Multi-scale simulation of diffusion behavior of deterrent in propellant

Concentration distribution of the deterrent in single-base propellant during the process of firing plays an important role in the ballistic properties of gun propellant in weapons. However, the diffusion coefficient calculated by molecular dynamics(MD) simulation is 6 orders of magnitude larger than the experimental values. Meanwhile, few simple and comprehensive theoretical models can explain the phenomenon and accurately predict the concentration distribution of the propellant. Herein, an onion model combining with MD simulation and finite element method of diffusion in propellants is introduced to bridge the gap between the experiments and simulations, and correctly predict the concentration distribution of deterrent. Furthermore, a new time scale is found to characterize the diffusion process. Finally, the time-and position-depended concentration distributions of dibutyl phthalate in nitrocellulose are measured by Raman spectroscopy to verify the correctness of the onion model. This work not only provides guidance for the design of the deterrent, but could be also extended to the diffusion of small molecules in polymer with different crystallinity.

Toxicity of several botanical essential oils and their combinations against females of Aedes albopictus(Skuse) and Anopheles minimus(Theobald): Oviposition deterrent, ovicidal and adulticidal efficacies

Objective: To investigate the efficacies of 12 essential oil(EO) formulations from three Zingiberaceae plants(Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus(E. globulus) EO against females of Aedes albopictus(Ae. albopictus) and Anopheles minimus(An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.

Adulticidal, larvicidal, pupicidal and oviposition deterrent activities of essential oil from Zanthoxylum limonella Alston(Rutaceae) against Aedes aegypti(L.) and Culex quinquefasciatus(Say)

Objective: To evaluate adulticidal, larvicidal and oviposition deterrent response of the essential oil from dried Zanthoxylum limonella(Z. limonella) fruit against Aedes aegypti(Ae. aegypti) and Culex quinquefasciatus(Cx. quinquefasciatus).Methods: Z. limonella oil was tested by biological assays at 1%, 5% and 10% concentrations in ethanol. Adulticidal efficacy was tested against the 2–3 day old adult females. Larvicidal activity was tested against immature stage of mosquitoes. Oviposition deterrence of the oil was evaluated on gravid females.Results: The adult mortality was observed after 24 h with the LC50 of 6.0% for Ae.aegypti, and 5.7% for Cx. quinquefasciatus. Larvicidal bioassay was carried out with the 10% Z. limonella oil against immature stages of Ae. aegypti and Cx. quinquefasciatus,which caused 100% mortality after 12 h and 24 h. In the larvicidal experiment,Z. limonella showed effective result at 1%, 5% and 10% concentrations with the values of LT50 Ae. aegypti = 9.78, 5.61, 0.24 h for larvae and LT50= 64.08, 21.23 h for pupae;Cx. quinquefasciatus had LT50= 28.46, 20.25, 1.01 h for larvae and LT50= 67.52, 27.96,4.11 h for pupae, respectively. Oviposition deterrence of the oil was evaluated on gravid females. In the study, 10% Z. limonella showed 100% repellency for Ae. aegypti and99.53% for Cx. quinquefasciatus. Likewise, oviposition activity indexes of these oil concentrations were all negative values ranging from–0.89 to-1.00 for Ae. aegypti and–0.64 to–0.99 for Cx. quinquefasciatus. The oviposition activity indexes values revealed that Z. limonella oil has deterrent effect, and it caused a remarkable negative response resulting in very few eggs.Conclusions: This result indicates that Z. limonella oil can be used as an effective adulticide, larvicide and oviposition deterrent against Ae. aegypti and Cx. quinquefasciatus.

Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito, Aedes aegypti Linn.(Diptera: Culicidae)

Objective:To evaluate larvicidal,pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga(L.)Willd rhizome,Anethum graveolens L.(An.graveolens)fruit,Foeniculum vulgare Mill.fruit,and Pimpinella anisum L.fruit against Aedes aegypti(Ae.aegypti).Methods:Four essential oils at 1%,5%and 10%concentrations were assessed for insecticidal activity against larvae and pupae of Ae.aegypti,following the procedure of a dipping method assay.Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae.aegypti by a dual-choice oviposition bioassay.Results:The results revealed that An.graveolens oil provided the strongest larvicidal activity against Ae.aegypti among four tested plant essential oils with the highest mortality rate of 100%and LC_(50)value of-0.3%.From the pupicidal experiment,An.graveolens also showed the highest toxicity against Ae.aegypti pupae with the highest mortality rate of 100%at 72 h and LC_(50)value of2.9%.In addition,10%An.graveolens had an oviposition deterrent effect against Ae.aegypti with effective repellency of 100%and an oviposition activity index of-1.0.Conclusions:An.graveolens oil has a good potential as a larvicidal,pupicidal and oviposition deterrent agent for controlling Ae.aegypti.

Insect feeding deterrent and growth inhibitory activities of scopoletin isolated from Artemisia annua against Spilarctia obliqua （Lepidoptera： Noctuidae）

Artemisia annua （Asteraceae） is well known for its antimalarial activities due to presence of the compound artemisinin. We isolated a methoxy coumarin from the stem part of A. annua and confirmed its identity as scopoletin through mass spectral data. The structure was established from 1H-nuclear magnetic resonance （NMR）, 13C-NMR. The compound scopoletin was evaluated for its feeding deterrence and growth inhibitory potential against a noxious lepidopteran insect, Spilartctia obliqua Walker. Scopoletin gave FD50（feeding deterrence of 50%） value of 96.7 μg/g diet when mixed into artificial diet. S. obliqua larvae （12-day-old） exposed to the highest concentration （250μg/g diet） of scopoletin showed 77.1% feeding-deterrence. In a growth inhibitory assay, scopoletin provided 116.9% growth inhibition at the highest dose of 250μg/g diet with a GI50 （growth inhibition of 50%） value of 20.9μg/g diet. Statistical analysis showed a concentrationdependent dose response relationship toward both feeding deterrent and growth inhibitory activities. Artemisinin is found mainly in the leaves of A. annua and not in the stems, which are typically discarded as waste. Therefore identification of scopoletin in stems of A. annua may be important as a source of this material for pest control.

Effect of Ficus benghalensis Latex Based Combinatorial Formulations on Various Bio-Molecules in Indian White Termite Odontotermes obesus

In present investigation, various bioassays were conducted to evaluate the alteration in levels of certain biomolecules, such as glycogen, protein, amino acid, DNA, RNA and lipids. For this purpose, worker termites were treated with sub-lethal dose 40% and 80% of 24 hrs LD50 values and observations were taken at 4 hrs interval up to 24 hrs. Crude latex and its combinatorial mixtures, like S-MLT-A, B-MLT-A, C-MLT-A, CU-MLT-A, AQ-MLT significantly altered level of bio-molecules in Odontotermes obesus. This effect was found time and dose dependent. Reduction or increase in biomolecules was calculated by using corresponding control. Maximum decrease in glycogen level was observed at 16 h when termites were treated with 80% of LD50 of Ficus benghalensis aqueous extract i.e. 56.88% at 16 h of treatment. A similar dose caused very slight decrease in lipid contents at 4 h of treatment but it was found further significantly (p > 0.05) decreased in other successive treatments. 40% and 80% of LD50 of C-MLT-B mixture caused significant (p > 0.05) decrease in DNA and RNA level at 16 h treatment. The level of DNA and RNA level was recorded 83.90%, 90.18% and 85.42% and 74.05% respectively. Similarly, total proteins were also found to be decreased with 40% and 80% of LD50 of C-MLT-B mixture i.e. 71.47% and 66.45% respectively. All these alterations found in levels of various bio-molecules confirm the action of latex ingredients on worker termites that was antifeedant or deterrent types. These ingredients can be used to control not only termites but also other phytophagous insects in a sustainable and eco-friendly way.

Toxic and Antifeedant Effects of Different Pesticidal Plant Extracts against Beet Armyworm (Spodoptera exigua)

The beet armyworm(BAW),Spodoptera exigua(Lepidoptera:Noctuidae)is a highly destructive pest of vegetables and field crops.Management of beet armyworm primarily relies on synthetic pesticides,which is threatening the beneficial community and environment.Most importantly,the BAW developed resistance to synthetic pesticides with making it difficult to manage.Therefore,alternative and environment-friendly pest management tactics are urgently required.The use of pesticidal plant extracts provides an effective way for a sustainable pest management program.To evaluate the use of pesticidal plant extracts against BAW,we selected six plant species(Lantana camara,Aloe vera,Azadirachta indica,Cymbopogon citratus,Nicotiana tabacum,and Ocimum basilicum)for initial screening experiment.Four out of six plant species such as A.indica,N.tabacum,C.citratus and O.basilicum showed promising mortality of more than 50%.Therefore,we selected these four plant extracts for the subsequent experiments.Through contact bioassay,A.indica showed high mortality 66.63%,followed by the N.tabacum 53.33%,at 10%w/v concentration.Similarly,N.tabacum showed the highest mortality rate,66%at 10%w/v concentration,followed by the A.indica 46%through feeding bioassay.Furthermore,the feeding deterrence assay showed that C.citratus had a high antifeedant index(−50)followed by A.indica(−39),and N.tabacum(−28).In living plant assay,the N.tabacum extract showed a low mean damage score 3.6 on living cotton plant followed by C.citratus 4.5 and A.indica 5.5.Hence,extracts of three plant species provided promising results against the BAW,which can minimize the use of synthetic chemicals,particularly for small landholding farmers.Further studies are also required to evaluate the effects of these plant extract against BAW on cotton plants under field conditions to optimize the further use.

The Control Efficiency of Plant Alcohol Extracts on the Laboratory Populations of Myzus persicae(Sulzer)and Lipaphis erysimi (Kaltenbach)

The effects of semiochemicals extracted from 63 species of plants, on peach aphid (Myzus per-sicae) and mustard aphid (Lipaphis erysimi), were studied in laboratory. The deterrent rate, reproduction deterrent index and the interferential index of population control (IIPC) was used to evaluate the efficiency of semiochemicals on population control of the two target aphids. The results showed that the extracts of 34 species of common plants have noticeable effect on both aphid populations, especially, Xanthium sibiricum Petr. Et Widd. and Syngonium podophyllum Schott. These plant extracts could be used to construct the plant pro-tectant to protect crops.

Study on the analysis method on ballistic performance of deterred propellant with large web size in large caliber artillery

As for the characteristics of combustibility of deterrent propellant with large web size which is used in large-caliber gun and interior ballistic performance, the combustion characteristics of deterrent propellant are obtained by using closed-bomb experiments. The combustion law of deterrent propellant and the classic interior ballistic model of composite charge are given. By simulation and analysis the results of the artillery firing test, the burning rate variation law and the interior ballistics simulation parameters of propellant A are determined, and the burning rate relationship between propellant A and propellant B obtained from closed-bomb, then the ballistic performance of propellant B is predicted. The results show that the predicted results are in good agreement with the experimental results. The study shows that the burning rate law of deterrent propellant with large web size can be obtained by closed-bomb experiment. Using the method provided in this paper can accurately predict the interior ballistic performance and provide an important basis for improving the accuracy of interior ballistic calculation.

The Influence of Phlorotannins and Bromophenols on the Feeding Behavior of Marine Herbivorous Gastropod <i>Turbo cornutus</i>

The influence of phlorotannins and bromophenols on the feeding behavior of marine herbivores was determined using bioassay of Turbo cornutus. It was found that phloroglucinol and its oligomers isolated from the brown alga Eisenia bicyclis (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8’-bieckol) had a deterrent effect against feeding behavior of T. cornutus in the concentration of algal body, respectively. In the case of the examination of 0.1 mM concentration, although fucofuroeckol A and phlorofucofuroeckol A significantly reduced feeding by T. cornutus, phloroglucinol and 8,8’-bieckol did not show any significant influence on feeding behavior, and eckol and dieckol had stimulating activity. 2,4-Dibromophenol and 2,4,6-tribromophenol, which are major components of extracellular secretions from Eisenia and Ecklonia species, caused the death, the torpidity, and the decreased appetite of T. cornutus at the concentration of 0.1 mM. In addition, 2,4-dibromophenol had strong feeding deterrent activity at the concentration of 1 μM. These results indicate that phlorotannins and bromophenols act as chemical defense agents of brown algae against environmental stresses such as the herbivore attack.

Protection effect of the anthraquinones, cassiatorin and aurantio-obtusin from seeds of Senna tora against cowpea weevil attack

Objetive: To explore the potential insecticidal, ovipositor deterrent and antifeedant effects of ethyl acetate extract of the seeds of Senna tora(Syn. Cassia tora) against cowpea weevil(Callosobruchus maculatus).Method: The activities were evaluated using standard protocols.In these bioassays, the cowpea seeds were used directly as an insect feed. The activity of the extract and isolated compounds were tested at concentrations of 100, 200 and 300 μg/mL and compared to neem oil and cinnamaldehyde(as standard positive controls). Phytochemical analysis of the ethyl acetate extract was done through a number of chromatographic techniques and the structures of the isolated compounds were established through comprehensive spectroscopic analysis including 2 D-NMR and ESI-MS studies.Results: Fractionation of the active ethyl acetate extract resulted in the isolation of one known anthraquinone,aurantio-obtusin(1) and a novel compound that was named as cassiatorin(2). Compounds1 and 2 showed comparable insect antifeedant properties with the positive controls while their insecticidal and ovipositor deterrent effects were far superior to the standard controls.Conclusions: It is thus concluded that Senna tora extracts and the isolated compounds(1 and2) may be employed in the postharvest management of stored cowpea seeds and as other crop protectants.

Behavioral and Electrophysiological Responses to Caffeine of Helicoverpa armigera Larvae and H. assulta Larvae

The dual-choices tests of behavioral test were used to study the gustatory behavioral responses to caffeine of Helicoverpa armigera larvae and H. assulta larvae. Electrophysiological responses were studied by electrophysiological tip recording. Behavioral experiments showed that caffeine was a feeding deterrent for both larvae, but it showed a stronger feeding deterring effect on the oligophagous H. assulta . The electrophysiological tip-recording results showed that both H. armigera larvae and H. assulta larvae had one caffeine-sensitive feeding deterrent neuron at the medial sensilla, and the electrophysiological pulse response of H. assulta larvae was significantly stronger than that of H. armigera larvae. Therefore, caffeine had a stronger feeding deterring effect on the oligophagous H. assulta than the polyphagous H. armigera . The difference in behavioral effect was closely related to the sensitivity of to caffeine the feeding deterrent neurons at the medial sensilla.

Feeding Deterrence of Common Spices against <i>Helicoverpa armigera</i>Larvae

Edible spices with strong smells or heavy tastes may be a promising resource of feeding deterrents. We compared the feeding deterrence of the ethanol extracts of 21 common spices against the larvae of a generalist pest species, Helicoverpa armigera, using a multiple-choice leaf disc bioassay. The results show that Zanthoxylum bungeanum extract (as a reference) always evoked significant feeding deterrence, while Piper nigrum (both black pepper and white pepper), Piper longum, and Angelica dahurica evoked the strongest and equivalent feeding deterrence. The potent feeding deterrent activity of Piper species may be a common characteristic at genus level.

Antifeedant Activity of Caesalpinia coriaria Essential Oil Against Incisitermes marginipennis (Latreille)

This study scrutinized the possibility of finding toxicant or deterrent plant metabolites against the dry wood termite Incisitermes marginipennis(Latreille).Plant deterrent agents act as repellents or antifeedants to prevent wood decay and increase its useful life.The potential of the tree Caesalpinia coriaria(Fabaceae)as a biological source of molecules with deterrent effects against the dry wood termite was assessed by a phytochemical fractionation guided by repellence and antifeedant activities.The gas chromatography-mass spectrometry analysis of the leaf essential oil showed geraniol to be one of the major components and its repellent and antifeedant effects were determined.Geraniol had only an antifeedant effect without affecting the body weight or survival of the dry wood termite.Unlike the leaf essential oil,geraniol did not exhibit a repellency effect.An in-silico approach of the activity of acetylcholinesterase in interaction with geraniol resulted in an affinity energy of−7.5 Kcal/mol.Geraniol interacted with the amino acid tyrosine 324 located in the enzyme’s active site while citronellol(negative control)interacted with tryptophan 83 located adjacent to the active site.These deterring terpenes have not been implemented for the preservation and restoration of wood products exposed to the attack of the dry wood termite.However,they are an important natural control alternative.

Avian-power line interactions in the Gobi Desert of Mongolia:are mitigation actions effective?

Background:Electrocution and collisions on power lines are among the leading causes of non-natural mortality for birds.Power lines are exponentially increasing,particularly in developing countries,but mitigation strategies to prevent bird mortality are questionable.Mongolia combines a recently increased power line network,an abundant raptor population,a dangerous crossarm configuration and a habitat with no natural perches,producing many bird-power line interactions.Our aim is to assess the bird mortality caused by power lines in the Gobi Desert of Mongolia,to determine the factors increasing the risk of bird electrocution,and to evaluate the effectiveness of used retrofitting measures.Methods:In July 2019 we covered 132.9 km of 15 kV power lines checking 1092 poles.We also conducted bird tran-sects to record raptor and corvid richness and abundance,to assess species vulnerability to electrocution.Results:We recorded 76 electrocuted birds of 7 species.Electrocution rate was 6.96 birds/100 poles.The most affected species were Common Raven(Corvus corax)and Upland Buzzard(Buteo hemilasius),highlighting the electro-cution of 5 endangered Saker Falcons(Falco cherrug).By contrast,we only recorded 8 individuals of 5 species collid-ing with wires,the most affected being Pallas’s Sandgrouse(Syrrhaptes paradoxus).About 76.1%of sampled poles had some mitigation measure.Of these,96.6%were brush perch deflectors and 3.4%rotating-mirrors perch deter-rents.We found differences in electrocution rates among crossarm configurations,with the strain insulator with one jumper being the most lethal.Additionally,we found no correlation between bird abundance and electrocution rates,suggesting that some species are more sensitive to electrocution.Although no differences in total bird electrocu-tion rates were detected between poles with and without perch deterrents,when bird size is considered,deterrents reduced the mortality rate of small birds,while they were ineffective for medium-sized birds.Conclusions:Despite the widespread use of perch deterrents in the Mongolian power line network,there is still an alarming electrocution rate.This strategy is ineffective and some mechanisms,such as brush perch deflectors,may increase the electrocution rate for some medium-sized birds.Finally,we propose strategies to minimize the avian electrocution rate in the Gobi Desert.

Disulfiram in the management of alcohol dependence: A comprehensive clinical review

Disulfiram remains a viable option as a treatment for alcohol dependence and has been shown in recent studies to be successful in treating patients with alcohol dependence in a manner that is superior to both naltrexone and acamprosate. It is also useful in dual diagnosis patients and those with co-morbid cocaine and alcohol dependence. Although disulfiram’s mechanism of action in alcohol dependence was long thought to be its effects as a psychological deterrent, more recent studies have uncovered potential anticraving effects as well. Recent reviews exhort to the importance of supervised disulfiram therapy in highlighting many of the potential and unique benefits of disulfiram. The present article will review the major clinical trials of disulfiram spanning nearly 60 years. It also discusses the usage of disulfiram across diverse populations along with monitoring for compliance and various adverse effects that may be encountered. The paper also reviews certain studies on long acting disulfiram therapy, recent comparative trials of disulfiram and its use in alcohol dependence. The review concludes with the role of disulfiram in the present day and long-term pharmacotherapy of alcohol dependence along with future research needs in this area.

Interspecific Competition and Grain-Hosts Selection of Maize Weevil, <i>Sitophilus zeamais</i>(Motsch.) (Coleoptera;Dryophtoridae) and Larger Grain Borer, <i>Prostephanus truncatus</i>(Horn) (Coleoptera;Bostrichidae)

Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.

A Secured Iran？ Iran＇ s Independent Active Deterrence Strategy

Until now the Islamic Republic of Iran's adoption of an independent active deterrence strategy,a strategy based on threat assessment and self-assessment,has overall been a success.The sole exception involved Iraq in 1980 and was due to Iran's initial vulnerability following the revolution.As Saudi Arabia maneuvers with influence from US President Donald Trump,and given that Iran is unlikely to withdraw its military nuclear program under the existing security environment,the US and Israel ought to strengthen their nuclear deterrence capabilities against Iran.They need to issue clear,open,official retaliation commitments under a hypothetical nuclear scenario and bolster them with corresponding military and diplomatic capability.

Chinese Customers' WTP for Legal Digital Music Downloading

This study is to examine the effects of some significant factors on consumers' willingness to pay( WTP) for digital music via the moderating variables of music affinity and the deterrence effect of the legislation. Based on 517 Chinese respondents with access to digital music,using the multiple liner regression model,this study indicates that free ideology,perceived benefits of free downloading,perceived benefits of paid downloading,subjective norm,habit strength have direct influence on WTP,and music affinity and the deterrence effect of the legislation have moderating effects. This study contributes theoretically to research on Chinese consumers' WTP for digital music and offers practical recommendations for the digital music charging system setup.

U.S.Deterrence and Coercive Diplomacy and China's Coping Strategy

Deterrence and coercion are two kinds of strategies,the latter being more aggressive than the former.The U.S.Asia-Pacific Rebalancing strategy is an important diplomatic legacy of Obama's administration.For the issues involving the Diaoyu Islands,the South China Sea,cyber security,DPRK's nuclear program,and Iran's nuclear program,the U.S.has carried out military deterrence and non-force coercion against China.But generally,these are low-level coercive measures and distinct from the severe economic sanction and diplomatic isolation imposed by the U.S.on Russia,Syria,DPRK and Iran in recent years.Concerning issues where the U.S.and China hold distinct views,there would be less strategic leeway for the two countries.If the U.S.is to strengthen deterrence and coercion towards China,China can respond more actively and effectively,but it will be more difficult to build a new model of China-U.S.major-country relationship.