用前馈控制方案保护在马尔可夫和非马尔可夫环境下的量子态

运用前馈控制方案来保护在马尔可夫和非马尔可夫环境下的量子态,发现该方案可以有效地保护两比特纠缠态.对于两比特纠缠态最佳的反馈控制方案能够产生更多的纠缠,而且在非马尔可夫环境下产生的纠缠要比在马尔可夫环境下保持得时间更长,也就是说两比特量子态在非马尔可夫环境下保护效果更好.

Quantum Communication Scheme Using Non-symmetric Quantum Channel

A theoretical quantum communication scheme based on entanglement swapping and superdense coding is proposed with a 3-dimensional Bell state and 2-dimensional Bell state function as quantum channel,quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme.The scheme is secure and has high source capacity.At last,we generalize the quantum communication scheme to d-dimensional quantum channel.

Quantum Secure Communication by Using GHZ State in High-Dimensional Hilbert Space

We propose a quantum superdense coding secure communication scheme by using GHZ state.This scheme combines the ideas of quantum superdense coding and sequence transmission.Its distinct advantage is high source capacity.In addition,in checking eavesdropping,we need not to destroy quantum entanglement.

A Preliminary Study on the Calculating Method for the Evolution of Siltation and Erosion of Tidal Flat Based on GIS

T he estuary and coast is an area where the land and the sea interact and a place in which human beings frequently move about so that understanding and controlling the change and development modes of the coastal landform plays a vital part in exploiting and protecting coastal resources. A model is the generalization and abstraction of objective things. This paper summarizes four methods for the landform development of the tidal shore and underwater delta, mainly discusses the model’s structural elements, and presents their specific application on the basis of the authors’ case study. With the application of the profile model, the dynamic change of coastal landform can be clearly seen by contrasting the different profiles of different years. Through the shrinking, expanding and transformation of the isobath, plane model is used to study the macro-change of the shoal and the coastal landform. Speed model is an efficient means to analyze the trend of erosion and deposition and the local change in a great area of the sea. Statistical survey model is a static analysis, which can be used to establish the relationship between the erosion and deposition of the shoal and the altitude and slope of survey spot.

Effects of soil and water conservation and its interactions with soil properties on soil productivity

The effects of soil and water conservation （SWC） on soil properties are well documented. However, definitive and quantitative information of SWC and its interactions with soil properties on soil productivity is lacking for hilly red soil region of southern China. Experiments were conducted in the hilly red soil region of southern China for seven years in three rtmoffplots, each of which represented different SWC forest-grass measures. Principal component analysis and multiple regression techniques were used to relate the aboveground biomass （representing soil productivity） to soil properties. Based on the final regression equations, soil organic carbon content （Sot） is significantly correlated with soil productivity under the condition of forest-grass measures, whereas pH value and cation exchange capacity （Cee） are the main factors for soil productivity without SWC. Therefore, SWC plays an important role in sequestering Soc and improving soil productivity.

Soil and Vegetation Seasonal Changes in the Grazing Andean Mountain Grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna(Vicugna vicugna) and alpaca(Lama pacos). The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined: total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.

Quantum State Preparation and Protection by Measurement-Based Feedback Control Against Decoherence

We consider an open quantum system subjected to a noise channel under measurement-based feedback control and two prototypical classes of decoherence channels are considered： phase damping and generalized amplitude damping. Based on quantum trajectory theory, we obtain an extended master equation for the dynamics of the reduced system in the presence of feedback control. For a qubit system we analytically solve this master equation and obtain the solution of the state vector dynamics. Then we propose an effective feedback control scheme for preparing an arbitrary quantum pure state. We also study how to protect two nonorthogonai states effectively, and find that projective measurement with unbiazed basis is not optimal for this task, while weak measurement with biased basis could realize the best protection of two nonorthogonal states. Furthermore, the inefficiencies in the feedback process are also discussed

The herbal compound geniposide rescues formaldehyde-induced apoptosis in N2a neuroblastoma cells

The herbal medicine Tong Luo Jiu Nao （TLJN） contains geniposide （GP） and ginsenoside Rgl at a molar ratio of i0：1. Rgl is the major component of another herbal medicine, panax notoginseng saponin （PNS）. TLJN has been shown to strengthen brain function in humans, and in animals it improves learning and memory. We have previously shown that TLJN reduces amyloi- dogenic processing in Alzheimer＇s disease （AD） mouse models. Together this suggests TLJN may be a potential treatment for patients with dementia. Because chronic damage of the central nervous system by formaldehyde （FA） has been presented as a risk factor for age-associated cognitive dysfunction, in the present study we investigated the protective effect of both TLJN and GP in neuron-like cells exposed to FA. FA-exposed murine N2a neuroblastoma cells were incubated with TLJN, its main in- gredient GP, as well as PNS, to measure cell viability and morphology, the rate of apoptosis and expression of genes encoding Akt, FOXO3, Bcl2 and p53. The CCK-8 assay, cytoskeletal staining and flow cytometry were used to test cell viability, mor- phology and apoptosis, respectively. Fluorescent quantitative real-time PCR （qRT-PCR） was used to monitor changes in gene expression, and HPLC to determine the rate of FA clearance. Treatment of N2a cells with 0.09 mmol L-1 FA for 24 h signifi- cantly reduced cell viability, changed cell morphology and promoted apoptosis. Both TLJN and GP conferred neuroprotection to FA-treated N2a cells, whereas PNS, which had to be used at lower concentrations because of its toxicity, did not. Our data demonstrate that TLJN can rescue neuronal damage caused by FA and that its main ingredient, GP, has a major role in this ef- ficacy. This presents purified GP as a drug or lead compound for the treatment of AD.

Overview of quantum memory protection and adiabaticity induction by fast signal control

A quantum memory or information processing device is subject to the disturbance from its surrounding environment or the inevitable leakage due to its contact with other systems. To tackle these problems, several control protocols have been proposed for quantum memory or storage. Among them, the fast signal control or dynamical decoupling based on external pulse sequences provides a prevailing strategy aimed at suppressing decoherence and preventing the target systems from the leakage or diffusion process. In this paper, we review the applications of this protocol in protecting quantum memory under the non-Markovian dissipative noise and maintaining systems on finite speed adiabatic passages without leakage therefrom. We analyze perturbative and nonperturbative dynamical equations for leakage and control, including second-order master equation, quantum-state-diffusion equation, and one-component master equation derived from Feshbach PQ-partitioning technique. It turns out that the quality of fast-modulated signal control is insensitive to configurations of the applied pulse sequences. Specifically, decoherence and leakage will be greatly suppressed as long as the control sequence is able to effectively shift the system beyond the bath cutoff frequency, almost independent of the details of the control sequences that could be ideal pulses, regular rectangular pulses, random pulses and even noisy pulses.