Synthesis and Herbicidal Activities of Sodium Hydrogen 1-(Substituted Phenoxyacetoxy)Alkylphosphonates

Abstract

A series of sodium hydrogen 1-(substituted phenoxyacetoxy) alkylphosphonates was designed and synthesized. The test for herbicidal activity indicated that most of the phosphonates (8) possessed excellent postemergence herbicidal activities against broadleaf weeds. Especially, 8f and 8g showed the best herbicidal activity against rape and amaranth with more than 95% inhibitory rate.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

投影机用UHP灯性能及寿命延长措施

超高压汞灯(UHP)是液晶投影仪和液晶背投电视的光源,具有光效高、寿命长、光谱好和接近理想的点光源等特点,在DLP,LCD,LCOS等各种液晶投影显示系统中应用广泛。从安全使用的角度介绍了UHP灯芯和灯碗结构特点和设计要求,对UHP灯光谱特征以及延长UHP灯使用寿命的关键措施进行了讨论,并强调了合理的电气工作条件的重要性。     

Geometric conservation law and applications to high-order finite difference schemes with stationary grids

The geometric conservation law (GCL) includes the volume conservation law (VCL) and the surface conservation law (SCL). Though the VCL is widely discussed for time-depending grids, in the cases of stationary grids the SCL also works as a very important role for high-order accurate numerical simulations. The SCL is usually not satisfied on discretized grid meshes because of discretization errors, and the violation of the SCL can lead to numerical instabilities especially when high-order schemes are applied. In order to fulfill the SCL in high-order finite difference schemes, a conservative metric method (CMM) is presented. This method is achieved by computing grid metric derivatives through a conservative form with the same scheme applied for fluxes. The CMM is proven to be a sufficient condition for the SCL, and can ensure the SCL for interior schemes as well as boundary and near boundary schemes. Though the first-level difference operators δ₃ have no effects on the SCL, no extra errors can be introduced as δ₃ = δ₂. The generally used high-order finite difference schemes are categorized as central schemes (CS) and upwind schemes (UPW) based on the difference operator δ₁ which are used to solve the governing equations. The CMM can be applied to CS and is difficult to be satisfied by UPW. Thus, it is critical to select the difference operator δ₁ to reduce the SCL-related errors. Numerical tests based on WCNS-E-5 show that the SCL plays a very important role in ensuring free-stream conservation, suppressing numerical oscillations, and enhancing the robustness of the high-order scheme in complex grids.     

On the Comparisons of Unit Dual Quaternion and Homogeneous Transformation Matrix

This paper reveals the differences and similarities between two popular unified representations, i.e. the UDQ (unit dual quaternion) and the HTM (homogeneous transformation matrix), for transformation in the solution to the kinematic problem, in order to provide a clear, concise and self-contained introduction into dual quaternions and to further present a cohesive view for the UDQ and HTM representations as used in robotics. Specifically, after investigating some fundamental algebraic properties of the UDQ, it is revealed that the kinematical equations represented by the UDQ and the HTM are accordant, and afterwards the direct relationship of UDQ-based error kinematical models in spatialframe and in body-frame are further discussed, with conclusion that either error kinematic model can be chosen for designing kinematical control laws. Finally, the comparative study on the proportional control algorithms based on the logarithmical mapping of the HTM and the UDQ shows that the UDQ-based control law is indeed higher in computational efficiency.     

Gaussian Beam Scattering by a Spheroidal Particle with an Embedded Conducting Sphere

A method is provided for calculating the scattering of Gaussian beam incident obliquely on a spheroidal particle with a conducting spherical inclusion within the framework of the generalized Lorenz-Mie theory (GLMT). By virtue of a transformation between the spheroidal and spherical vector wave functions, a theoretical procedure is developed to deal with the boundary conditions. Numerical results of the normalized differential scattering cross section are presented, and the scattering characteristics are discussed concisely.     

Investigation on the critical velocity for liquid loss in immersion lithography

Immersion lithography seeks to extend the resolution of optical lithography by filling the gap between the final optical element and the wafer with a liquid characterized by a high index of refraction. The semiconductor industry demands high throughput, leading to relatively large wafer scanning velocities and accelerations. For higher scanning velocities, an issue that has been identified is the deposition of the immersion liquid while confining a relatively small amount of liquid to the under-lens region. Liquid loss occurs at the receding contact line that forms when a substrate is withdrawn from a liquid, which potentially leads to defects on printed patterns. There has been substantial prior work relative to understanding and building semi-empirical correlations and numerical models to investigate this behavior of the receding three-phase contact line. In the current work, a new liquid injection and collection model with analytic solutions is presented and compared with experimental results, in which the critical velocity for liquid loss is mainly a function of the vacuum degree, the injection flow rate, the properties of the immersion liquid. This correlation allows the critical velocity to be predicted with a given gap height between wafer and lens using only a measurement of the injection speed and knowledge of the fluid properties. Experimentally, glycerin–water mixtures of varying viscosities and different injection flow rates were tested, with variable outlet vacuum degree and inlet speed, showing a mean average error within 12%. This correlation represents a useful tool that can serve to approximately guide the development of fluid control for immersion systems as well as to evaluate alternative immersion fluid candidates to minimize liquid deposition while maximizing throughput.     

DYNAMIC SIMULATION ANALYSIS OF CAPTURE AND BUFFER SYSTEM BASED ON CLAW-TYPE DOCKING MECHANISM

现有在轨服务的对接机构由于其尺寸大、结构复杂、对接目标单一等局限性因素,无法很好地为后续我国探月工程任务提供有力支撑,且受限于运载能力,对接机构的轻量化也是必不可少的一项环节.为研究可服务于未来月球空间站以及载人登月等高轨道任务的对接机构,设计了一种新型抱爪式对接机构,其采用异体同构周边式构型,可以实现主/被动飞行器之间的互换.利用 V 型槽与爪钩等结构部件实现飞行器对接过程中的捕获以 及能量消耗功能,从而实现两飞行器之间的稳固联接.该对接机构具备尺寸小、重量轻、结构简单、功能易实现等优势. 对其捕获缓冲系统进行了动力学分析,计算了缓冲元器件的参数对其捕获性能的影响,在 ADAMS 完成了数字虚拟样机的建立,结合实际两种典型的对接初始条件工况进行了仿真研究.研究结果表明,两种工况下的对接过程能量消耗满足设计要求,能够以较小的 V 型槽的碰撞力完成捕获,结果证明了捕获缓冲系统的可行性以及该构型对接机构具备较好实现任务的能力.     

川藏公路培龙沟路段堆积物的分形特征及其地质意义

川藏公路培龙沟路段有多种不同类型的堆积物。本文应用分形理论,探讨了培龙沟路段泥石流堆积物、冰碛堆积物、冲洪积堆积物以及坡积或者残坡积物的分形特征。通过粒度分析法计算出不同类型堆积物的粒度分维,得到泥石流堆积物分维最大,冰碛堆积物分维较大,坡积或者残坡积堆积物较小,冲积物或者洪积物分维最小的规律。最后系统论述了堆积物粒度分维的地质意义,认为堆积物粒度分维是对堆积物物质组成的复杂性和自组织性、堆积物形成过程和形成时间以及泥石流、冰川、河流和洪水等搬运能力和运动过程的反映和度量。该研究为野外不同类型堆积物的区分、成因、形成过程等研究提供了一种新的方法,具有一定参考价值。     

汶川震区文家沟泥石流成灾机理与特征

文家沟位于绵竹市清平乡,属于 5 ·12 汶川Ms8.0级地震极重灾区。地震发生后的3个汛期内,文家沟曾先后发生5次典型泥石流灾害,其中以2010年8月13日泥石流灾害最为严重,规模与灾情巨大,社会影响深远。在对文家沟泥石流跟踪调查的基础上,探讨了泥石流的成灾机理和特征。研究表明:(1)文家沟泥石流是地震和强降雨共同作用的结果,其成因可归纳为震因与物源以及雨因与水源两个方面,在整个泥石流形成和发生的过程中,呈现出洪流-侵蚀下切-崩滑-席卷-进一步侵蚀下切-进一步崩滑-增大泥石流规模—……的"滚雪球式"循环过程; (2)泥石流发生所需的雨量、雨强条件和水动力条件都显著降低,泥石流规模和雨量之间呈现出明显幂函数关系; (3)发生过程呈现出持续时间长、运动距离远的特征; (4)成灾过程呈现出明显的链式效应,危害形式多样; (5)泥石流频率呈现出高发性,规模呈现出放大性。最后提出了文家沟泥石流研究与防治的建议。