Anisotropic refraction and valley-spin-dependent anomalous Klein tunneling in a 1T'-MoS_(2)-based p–n junction

We investigate the transport properties of electron in a 1T'-MoS_(2)-based p–n junction.The anisotropic refraction of electron is found when the electron beam crosses the p–n junction,which brings the phenomenon of valley splitting without any external fields.Moreover,it is found that the valley-spin-dependent anomalous Klein tunneling,i.e.,the perfect transmission exists at a nonzero incident angle of valley-spin-dependent electron,happens when the vertical electric field is equal to the critical electric field.These two peculiar properties arise from the same reason that the tilted band structure makes the directions of wavevector and velocity different.Our work designs a special valley splitter without any external fields and finds a new type of Klein tunneling.

Emergy Analysis of Sustainability of Eco-economic System in Sichuan's Baisha River Valley

Using emergy analysis method,I conduct quantitative analysis of social,economic and natural systems in Sichuan's Baisha River valley during the period 2002-2006,through the establishment of indicators.I compare the emergy of Baisha River valley,with that of Xinjiang's Manas River valley and Sichuan Province,and evaluate the sustainable development conditions in Baisha River valley,in order to provide corresponding reference for the development and utilization of Baisha River valley in the future.The results show that from the perspective of emergy input of economic system,Baisha River valley is a typical ecological and economic zone with rich resources to be developed;in terms of the development of natural conditions and utilization of ecological resources,the resource utilization intensity of Baisha River valley is weak and the environmental loading ratio there is low,thus the level of emergy yield needs to be improved;the system of Baisha River valley has enormous capacity for sustainable development and good potential for development.

How to Improve Tea Farmers' Livelihoods in the Sightseeing Place along Lijiang River Valley?

The unbalance of tourism development and comparative superiority of the tea industry brings new opportunities to the poor groups along Lijiang River Valley for improving their livelihoods. From the perspective of sustainable livelihoods,we analyze the problems in tea farmers' livelihoods,such as lack of fund,low capacity in price negotiation,and high cost of resisting various risks. Recommendations are put forward for tea farmers to improve their livelihoods through ways of enterprise cooperation,innovative marketing,brand cultivation,industrial integration and so on.

Imaging the Deep Structure of the Central DeathValley Basin Using Receiver Function, Gravity,and Magnetic Data

We use receiver function, gravity, and magnetic data to image the deep structures of central Death Valley. Receiver function analysis suggests the Moho is 24 km deep in the central part of the basin and deepens to 33 km to the east and 31 km to the west. The estimated lower crustal density is 2900 kg/m3, which suggests a gabbroic composition, whereas the upper crustal density, excluding basin sediments, is estimated to average 2690 kg/m3 or approximately a quartzofeldspathic composition. We modeled the magnetic sources as upper crustal to suggest a relatively shallow Curie depth in this region of high heat flow. We developed models to test the hypothesis that a low-density, non-magnetic body (magma or fluid-rich material?) within the lower crust at a depth of 15 km could coincide with the location of the Death Valley bright spot imaged on a deep seismic reflection profile. Those models suggest that if there is a low density region in the mid to lower crust in the area of the bright spot, then the region is also likely to be underplated by mafic or ultramafic materials which may have contributed to heating, uplift, and thinning of the crust during extension.

Zhongguan Village,China's Silicon Valley

In 1999,driven by the dream of using technology to change people's lives, Li Yanhong,returned to Zhongguan- cun (Zhongguan Village in Chinese), Beijing from Silicon Valley in the U.S.to create Baidu.com.Over the years,Baidu has become the most frequently hitted website in China as well as the largest Chinese search engine and Chinese lan- guage website in the world.In

Anomalous valley Hall effect in two-dimensional valleytronic materials

The anomalous valley Hall effect(AVHE)can be used to explore and utilize valley degrees of freedom in materials,which has potential applications in fields such as information storage,quantum computing and optoelectronics.AVHE exists in two-dimensional(2D)materials possessing valley polarization(VP),and such 2D materials usually belong to the hexagonal honeycomb lattice.Therefore,it is necessary to achieve valleytronic materials with VP that are more readily to be synthesized and applicated experimentally.In this topical review,we introduce recent developments on realizing VP as well as AVHE through different methods,i.e.,doping transition metal atoms,building ferrovalley heterostructures and searching for ferrovalley materials.Moreover,2D ferrovalley systems under external modulation are also discussed.2D valleytronic materials with AVHE demonstrate excellent performance and potential applications,which offer the possibility of realizing novel low-energy-consuming devices,facilitating further development of device technology,realizing miniaturization and enhancing functionality of them.

Progress on two-dimensional ferrovalley materials

The electron's charge and spin degrees of freedom are at the core of modern electronic devices. With the in-depth investigation of two-dimensional materials, another degree of freedom, valley, has also attracted tremendous research interest. The intrinsic spontaneous valley polarization in two-dimensional magnetic systems, ferrovalley material, provides convenience for detecting and modulating the valley. In this review, we first introduce the development of valleytronics.Then, the valley polarization forms by the p-, d-, and f-orbit that are discussed. Following, we discuss the investigation progress of modulating the valley polarization of two-dimensional ferrovalley materials by multiple physical fields, such as electric, stacking mode, strain, and interface. Finally, we look forward to the future developments of valleytronics.

Recent progress on valley polarization and valley-polarized topological states in two-dimensional materials

Valleytronics, using valley degree of freedom to encode, process, and store information, may find practical applications in low-power-consumption devices. Recent theoretical and experimental studies have demonstrated that twodimensional(2D) honeycomb lattice systems with inversion symmetry breaking, such as transition-metal dichalcogenides(TMDs), are ideal candidates for realizing valley polarization. In addition to the optical field, lifting the valley degeneracy of TMDs by introducing magnetism is an efficient way to manipulate the valley degree of freedom. In this paper, we first review the recent progress on valley polarization in various TMD-based systems, including magnetically doped TMDs,intrinsic TMDs with both inversion and time-reversal symmetry broken, and magnetic TMD heterostructures. When topologically nontrivial bands are empowered into valley-polarized systems, valley-polarized topological states, namely valleypolarized quantum anomalous Hall effect can be realized. Therefore, we have also reviewed the theoretical proposals for realizing valley-polarized topological states in 2D honeycomb lattices. Our paper can help readers quickly grasp the latest research developments in this field.

Valleytronic topological filters in silicene-like inner-edge systems

Inner edge state with spin and valley degrees of freedom is a promising candidate for designing a dissipationless device due to the topological protection. The central challenge for the application of the inner edge state is to generate and modulate the polarized currents. In this work, we discover a new mechanism to generate fully valley-and spin–valley-polarized current caused by the Bloch wavevector mismatch(BWM). Based on this mechanism, we design some serial-typed inner-edge filters. By using once of the BWM, the coincident states could be divided into transmitted and reflected modes, which can serve as a valley or spin–valley filter. In particular, while with twice of the BWM, the incident current is absolutely reflected to support an off state with a specified valley and spin, which is different from the gap effect.These findings give rise to a new platform for designing valleytronics and spin-valleytronics.

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Topological zero-line modes(ZLMs) with spin and valley degrees of freedom give rise to spin, valley and spinvalley transport, which support a platform for exploring quantum transport physics and potential applications in spintronic/valleytronic devices. In this work, we investigate the beam-splitting behaviors of the charge current due to the ZLMs in a three-terminal system. We show that with certain combinations of ZLMs, the incident charge current along the interface between different topological phases can be divided into different polarized currents with unit transmittance in two outgoing terminals. As a result, fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters are generated. The mechanism of these splitters is attributed to the cooperative effects of the distribution of the ZLMs and the intervalley and intravalley scatterings that are modulated by the wave-vector mismatch and group velocity mismatch. Interestingly, half-quantized transmittance of these scatterings is found in a fully spin-valley-polarized electron beam splitter.Furthermore, the results indicate that these splitters can be applicable to graphene, silicene, germanene and stanene due to their robustness against the spin–orbit coupling. Our findings offer a new way to understand the transport mechanism and investigate the promising applications of ZLMs.

Topological slow light and rainbow trapping of surface wave in valley photonic crystal bounded by air

Topological slow light and rainbow trapping tend to rely on large-scale interface structure in previous research work,which have restricted further miniaturization.In this work,we propose a method to realize slow light and rainbow trapping at the zigzag edge of a single valley photonic crystals(VPCs)bounded by air,which is very different from previous studies where rainbow trapping is supported at the interface separating two VPCs with inversion symmetry.By constructing the VPC–air boundaries and VPC–VPC interfaces experimentally,we have observed the topologically protected rainbow trapping simultaneously at the external and internal boundary.This work provides a feasible platform for the miniaturized optical communication devices such as optical buffers,optical storage and optical routing.

Valley switch effect in anα-T3 lattice-based superconducting interferometer

Dirac electrons possess a valley degree of freedom,which is currently under investigation as a potential information carrier.We propose an approach to generate and manipulate the valley-switching current(VSC)through Andreev reflection using an interferometer-based superconductor hybrid junction.The interferometer comprises a ring-shaped structure formed by topological kink states in the a-T3 lattice via carefully designed electrostatic potentials.Our results demonstrate the feasibility of achieving a fully polarized VSC in this device without contamination from cotunneling electrons sharing the same valley as the incident electron.Furthermore,we show that control over the fully polarized VSC can be achieved by applying a nonlocal gate voltage or modifying the global parameter a.The former alters the dynamic phase of electrons while the latter provides an a-dependent Berry phase,both directly influencing quantum interference and thereby affecting performance in terms of generating and manipulating VSC,crucial for advancements in valleytronics.

The 2022 Extreme Heatwave in Shanghai,Lower Reaches of the Yangtze River Valley:Combined Influences of Multiscale Variabilities

In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.

Features of sampling stream sediments of large river valleys under cryolithogenesis conditions in the Balygychan-Sugoy trough,North-East of Russia

Comprehensive research has been implemented to raise the efficiency of the geochemical survey of stream sediments(SSs)that formed under the cryolithogenesis conditions.The authors analysed the composition,structure and specific features of the formation of exogenous anomalous geochemical fields(AGFs)identified through SSs of large river valleys of IV order.In our case,these were the valleys of Maly Ken,Ken and Tap Rivers.These rivers are located in the central and southern parts of the Balygychan-Sugoy trough enclosed in the Magadan region,North-East of Russia.The authors proposed a new technique to sample loose alluvium of SSs in the large river valleys along the profiles.The profiles were located across the valleys.The AGFs of Au,Ag,Pb,Zn,Sn,Bi,Mo and W were studied.Correlations between elements have been established.These elements are the main indicator elements of Au-Ag,Ag-Pb,Sn-Ag,Mo-W and Sn-W mineralization occurring on the sites under study.The results obtained were compared with the results of geochemical surveys of SSs.It is concluded that the AGFs recognized along the profiles reflect the composition and structure of eroded and drained ore zones,uncover completely and precisely the pattern of element distribution in loose sediments of large water flows.The alluvium fraction<0.25 mm seems to be most significant in a practical sense,as it concentrated numerous ore elements.Sampling of this fraction in the river valleys of IV order does not cause any difficulty,for this kind of material is plentiful.The developed technique of alluvium sampling within large river valleys is efficient in searching for diverse mineralization at all stages of prognostic prospecting.It is applicable for geochemical survey of SSs performed at different scales both in the North-East of Russia,as well as other regions with similar climatic conditions,where the SSs are formed under the cryolithogenesis conditions.

Topological edge and corner states of valley photonic crystals with zipper-like boundary conditions

We present a stable valley photonic crystal(VPC)unit cell with C_(3v)symmetric quasi-ring-shaped dielectric columns and realize its topological phase transition by breaking mirror symmetry.Based on this unit cell structure,topological edge states(TESs)and topological corner states(TCSs)are realized.We obtain a new type of wave transmission mode based on photonic crystal zipper-like boundaries and apply it to a beam splitter assembled from rectangular photonic crystals(PCs).The constructed beam splitter structure is compact and possesses frequency separation functions.In addition,we construct a box-shaped triangular PC structures with zipper-like boundaries and discover phenomena of TCSs in the corners,comparing its corner states with those formed by other boundaries.Based on this,we explore the regularities of the electric field patterns of TESs and TCSs,explain the connection between the characteristic frequencies and locality of TCSs,which helps better control photons and ensures low power consumption of the system.

Protectivity of Freeze Dried Inactivated Rift Valley Fever Vaccine

Background: Vaccinations for animals are crucial for food production, animal welfare, public health, and animal health. They are an affordable way to stop animal sickness, increase food production efficiency, and lessen or stop the spread of zoonotic diseases to humans. Animal vaccines that are both safe and efficacious are vital to modern culture. The vaccine should induce a strong, protective and prolonged immune response against the antigenic factor. In order to achieve these goals, novel vaccination techniques and an efficient adjuvant are required to render the vaccine immunogenically protective and trigger a strong immune response. Aim: Our study aims to promote and enhance the immunogenicity against RVF virus disease through lyophilized inactivated RVF vaccine through induction of early cellular, high and prolonged humeral immunity in vaccinated animals using cabopol as stabilizer and Saponin or normal saline as a diluent at time of vaccination. Moreover, manufacturing of these vaccines is easy to be done. Results: The gained results revealed that RVF freeze-dried vaccine with Carbopol that reconstituted using Saponin elicited better immune response than that reconstituted using normal saline (NaCl). The cell mediated immune response as represented by lymphocyte blastogenesis and phagocytic activity were markedly increased with high levels when we used Saponin as a diluent than that in group vaccinated with vaccine diluted with NaCl, on the other side the humeral immune response in group vaccinated using the Saponin as diluent is more detected and stayed within the protective level till the end of 11th month post vaccination (1.5 TCID50) while the immune response induced after using normal saline as a diluent stayed within the protective level till the end of 10th month post vaccination (1.8 TCID50). Conclusion: The use of Saponin as a diluent for reconstitution of the freeze dried RVF vaccine is preferable than the use of normal saline enhancing both sheep cellular and humeral immune response.

Temporal, Spatial, and Hypsometrical Dispersion of Nutrients in the Hula Valley, Israel

Until 1957 most of the Hula Valley was occupied by swampy wetland covered by dense vegetation and old Lake Hula. Organic matter was accumulated in the bottom, decomposed under anoxic conditions creating Peat material. The wetland and the old lake were drained and the land-use was converted into agricultural development. Nutrients migrations from the Hula Valley through the headwater discharges carrying nutrients, where nitrogen enhancement is critical, significantly affecting water quality in down-stream Lake Kinneret. The fate of the Hula originated nutrients is partly known whilst fate of the others which might be probably a threat on the Kinneret water quality is unknown. The hypsometrical and spatial distribution of the Hula Valley originated nutrients within three depths level was indicated: shallowest level of surface water, intermediate level of underground water table and the deepest level of Lignite waters. The Hypsometrical and spatial distribution and regional origin of the nutrient in the Hula Valley was defined. Organic Nitrogen, Sulfate and Nitrates are mostly Hula Valley originated nutrients whilst most of the Phosphorus externally contributed to Lake Kinneret originate outside the Hula Valley. An underground north-south Hydrological gradient and nutrient migration along was indicated. It is suggested that an underground plastic barrier do not totally prevent horizontal nutrient migration. Hypsometrical downward migrated nutrients probably accumulate within the “Lignite” depth level. Management policy of increasing Peat Soil moisture, is recommended.

Salinization-Desalinization (SDS) Processes—A Linkage between Hula Valley and Lake Kinneret Ecosystem Management

The salinization process resulted in agricultural damage in the Hula Valley and water quality deterioration in Lake Kinneret. Therefore, salinization-desalinization (SDS) processes have been emphasized in the last two decades. Global and regional extreme climatological events and water scarcity strengthen the link between Hula Valley and Lake Kinneret management design. A bond between optimizing Hula agricultural maintenance and Kinneret water quality protection is conclusively suggested. Saline contribution originated from the southern Hula Valley region to the underground and surface water is higher than from the northern organic soil. The impact of eastern water Intrusion from the Golan Heights as surface waters, river discharge and underground seepage into the Hula Valley represent north-south gradient enhancement. Salinized surface water contribution from the Hula Valley to Lake Kinneret is unwanted because presently Kinneret desalinization management policy is critically required. The present salinization of surface and underground water in the Hula Valley indicates the upper limit suitable for agricultural crop optimization and the decline of salinity is crucial. Enhancement of the portion of Jordan water within the total balance in the valley is beneficial for Hula agricultural crops but serves as a disadvantage to Kinneret desalinization implementation. Therefore, the enhancement of lake water exchange is recommended.

Valley transport in Kekulé structures of graphene

Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studied, Kekulé distorted graphene has emerged as a promising material for valleytronics applications. Graphene can be artificially distorted to form the Kekulé structures rendering the valley-related interaction. In this work, we review the recent progress of research on Kekulé structures of graphene and focus on the modified electronic bands due to different Kekulé distortions as well as their effects on the transport properties of electrons. We systematically discuss how the valley-related interaction in the Kekulé structures was used to control and affect the valley transport including the valley generation, manipulation, and detection. This article summarizes the current challenges and prospects for further research on Kekulé distorted graphene and its potential applications in valleytronics.

Using a New Glacial History Paradigm and Bald Eagle Through Valley Topographic Map Evidence to Determine Central Pennsylvania’s Geomorphic History, USA

A new glacial history paradigm that describes huge and prolonged southwest-oriented meltwater floods flowing along the rising rim of a deep “hole” (which a large continental icesheet created and occupied) is used to explain previously unexplained or poorly explained central Pennsylvania Bald Eagle through valley region topographic map evidence. Pennsylvania’s Bald Eagle through valley as defined here extends in a northeast direction from near Altoona to near Williamsport along the Allegheny Front escarpment base and forms the boundary between the Appalachian Plateau to the northwest and the Ridge and Valley Province to the southeast. The Lycoming and Towanda Creek valleys follow a probable northeastern Bald Eagle through valley extension and a probable southern extension continues southward along the Allegheny Front base by crossing Juniata River tributary drainage basins to reach the Potomac River drainage basin. Landform features identified on topographic maps, which include through valleys (valleys crossing drainage divides), barbed tributaries, drainage route orientations, drainage route direction changes, water gaps, and gaps located along the Allegheny Front crest, are used to reconstruct how the Pennsylvania Susquehanna and Juniata River drainage systems developed. The resulting geomorphic history describes how massive southwest-oriented floods moving across what was probably a low relief and rising surface (now preserved if preserved at all by the region’s highest elevations) flowed to an actively eroding Potomac River drainage system before being captured and sometimes reversed first by Juniata River valley headward erosion, second by West Branch Susquehanna River valley headward erosion (to create northeast-oriented Bald Eagle Creek and the northeast-oriented West Branch Susquehanna River segment) and third by North Branch Susquehanna River valley headward erosion. This interpretation explains most if not all of the previously poorly explained and unexplained topographic map evidence.