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Quantification of emission variability for off-road equipment in China based on real-world measurements

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Frontiers of Environmental Science & Engineering 2022年第2期16卷 125-136页

作者： Kaili Pang Kaishan Zhang Shuai ma Xiangrui Meng Department of Environmental Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China

The objective of this paper is to quantify the variability in emissions of off-road equipment using a portable emission measurement system.A total of 53 commonly used equipment for agriculture,base construction,paving construction,and material handling were ***-based and fuel-based emissions were quantified by different duty and engine *** duty modes(idling,moving,and working)were *** engine modes were defined based on normalized engine revolutions-per-minute and manifold absolute pressure,*** emission factors taking into account both duty modes and its corresponding time percentage during a typical duty cycle were *** showed that there existed a large off-road equipment variability in *** on duty and engine modes,time-based NO emissions ranged from 3.1 to 237.9,29.1‒1475.6,83.2‒681.6,and 3.2‒385.2 g/h for agriculture,base construction,paving construction and material handling equipment,respectively while for fuel-based NO emissions these ranges were 5.3‒52.0,11.7‒69.0,4.8‒30.8,and 11.0‒54.6 g/kg,***,emission factors derived from this study exhibited a much larger variability compared to those used in NONROAD by us EPA and National Guideline for Off-road Equipment of *** implied that localized measurements of emissions are needed for improvement of accuracy of emission ***,both equipment types and operations should be considered for development of emission inventory and control strategy.

关键词： Off-road equipment Portable emission measurement system(PEMS) Real-world emissions Diesel engine

Near-field terahertz nonlinear optics with blue light

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Light(Science & Applications) 2023年第5期12卷 838-846页

作者： Angela Pizzuto Pingchuan ma Daniel M.Mittleman Department of Physics Brown UniversityProvidence RI 02912USA School of Engineering Brown UniversityProvidence RI 02912USA

The coupling of terahertz optical techniques to scattering-type scanning near-field microscopy(s-SNOM)has recently emerged as a valuable new paradigm for probing the properties of semiconductors and other materials on the *** have demonstrated a family of related techniques,including terahertz nanoscopy(elastic scattering,based on linear optics),time-resolved methods,and nanoscale terahertz emission ***,as with nearly all examples of s-SNOM since the technique’s inception in the mid-1990s,the wavelength of the optical source coupled to the near-field tip is long,usually at energies of 2.5 eV or *** in coupling of shorter wavelengths(i.e.,blue light)to the nanotip has greatly inhibited the study of nanoscale phenomena in wide bandgap materials such as Si and ***,we describe the first experimental demonstration of s-SNOM using blue *** femtosecond pulses at 410 nm,we generate terahertz pulses directly from bulk silicon,spatially resolved with nanoscale resolution,and show that these signals provide spectroscopic information that cannot be obtained using near-infrared *** develop a new theoretical framework to account for this nonlinear interaction,which enables accurate extraction of material *** work establishes a new realm of possibilities for the study of technologically relevant wide-bandgap materials using s-SNOM methods.

关键词： scattering optics nonlinear

Engineering the interface of porous CoMoO_(3)nanosheets with Co_(3)Mo nanoparticles for high-performance electrochemical overall water splitting

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Journal of materials Science & Technology 2023年第6期137卷 184-192页

作者： Haibin ma Xuejing Yang Zhili Wang Qing Jiang Key Laboratory of Automobile materials Ministry of Educationand School of Materials Science and EngineeringJilin UniversityChangchun 130022China

The design of high-performance electrocatalysts for alkaline water splitting is of significant importance for the development of a sustainable hydrogen ***,heterostructured Co_(3)Mo nanoparti-cles/porous CoMoO_(3)nanosheets(Co_(3)Mo/CoMoO_(3)NPSs)were constructed for alkaline water splitting by annealing CoMoO x nanosheets under controlled *** to its interfacial electronic structure and increased electrochemical active area,Co_(3)Mo/CoMoO_(3)NPSs exhibit impressive hydrogen evolution reaction(HER)activity with an overpotential of 334 mV at 1000 ma cm^(-2) and a Tafel slope of 46.4 mV per decade in 1.0 M KOH,which outperforms Pt/C catalyst(621 mV and 74.7 mV per decade).Density functional theory calculations illustrate the electron transfer from Co_(3)Mo to CoMoO_(3)at the interfaces,where electron accumulation on CoMoO_(3)favors the dissociation of H_(2)O molecule,and electron-deficient Co atoms in Co_(3)Mo have optimized H∗absorption energy for *** Co_(3)Mo/CoMoO_(3)NPSs also exhibit higher oxygen evolution reaction activity than the RuO_(2)***,the water electrolyzer us-ing Co_(3)Mo/CoMoO_(3)NPSs as both cathode and anode only requires 1.59 V to deliver a current density of 100 ma cm^(-2)in 1.0 M KOH,which outperforms benchmark Pt/C||RuO_(2)electrodes couple with 1.69 V to reach the same current density,providing great potential for large-scale applications.

关键词： Interface engineering Heterostructures Interfacial electronic structure Hydrogen evolution reaction Overall water splitting

Forecasting us Stock market Returns:A Japanese Candlestick Approach

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Journal of Systems Science & Complexity 2021年第2期34卷 657-672页

作者： MENG Xiaoge ma Jun QIAO Han XIE Haibin School of Economics and management Institute of Disaster PreventionSanhe 065201China Business School University of International Business and EconomicsBeijing 100029China School of Economics and management University of Chinese Academy SciencesBeijing 100190China School of Banking and Finance University of International Business and EconomicsBeijing 100029China

A Japanese candlestick chart consists of not only the closing price but also the high,low and opening price *** the Japanese candlestick,this paper investigates the forecasting power of the shadow in Japanese candlestick *** studies performed with the us stock market show that 1)there is a significant Halloween effect in the shadow;2)shadow is valuable for predicting the stock market returns in both statistical and economic sense;3)the predictability reported by the shadow can not be explained by either the CAPM model or the Fama-French three-factor *** paper confirms that predictability of the stock market can be improved if more price information is used.

关键词： Japanese candlestick out-of-sample predictability us stock market

Analysis of the Formulation of American Plan of Retreating from Tsingtao in 1949 -------On the Debate Among Departments within American Government

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学术界 2015年第8期 277-281页

作者： ma Ding Department of Modern History Graduate School of Chinese Academy of Social Sciences Beijing 102488

Tsingtao was not only the most important military point of the us in the Eastern Asia mainland after WWII,but also the frontline resisting Soviet army located in Lvda. After the CCP controlled Shandong peninsula,the American force in Tsingtao depended on a thread. However,not only considering the harm of American withdrawing to the face of the us and the moral of KMT,but also for preserving American's interest in Tsingtao,American government did not immediately withdraw its force,but hesitated. The Military and the State Council could not reach agreement on this issue. The instructions to the American force in Tsingtao changed frequently. The withdrawing of the KMT Navy Training Base offered the excuse for American's withdrawing without losing face,and America began to reduce the military force in Tsingtao. But American did not completely withdraw the military force until the PLA seized hold of Nanking and Shanghai.

关键词：美国政府青岛政府计划军事力量亚洲东部苏联军队山东半岛训练基地

Lie Subalgebras in a Certain Operator Lie Algebra with Involution

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Acta mathematica Sinica,English Series 2011年第8期27卷 1521-1534页

作者： Shan Li SUN Xue Feng ma P. R. China

We show in a certain Lie-algebra, the connections between the Lie subalgebra G＋：= G-t-G＊ 4- [G, G＊], generated by a Lie subalgebra G, and the properties of G. This allows us to investigate some useful information about the structure of such two Lie subalgehras. Some results on the relations between the two Lie subalgebras are obtained. As an application, we get the following conclusion： Let ,4 C /3（2d） be a space of self-adjoint operators and L：：= A ~ i^4 the corresponding complex Lie＊-algebra. G＋ = G 4- G＊ 4- [G, G＊] and G are two LM-decomposable Lie subalgebras of L： with the decomposition 6＋ = 7^（6＋） 4- S, G -- T~~ 4- 86, and T^6 C T^（6＋）. Then 6＋ is ideally finite iff T~ ：= 7~6 4- ~ 4- [T^6,7~] is a quasisolvable Lie subalgebra, S^- ：= 86 4- S~ 4- [$6, $~] is an ideally finite semisimple Lie subalgebra, and [7~6,86] = [R.~, 86] = us.

关键词： Skew operator generalized scalar operator E-solvable Lie algebra ideally finite

Innovative designs of permafrost roadbed for the Qinghai-Tibet Railway

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Science China(Technological Sciences) 2009年第2期52卷 530-538页

作者： CHENG GuoDong WU QingBai ma Wei State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China

Under global warming scenarios, the passive method of simply increasing the thermal resistance by raising the embankment height and using insulating materials has been proven ineffective in warm and ice-rich permafrost areas and therefore could not be used in the Qinghai-Tibet Railway engineering. Instead, a proactive "cooled-roadbed" approach was developed and used to lower the ground temperature in order to maintain a perennially frozen subgrade. The concept that local and site-specific factors play an important role in the occurrence and disappearance of permafrost has helped us to devise a number of measures to cool down the roadbed. For example, we adjust and control heat transfer by using different embankment configurations and fill materials. The Qinghai-Tibet Railway project demonstrates that a series of proactive roadbed-cooling methods can be used to lower the temperature of permafrost beneath the embankment and to stabilize the roadbed. These methods include solar radiation control using shading boards, heat convection control using ventilation ducts, thermosyphons, air-cooled embankments, and heat conduction control using "thermal semi-conductor" materials, as well as combinations of above mentioned three control measures. This road-bed-cooling approach provides not only a solution for engineering construction in sensitive permafrost areas but also a countermeasure against possible global warming.

关键词： warm permafrost global warming Qinghai-Tibet Railway cooled roadbed

Facile NiCo_(2)S_(4)/C nanocomposite: an efficient material for water oxidation

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Tungsten 2020年第4期2卷 403-410页

作者： Umair Aftab Aneela Tahira Raffaello mazzaro Vittorio Morandi Muhammad Ishaq Abro Muhammad Moazam Baloch Junaid Ali Syed Ayman Nafady zafar Hussain Ibupoto Mehran University of Engineering and Technology Jamshoro 76080Pakistan Department of Science and Technology Linköping University60174 NorrköpingSweden Institute for Microelectronics and Microsystems Italian National Research CouncilSection of Bologna40129 BolognaItaly College of Science King Saud UniversityRiyadh 11451Saudi Arabia Dr.M.A Kazi Institute of Chemistry University of SindhJamshoro 76080Pakistan

The water oxidation in alkaline media is a kinetically sluggish process and it requires an active electrocatalyst for overall water splitting which is a challenging task to ***,we formulate a platform for the design of efficient NiCo_(2)S_(4)/C nanocomposite using earth abundant and nonprecious *** nanocomposites are prepared by scale up hydrothermal method using different carbon contents from acid dehydrated *** are structurally and morphologically character-ized by various analytic *** scanning electron microscopy has shown few microns flower-like morphology of nanocomposite and hexagonal crystalline phase is identified by X-ray diffraction(XRD).Further,high-resolution transmission electron microscopy supported the XRD results,and C,Ni,Co and O elements were found in the composition nanocomposite as investigated by energy-dispersive *** most active nanocomposite reaches a current density of 20 ma·cm^(−2) at potential of 285 mV vs reversible hydrogen *** nanocomposite is kinetically supported by 61 mV·dec^(−1) as small Tafel *** nanocomposite is stable and durable for 40 *** electrochemical impedance spectroscopy described a small charge transfer resistance of 188.4Ω.These findings suggest that the NiCo_(2)S_(4)/C nanocomposite could be used as a promising material for an extended range of applications particularly in energy technology.

关键词： NiCo_(2)S_(4)/C Water oxidation Alkaline media Stable and durable

Research advances in gene therapy for Parkinson's disease

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Chinese Science Bulletin 1998年第5期43卷 363-368页

作者： ma Duanduan WANG Xiaomin HAN Jisheng Neuroscience Research Institute Beijing Medical UniversityBeijing 100083China.

During the long period of time when people have been seeking for an effective therapeutic method for PD, the gene therapy has shown greater and greater advantages over other methods. It can be performed mainly in two ways: ex vivo and in vivo. With the former, TH gene as well as some neurotrophic factor genes (such as GDNF, BNDF genes) can be invited to some cell lines or primary cells thus forming engineered cells and then implanting them into brain. While with the latter, viral vectors including HSV-1, Ad, AAV that can be utilized to construct recombinant viruses, or non-virus vectors can be used to delived DNA into brain directly. The present review summarizes the recent research advances in the gene therapy for PD, and it is reasonable for us to predict a notable progress in prevention and treatment for PD in the next decade.

关键词： Parkinsion's disease(PD) gene therapy tyrosine hydroxylase(TH) GDNF virus vector