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| 1 | Experimental definition and its significance on the minimum safe distance of blown sand between the proposed Qinghai-Tibet Expressway and the existing Qinghai-Tibet Railway显示文摘The Qinghai-Tibet Expressway is a major strategic project planned by China that will be built along the Qinghai-Tibet Engineering Corridor. At present,important traffic line projects,such as the Qinghai-Tibet Railway,have been built within this narrow corridor,particularly at the blown sand sections. How to ensure that the wind speed and its flow field between the new expressway and existing railway subgrades are not affected by each other is a priority to prevent breaking the dynamic balance of the blown sand movement of the existing subgrade,thereby avoiding aggravating or inducing new blown sand hazards and ensure the safe operation of the existing Qinghai-Tibet Railway. Therefore,defining the minimum distance of the wind speed and its flow field,which are not affected by each other,between the subgrades become a scientific problem that should be solved immediately to implement the construction of the Qinghai-Tibet Expressway. For this purpose,the minimum safe distance between the subgrades of the Qinghai-Tibet Expressway and Qinghai-Tibet Railway was investigated from the perspective of blown sand by making subgrade models for conducting wind tunnel experiments and combining the observation data of the local field. Results indicated that the minimum safe distance between the two subgrades is 45–50 times the subgrade height when the Qinghai-Tibet Expressway is located at the downwind direction of the Qinghai-Tibet Railway,and 50 times the subgrade height when the former is located at the upwind direction of the latter. These results have guiding significance for the route selection,survey,and design of the Qinghai-Tibet Expressway at the blown sand sections and for the traffic line projects in other similar sandy regions. | XIE ShengBo QU JianJun HAN QingJie PANG YingJun | 2020 | Science China(Technological Sciences)2020，63，12： | 5 |
| 2 | Quantitative analysis on the dynamic characteristics of megadunes around the Crescent Moon Spring, China显示文摘The Crescent Moon Spring is a precious natural heritage. However, the dynamic characteristics of megadunes around the Crescent Moon Spring are not well known. This paper quantitatively studied the character- istics and changes of megadunes around the Crescent Moon Spring by interpreting aerial photographs taken in 1985 and 2004 and analysing the dune crestlines and the wind data collected from 2011 to 2012. Results revealed that pyramid dunes were formed by a complex wind regime. The Crescent Moon Spring was not buried by shifting sands because of the stable wind regime and relative stability of pyramid dunes. The crestlines of the dunes around the spring moved northward between 1985 and 2004. The south-facing slip faces were also exposed to wind ero- sion, whereas the other faces were under deposition, thus indicating that the southerly wind was relatively en- hanced. Limiting the scale of tall windbreaks and architectures in the Dunhuang oasis at the north of the spring was necessary to maintain the dynamic equilibrium of the wind regime and sand transport. | YingJun PANG JianJun QU KeCun ZHANG ZhiShan AN QingHe NIU | 2014 | Journal of Arid Land2014，6，3： | 4 |
| 3 | Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau显示文摘The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za'gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes. Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a 'narrow-pipe effect', which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form:(1) strong winds, sufficient sand, suitable obstacles and a dry climate;(2) one or both sides of the obstacle forming the shadow zone must have a hill pass; and(3) the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology. | JianHua XIAO JianJun QU ZhengYi YAO YingJun PANG KeCun ZHANG | 2015 | Journal of Arid Land2015，7，1： | 4 |
| 4 | Dynamic dispersion stability of graphene oxide with metal ions显示文摘Graphene oxide(GO),an important chemical precursor of graphene,can stably disperse in aqueous surrounding and undergo aggregation as metal cations introduced.The usual instability of GO with ions is caused by the shielding effect of ions and crosslinking between GO and ions.However,the dynamic stability of GO under ions exchange still remains unclear.Here,we investigated the dynamic dispersion stability of GO with metal ions and observed a redispersion behavior in concentrated Fe3+solution,other than permanent aggregation.The exchange with Fe3+ions drives the reversion of zeta(ζ)potential and enables the redispersion to individual GO-Fe3+complex sheets,following a dynamic electric double layer(EDL)mechanism.It is found that the specifically strong electrostatic shielding effect and coordination attraction between Fe3+and functional oxygen groups allows the selective redispersion of GO in concentrated Fe3+solution.The revealed dynamic dispersion stability complements our understanding on the dispersive stability of GO and can be utilized to fabricate graphene-metal hybrids for rich applications. | Yinghui He Yingjun Liu Fan Guo Kai Pang Bo Fang Ya Wang Dan Chang Zhen Xu Chao Gao | 2020 | Chinese Chemical Letters2020，31，6： | 2 |
| 5 | Wind-proof and sand-fixing effects of Artemisia ordosica with different coverages in the Mu Us Sandy Land,northern China显示文摘Wind erosion is a key global environmental problem and has many adverse effects.The Mu Us Sandy Land of northern China is characterized by an arid climate,where vegetation patches and bare sand patches are usually distributed mosaically,and aeolian activities occur frequently.Vegetation plays a significant role in controlling wind erosion.Artemisia ordosica is the most dominant native plant species in the Mu Us Sandy Land.It is urgent to study the wind-proof and sand-fixing effects of Artemisia ordosica in the Mu Us Sandy Land.This study analyzed the wind-proof and sand-fixing effects of Artemisia ordosica based on the field data of wind regimes,aeolian sediment transport,and surface change of Artemisia ordosica plots with four coverages(denoted as site A,site B,site C,and site D)in the Mu Us Sandy Land during the period from 1 June 2018 to 29 June 2019.The coverages of Artemisia ordosica at site A,site B,site C,and site D were 2%,16%,29%,and 69%,respectively.The annual average wind speeds at 2.0 m height above the ground for site A,site B,site C,and site D were 3.47,2.77,2.21,and 1.97 m/s,respectively.The annual drift potentials were 193.80,69.72,15.05,and 6.73 VU at site A,site B,site C,and site D,respectively.The total horizontal aeolian sediment fluxes during the period from 2-3 June 2018 to 6 June 2019 at site A,site B,site C,and site D were 4633.61,896.80,10.54,and 6.14 kg/m,respectively.Site A had the largest surface changes,and the surface changes at site B were significantly weaker than those at site A,whereas the surface changes at site C and site D were minimal.The results indicated that Artemisia ordosica significantly reduced the wind speed,drift potential,aeolian sediment transport,and surface changes.The higher the coverage of Artemisia ordosica is,the more obvious the effects of wind-proof and sand-fixing.Wind erosion would be effectively controlled in the Mu Us Sandy Land if the coverage of Artemisia ordosica is greater than 29%.These results provide a scientific basis for evaluating the ecosystem service function of Artemisia ordosica and the vegetation protection and construction projects in the Mu Us Sandy Land. | PANG Yingjun WU Bo JIA Xiaohong XIE Shengbo | 2022 | Journal of Arid Land2022，14，8： | 2 |
| 6 | Precise Thermoplastic Processing of Graphene Oxide Layered Solid by Polymer Intercalation显示文摘The processing capability is vital for the wide applications of materials to forge structures as-demand.Graphene-based macroscopic materials have shown excellent mechanical and functional properties.However,different from usual polymers and metals,graphene solids exhibit limited deformability and processibility for precise forming.Here,we present a precise thermoplastic forming of graphene materials by polymer intercalation from graphene oxide(GO)precursor.The intercalated polymer enables the thermoplasticity of GO solids by thermally activated motion of polymer chains.We detect a critical minimum containing of intercalated polymer that can expand the interlayer spacing exceeding 1.4 nm to activate thermoplasticity,which becomes the criteria for thermal plastic forming of GO solids.By thermoplastic forming,the flat GO-composite films are forged to Gaussian curved shapes and imprinted to have surface relief patterns with size precision down to 360 nm.The plastic-formed structures maintain the structural integration with outstanding electrical(3.07×10^(5) S m^(−1))and thermal conductivity(745.65 W m^(−1) K^(−1))after removal of polymers.The thermoplastic strategy greatly extends the forming capability of GO materials and other layered materials and promises versatile structural designs for more broad applications. | Zeshen Li Fan Guo Kai Pang Jiahao Lin Qiang Gao Yance Chen Dan Chang Ya Wang Senping Liu Yi Han Yingjun Liu Zhen Xu Chao Gao | 2022 | Nano-Micro Letters2022，14，1： | 1 |
| 7 | Highly electrically conductive graphene papers via catalytic graphitization显示文摘The highly electrically conductive graphene papers prepared from graphene oxide have shown promising perspectives in flexible electronics,electromagnetic interference(EMI)shielding,and electrodes.To achieve high electrical conductivity,the graphene oxide precursor usually needs to be graphitized at extremely high temperature(~2,800°C),which severely increases the energy consumption and production costs.Here,we report an efficient catalytic graphitization approach to fabricate highly conductive graphene papers at lower annealing temperature.The graphene papers with boron catalyst annealed at 2,000°C show a high conductivity of~3,400 S·cm^(-1),about 47%higher than pure graphene papers.Boron catalyst facilitates the recovery of structural defects and improves the degree of graphitization by 80%.We further study the catalytic effect of boron on the graphitization behavior of graphene oxide.The results show that the activation energy of the catalytic graphitization process is as low as 80.1 kJ·mol^(–1)in the temperature ranges studied.This effective strategy of catalytic graphitization should also be helpful in the fabrication of other kinds of highly conductive graphene macroscopic materials. | Huanqin Peng Xin Ming Kai Pang Yanru Chen Ji Zhou Zhen Xu Yingjun Liu Chao Gao | 2022 | Nano Research2022，15，6： | 1 |
| 8 | Morphological characteristics and dynamic changes of seif dunes in the eastern margin of the Kumtagh Desert,China显示文摘The seif dune field over the gravel desert surface in the eastern margin of the Kumtagh Desert is a valuable experimental site for the observation of dune formation and dynamics.We used high-resolution remote sensing and station observation approaches,combined with wind and grain size data,to study the characteristics of the aeolian environment and the morphologies of and dynamic changes in seif dunes.We observed the ratio of the resultant drift potential(RDP)to the drift potential(DP),which was 0.37,associated with an obtuse bimodal wind regime.The drift potentials in the west-northwest(WNW)and east-northeast(ENE)directions were dominant,and the angle between the two primary DP directions was 135.00°.The dune orientations ranged from 168.75°-213.75°,which were parallel to the resultant drift direction(186.15°).The dune lengths ranged from 51.68 to 1932.1 m with a mean value of 344.91 m.The spacings of the dunes ranged from 32.34 to 319.77 m with a mean value of 93.39 m.The mean grain size of the sediments became finer,and the sorting became better from upwind tail to downwind tip,which indicated that the sediment of the seif dunes in the study region may be transported from northward to southward.The rate of increase in the length,the mean longitudinal migration rate of the dune tail,and the mean longitudinal extension rate of the dune tip(also called elongation rate)were 4.93,4.63,and 9.55 m/a,respectively.The mean lateral migration vector of the seif dunes was approximately 0.11 m/a towards the west(-0.11 m/a),while the mean amplitude of lateral migration was 0.53 m/a,ignoring the direction of lateral migration.We found that the seif dune field formed first beside seasonal rivers,which can provide sediment,and then expanded downwind. | PANG Yingjun WU Bo LI Yonghua XIE Shengbo | 2020 | Journal of Arid Land2020，12，5： | 0 |
| 9 | Progress on research and mitigation of wind-blown sand risk in Dunhuang Singing Sand Mountain and Crescent Spring Scenic area,China显示文摘The Singing Sand Mountain and Crescent Spring Scenic Spot in Dunhuang,Northwest China is a world-renowned desert attraction that is also an integral component of the Dunhuang UNESCO Global Geopark.This scenic area underwent a 30-year transformation,i.e.,from a severe sand risk with spring water threatened by sand burial due to dune deformation,to restoration of the original sand flow field and mitigation of the sand burial problem.The current paper summarizes the research on the intensive monitoring of the dynamic change of star dunes near the spring,observation of wind and sand flow movement,and then restoring the harmonic vibration of the sand particles(singing sand)that were previously silenced.The existing and prospective impacts of anthropogenic and natural forces on the deformation of the sand dunes are investigated by integrated methods,guiding the implementation of mitigating measures with significant ameliorative effects.Contrast to common sand control practices that aim to reduce wind speed and stop blown sands,our research highlights the importance of maintaining the natural wind flow field in stabilizing surrounding dunes.These mitigation measures consist of removing excessive vegetation and newly constructed buildings to recover the original wind flow field and sand transport activity.Such research and mitigation efforts ensure the scientific protection and restoration of the special desert landform,and contribute to the mutual enhancement of the conservation and exploitation of this desert scenic spot and similar sites. | BenLi Liu KeCun Zhang JianJun Qu HaiJiang Li QingHe Niu ZhiShan An YingJun Pang LiHai Tan GenSheng Yang | 2023 | Research in Cold and Arid Regions2023，15，3： | 0 |
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