shown in Fig. 4, A to D ( 10, 13, 32) (table S1 and
fig. S27). All neat films of these polymers severely
crack when subjected to 100% strain (middle
column in Fig. 4, A to D), leading to degraded
mobilities as shown. Upon using our CONPHINE
method, we again obtained nanoconfined mor-phologies with deformable interfaces (fig. S28).
The stretchability of all these films (CONPHINE-
2 to CONPHINE- 5) is significantly improved, displaying only inhomogeneous deformations at
100% strain (right-column images in Fig. 4, A
to D, and fig. S29). As a result, both the on currents and mobilities (values are indicated in their
respective images) from these films at 100% strain
exceed their neat counterparts by one to four
orders of magnitude (Fig. 4, E and F). Notably,
four different conjugated polymers (including 1)
are imparted with mobilities >1.0 cm2/V·s at 100%
Polymer nanoconfinement enables high stretch-ablity in semiconducting materials. In this study,
we introduced the CONPHINE method to create
conjugated-polymer nanostructures with increased
chain dynamics and decreased crystallinity embedded in an elastomer matrix to maintain the mobility during stretching. We anticipate that this
general approach will advance the development
of stretchable semiconductors for stretchable
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J.X., S. W., and Z.B. conceived and designed the experiments;
J.X. fabricated the CONPHINE films; J.X., S. W., C.Z., and C.L.
fabricated the transistor devices and did the measurements;
G.-J.N. W, S.R.-G., B.C.S., Y.-H.K., and H. Y. provided the conjugated
polymers; S.L., D.Z., and G.X. performed the glass transition
measurement; L.J., Y. W., C.L., and W.C. carried out the mechanical
simulations; X.G. did the grazing incidence x-ray diffraction (XRD)
characterizations; S.C., V.R.F., and J. W.F. T. did the XPS and
scanning electron microscopy (SEM) characterizations; J.P. and
R.S. did the scanning transmission electron microscopy characterization;
J. Y.O. helped with the film transfer process; S. W., J.X., Z.B., J. W.C.,
and J.B.-H. T. organized the data and wrote the manuscript;
and all authors reviewed and commented on the manuscript. This
work is supported by Samsung Electronics (material fabrication
and devices) and the U.S. Department of Energy, Office of Science,
Basic Energy Sciences, under award DE-SC0016523 (material
characterization). S.R.-G. thanks the Fonds de Recherche du
Québec: Nature et Technologies for a postdoctoral fellowship.
B.C.S. acknowledges the National Research Fund of Luxembourg
for financial support (project 6932623). H. Y. thanks the Hong Kong
Innovation and Technology Commission for support through
ITC-CNERC14SC01. C.L. acknowledges support from the National
Science Foundation through CMMI-1553638. Y.-H.K. thanks the
NRF Korea (2015R1A2A1A10055620). J.X., Z.B., J. W.C., and
Sangyoon Lee are inventors on patent application no. 62/335,250
submitted by Samsung Electronics Co., Ltd., and the board of
Trustees of the Leland Stanford Junior University. The GIXD
measurements were performed in Advanced Light Source beamline
7. 3. 3 and SSRL 11-3, which are supported by the director,
Office of Science, Office of Basic Energy Sciences, of the U.S.
Department of Energy under contract nos. DE-AC02-05CH11231
and DE-AC02-76SF00515, respectively.
Materials and Methods
Tables S1 to S4
Figs. S1 to S29
References ( 33–47)
Movies S1 and S2
29 June 2016; accepted 2 December 2016
Permanent human occupation
of the central Tibetan Plateau in
the early Holocene
M. C. Meyer,1 M. S. Aldenderfer,2 Z. Wang,1 D. L. Hoffmann, 3 J. A. Dahl, 4
D. Degering, 5 W. R. Haas, 6 F. Schlütz7
Current models of the peopling of the higher-elevation zones of the Tibetan Plateau
postulate that permanent occupation could only have been facilitated by an agricultural
lifeway at 3. 6 thousand calibrated carbon- 14 years before present. Here we report a
reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau
at an elevation of ~4270 meters above sea level. The minimum age of the site is fixed
at 7. 4 thousand years (thorium-230/uranium dating), with a maximum age between
~ 8. 20 and 12. 67 thousand calibrated carbon- 14 years before present (carbon- 14 assays).
Travel cost modeling and archaeological data suggest that the site was part of an annual,
permanent, preagricultural occupation of the central plateau. These findings challenge
current models of the occupation of the Tibetan Plateau.
Thenatureandtiming of a permanent human settlement on the Tibetan Plateau and the accompanying cultural and physiological responses, including genetic adaptations, that facilitate life at high altitude are sub-
ject to ongoing debate (1– 5). Tibet forms the high-
altitude core of Asia (Fig. 1), and although access
to the northeastern fringes of the plateau from
the adjacent north Asian lowlands via the Yellow
River and the Qinghai basin is relatively easy, ven-
turing into the core of the plateau—with eleva-
tions well above 4000 m above sea level (masl)
and cold, arid, and periglacial conditions—is con-
siderably more challenging. Permanent human
occupation of the Tibetan Plateau was thus im-
peded by the combined effects of remoteness, low
primary productivity, and topography, as well
as by the physiological constraints of cold stress
and hypoxia ( 6). The climatic and paleoenviron-
mental constraints on this colonization process
are poorly understood ( 7–9). The number of chro-
nometrically dated archaeological sites remains
small, and most of them are located on the north-
eastern margin of the plateau (1, 7, 10). Ranging
in date from 9 to 15 thousand calibrated 14C
years before present (thousand years cal. B.P.),
1University of Innsbruck, Institute for Geology, A-6020
Innsbruck, Austria. 2School of Social Sciences, Humanities,
and Arts, University of California, Merced, CA 95343, USA.
3Department of Human Evolution, Max Planck Institute for
Evolutionary Anthropology, D-04103 Leipzig, Germany.
4National Isotope Centre, GNS Science, Lower Hutt 5040,
New Zealand. 5ADD Ideas Albrecht and Detlev Degering, zum
Erzengel Michael 19, D-01723 Mohorn, Germany. 6Department
of Anthropology, University of Wyoming, Laramie, WY 82071,
USA. 7Lower Saxony Institute for Historical Coastal Research,
D-26382 Wilhelmshaven, Germany.
*Corresponding author. Email: firstname.lastname@example.org
(M.C.M.); email@example.com (M.S.A.)