标准号: LY/T 3018-2018

摘要： 本标准规定了以锂离子电池为动力源的旋刀步进式草坪修剪机（以下简称“锂电草坪机”）的术语和定义、型号编制方法、基本参数、技术要求及试验方法、标志、使用说明书、包装、运输、贮存和处理。 本标准适用于以标称电压不大于直流75 V可充电锂离子电池包（电池组）供电的旋刀步进式草坪修剪机。 本标准不适用于： 以使用者自行安装的通用电池包或电池组为动力源的旋刀步进式草坪修剪机；其他非锂离子电池动力源的旋刀步进式草坪修剪机。

标准号: LY/T 3020-2018

摘要： 本标准规定了以锂离子电池为动力源的手持式绿管修剪机（以下简称“锂电绿臂机”）的术语和定义、型号编制方法、基本参数、技术要求及试验方法、标志、使用说明书、包装、运输、贮存及处理。 本标准适用于一般环境条件下，以标称电压不大于直流75V可充电锂离子电池包（电池组）供电的、单人操作的、由一个或多个线性往复切割器件对绿篱和灌木进行修剪切割作业的绿筒修剪机。 本标准不适用于： 带旋转刀片的锂电绿篱机；以使用者自行安装的通用电池包或电池组为动力源的手持式绿筒修剪机；其他非锂离子电池为动力源的手持式绿篱修剪机。

标准号: LY/T 3019-2018

摘要： 本标准规定了以汽油机为动力的便携式割灌机和割草机（以下简称“割灌机和割草机”）的切割效率及切割燃油消耗率的测试方法。 本标准适用于以汽油机为动力的便携式割灌机和割草机，以其他内燃机为动力的割灌机和割草机亦可参照使用。

关键词： enzyme kinetics   enzyme-substrate interactions   enzyme activity   insulin   metalloproteases   protease inhibitor  

摘要： Despite the enormous number of therapeutic advances in medicine, nowadays many diseases are still incurable, mainly due to the lack of knowledge of the pathological biochemical pathways triggering those diseases. For this reason, it is compulsory for the scientific community to investigate and unveil the biomolecular mechanisms responsible for the development of those diseases, such as Alzheimer's disease and diabetes, which are widespread all over the world. In this scenario, it is of paramount importance to develop new analytical techniques and experimental procedures that are capable to make the above-mentioned investigations feasible. These new methods should allow easy performable analysis carried out in a label-free environment, in order to give reliable answers to specific biochemical questions. A recent paper published on Bioscience Reports by Ivancic et al. (https://***/10.1042/BSR20181416) proposes a new analytical technique capable to reveal some mechanistic insights into the regulation of insulin-degrading enzyme (IDE), a protein involved in the above-mentioned diseases. IDE is a multifaceted enzyme having different and not well-defined roles in the cell, but it is primarily a proteolytic enzyme capable to degrade several different amyloidogenic substrates involved in different diseases. Moreover, many molecules are responsible for IDE activitymodulation so that understanding how IDE activity is regulated represents a very challenging analytical task. The new analytical approach proposed by Ivancic et al. reports on the possibility to study IDE activity in an unbiased and label-free manner, representing a valid alternative assay for the investigation of any proteases degradative activity.

关键词： circular dichroism   insulin-degrading enzyme   insulin   Michaelis-Menten kinetics  

摘要： Insulin-degrading enzyme (IDE) is a zinc metalloprotease that selectively degrades biologically important substrates associated with type 2 diabetes and Alzheimer's disease (AD). As such, IDE is an attractive target for therapeutic innovations. A major requirement is an understanding of how other molecules present in cells regulate the activity of the enzyme toward insulin, IDE's most important physiologically relevant substrate. Previous kinetic studies of the IDE-dependent degradation of insulin in the presence of potential regulators have used iodinated insulin, a chemical modification that has been shown to alter the biological and biochemical properties of insulin. Here, we present a novel kinetic assay that takes advantage of the loss of helical circular dichroic signals of insulin with IDE-dependent degradation. As proof of concept, the resulting Michaelis-Menten kinetic constants accurately predict the known regulation of IDE by adenosine triphosphate (ATP). Intriguingly, we found that when Mg2+ is present with ATP, the regulation is abolished. The implication of this result for the development of preventative and therapeutic strategies for AD is discussed. We anticipate that the new assay presented here will lead to the identification of other small molecules that regulate the activity of IDE toward insulin.

关键词： Metastable austenite   Martensite   TRIP-maraging steels   Mechanical twins   Strain gradients   Twinning pattern  

摘要： A computational study is conducted to examine the influence of mechanical twins on the kinetics of martensitic transformation in TRIP-maraging steel. Simulations are performed using a non-local crystal plasticity (CP) phase transformation model describing the deformation behavior of TRIP-maraging steel. This work is inspired by the experimental observations of Wang et al. (2014), where authors reported a twinning induced stability against the phase transformation in austenite islands embedded in the martensitic matrix. Finite element (FE) analysis is used to simulate the stability of austenite against the phase transformation in the presence and absence of mechanical twins, respectively. Depending on the parent crystal orientation, macroscopic outcome of FE calculations manifested a slower/faster transformation kinetics for austenitic islands with mechanical twins as compared to islands without twins which is found to be in a good qualitative agreement to experimental observations. Models with two austenite islands of different sizes confirmed the twinning induced alteration in the transformation kinetics. Microscopic observations from the simulations demonstrated that the twin orientations generated during mechanical twinning are less or more favorable for the strain induced or stress assisted transformations. This directly indicates that the basis of the alteration in the transformation kinetics could be the strong orientation dependence of the martensitic transformation. Thus, a model based analysis was used to explain the experimental findings related to phase transformation kinetics of TRIP-maraging steels. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： CO2   Storage   Methane   Sorption kinetics   Adsorbed phase density  

摘要： Evidence from experimental studies related to sorption on nanoporous materials, coals, and most recently on shales suggests that the sorption of gas in these targets is not instantaneous, i.e. the time it takes for the gas to adsorb to its maximum capacity is not negligible. A recent experimental study showed that the sorption in shale rocks is non-instantaneous, i.e. there is a delayed effect in adsorption due to different mechanisms of sorption in different materials of shale, for e.g. in inorganic and organic matter. The current suite of models used to predict sorption in shale (e.g. Langmuir, BET, etc.) assumes an instantaneous equilibrium, which is not justifiable for sorption in shales. Sorption of hydrocarbons and carbon dioxide in shale stratum is a complex mechanism that is affected by micro-scale affinity between the adsorbent-adsorbate, pore-scale heterogeneity of the surface with respect to the pore distribution, and structural heterogeneity of the system. These mull-phenomena effects are mull-scale in nature, and their impact on sorption cannot be predicted using simple models that assume instantaneous equilibrium. A model for reliable prediction of sorption in shales must take into account above discussed effects. This study proposes a mechanistic model for mull-scale sorption dynamics (referred as "MSSD") in shale that accounts for molecular and pore-scale effects, in addition to the continuum-scale effects, by corresponding parameters that are relevant on those scales. Proposed model is validated against three experimental datasets that depict sorption dynamics in shale. The MSSD model is then used to investigate the efficiency of carbon storage in shale by adsorption when it is injected as a binary mixture with methane. The proposed model makes it convenient to study the effects of molecular-scale to continuum-scale parameters on sorption in shale that are otherwise possible only through expensive means of experiments or molecular dynamic simulation

关键词： Transport properties   Free energy   Diffusion   Molecules   Kinetics  

摘要： The analysis and interpretation of single molecule force spectroscopy (smFS) experiments is often complicated by hidden effects from the measuring device. Here we investigate these effects in our recent smFS experiments on the ultrafast folding protein gpW, which has been previously shown to fold without crossing a free energy barrier in the absence of force (i.e., downhill folding). Using atomic force microscopy (AFM) smFS experiments, we found that a very small force of similar to 5 pN brings gpW near its unfolding midpoint and results in two-state (un)folding patterns that indicate the emergence of a force-induced free energy barrier. The change in the folding regime is concomitant with a 30,000-fold slowdown of the folding and unfolding times, from a few microseconds that it takes gpW to (un)fold at the midpoint temperature to seconds in the AFM. These results are puzzling because the barrier induced by force in the folding free energy landscape of gpW is far too small to account for such a difference in time scales. Here we use recently developed theoretical methods to resolve the origin of the strikingly slow dynamics of gpW under mechanical force. We find that, while the AFM experiments correctly capture the equilibrium distance distribution, the measured dynamics are entirely controlled by the response of the cantilever and polyprotein linker, which is much slower than the protein conformational dynamics. This interpretation is likely applicable to the folding of other small biomolecules in smFS experiments, and becomes particularly important in the case of systems with fast folding dynamics and small free energy barriers, and for instruments with slow response times.

关键词： Global phase portrait   Limit cycle   Grazing bifurcation   Grazing-sliding bifurcation   Discontinuous piecewise differential system  

摘要： The global dynamics of a mechanical system with dry friction is completely analyzed. This mechanical system is a class of discontinuous and transcendental piecewise smooth differential systems. Moreover, it can exhibit rich and complex dynamical phenomena, such as Hopf bifurcation, grazing bifurcation, grazing-sliding bifurcation and bifurcations of limit cycles. Finally, all global phase portraits of the system are presented on the Poincare disc. (C) 2018 Elsevier Inc. All rights reserved.

关键词： 数值分析   机械系统动力学   应用  

摘要： 通过对数值分析的简介,结合该方法在机械系统动力学中的应用实例,指导机械系统动力学在数值分析的基础上更好更快的发展。