A Note on Pretzelosity TMD Parton Distribution

We show that the transverse-momentum-dependent parton distribution, called as Pretzelosity function, is zero at any order in perturbation theory of QCD for a single massless quark state. This implies that Pretzelosity function is not factorized with the collinear transversity parton distribution at twist-2, when the struck quark has a large transverse momentum. Pretzelosity function is in fact related to collinear parton distributions defined with twist-4 operators. In reality, Pretzelosity function of a hadron as a bound state of quarks and gluons is not zero. Through an explicit calculation of Pretzelosity function of a quark combined with a gluon nonzero result is found.Comment: improved explanation, published version in Phys. Lett.

Ho3+ To Yb3+ Back Transfer And Thermal Quenching Of Up-Conversion Green Emission In Fluoride-Crystals

Energy transfer from Ho3+ to Yb3+ has been demonstrated in fluoride crystals such as KYF4, BaY2F8, and LiYF4. This transfer was found to occur above a certain temperature and its efficiency increases with temperature. It accounts for the thermal quenching of green emission from upconverted Ho3+ and partly explains the failure, to date, to obtain room temperature, Yb3+ sensitized Ho3+ upconversion lasers in these three hosts. Low Yb3+ concentration is suggested for future attempts to achieve room temperature Yb3+, Ho3+ upconversion green laser operation of these crystals

Lamp-pumped laser performance of Nd3+:Sr-5(PO4)(3)F operating both separately and simultaneously at 1.059 and 1.328 mu m

Lamp-pumped laser performance of Nd3+-doped strontium fluorapatite, Sr-5(PO4)(3)F or S-FAP, has been characterized and compared with that of Nd3+-doped yttrium aluminum garnet (YAG) at both 1.06 and 1.3 mu m. Nd3+:S-FAP was found to exhibit lower thresholds and lower slope efficiencies than Nd3+:YAG. The former is attributed to the higher emission cross section, and the latter to lower Nd3+ concentration in S-FAP. The 1.3 mu m lasing of Nd3+:S-FAP is of particular interest because of its high emission cross section (2.4X10(-19) cm(2)). Q-switched and dual-wavelength lasing operation were also demonstrated in Nd3+:S-FAP

Development of Chengdu and sustainable utilization of the ancient Dujiangyan Water-Conservancy Project

The Dujiangyan Water-Conservancy Project is a great water irrigation works in Chinese cultural history, which led the Min River water to the vast Chengdu Plain, and created fertile and pretty "land of abundance". Now Chengdu is facing increased water demand stress due mainly to rapid urbanization. This paper first analyses the available water resources of Chengdu based on historical hydrological data from 1964 to 2008. The results show that the average annual water resources were 8.9 billion m3 in 1986 and 7.9 billion m3 in 2008 under various environmental conditions. The future tendency of water demand in city development planning is predicted by the Policy Dialogue Model (PODIUM). Finally, the strategies for water resources exploitation accompanying the sustainable development pattern are studied. The result illustrates that rational and careful management are required to balance the gap between water supply and deman

Strong Southward Transport Events Due to Typhoons in the Taiwan Strait

Transport through the Taiwan Strait under the influence of five typhoons was investigated using both buoy observations and numerical model simulations during the period of 27 August to 5 October 2005. The results show that the effects of typhoons on the Taiwan Strait and its adjacent sea area caused strong southward transport events in the Taiwan Strait, which changed the direction of the Taiwan Strait northward transport temporarily. Typhoon-generated local wind stress and/or along-strait water level gradient were the direct driving factors in these southward transport events. The numerical results show that the Coriolis force made a negative contribution to these events and the contribution of the along-strait momentum gradient was insignificant

Metal–Organic Framework Decorated Cuprous Oxide Nanowires for Long-lived Charges Applied in Selective Photocatalytic CO₂ Reduction to CH₄

Improving the stability of cuprous oxide (Cu2O) is imperative to its practical applications in artificial photosynthesis. In this work, Cu2O nanowires are encapsulated by metal–organic frameworks (MOFs) of Cu3(BTC)2 (BTC=1,3,5-benzene tricarboxylate) using a surfactant-free method. Such MOFs not only suppress the water vapor-induced corrosion of Cu2O but also facilitate charge separation and CO2 uptake, thus resulting in a nanocomposite representing 1.9 times improved activity and stability for selective photocatalytic CO2 reduction into CH4 under mild reaction conditions. Furthermore, direct transfer of photogenerated electrons from the conduction band of Cu2O to the LUMO level of non-excited Cu3(BTC)2 has been evidenced by time-resolved photoluminescence. This work proposes an effective strategy for CO2 conversion by a synergy of charge separation and CO2 adsorption, leading to the enhanced photocatalytic reaction when MOFs are integrated with metal oxide photocatalyst

A finite-frequency domain approach to fault detection filter design for vehicle active suspension systems

This paper is concerned with the problem of fault detection filter for vehicle active suspension systems. The aim of this paper is to design a fault detection filter in finitefrequency domain. A sufficient condition for residual system with the prescribed H1 performance index is derived based on the generalized Kalman-Yakubovich-Popov (KYP) lemma. In view of the obtained condition, the fault detection filter is designed in middle-frequency domain. A numerical example shows the effectiveness and potential of the proposed results.Xiaodan Zhu, Yuanqing Xia and Senchun Chai, Peng Sh

The SHER-HIAF Ring Lattice Design

Super Heavy Experimental Ring (SHER) is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP[4]. Here, present ideas of the lattice design for the operation of the large acceptance ring are presented. The SHER ring has to be optimized for e-cooling and the lattice is designed for different modes. First of all, it is designed in the so called isochronous mode as time-of-flight mass spectrometer for short-lived secondary nuclei. Secondly, SHER can also be used to be a storage ring for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfil it's purpose, the ion optics can be set to different ion optical modes