (p = 4.0 × 10-7). This suggested that the characteristic of the potential power of the PS, which is considered to exist near the PS apex, is distinctive. We also found that the non-contact effect due to the potential power of the PS varies with the season, and is large in summer and small in winter. In our discussion, we proposed a model that could theoretically explain the experimental results that the non-contact effect on the upper biosensors at the PS apex is larger than the lower biosensors. In proposing this model, we assumed that there were two different types of potential power at the PS apex and that the biosensors had two different gas-generating reactions. In a simulation using the model, the experimental results were well approximated in which the non-contact effect on the biosensors differs depending on the difference between the upper and lower layers. The results of this paper are the world’s first to prove aspects of the “pyramid power” through scientifically rigorous experiments and analysis. These results will become a new field of science in the future, and their broad applications are expected.

Potential Power of the Pyramidal Structure

There have been various traditions and books which describe a so-called “pyramid power”, but there have been almost no reliable academic studies and no statistically significant data about it. We have continued scientifically rigorous experiments using biosensors to elucidate unexplained functions of a pyramidal structure (PS) since 2007. We used edible cucumber sections as biosensors and measured the concentrations of gas emitted from the sections by a technique developed by our group. From them we have demonstrated with high statistical accuracy the existence of the “pyramid power”, which was often recognized as having no scientific basis. We reached two conclusions from the work. 1) The PS converted the unconsciousness of a human (the test subject) more than 6 km away to energy detectable by the biosensors (1% significance). 2) The PS accumulated the influence that a human (the test subject) had when meditating within the PS. Then the PS converted the influence into the energy detectable by the biosensors (10-3% significance). These two conclusions showed that the functions of the PS were detected when “the PS and a human were related”. On the other hand, we hypothesized that the potential power of the PS could be detected even when “the PS and a human were not related”. In this paper, our purpose is to verify the existence of the potential power of the PS alone by experiment when “the PS and a human were not related”. The following three results were obtained by experiment. 1) The presence of the potential power of the PS was demonstrated with 1% significance. 2) The potential power of the PS changed in value between summer and winter, and it was clear that the non-contact effect on the biosensors was larger in summer and smaller in winter. 3) The potential power of the PS affected only the biosensors placed at the PS apex, and did not affect the biosensors placed at the calibration control point 8 m away from the PS. This paper is the first report in the world to show this type of effect by scientific measurements. Our research results may open up a new science field of “pyramid power”, from which we expect further development of fields applying this “pyramid power”.

Contact resistance asymmetry of amorphous indium–gallium–zinc–oxide thin-film transistors by scanning Kelvin probe microscopy

In this work, a method based on scanning Kelvin probe microscopy is proposed to separately extract source/drain（S/D） series resistance in operating amorphous indium–gallium–zinc–oxide（a-IGZO） thin-film transistors. The asymmetry behavior of S/D contact resistance is deduced and the underlying physics is discussed. The present results suggest that the asymmetry of S/D contact resistance is caused by the difference in bias conditions of the Schottky-like junction at the contact interface induced by the parasitic reaction between contact metal and a-IGZO. The overall contact resistance should be determined by both the bulk channel resistance of the contact region and the interface properties of the metalsemiconductor junction.

Potential Power of the Pyramidal Structure III: Discovery of Pyramid Effects with and without Seasonal Variation

Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify the pyramid effects by the PS into the following two types. (i) The pyramid effects in which the PS converted the test subject’s unexplained energy to affect biosensors when the test subject entered the PS and meditated. (ii) The pyramid effects in which the potential power of the PS affected biosensors if the test subject had not been inside the PS for at least 20 days and the test subject’s unexplained energy was excluded. In this paper, we report new results regarding (ii). As a result of dividing a year according to the four seasons of winter, spring, summer, and autumn and analyzing the pyramid effect of each period, the following points were found. 1) There was a pyramid effect without seasonal variation. The pyramid effect on the lower and upper layers was different throughout the year for the biosensors placed at the PS apex in two layers, regardless of the season. 2) There was a pyramid effect with seasonal variation. The value of the psi index, which indicates the magnitude of the pyramid effect, changed as the seasons changed, while different pyramid effects were maintained on the lower and upper layers. Regarding the change in the pyramid effect depending on the season, the psi index in summer was larger than that in winter in both the lower and upper layers. From these results, we found that there are two types of potential power at the PS apex: seasonal potential power and non-seasonal potential power.

Predicting residue contacts for protein-protein interactions by integration of multiple information

Detailed knowledge of interfacial region between interacting proteins is not only helpful in annotating function for proteins, but also very important for structure-based drug design and disease treatment. However, this is one of the most difficult tasks and current methods are constrained by some factors. In this study, we developed a new method to predict residue-residue contacts of two interacting protein domains by integrating information about evolutionary couplings andamino acid pairwise contact potentials, as well as domain-domain interaction interfaces. The experimental results showed that our proposed method outperformed the previous method with the same datasets. Moreover, the method promises an improvement in the source of template-based protein docking.

Contact Pressure between the Outside Surface of the Sealer and Cylinder Wall

Character of contract pressure distribution between the outside surface of the sealing material and rigid cylinder wall depending on geometrical sizes and mechanical properties of a sealer under its unilateral compression, is defined. The magnitude of the axial load for achieving tightness is determined. The dependence between the magnitude of the axial load necessary for achieving tightness and geometrical sizes is determined. It is shown that with a decrease in the height of the sealing element, the axial load necessary for achieving tightness greatly increases. Threshold height of the sealer, above which contact pressure depends little on the magnitude of the axial load, is defined. The stress-strain state of the sealing element is defined with regard to viscous-elastic properties of its material. It is shown that this greatly influences its sealing ability.

Potential Power of the Pyramidal Structure IV: Discovery of Entanglement Due to Pyramid Effects

Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify pyramid effects by the PS into the following two types: (i) the pyramid effects due to the potential power of the PS and (ii) the pyramid effects due to the influence of the test subject meditating inside the PS. We have been using edible cucumber sections as the biosensors. The pyramid effect existence was clarified by measuring and analyzing the concentration of volatile components released from the biosensors. The biosensors were arranged as a pair: one member of the pair was placed at the PS apex and the other was placed at the calibration control point 8.0 m away from the PS. In this paper, we report a new discovery regarding the type (i) pyramid effects. We discovered a phenomenon considered to be entanglement between the biosensor pairs detecting the pyramid effects. In other words, the biosensors at the PS apex, which were affected by the potential power of the PS, affected the biosensors at the calibration control point. We also confirmed that the effects on the biosensors placed at the calibration control point were not due to the potential power of the PS. Furthermore, we showed that the magnitude of the effect of entanglement changed with the seasons. We expect that our research results will be widely accepted in the future and will become the foundation for a new research field in science, with a wide range of applications.

Load distribution of involute gears along time-varying contact line

Base on the theory of energy minimization, a numerical algorithm is established to calculate load distribution, and the relationship curve of spur gear load distribution is obtained, and the load distribution ratio changes from 033 to 067 in double contact zone. This theory is adopted to compute the load distribution of helical gear along time-varying contact line, and the load distribution varies with the instantaneous position of the meshing point and the length of contact line, and the maximum value of load appears at the pitch point. Compared with the load distribution results, the helical gear changes more smoothly than spur gear. The load distribution provides a basis for calculate tooth bending deformation and critical stress.

n型MoS_(2)/p型c-Si太阳电池前后接触势垒的模拟优化

基于提高n型MoS_(2)/p型c-Si太阳电池转换效率的目的,采用美国滨州大学研发的AMPS-1D软件,针对电池前后接触势垒对光伏性能的影响进行模拟优化。模拟结果表明:前接触势垒(对于电子)越低,电池性能越好,当前接触势垒为0.1 eV时,电池转换效率达17.617%;背接触势垒越高,电池短路电流升高越明显,光伏性能越好,当背接触势垒为1.1 eV时,电池转换效率达17.762%。为电池增加带隙为1.8 eV的非晶硅背场后,电池的光伏性能明显改善。电池有背场后,背接触势垒越高,电池的开路电压升高越显著,当背接触势垒为1.7 eV时,电池的转换效率提高至27.641%。此研究旨在为n型MoS_(2)/p型c-Si太阳电池的实验制备提供一定的理论参考。

食品接触材料中非邻苯类塑化剂迁移及潜在危害的研究进展

近年来,邻苯类塑化剂不断被曝出各式各样的安全隐患问题,其使用已经被严格限制。与此同时,非邻苯类塑化剂由于具有比邻苯类塑化剂更低的毒性,在实际应用中越来越受到厂家的青睐,被广泛使用于食品接触材料当中。然而,伴随着其使用范围的不断拓展以及使用量的持续增加,食品接触材料中非邻苯类塑化剂的迁移情况以及其可能带来的危害绝不能忽视。本文对食品接触材料中非邻苯类塑化剂的相关概念及种类、迁移情况、潜在危害、检测方法进行了综述,旨在为针对食品接触材料中非邻苯类塑化剂进行准确的风险评估提供重要的参考依据。

马尾松不同部位挥发物对松墨天牛触角电位和行为反应的影响

【目的】探究马尾松健康植株不同位置挥发性物质,比较其不同部位的挥发物的种类差异及含量,分析松墨天牛成虫对健康马尾松各部位挥发物的触角电位反应和嗅觉反应,为开展松墨天牛的行为调控技术提供依据。【方法】采用静态顶空法和气相色谱-质谱联用技术分析了马尾松松针、1 cm枝条、5 cm枝条、20 cm树干、30 cm树干、松油脂6个部位的挥发物,并对松墨天牛雌雄成虫进行触角电位测定和行为反应观测。【结果】6个部位的挥发物提取物中,共检测出36种挥发性物质,各部位挥发物种类相近,相对含量差异较大,但其主要挥发物均为萜烯类物质,主要包括月桂烯、蒎烯、左旋-beta-蒎烯、莰烯等。在触角电位试验中,5 cm枝条挥发物提取物的触角电位值最高,松油脂挥发物提取物的触角电位值最高;在行为反应试验中,各部位挥发物对松墨天牛成虫均有一定的引诱作用,其中雌成虫对5 cm枝条挥发物提取物的趋向性最高,雄成虫对30 cm树干和松油脂挥发物提取物的趋向性最高。【结论】健康状态下,马尾松5 cm枝条及30 cm树干和松油脂中萜烯类挥发物制成的植物源引诱剂对松墨天牛两性成虫具有更好的引诱作用,这将为提高现有的诱捕剂效果提供参考,同时为松墨天牛虫害防治提供科学依据。

超低渗火山岩储层压裂液伤害实验及机理研究

胍胶与聚合物压裂液体系对超低渗火山岩储层具有不同的伤害特征,胍胶压裂液破胶后残渣含量高,易堵塞填砂裂缝,降低裂缝导流能力。聚合物压裂液具有破胶彻底、残渣含量小等特征。通过X射线衍射、BET技术对取自4045~4669 m的查干花地区某井区5组火山岩样品的矿物组成和比表面积进行表征。通过岩心吸附实验定量评价了压裂液对储层岩心的伤害。测试伤害前后的Zeta电位、接触角、红外光谱和SEM等实验分析压裂液对储层的伤害机理。结果表明,两种压裂液在岩心粉末表面只发生了物理吸附,胍胶吸附量比聚合物高33.6%;胍胶与岩心粉末接触引起Zeta电位绝对值变小,体系失稳易在岩心表面吸附滞留;疏水性增加导致接触角变大。

变位设计对斜齿轮系统动态特性影响研究

为了研究不同变位设计下斜齿轮的动态特性,以标准斜齿轮和变位斜齿轮为对比研究对象,基于拉格朗日动力学建立了斜齿轮传动系统动力学模型;采用解析法求解变位斜齿轮时变啮合刚度,分析了不同变位系数对啮合刚度的影响;将不同变位设计下的斜齿轮时变啮合刚度与动力学模型结合,分析了不同变位设计对斜齿轮系统动态特性的影响。结果表明,斜齿轮正传动修正能够减小时变啮合刚度,从而减小啮合力;负传动修正能够增大时变啮合刚度,从而增大啮合力。研究可为后续斜齿轮传动的设计和优化提供一定的参考。